Cold weekend - good lathe repair time!

COLD!

I got up to the farm late Friday evening.  Freaking COLD!  It hovered around 4F - never higher that 14F during the whole weekend!  Snow was coming down Friday evening for the trip and then Saturday the winds kicked up.  Here are some pictures from Saturday morning.

Logan Lathe threading/powerfeed gear train repair

I had purchased a number of items to help me attack the stuck key and gear issue that i left last weekend.  I used a small (5/64" diameter - 6 inches long!) "aircraft extension drill bit" that I got from Enco to drill out the old key from the between the shaft and the stuck gears.  Once the keystock was drilled through I was able to drive it out some.  Between that and twisting the gears by holding them with channel-lock pliers and holding the shaft with pliers, I was able to get the gears off.  Whew!  Then I needed to clean up the shaft, gears and new keystock so that everything fit together with a "slip" fit.  Lots of mini-file work.

The shaft, after gear removal, and some new under-sized keystock.

Filed and fitted!

The gears and keystock fitted fully and with a "slip" fit.

I had also purchased a adjustable reamer to clear out the gears - some of them were catching - I guess they got marred from being driven off the shaft.  They reamed out nicely.  Fit is superb.

Installing the gears into the casting is the tricky part!  I decided the only way that this was going to work was to remove the bushing from the keyed side of the casting.   I would have liked to press out the bushing using the arbor press, but there was no room.  I would have to "tap" them out using a mallet or hammer.  To keep from damaging the bushing I used the lathe to create a little tool that fit inside the bushing but with a lip to hold onto the bushing and provide a surface to hit the bushing evenly.  Its nice have a lathe!  I used an old bolt from the leftovers that were left in the garage when I bought the place.  It is a throw away tool so I didn't want to use anything nice...

Before and after...

The bushing removal tool made from an old tractor bolt

Bushing removal tool pushed in and ready to hit!

Bushing removed!!

Worked like a charm!  Even though I discovered that the bushing was thicker than I originally thought - it was just covered with dirt...

Only problem is... I removed the wrong bushing!  I needed to remove the bushing from the keyed side of the casting!

So, I reinstalled the bushing on the opposite side...

And then i took out the correct bushing!

Pushing the shaft in - no bushing on the right there

The end of the shaft as seen from the keyed side of the casting.  See that there is plenty of room there for the key between the shaft and the casting?

The free floating gears are installed on the left and the key is shown in the keyway here.  

Key is cut to correct length so that there is room for bushing to be reinserted but without room for the key to slip and allow the keyed gears to rotate on the shaft.

 

The gears are on the shaft and aligned so that I can slide the key in from the right...

Because I had cleaned up the gears, shaft, keyway, and key to ensure that they all had a nice "slip" fit - I was able to get the key in without too much trouble - no mallet required!

Key pushed in almost all the way here.  

Ready to put the bushing back in!

Bushing reinstalled!  

 

Everything back together!  Gears move nicely and selectors move and engage well.  Gearbox ready to install on the lathe!

Repaired and rebuilt thread gear - powerfeed assembly! TaDa!

VIDEO: Power feeds are working!

Backgears are next!

After reattaching the threading gear assembly onto the lathe I decided to check out the backgears.  The back gears are located in the headstock "crankcase" (essentially).  i was super worried that I would find some gear teeth missing when I opened it up, but nope!  All gears in good shape and even a decent amount of oil in the case!

The "bull-gear"

This shows the spindle handwheel and pulley assembly.  Somehow, the pulley-drive has to disconnect from the spindle so that the backgears can engage and drive the spindle.  If you engage the backgear and don't disengage the pulley drive, the spindle is LOCKED!  Locking the spindle this way is a convenient way to install things in the chuck or do whatever you need to do that requires the spindle to be still.  Hoewever, after watching many youtube videos on the subject, DO NOT EVER lock the spindle this way and HAMMER or aply great force to the spindle - this can destroy the bullgear!

I tried looking up how to disengage the pulley from the spindle by checking many youtube videos and even reading the manual.!  The manual (which I got direct from Logan)  shows several different headstock assemblies, the correct diagram for mine would need to be identified by the serial number of the lathe.  I found the number!  77770

Well, I found the diagram that Logan said was for my lathe, but my head stock does not look like that diagram!  My headstock looks more like the headstock in the series following mine.  But not quite!  So I was left just trying to disassemble my headstock to see what I could figure out!  And I did!  I was so frustrated that I couldn't find a description of how to do this that I made a youtube video of the process so that someone else may benefit from my frustration!

How to engage the backgears!

Backgears engaged and working! Yay!

Fully functional lathe!

Well, pretty darn close anyway!

I would like to get a collet system setup for the spindle and maybe a morse taper adapter for spindle as well.  A 4-jaw chuck seems to be a good idea too, since 3-jaw chucks aren't very precise.

All put back together!

I still need to adjust the tail stock alignment and check the run out on the spindle.

Not to mention, there is a nut on the end of the leadscrew inside of the gearbox that I can't get tightened to my satisfaction.  I need to work on that.

So anyway, I went to take off the 3-jaw chuck to see what kind of spindle I have to deal with

Back of the 3-jaw chuck, for reference

Well crap.  I can't get the faceplate off the spindle.  However, I see threads there!

I have a text file that I saved from somewhere that indicates that my lathe, Model T6560H, has a threaded spindle that is 2 1/4" with 8 TPI threads.  Through bore should be 1 3/8"   Now, I measured the inside bore from the front using calipers (as best I could) and found the through hole to be 1.626" or about 1 5/8" - but it was hard to get to the inside bore from the front since the faceplate obstructed access.  I should have measured from the rear of the lathe I guess.  I measured the threaded portion, again, as best I could, and found about 2.135" - far from the 2.25" they say - but then again - its hard to measure a threaded outside diameter considering I can't actually get to the outside... I figure 2 1/4" is probably reasonable.

The stuck faceplate is evidently a global issue for machinists.  Advice from the internet and youtube sees to indicate that I should put the 3-jaw chuck back on and get some hex-bar stock to place in the jaws.  Then I should use an impact wrench to try to loosen the screw.  Important that the back gears should NOT be engaged!  leave the spindle unlocked or brace it some other way.  Do not brace it with gear teeth!

Time to leave already

weather turning bad - more snow then freezing rain!  Just before I took off I took these neat pictures of some super fluffy snow that fell early this morning.  Look close and you can see the individual snow flakes!