# It's Time To Finish The Felt Job On My Sb 10k



## DoogieB (Aug 21, 2016)

Awhile ago I replaced the spndle felts, set the bearing clearance etc on my South Bend 10K as documented here:

http://hobby-machinist.com/threads/removed-the-spindle-from-the-sb-10k.25750/#post-227652

I intended to finish the rest of the lathe in a month or so, but now it's two years later!  That's the trouble when you have a working lathe, you would just rather use it then do the maintenance, but now it's past time to finish the job that was started.  It also didn't hurt that I made a pledge to myself not to put a DRO on the mill until the lathe is finished. 

Small projects like the tailstock and reverse tumblers were quick afternoon jobs, but the QCGB and apron are much more labor intensive and would span a couple weekends.  I decided to knock them both out at the same time and just get it over with.  I took some pictures while I was at it and thought I would post them for the amusement of the readers.

I'm glad my lathe was from 1974 and used socket-head screws to hold the QCGB, because I don't think I could have loosened the the slot-head type without removing the head stock.  As it was, one of the screws was captured by the headstock, but I was still able to remove the gearbox from the bed without too much difficulty.  So what does 40 years of gunk look like?




Yuck!  Definitely time for a good clean and some new felt!  One thing of note was that this lathe used a lock-nut to hold the leadscrew.  The nylon started to deteriorate and the lead screw was getting sloppy.  I tossed that nut in the trash and replaced it with two jamb nuts as described in the rebuild manual.

So, after a bit of work, a few days in the parts soak and 3 or 4 cans of brake cleaner you get this:




After everything was good and clean I was happy to see the gearbox was still in fine shape.  Of course the gears were all fine and I didn't need to replace any of the bronze bushings either.  At first I was a little worried about the needle bearings in the selector levers, but after a clean and repack with grease they seem to be fine.  Just in case they cause any problems down the road, I was able to source exact replacements at Amazon.  They are listed as:

*Koyo GB-88 Precision Needle Roller Bearing*

For you rebuilders, that tool in the middle of the picture is an ear polypus and it's the handiest thing to remove stubborn old felt or pull new through the oil channels.  You can find them on Ebay or speciality hobby stores like Micromark.

Also had a few stubborn taper pins during disassembly, but they loosened right up with a little heat from the torch.  Overall, things went better than expected.




And that's what the gearbox looks like ready to install.  It's going to have to wait a bit, however, because the apron is next.  What horrors will we find in there?


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## DoogieB (Aug 22, 2016)

With the QCGB and lead screw removed, removing the apron was a piece of cake: just remove the two cheesehead screws.  Here's what it looked like.




Oh, yeah... it's completely full of crap.  And that folks is why South Bend touted the double-walled apron on their bigger lathes.  It's a wonder it was still working at all, although I did have a problem with the half-nuts interlock which would need to be fixed.

The dissembly was going as described in the book, but sometimes things just don't work out.  The one gear shaft was super-tight (it certainly didn't need a set screw) and I didn't want to pound any harder on that cast iron.  Big Orange to the rescue!




That shaft got chucked-up in the lathe and little work done with a file for easier installation.

So after several baskets of stuff in the parts dip and about 4 cans of brake cleaner you end-up with this:




At one point, I think I had to loosen the gunk inside the apron with a screw driver but, like the QCGB, there wasn't any signs of damage or wear, besides the interlock pin which I will get to.  I don't think this lathe ever did much threading with the original owner because the half-nuts and lead screw are in really good shape.




The ear polypus ready to pull a felt through an oil passage.

Like I said earlier, the half-nut interlock didn't work.  Luckily I didn't find this out the hard way.   I needed to make a new rod, luckily I have a lathe.  Errr.  Well, it's just a simple part...




Since I didn't have an apron, I used the compound for the carriage travel.




Old versus new.  It took a couple of tries to get that "just right" size which locked-out the half-nuts when the feed selector wasn't in neutral, but released them when it was.




Everything in the apron is now cleaned-up and back together.

Before I installed the QCGB and lead screw, I wanted to make one change to the original design.




I was never that impressed with the open oil hole in the lead screw bracket, so I ordered a Gits oiler with the spare QCGB needle bearings from Amazon.  Installation is a snap- you just drill the hole bigger for the oiler.  There's plenty of meat in the casting so you won't drill near or through the bearing surface.  After banging in the Gits, I installed a small piece of round felt inside for oil control.  It seems to be working well.

I didn't take any pictures of the lathe afterwards because it looks basically the same as when I started, but _I_ know that the insides are working much better now.  It also feels good to finally close the book on this project.  Maybe in 15 years or so I'll do it all over again but actually strip and paint the old girl.


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