Milwaukee Model 0101 Drill Disassembly

I few weekends ago Christopher and I were out looking for tools.  I’d seen an ad on Craiglist that had “four warehouses” with various items listed and “TOOLS, TOOLS, TOOLS”.  I thought this sounded like a good place to go for obvious reasons.  We arrived to discover the “four warehouses” was a small convenience store sized building and two single wide mobile homes.  The “TOOLS, TOOLS, TOOLS” consisted of some random junk and a pile of drills.  Most all of them were cordless ones without chargers but I did manage to find a Milwaukee corded drill.  It is a smaller drill that had been heavily used but, after verifying it worked, I bought it for $10.  The data tag on the drill had been mangled beyond readability but some searching on the internet leads me to believe it is a model 0101 1/4″ drill.  Milwaukee still makes the model 0101 but now it is a model 0101-20.  I’ve never used it but I imagine it is a good drill based on their other projects.  A 1/4″ drill means that the diameter of the largest thing that can be put into the chuck is 1/4″.  The previous owner must have removed this chuck because there is now a Jacobs Multicraft 3/8″ chuck on it.  I think the Multicraft line was the lowest line Jacobs has.  I don’t plan to replace this chuck though if I ran into a beefier 3/8″ chuck that would fit I’d pick it up.

I brought the drill home and used it a couple of times.  It drills fine but it is louder than I think it should be.  It also has a screeching sound to it.  This looks like an older drill, possibly from the 60s, so it is a safe bet that the bearings need replacing.  It also looks like hell and could use some cleaning up.  So, that’s what I’ll do.  Here’s what it looks like as purchased.  To start though, it has to be disassembled.

MD2_1 MD2_2

As with all drills, I start with removing the chuck.  I held the drill body in my vise with some soft jaws and then chucked up an Allen wrench.  The chuck comes loose using the Allen wrench to rotate the chuck counter clockwise.  Next, the gear case is taken off by removing the four slotted screws that hold it in place.


The case holds the spindle which must be pressed or tapped out.  With the gear case removed, two slotted screws that hold the diaphragm on can be removed.  The bearing on the front of the armature fits tightly into the diaphragm which keeps the diaphragm from coming off.  To remove the diaphragm, inset two pry bars into the opening between the diaphragm and motor housing and gently pry.


With the diaphragm out of the way the motor’s armature can now be accessed.  There is a bearing on the rear of the armature shaft that is pressed into the motor housing which keeps the armature in place.


To remove the armature, the plastic handle halves must be removed first.  This is done by removing all of the slotted screws that hold them on.  There are six screws on the right handle half and two on the left.


Now that the back of the armature can be accessed, the drill is put back into the vise.  Again, use two pry bars to gently push the armature out of the rear bearing.  Be sure not to let the armature drop out of the motor housing on to the floor.MD2_7

Here is a picture of the armature.


Two long slotted screws hold the field assembly in place.  With the screws out, if desired, the field assembly can be pulled forward.  It cannot be completely separated as a couple of wires hold it in place.  One wire goes to the switch while the other is soldered to a clip on one of the brush assemblies.  While trying to remove the clip, the solder joint broke.  I’ll have to fix this later.


You may have noticed that the ball bearing on the rear of the armature did not come out with it.  It is still stuck in the motor housing.  It fits into a blind hole which is a hole that does not go completely through the piece.  Ideally, I’d use a blind hole bearing puller here.  This tool uses expanding collets to grab on to the bearing and a slide hammer to remove the bearing.  Sadly, I don’t have one of these.  Instead, I hydraulically forced the bearing out.   To do this, as much grease as possible is put into the bore of the bearing.  The grease will fill the blind hole that the bearing is in and the bearing’s bore.  Next, a cylinder approximately the size of the bore is forcefully driven into the bore.  I found a pin punch fit the bore nicely.  This puts pressure on the grease, which is incompressible, causing the grease to put pressure on the bearing.  If the pressure is great enough, the bearing will be pressed out a little.  Now more grease is put in the bore and the process is repeated.  In the picture below, you can see that the bearings has moved up some.


Eventually, the bearing is completely pressed out and you’re left with a mess to clean up.


With the rear bearing removed, I turned my attention to the bearing on the front of the armature.  I lack small enough pullers to grab the bearing and instead used a couple of Morse taper wedges.  I normally use the wedges on my lathe to remove whatever is sitting in the tailstock.  After a little bit of hammering on the wedges the front bearing came off.



Now to get the two bearings off the spindle.  I used the wedges again on the bearings.  The smaller bearing came off completely with the wedges..


The larger bearing required some gear pullers to fully remove it.  These gear pullers were barely small enough to work.


Out of the four bearings, one was is good condition.  Another one was questionable and the last two were toast.  The bearing that was on the rear of the armature felt dry and gritty.  It also made noise when turned by hand.  So, it was worth the trouble getting it out.  They’ll all be getting replaced.

With the drill completely dissembled, it is time to start cleaning.  I wanted to get all the paint flecks off of the aluminum pieces.  I’ve found that Jasco Paint and Epoxy Remover works wonderfully at removing stubborn paint.  Do wear gloves though when using it or you’ll regret it.  I used an old toothbrush to slather it onto the painted areas and then gave it a few minutes to work.  After a little bit, the paint can be removed using a paper towel or the toothbrush.  If any paint remains another round of the Jasco will get it off.  I also removed as much of the old grease as possible before putting the aluminum pieces into the ultrasonic cleaner.  I also dropped the spindle, bearings, and handle halves into the ultrasonic cleaner.  I cannot put the motor housing into the ultrasonic cleaner because of the wires that run through it.  I’m also not putting the armature in the ultrasonic cleaner as it could cause damage.  Note that the ultrasonic cleaner will contaminate the grease inside the ball bearings which will kill the bearings unless you plan to clean and relube them.  I’m planning to replace all the ball bearings and am only cleaning them to make the numbers on them easier to read.


Between the ultrasonic cleaner and some elbow grease, the handle halves were cleaned up pretty well.


Here’s everything as it stands currently.  I used some “Son of a Gun” car interior protectant on the plastic handle halves to try to freshen them up some.  It seemed to help.  I’m going to try to find another power cord as the current one is dry rotted and cracked.  On Monday I’ll make a call to Accurate Bearings for some new bearings.  I’m also going to try to polish the aluminum some.  I don’t want a mirror finish on it, but I should be able to make it look better.



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