Hardinge HLV Part 2: Apron

I’m working on multiple parts of the lathe at once.  I do this because I’m usually waiting on parts or tools to arrive.  I’m going to post about sub assemblies though.  This time I’m going to cover the apron and carriage.  Once again, for whatever reason, the flash on my camera shows rust that doesn’t show up in person.  So, it is not as bad as it looks.

I removed all the parts (clutch towers, hand wheel, and half nut lever) hanging off of the apron before removing it from the lathe.  Seen  below is the apron (on the left) and carriage (on the right).  There are some spring assemblies which pull the longitudinal and cross slide clutches closed.  They don’t have to be removed to split the apron as they hold some of the parts in place.   I removed them though because I was unaware of this at the time.

Removing five bolts allows the apron to be split but not easily as there are some pins that are a tight fit.  Once I got the apron apart I could fully appreciate all the gunk in the apron.  I’m still not sure if this is really old grease or old oil.  Either way, a bit of water made it in and caused some rust.  Most of the gears are loose at this point with the exception of the ones on the front (left side).   On the back half (right side of the pic) you can see parts of the clutches (gears with depressions in the middle) the gear that engages the cross slide (middle right), feed gear (lower left) and the half nut cam (bottom).  There are needle bearings or plain bearings under all the gears on both sides.  A lot of the roller needle bearings were suspect and replaced.Over on the front half of the apron there are the other halves of the clutches, a pinion gear, and the spring pin.  You can’t really tell in this pictures but the spring pin is about an inch long.  Half of it is about 1/4″ in diameter and the other half is about 1/8″ in diameter.  This will matter later on.  The pin fits into the bar with a spring between them and pushes the bar towards the half nut cam.  This acts as an interlock to keep you from engaging the longitudinal feed when the half nuts are engaged and vice versa.

The pinion gear exits the back of the apron and, though it has an oil seal, bits of metal made it in which chewed up the surface the bearing runs on.  The bearing needles are very hard and the shaft is not.  The shaft should be 0.75″ but was undersized in the worn area by 0.006″ allowing it to wobble.   I thought for a bit about how to fix it and decided on sleeving it with some 1144 steel.  There is also a taper pin which runs through the area that helps retain the small gear on end.  This is not the best spot for a pin in my opinion but thats how it is.  The first step was to turn it down to clear up the worn area.  I reduced the diameter to 0.7″ in preparation for the sleeve.I made the bushing to have a slight interference fit and pressed it on.  From there it’s back to the lathe to turn it back down to 0.75″.The best finish I can get is with a vertical shearing tool.  It did a good job and left a nice uniform surface.  Ideally, grinding the shaft would be the best choice but I think this should work for me.  Its certainly better that what I started with.  Next, it was over to the mill to drill the hole for the taper pin through the sleeve.  I pressed the small gear back in, made a new pin, installed it, removed the pin to shorten it several times, and got it to size.  It would have been better to install the pin before turning the diameter down so it could be trimmed to size easily.  A lesson for next time.

As before, all the parts got a bath in the parts cleaner and scrubbed.  I pressed all of the needle bearings out except for the cup needle bearing in the top of the pic below.  It was 10x the cost of the other bearings and looked to still be in good condition.  Here’s all the replacement bearings and an oil seal for the apron and carriage.    Most were needle bearings but two were sealed ball bearings.  The single oil seal is the one mentioned above for the pinion gear.

The arbor press made quick work of installing the bearings for the apron.  Here are the apron halves ready to be resembled.

All of the bearings were liberally oiled with ATF as it is the factory recommended lubricant and the parts and pieces put back into place.  You probably don’t notice it, I didn’t, but the bar that the spring pin goes into isn’t pushed over like it should be.  I accidentally flipped the pin over and the smaller half of the pin went inside the spring.

I applied some RTV onto one of the halves and put the apron back together.  I manually engaged the clutches and they operate as expected. 

Up in the carriage was another bearing and oil seal.  They were for the cross slide lead screw.  This bearing was also bad and the oil seal was very hard.  Both needed replacing.  I searched and searched but couldn’t find the appropriate replacement oil seal.  I decided to put an O-ring behind the bearing to act as a seal.  Behind the O-ring, I put a plastic bushing to keep the O-ring in place.  The oil will have to travel quite a bit to make it up here and I’m hopeful my makeshift seal will be adequate.       

Finally, I could put the apron and carriage back on the lathe.  Yay!  From here I started to reinstall the clutch towers.  As I was checking out the longitudinal one, I noticed the interlock wasn’t working.  Uh oh! Soon after I figured out why and had to remove the apron, crack it back open, flip the pin, and put it back together.  Oh well, better than not having the interlock.

 

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