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Archive for the ‘Repair’ Category

Froe Fixup

Posted by davidjbod on December 14, 2013

I picked up an old froe from a auction store last week.  A froe is a woodworking tool for splitting wood along the grain.  It was rusty and had no handle…but not for long.  Here it is as found.  I threw the ruler in for scale.  As you can see it is pretty large.


I picked one of the branches that I had left over from the ash tree I cut down.  It is larger than the eye in the froe and had a budge near the bottom I thought would work well to keep the froe in place.


I bandawed off the knots and limbs before taking it to the shaving horse.


Next came a lot of working with the draw knife.  I haven’t found a way to work the knots with the draw knife without getting really bad tear out.  To avoid them I worked around the knots and then hit most of the wood with a rasp. F4

When it came to shaping the part of the handle that would go into the froe’s eye, I slowly removed material and checked my progress.  After a little bit I had a good fit.


To keep the froe from flying off the handle I cut the end to insert a wooden wedge.  I also bandsawed a small wedge to fit.F6

The edge of the froe was pretty dull.  A few minutes with a white stone on the grinder resulted in a serviceable edge.  It could still use some touch up with a file though.


Next comes the joining of the pieces.  I tapped the froe into position and then flipped it over so I could hammer on the end of the handle.  This drove the froe head tightly onto the handle.  After that I tapped the wedge into place and oiled the handle.  The handle is longer than usually seen so I may cut it down after using it a bit.F8

Posted in Modification, Repair, Tools, Woodworking | Tagged: , , | Leave a Comment »

Orion Laser Collimator Collimation

Posted by davidjbod on November 3, 2013

On telescopes, all of the optical pieces need to be aligned.  Whether it is a mirror or lens, if they’re not pointing in the right direction the image will suffer.  A Newtonian reflector has two mirrors and they must be aligned to each other and the focuser.  There are a number of tools that can be used to accomplish this.  One of them is the “laser collimator.”  This device sits in the focuser like an eyepiece and shoots a laser out of the front of it.  The laser beam is reflected by the secondary mirror towards the primary mirror.  The secondary mirror is then adjusted until the laser strikes the exact center of the primary mirror.  Some laser collimator have a cutout with a screen built into them allowing the return beam from the primary mirror to be seen.  The primary mirror can be adjusted using the return beam.

All of this is a waste of time if your laser collimator not collimated.  Ideally, the laser should be emitted so that it is perfectly parallel to the body of the collimator.  If for some reason it is not, it must be fixed before it can be used.  I manged to pick up an Orion brand “Deluxe Laser Collimator” for cheap because it was out of collimation.  To fix it required some minor adjustments.  Here’s the steps I took to fix it.

The easiest way to check the alignment of the laser with respect to the body of the collimator is to spin it.  If the laser is not aligned to the body and the collimator is spun about the axis the laser should be on the laser beam will trace out a circle on a surface in front of it.  The further away the collimator is from the surface, the larger the circle will be.

To hold the collimator, I made a set of V blocks out of wood.  First, I ripped a V into a piece of 2×4 and cut it into pieces.



Next, I made a spacer block large enough to fit the central bulge of the collimator.



I attached it all to a base that I could use to clamp the block down to a fixed surface.



The laser emitter inside of the collimator is pointed via three set screws.  These set screws require a 2mm Allen wrench to be adjusted.  These set screws can be found under the label sticker on this collimator which should be removed during the procedure.  (Aside: The set screws are under the label on the regular Orion laser collimator too.)  The set screws are located in the little holes in the body.  Mine had some kind of RTV in the holes that had to be scraped away first.  LC4


The collimator was then placed into the V blocks and pressed against the front block to check the alignment.



On a wall across my living room, I put up a sheet of paper and marked out the circle traced by the laser.



Now the set screws are adjusted and the collimator is rotated to check the of the size circle it creates.  This is repeated over and over again until no movement in the spot can be noticed.  At this point, I marked where the laser point hit the paper to use as my new reference point.  As before you’ll iteratively adjust and check.  But now, since the movement is so small, you have to walk back and forth between the paper and collimator to see how the spot has moved.  Note that the set screws seem to push on some springs inside of the collimator which means you don’t have to turn one set screw in and reverse the other two at the same time.



Once the spot doesn’t move anymore when you rotate the collimator you’re finally ready to use it on the scope.  Once the scope is collimated correctly, the return laser spot should fall in the hole in the middle of the collimator.  This is the most accuracy the stock collimator can give and you’ll need to use different tools to improve upon the collimation.


Now to go look at Jupiter!


Posted in Astronomy, Repair | Leave a Comment »

Collins Axe

Posted by davidjbod on September 8, 2013

I found a Collins axe head at the flea market yesterday.  For some reason I like axes so I bought it for $5.  In my minimal experience with axes it seems the older ones are better than the modern day ones.

Here’s the axe head as I found it.  It is sitting next to a nice set of Allen ball end drivers I found at the flea market as well.



There’s two things wrong in this picture.  The first, is that someone tried to tighten the head by pounding a bunch of nails into the eye.  Bad idea.  The second issue, is that the bottom of the axe head is up in this picture.  Yup it was mounted upside down.  There’s a taper in the eye of an axe head that is smaller at the bottom to mechanically lock the handle in.  Mounting the head upside down guarantees it would never be tight.



That junk was hammered out.Ax3


The back of the head is called the poll.  It is not for hammering on with a steel hammer.  Doing so just mushrooms the back of the axe head and makes it look like crap.



I took it to the grinder and removed all of the mushrooming and lips where the head had been hammered on. I’d like it if the color was even on the head but I’m not sure what I could do to achieve that other and paint.  I’m sure it’ll even out over time though.



I ground a 25 degree angle on the edge and then refined it with a machinist’s file.  Then I put a small primary bevel on the cutting edge and honed it.



When I was trying to insert the handle into the head it wouldn’t go.  Inspection showed that hammering by the previous owner had also formed a lip inside of the eye.  I used a Dremel with a stone to remove this lip.


I used a store bought handle that I had around the garage.  This handle has a mix of heartwood and sapwood which isn’t ideal as it can cause the handle to fail earlier than it should.  I also prefer the curved handles but figured I should do something with this one.  Most store brought handles come with a varnish on them.  I like to scrape or sand the varnish off and then oil the handle with Boiled Linseed Oil.  The oil is better for the wood and isn’t as slippery as the varnish.  I sanded the handle with 120 and then used 220 everywhere except for the lower parts of the handle where the stationary hand is placed.  This helps with grip.  After a little fitting, I cut a wedge out and then attached the head.



Once I’d oiled and waxed the head it was out to give it a try.  The head remained attached and it chopped wood without wedging.  Success!


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Small Backsaw: Part 2

Posted by davidjbod on August 24, 2013

In the previous post I’d cleaned up my small backsaw but there were still a couple problems to address before the saw could be used.  First, the saw was dull.  Second, the handle rocked on the saw plate.

In order to find out how to sharpen I went to Google.  Eventually, I came two good pages on saws: The Norse Woodsmith and Vintage Saws. The Norse Woodsmith is a fan of saws and even went to the trouble of making a backsaw from scratch in his garage just to show it could be done.  On those pages, I found the Norse Woodsmith Sharpening page and Vintage Saw’s Sharpening page where there’s a lot of information on sharpening.  Both have good coverage of the topic but in slightly different ways.  I read over the pages a few times and decided to give it a try.  On the pages they say you need a triangular file and a saw vise.  While I have a triangular file, I didn’t have one small enough.  So, I picked up a 6″ double extra slim triangular file.  A saw vise clamps on the saw panel to hold it steady while you file the teeth.  I don’t own one, but I do have a 6″ Wilton vise which, with a couple of pieces of wood, held the saw suitably.  The first step in sharpening saw teeth is the joint the teeth.  To do this, you run a file across the top of the teeth points to bring them all to the same level.  Once most all of the teeth have small flat spots where the points used to be, it is time to file.


To create identical saw teeth the triangular file needs to be consistently held at the same angle.  To help the user hold the file at the correct angle, the pages recommend using a block with a line on it to make orienting the file easier.  The block has a hole drilled in it to stick the file’s tang in.  The angle of the line is determined by the amount of rake you want on the teeth.  Rake is the term that describes the angle between the front of the tooth and vertical.  A larger rake angle makes the saw more aggressive but harder to start.  The pages recommended 8 degrees which is what I went with.  The file is inserted in the block with a face of the file parallel to one side of the block.  Then while filing the block and file are held so that the line on the block is vertical.  This results in the file being rotated 8 degrees like we want.


Sharpening requires filing each tooth individually but it is recommended that you sharpen every other tooth from one side and then all the others from the opposite side.  This should balance any errors the sharpener has created while sharpening.  As this was my first saw sharpening, I took it slow and focused on the task.  I could describe how to sharpen more in depth, but I suggest you check out one of the pages linked above as they have much more experience than I.  After filing, I examined each tooth and found that a few required touching up.  When I was done, I noted that I have no inherent gift for sharpening as the teeth all seemed to be slightly different.  I tried it out on a piece of pine and was amazed.  The saw flew through the wood like a hot knife through butter.  Three cuts with the saw and I was 3/4″ into end grain.  So, while my saw teeth may not all be perfect, they seem to work very well.  Now about that handle rocking…


I started looking into the handle rocking and identified a few possible causes.  The first, seen below, is that one of the holes in the saw plate, where the barrel bolt goes through, was misshapen allowing the barrel bolt to move up and down.  The second cause is that one of the barrel bolts was stripped and wouldn’t tighten down.  The last possible cause, is that the barrel bolts could move freely around in the wood as the holes seemed to be slightly oversized.  I think the first issue was the main cause, because I tried some regular bolts which did tighten down but the handle still rocked.  Of course having a stripped barrel bolt is problematic too.  To solve all the problems I drilled the holes progressively larger until both holes were circular.  The final size ended up being 1/4″.


I drilled the handle to 1/4″ as well and temporarily used some regular bolts and nuts to see if the problem was solved.  Happily, it was and resulted in the handle being solidly attached to the saw plate.  I could leave this hardware in the saw, but you know I won’t.


There’s another style of hardware used to hold a handle on called a split nut.  It’s similar to a regular hex nut but is circular on the outside with a slot cut into the face of the nut to tighten it.  I found a page on the Norse Woodsmith where he made some and thought I could come up with something a little simpler for my saw.  I ran to Ace Hardware to find some brass 1/4″ hardware to use.  While there, I found some barrel nuts and bolts that were for a 1/4″ hole.  They fit a 1/4″ hole loosely and were no good.  On to the brass hardware I bought.  As you can see below, this is better than the zinc plated steel but still doesn’t fit the saw ascetically.



The first step to make my split nuts, is to cut the slot into the brass hex nut with a hacksaw.  I threaded the nut onto a bolt along with another nut and clamped it into the vise so I could cut it.


To make the hex nut round, I used my drill press and a flat file.  I cut the top off of a regular bolt to create an arbor to hold the brass nut in the drill press.  The shoulder of the unthreaded portion of the bolt holds the nut in place.



The drill press was turned on at a low speed and multiple light passes were made with my file.  Note to use a handle on the file so that the pointy tang doesn’t go through your palm if there is a catch.  Here’s a setup shot with the drill press off to show you what I’m talking about.



Once the nut was circular, I installed it on the saw to see what it’d look like.  That’s an improvement but I’d like to make the hardware not stick out so much.


Reducing the length of the brass machine screw is done easily enough with the belt sander.  While I was at it, I decided to flatten the dome on the other side of the machine screw which made it look a lot better.



To reduce the thickness of my split nuts, I threaded them onto a bolt along with another nut to hold things in place.  Back to the belt sander….



Here’s how the trimmed down nut looks compared to one at the original height.  The nuts are round but the irregular bevel on to the hex bolts still makes them appear slightly hex shaped.



Here’s my close to finished set of hardware.  I hit all the edges I created with some 2000 grit sand paper after this picture to remove some of the scratches.  Yes, I have a way to put a tool on each part to tighten it.  Typically, only one part of the hardware set on a saw allowed you to use a tool to tighten it.  I like it better my way.  The razor blade, which occasionally made it into some of the pictures, fits the slot in my split nuts perfectly.



Here’s how it turned out.  BS2_14 BS2_15 BS2_16 BS2_17


I’m happy with it.  The hardware holds the handle solidly to the saw plate and looks like it is supposed to go with the saw.


All in all, this project would have been easier with a metal lathe.  It’s on my list….


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Fire Extingusher

Posted by davidjbod on April 27, 2013

I ran across a pressurized water fire extinguisher in an antique store the other day for cheap.  I didn’t know if it worked or not so I gambled that I could fix it.  I already have one of these but it wouldn’t hurt to have another.  I gave it once over in the store and it looked good.  There was no rust that I could see and all of the parts were there.

This type of extinguisher is filled with water and then pressurized through a Schrader valve like you have on a tire up to 100psi.  I put water in mine and then put about 10 psi.  It started leaking around the collar nut (the big nut in the pic below) which didn’t surprise me that much.  It was made in 1980 and rubber O-rings have a limited life.



I took the valve assembly back off and replaced the big O-ring with one from the hardware store.



The surface inside the neck of the water tank, called a cylinder, had some corrosion on it that I cleaned up using a little Brasso.  Anything other than a clean smooth surface can result in leaks.



That’s a little better.  I smeared some Plumber’s silocon on this surface and reassembled the extinguisher.



I put 10 psi back on it and heard some faint hissing from the nozzle and the Schrader valve.  I removed the Schrader valve, blew it out, and put some silicone on the rubber surface.  The main valve inside of the extinguisher is held closed with a spring under the brass nut seen in the second picture.  I removed all of this, cleaned up the mating surfaces and reassembled it.



I put 10 psi back on it and listened.  No leaks this time.  I slowly increased the pressure up about 50 psi when I heard a “tink” and saw water leaking out of the bottom.  That’s not good.



I took off the bottom plastic foot and was greeted with a small pinhole in the bottom of the cylinder.  It looks like a little bit of rust had built up around here and weakened the cylinder.  It also looks like there are a couple more bad spots near the hole.



At this point I threw in the towel on the extinguisher.  Maybe I’ll run across a good cylinder in the future or find someone who can weld stainless.  But for now I’ve just put it aside.  You can’t win them all I suppose.

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Microwave Repair

Posted by davidjbod on March 9, 2013

My microwave decided to stop working last week.  Everything seemed normal but it didn’t warm anything up.  It is a GE Space Saver model JVM1631.


I’ve never worked on microwaves before so I did some research on the internet and found out they’re pretty simple devices.  The Sci.Electronics.Repair FAQ has some excellent information in it and I highly suggest you check it out if you’re repairing any appliances.  Youtube also had some good videos on the topic.  I couldn’t find a schematic for my microwave but was able to find one for a JVM1450 which seems pretty similar.  I didn’t want to repost the entire picture but did hack out the important bits out which I’ve posted in the picture below.  The top is the plug that goes into the wall and receives 120VAC.  The two gaps on either side is where I’ve cut stuff out of the diagram.  In the gap, there are thermal cutouts, switches, fan motors, the control panel, etc.  All of this stuff can be ruled out though with a simple test that I’ll cover below.  The High Voltage transformer (marked H.V. Trans) bumps the line voltage up to around ~2000V.  The capacitor (marked H.V. Capacitor) stores energy during one half of  the 60Hz cycle and dumps it during the other half.   This is controlled by the High Voltage diode (marked H.V. Diode).  When the capacitor discharges, its voltage is combined with the transformers to send ~4000V-5000V to the magnetron.  The magnetron uses these high voltage pulses to generate microwaves and cook your food.   I edited the resistance and capacitance values to what I’d measured.

schematicSafety time.  Microwaves contain high voltages that will ruin your day quickly.  Be careful if you decide to work on yours.

I don’t show it in the schematic above but microwaves also contain a fuse.  The way the fuse is wired in mine, if it blew, the microwave wouldn’t do anything.  This indicates that the fuse wasn’t the problem on my microwave but I showed it here anyway.



I mentioned above that I’d cut part of the pieces out in my schematic above.  I can do this because the functions of all the thermal cut outs and switches are to keep line voltage from reaching the transformer.  If I run the microwave and check the voltage going to the transformer I can quickly rule out everything upstream of the plug.  Shown below is the side of my microwave.  The silver box in the middle top of the picture is the magnetron.  Below it is the transformer.  The black and blue/white wires supply 120V to the transformer.  To the top left, out of the picture is where the capacitor and diode are.



To see if voltage is present at the transformer, disconnect the plug and test for voltage when the microwave is running.   With the transformer disconnected, there is no high voltage being generated.  If you have line voltage here everything above it in the schematic is good.  I had 120VAC here as I should.



The next item to test is the transformer.  Transformers are simple loops of wire that are near each other.  This means you can test each loop for continuity.  If you have continuity through all the loops the transformer is probably good.  My transformer has three loops.  The loop that hooks up to the 120VAC is called the primary.  The  other two loops are secondary loops. On the schematic, the primary loop is on top and the two secondaries are on the bottom of the symbol.  The secondary winding on the left provides a low voltage to the magnetron all the time while the one on the right, combined with the capacitor, pulses the magnetron with high voltage.  With the transformer disconnected each of the loops can be checked fro continuity with a DMM.  I did this to my transformer and had continuity through each loop.  It appears the transformer is good.  Transformers are more complicated in practice and you can read more here.

The next item to test is the capacitor.  My DMM has a capacitance mode that allows me to test it.  The capacitor can shock you with high voltage if charged.  Be sure it is discharged before trying to measure it.  Disconnect the wires connected to it and test.  My DMM showed a value close to what the capacitor’s label said indicating it too was good.



The last item I can test is the high voltage diode.  Diodes are a one way valve for electricity.  So, they pass current in one direction but not in the other.  High voltage diodes are slightly different from regular diodes.  They have a higher “cut-in” voltage.  This is the voltage that is required before the diode will pass current.  As such, a regular DMM cannot provide enough voltage to “turn-on” the diode. If you try to test it with your DMM, the diode while block current in both directions leading you to falsely think it is bad.  The diode is hiding under the capacitor and must be removed to test.



To test the high voltage diode requires more voltage.  A simple 9V battery can provide this voltage.  To test the diode, create a circuit loop that has a battery, resistor, DMM, and the diode in it.  The resistor adds some resistance to the circuit to reduce the current.  Set the DMM to measure voltage and then connect everything.  When the diode is functioning with current in the correct direction, the meter will read the voltage minus the “cut-in” voltage.  Shown below is the test on the diode when current is flowing in the correct direction.  If you look at the diode carefully, you’ll see a little arrow on it that indicates the direction current flows through it.



If I reverse the direction of the diode in the circuit loop, it should not pass current.  You can see below that this is what happens.  So, this indicates that the diode is good.



This only leaves the magnetron, which I cannot really test.  I found some instructions saying you could test both prongs in the connector for continuity and then check each prong of the connector against the casing for continuity.  It should have continuity between the two prongs but net between a prong and case.  I did this and the magnetron appeared good, but I wondered about the validity of this test.  The inside of the magnetron is evacuated (under vacuum) and if that were no longer true it would still pass the test above but not work.  To really test the magnetron correctly, requires specialized equipment I don’t own.  After thinking about it some and talking with my father, we decided it had to be the magnetron.  Everything else tested fine and I couldn’t really test it correctly.  So, my dad ordered a new magnetron and it arrived here yesterday.  In the picture below is the new (left) and old (right) magnetrons.  Note the little black thing on the front, a thermal cut out, needs to be switched as the new one doesn’t come with one.



To remove the old magnetron requires removing four nuts and lowering the shelf the transformer sits on.  After this the magnetron can just barely be removed.  Then you swap the new one back in place and connect everything back up.  To see if it worked I grabbed a cup of water and put it in the microwave for a minute.  As you can see the microwave is working once more!  Hurray!



That’s the end of the section on microwave repair.  Now it is time to dig into the magnetron.  I’d noticed that there were a couple of large magnets in it and I was also curious what was inside of it.  Wikipedia has an entry on magnetrons that shows how they work and what the insides look like.  I decided to check it out for myself though.  The first thing to do is remove the metal casing off the top of it.



I thought I’d also see what was on the bottom.  They’d crimped the cap on pretty well but the grinder took care of it.  Nothing interesting here.  I clipped the two wired that allowed me to separate the magnetron from the metal casing. With it apart I could take off the two magnets (pictured at the bottom of this post).



Back to the top of the Magnetron.  Hmm I wonder what is in here?



That looks like the cavities they were talking about on Wikipedia.



A little work with a hacksaw shows the cavities.



Anyways, here’s the two magnets I was after.  They’re stacked on a 3/4″ dowel.



That concludes my post on microwave repair.  I’m happy to say I was never shocked while working on it and now have a couple more magnets stuck to my toolbox.

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Free Black and Decker Drill Fix

Posted by davidjbod on February 23, 2013

I went to an estate sale today on a whim.  It was around 11:00 and the sale had been mostly picked over but there were still a few things I was interested in.  I spied an old drill off to the side of the garage and went to pick it up.  One of the workers said that it was broke.  He said it used to work but when he’d tried to demo it to a customer it stopped working.  I asked how much it was.  He said they were just going to toss it into the garbage and I could have it for free.  Sounds good to me.

Here’s what I have.  It is a “Home-Utility” 1/2″ drill press made by Black and Decker from when they used to make stuff in the US before plastic was the rage.  It’s pretty heavy and the cord is crumbling but thats pretty much a given on old hardware.  Everything else looks pretty good.



Here’s a closer view of the tag.  It says it runs on regular 120V (yes it says 110 because that used to be the standard) and pulls 2.9A at 375 RPM.



The first thing I did was grab my digital multimeter to check for continuity through the body from either prong on the cord with and without the switch engaged.  No continuity which means I won’t get shocked.  Continuity between the cord’s prong showed nothing with the switch off and 12 ohms of resistance with the switch on.  This shows that the motor isn’t shorted and that the switch works.  After these tests, I plugged it in and squeezed the trigger.  It just buzzed and didn’t turn.  I unplugged the drill and tried to turn the chuck by hand.  It was stuck.  In retrospect, this is another quick test that could be done before plugging it in.  At this point, the problem could be in the gearbox or the motor itself.  To determine where the problem was, I needed to remove the chuck to get into the gearbox.  The chuck is threaded on like on my Milwaukee drill.    To remove it I chucked up a Allen key and then struck the key with a hammer.  The key is struck in the counter-clockwise direction when looking at the chuck from the front.  It came loose after a couple of blows.



After the chuck was off, I removed the four screws holding the cover on the gear box.  A couple taps with a rubber mallet loosed the cover enough to slip off.  Once the cover was removed I was greeted with the sight in the picture below.  It appears that water had sat in the gearbox at some point and rusted some of the gears.  This is probably the problem but the gears won’t come out even though they just sit in a bearing sleeve.



I shot the rusty areas with some PB Blaster and was finally able to work the gears back a forth a little bit.  After  moving them some more I was able to get the gears removed by pulling them out.  Now I can check if the motor will turn by spinning the gear on it by hand.  Yes! It does spin.  Now, I’m certain it was the gears causing the issue because rust was not allowing them to mesh.  I plugged the drill back in to test it with the gears out and it ran like normal.  Here’s the cruddy looking gears.



I put them in the ultrasonic cleaner to let it remove what it could.



After a little bit of scrubbing and another dip in the ultrasonic cleaner, the parts cleaned up pretty well.  I also removed the spindle for the chuck and cleaned it as well.



Here’s some of the old grease in the gearbox.  It showed signs of water contamination and some of the grease had dried into chunks.BD7


I cleaned what grease I could out of the gearbox compartment and added new grease in.  Going off of the amount of grease in the Milwaukee drill, I put a good amount of grease in.  Since it is red, the new grease should work better than the old grease!



Once it was all back in one piece I put the chuck on and tried it out.  Works great!

Next, I turned my attention to the disintegrating electrical cord.  It is accessed by removing the handle that is held on by four screws.  The wires are each pinched under screws allowing the cord to be removed easily.  Unfortunately, there’s no strain relief on the cord which means a sharp tug on it could rip a wire loose.



I replaced the old cord with a spare one that had come off of my lathe from when I converted it to 220V.  I attached it as seen in the picture below.  I ended up having to shorten the black wire to get the handle to fit back on.  There was very little room inside the handle and it took a couple tries to get everything to fit in just right.



I put the screws back in to reattach the handle and gave it another check with the multimeter.  Everything checked out fine.  I tried it out by drilling a couple holes with it and it worked perfectly.  The only complaint I have against it is that, since it runs at 375 RPM, it doesn’t drill holes very quickly.  Still, it gets the job done.



In case you’re wondering about the odd shape at the top of the drill, it is for a handle.  It is threaded to fit 3/4″ iron pipe.  The picture blow shows a piece of pipe attached to the drill.
This is the shortest piece of pipe I had sitting around.  I smaller one would be used normally.



That’s my kind of recycling!  It just goes to show that the old adage of  “One man’s trash is another man’s tertiary large drill” is true….or something like that.


Posted in Repair, Restoration, Tools | 2 Comments »

Firebird Clutch Master Cylinder

Posted by davidjbod on November 11, 2012

For the past month or so the clutch pedal in the Firebird has been acting weird.  Sometimes it would be normal but other times you’d feel the resistance stop before the pedal was all the way up.  Then, when you went to press it down again there’d be a greater zone of no resistance (aka play).  It’d come and go randomly.  The clutch system in the Firebird is hydraulic and consists of a master and slave cylinder.  The master cylinder has a rod that is depressed by the clutch pedal.  It is located in the firewall near the clutch pedal.  The slave cylinder is bolted onto the front of the transmission around the input shaft.  A hydraulic hose connects the two.  The stock clutch master cylinder has design issues with it that you can read about online and isn’t regraded fondly.  The slave cylinder has a good reputation and the stock one is used in high power applications without issue.  There is also a reservoir that holds extra fluid and connects to the clutch master cylinder.  It isn’t under pressure.
I’ve had to replace the clutch master cylinder before.  It was leaking and would slowly drop the pressure in the line resulting in the clutch slowly reengaging even when you had the pedal all the way pressed down.  You can test for a leak by finding some place level, putting the car in first gear, foot off the brake, and holding the clutch in.  If after a little bit, you start moving forward , you have a leak.  So, go look around your clutch master cylinder.  That time, I could see fluid leaking around the rod when I stuck my head under the dash.

Unfortunately, the clutch master cylinder can also leak internally.   By this I mean that inside of the cylinder, fluid can seep past the piston and return to the line going to the fluid reservoir.  When this occurs you’ll lose pressure but you won’t see any leaks.  The clutch slave cylinder can also leak.  If it does, you may notice fluid leaking from the bits of it that protrude out of the bell housing or fluid leaking from the bell housing.  My car leaks oil which is all over the bell housing and transmission so I wouldn’t be able to tell if it were leaking.

Using the time tested method of narrowing the problem down to two things and picking the simpler thing, I decided to replace the clutch master cylinder.  I wasn’t able to take a ton of pictures because of where it is located and my hands were messy.  So, this will mostly be verbal.  Out of the ordinary I know.

Anyways, there are a couple of panels that need to be removed to get under the dash.  After you do that, it looks like this.  The thing being pointed out with the arrow is the clutch master cylinder.  The rod that extends out of it has a circle on the end that attaches to the clutch pedal arm near the pivot point.  It is retained by an E clip.  Remove the E clip without shooting it up into the dash and remove the end of the rod off the stud.  Next, remove the two nuts that are beside where the clutch master cylinder comes through the firewall.


The rest of the clutch master cylinder can be found under the brake master cylinder.  It’s the black cylinder pointed at in the picture below.  Note this picture is taken from in front of the car which isn’t where you’ll be if you try to remove it.  Thanks to GM, you get to do this completely sight unseen.  Now you need to remove the hose from the clutch fluid reservoir.  It is held on with a zip tie which you can just snip to remove.  With a rag at the ready, pull the hose off and mop up the leaking fluid.  The clutch fluid is actually brake fluid.  Brake fluid and paint don’t agree with each other so keep it off your paint.   Go ahead and remove the reservoir as well.  You’ll need the room.  Removing the clutch master cylinder is the easy part though since you just pull it out from the firewall.  The two nuts that you removed earlier under the dash don’t go onto bolts.  They go on to a U shaped piece of metal that has threads and flanges at the end.  You’ll need to pull it out of the clutch master cylinder before you can proceed under the car. 


Once the car is jacked up and on stands. look near the driver’s side exhaust manifold and follow the hydraulic line up.  First you’ll need to move the metal heat shield on the fuel and brake lines out of the way.  Take the nuts that hold it in place off and bend it out of the way without creasing it.  Now reach up and move, jiggle, rotate the clutch master cylinder to get it out from between the steering linkage, body of the car, and the fuel/brake lines.   Now, only the hydraulic hose keeps it connected to the car.  The hose is held in by a small roll pin near where the line connects.  Drive it out using a punch and hammer.  A piece of wood with a small hole in it works well to hold the clutch master cylinder while you drive the pin out.


Yay, it is finally out.  Here’s what it looks like.  There are two holes on the flange that the U shaped bolt goes through to hold it on the fire wall.  The rubber hose goes to the reservoir and the elbow looking part on the right end is where the line to the clutch slave cylinder connects. 


I returned from the parts store a little surprised.  The replacement part was made of metal while the previous one (and the other one or two I’ve replaced before) have all been plastic.  It was the right part number though.  The metal one was a little bigger than the plastic one which had me worried because it was tight getting the old one out.


Re installation is the reverse of removal but it goes slower and involves more choice words.  Under the car, replace the rubber washer on the end of the hydraulic line and reinstall it with the roll pin.  Now get the clutch master cylinder sitting beside the steering linkage then go inside the car to pull the rod through the hole in the firewall.  Back under the car for more struggling until it is on the other side of the steering linkage in approximately the right place.  Now the fun starts.

Inside the car is a bracket that limits how far the clutch pedal can move down.  If you look back at the first picture and the silvery piece near the clutch master cylinder, you’ll see it is also held in place by the U shaped bolt.  This piece won’t sit in place to line the holes up so you’ll need to find a way to hold it in the correct position.  If you don’t, it will block the holes in the firewall and keep you from pressing the U shaped bolt in.

Now, go to the driver’s side of the engine bay.  You’ll need to reach your right hand around and under the brake master cylinder while your left hand goes under the flexible fuel lines and above the steering linkage.  Now you can inefficiently move the clutch master cylinder around but you’re not able to push it that hard.  Now move it into the right position while trying to match the holes in the clutch master cylinder and fire wall up…which you can’t see.  Once you’ve got that, hold it with your left hand and try to put the U-shaped bolt in.  If you try to put the U shaped bolt in before getting the clutch master cylinder in place it will hit the brake master cylinder.  Previously, I’ve shoved and pushed and finally gotten the U shaped bolt in enough to put the nuts on it and draw it into the correct position.  That wasn’t happening this time.

Try as I might, I could not get both bolt holes to line up at the same time no matter what I tried.  I finally decided that the cylinder of the clutch master cylinder was a little larger in diameter than the old one.  As such, it was hitting the top of the hole in the firewall keeping the last bolt hole from lining up.  As opposed to grinding the opening a little larger I filed the bolt hole a little larger.  After that I was finally able to get the U-shaped bolt back in place.  Now put the nuts back on and re assemble the dash.  Also reattach the reservoir hose to the reservoir with the supplied zip tie.  Swapping the part is done.  Now on to bleeding the system.
Since you opened up the hydraulic system there is now air in the line.    Top off the now empty reservoir with fresh fluid.  You’ll see some bubble and the fluid level will drop.  Add a little more until that stops.  Now to get the rest of the air out.  There are multiple ways of removing the air.

The “regular” method  requires two people.  One of them pumps the clutch pedal vigorously numerous times and holds it down.  The second person is under the car and opens the bleeder valve connected to the slave cylinder.  See it in the middle of the picture below.  Opening the valve will shoot fluid onto the underside of your car.  So, put a hose on the end of it that leads down to a cup of some type.   Once it is done dripping snug the bleeder valve closed.  Your assistant can then let up on the pedal and start pumping again.  Repeat as needed until the pedal feels like normal.  This method may or may not work on this system.  Apparently, something in the design makes it trap air.

The second option is called vacuum bleeding.  You apply a vacuum to the clutch fluid reservoir while you assistant vigorously pumps the clutch pedal.  After a bit it will stop coming up all the way and you’ll have to pull it back up.  Keep pumping.  Let the vacuum off and pump the pedal until pressure builds back up.  Repeat as needed until you get a good pedal.   For vacuum you can use a hand pump and fab up a way to create an air tight seal on the reservoir.

The third method is called gravity bleeding.  It has the advantage of needing only one person. I can be slow though.  It usually works well.  All you do is take the top off the reservoir and crack the bleeder valve open until you get a decent rate of drops coming out.  Leave it this way and periodically monitor the fluid level in the reservoir.  Keep it topped off because, if it gets low, air will be sucked in and you’ll be back at square one.  Keep this up for a while and periodically check the pedal.
You can use all the methods.  I usually use the first to get a large amount of air out of the system and to remove the old fluid.  Then, I use the second and/or third method to finish it up.  Once you’re convinced you’ve got a good pedal for for a test drive.  If everything is good you’re lucky.  If the pedal doesn’t stay the same you probably still have a little bit of air in the system that has moved from wherever it was hiding to cause trouble.  Go bleed it again.  You may come back the next morning and find that the pedal is not good again.  I don’t know why, but lots of folks say it happens.  Bleed it some more.  Once you reach the point where the pedal is good enough to operate but not perfect drive the car a bit.  The motion of driving the car will shake the last little bit of air out of the system.

I’m currently at this point.  The clutch feels good and operates like normal but isn’t quite right.  When I let off with my foot the clutch pedal will stay still and then slow move the last little bit into place.  I’m not sure if there is a tiny bit of air left in the system or it is related to the metal clutch master cylinder.  I’m going to drive it in hopes that if it is air, it will work its way out.
I’ve also recently noticed the air conditioning compressor rattling on the car.  I don’t think this is a good sign.

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Auto Repair: Door Hinge Pin Replacement

Posted by davidjbod on October 12, 2012

If you have an older vehicle you may have noticed that your door has dropped, squeaks, rubs, or doesn’t swing as easily as it once did.  This is probably due to the bushings wearing on the door.  On my S10, the driver’s side door hasn’t dropped but it does squeak.   My doors are held on by two hinges.  Each hinge is held together with a pin with two flanged bushings in between the halves.  Here’s a picture of the top hinge.  The green arrow points to the lower bushing which is clearly worn.  The pin has worn through the bushing allowing the pin to rub directly on the hinge.  This is bad.  The pin is easily replaced but the hinge is welded to the truck.  If the hinge wears badly it would be a pain to repair.  So, fix it before it becomes a problem.



Here’s the lower pin and bushing.  It looks ok but it has to come out to replace the top pin and bushings.  So, it should be replaced as well.


The first thing to do is to remove the spring, seen in the top picture, that holds the doors in the detent positions.  I used a pry bar to carefully pop it out of the way.   Before you can remove the pins the door needs to be supported.  You want to neutrally support it at the normal height so that there is no force on the pins.  Here’s my cheap way of supporting the door.  Another option I’ve seen is to support the door with a jack while someone holds it.  This method allows the door to hang in position without needing another person.


Now I can start removing the pins.  The first thing to do is remove the ring that fits into a grove on the pin.  It keeps the pin from falling out.  On the top pin, the ring is on the top and the pin is removed by pulling it down.  On the bottom pin, the ring is on the bottom and the pin is removed by pulling it up.   The ring can be destroyed in the removal process as it is not reused.  I split it with a cold chisel and removed it with some pliers.


Next, drive the top pin down and out with a punch.  You shouldn’t have to beat the pin with a ton of force.  If so, then the door is probably putting a lateral load on the pin.  Try adjusting the door’s height and try again.



Once the pin out of the top holes it can be pulled the rest of the way out.  The bottom pin is driven up and out.


Here’s the top pin.  I think it is worn a bit.


Once the pin is removed the bushings can be removed.  The bushings are flanged meaning they only go in and out from one side.  On mine the flange was almost completely worn off the top bushing because it supported most of the door load.   I’ve pointed out the bushings with the green arrows.  The top bushing goes up to be removed while the lower bushing goes down.  Punch them out with a pin or collapse them with a cold chisel and pick the bits out.


The bushings on the lower hinge are in the door hinge half.  I’ve already removed the bottom bushing in this picture.  Put a towel or cardboard between the door and body to keep the two from rubbing on each other.


Here’s the old pins and bushings.  The bushing on the right is the worn one from the top hinge.


Here’s the shiny, non-rust colored, new pins and bushings.


It is important to note that the bushings are not identical.  One of the bushings is larger, inside and out, than the other.  It needs to go near the end of the pin that has the cap .  Accordingly, the holes in the hinges are differently sized as well.  The larger bushings won’t fit in the smaller holes.  The like colored arrows indicate which pieces go where.


Once you’ve identified which bushing goes where they can be reinstalled.  I tapped them in with a ball peen hammer but I’ve also seen online where folks have used a bolt, nut, and a couple washers as a press.  To use this method, position the bushing in place and then insert a bolt and washer.  Put another washer and the nut on and then tighten the nut down.  Using wrenches the bushing can be drawn into position.  Here’s the top bushings reinstalled.


Here’s the bottom bushings reinstalled.  Tap carefully with the hammer or a bit of the bushing might break off. 


With all the bushings in place, reposition the door to align the holes.  Add a little grease to the pins and/or bushings and reinsert the pins.  The new pins have a flat spring clip that fits in a groove on the pin.  The best way I found to install the clip, is to use a deep well socket and extension.  Place the clip in place and then push down on it with the socket end until it clicks in place.


Here’s the clip and pin in place.


To reinstall the door spring, it must first be compressed.  Of course there is a special tool for doing this.  You insert the spring in the tool and then tighten the nut down which compresses the spring.  Be careful as the spring may shoot out.  Once compressed, the tool and spring should be treated like a weapon.  Strong compressed springs contain a lot of energy.  If this spring were to fly out it could damage yourself or something else.


The door has tabs to hold the spring in place.  Put some grease on the wheel that the detent arm moves against.  Insert the spring and tool into the correct position and open it up.  Hopefully, the spring will end up in the right place.  If not, carefully it reposition with the tool or nudge it with a prybar while standing back.


Here’s the spring back in position.


That completes the pin and bushing replacement.  Now the door swings easily like it should.  Before I put the spring in place is swung with practically no resistance.  I can’t recommend this for everyone unless you feel you’re up to the task though.

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Auto Repair: Windshield Washer Motor Replacement

Posted by davidjbod on October 6, 2012

I have no exciting tool restoration to post about today.  Just simple, money saving, diy car repair.  As I was driving to work the other day, I decided to clean off the windshield using the washer built into the car.  I rotated the control stalk to spray the windshield with fluid but there was no spray.  Of course the wipers moved and smeared what ever it was all over the windshield but that is beside the point.  The first thing one thinks, I suppose, is that it is simply out of fluid.  Due to the shape of the tank I can’t tell how much is in there.  I went ahead and topped it off but it still wasn’t working.  Hmm, what’s wrong.
The washer system is pretty simple.  You close a switch, rotating the control stalk in my truck, and voltage is supplied to a pump on the washer pump tank.  The pump pumps water up a hose that connects to the spray nozzles that shoot the fluid out.  As you can see, there’s not that much to go wrong with the system.  Still, we can take a systematic approach to the problem to solve it.
The first step was to refill the tank.  Obviously, the pump can’t move the washer fluid if it isn’t there.  If it still doesn’t work, the second step is to turn the washer on again and listen for the sound of the pump running.  If the pump is running, but no fluid is spraying then you probably have a break in the line from the pump or the pump is clogged.  Sure the nozzles could be clogged too, but the chance of both clogging completely without any previous signs (poor spray pattern) is pretty remote.  I didn’t hear the pump running which leads to two options: the pump is dead or not receiving voltage.

To test for voltage I needed to find the motor and disconnect the connector on it.  Logic dictates that the pump will be at the lowest part of the tank and once the air cleaner box was out of the way, sure enough, there it was.  You can see the pump and the disconnected connector in the picture below.  Note that there is a pink and black wire on the connector.  Black is pretty much always a ground meaning that the pink wire is the positive wire.


To test the voltage is pretty simple if you have a multimeter. I’ve found that small paper clips fit into connectors well without damaging them.  Once they’re inserted, and NOT touching each other, the multimeter leads can be hooked up to the paper clips.  Next, attempt to run the washer and see what voltage is present.


I used my Fluke 87 multimeter to test the voltage.  It turns out that the pump is pulsed by the wiper control module meaning that the voltage varies up to a max of battery (or alternator) voltage and down to zero.  Luckily, my Fluke has a max and min recording ability which allowed me to easily see the peak voltage.  It also allowed me to easily get this picture!  The truck isn’t running so the voltage seen is ok.  If it was running and I saw this voltage I’d be worried about my alternator.  Since I have the correct voltage, this leads me believe the problem is the pump.


What if you don’t have a multimeter?  Then you should get one.  Seriously, they’re pretty cheap especially at Harbor Freight.  Ok ok, if you don’t have one you can use a test light.  The factory service manual makes use of a test light to troubleshoot the washer system.  What is a test light?  It is nothing but a small light bulb connected to two leads.  As you can see below, one of the leads goes to a clip and the other goes to a pointed metal rod.  So, if you connect it between a voltage source and a ground it lights up.  Very simple and useful.


The manual has a flow chart that tells you how to hook up the test light to narrow down the problem.  You preform a step and the result leads you to another specified step.  The first step is to connect the test light to a ground and probe the pink wire while attempting to run the washer pump.  If the test light lights it means you’re getting voltage to the pump.  Next, it says to hook the test light to the black wire at the connector and probe the pink wire again while attempting to run the washer pump.  It lit again meaning I had a good ground and thus a good circuit.  At this point the manual instructed me to replace the washer pump.   Pictured below is the test light lit up in a successful test.


At this point the washer pump has been confirmed as being defective via two different, though similar, methods.  Time to replace it.  To remove the pump, I disconnected the line to the pump and  pulled the washer tank, which required removing one bolt.  Of course, once I had it out I found that I could have removed the pump without pulling the tank but I think it was easier with it out.  So, there’s the stock pump dated 1994.  The pump has a peg that pops into a recess in the tank and a bottom pickup that fits into a hole with a grommet in the tank.  Replacement is simple, remove the old pump and grommet, put the new grommet in, then put the new pump in.


Here’s the old pump (left) and the new pump (right).  They don’t match up perfectly but it turns out that you can rotate the bottom of the pump to align the output tube.  I had plenty of space either way.  If you look closely at the bottom left of the old pump, you’ll notice a few ants.  A colony of tiny ants had decided to take up residence at some point.  Odd.  Maybe they killed it.


So, there ya go, simple diagnosis and replacement.  At $15 for a new pump, it was pretty cheap too.  It took me longer to take the pictures and write this post than the actual diagnosis and replacement took.

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