What make/model of lathe is this?
- -
Rex Burkheimer
WM Automotive
Fort Worth TX

xray wrote:
I posted another question about replacing belts on my Taiwan lathe. I
think I am now convinced that I should pull the guts out of my headstock
and replace the standard belts.

I'm hoping I can get a little advice to see if I know what I need to do
to get the spindle out.

I scanned the parts diagram from the manual and colored in the different
parts so I could more easily see how things are arranged. I have posted
the inmage in my own webspace he
http://www.xertech.net/pub/Headstk_col.gif

Here's about what I think I need to do:

1) Loosen the spindle front cover. It won't actually come off because
the lathe spindle shoulder is actually bigger than the hole in this
cover. (Not like the diagram.)

2) Loosen the lock nuts one the back end of the spindle and remove them,
the gear, and the spacer. I could remove the Spindle rear cover, but not
sure I really need to.

3) Loosen the set screw on the spacer inside the headstock on the back
end.

4) Tap on the back of the spindle to free it toward the chuck end.


Am I on the right track? Should I expect the shaft to slide inside the
bearings without lots of effort? How about the key on the big gear; is
that likely to slide out easily too.

I think I see how to get the other shafts apart, so I am not worried
about that yet.

Thanks for any guidance on my approach or what to watch for.

I could post my parts picture in the drop box too, if that would be
useful, either now of after I get the job done.

-Rex

This looks a little like my Voest. My manual describes changing the
belts similar to what you describe, removing the front/rear spindle
covers and lock-nut, then driving the main spindle (with a block of
wood) out the front to free the V-pulley. It says to drive the spindle
about 4", then it will come out freely. It also mentions removing a
check ball/spring to keep them from falling into the sump. Good luck.

You could you a tab belt. Did that on my buddies machine 3 years ago
and its been running fine ever since. Takes a lot less time... just a
suggestion. (his required a 5/8" belt, think he paid ~$20)
hth
Doug

Okay, saw your other post. If you are bent on pulling the spindle, keep
in mind that you'll have to preload the bearings when you put it back
together. You may also need to replace one or both of those seals. The
outboard seal invariably gets damaged when the threads from the spindle
drag across them while you are beating on the spindle end... And while
you are at it, I'd recommend throwing away the second preload nut. It
will increase the preload after you have set it with the first nut.
Don't know why they made them this way. Take one of them and cross
drill and tap for a 10-32 or such and after getting the preload set,
drop a piece of lead or copper in the hole and tighten a set screw in
the threaded hole. Nut won't back off and you won't damage the threads.
Preload on the machines I'm used to working on is between .002" and
..005". You should find out if the manufacturer has specs on this, some
I've contacted refered me back to the bearing manufacture (who didn't
seem to want to get involved). You can set preload like this:
Reassemble all of the components. Tighten the preload nut unitl the
spindle is just a little loose. Set a dial indicator up so it is
pointing at the nose of the spindle. Tighten the nut and watch the
dial. Just as the dial stops moving is where Zero preload is. If you go
past this point you are setting preload so be careful when you
establish Zero. If you go too far and are not sure where preload is
back off the nut and remove the preload with a mallet. Once you have
established Zero preload, count threads per inch on the outboard end of
the spindle. A pitch of 16 yeilds .0625" of motion per rotation of the
preload nut. Measure the outside diameter of the nut and multiply by
3.14159. Divide this number by 62.5 and that gives you the amount of
circumfrence motion of the nut per .001" of preload. In the case where
your pitch is 16 the amount of motion needed per .001" preload would be
..113". HTH
Doug

I have the same headstock exactly as your gif.
You are on the right track. Nothing complicated, just take your time and
make sure you get everything back the same way.
The only thing I changed when I did mine was to replace the M6 set screw in
the spacer 11-0111.
It had marred the shaft and I replaced with a silver tipped set screw from
Pic design.
Do not overtighten the bearings when you re do the preload.
~d




"xray" wrote in message
news
I posted another question about replacing belts on my Taiwan lathe. I
think I am now convinced that I should pull the guts out of my headstock
and replace the standard belts.

I'm hoping I can get a little advice to see if I know what I need to do
to get the spindle out.

I scanned the parts diagram from the manual and colored in the different
parts so I could more easily see how things are arranged. I have posted
the inmage in my own webspace he
http://www.xertech.net/pub/Headstk_col.gif

Here's about what I think I need to do:

1) Loosen the spindle front cover. It won't actually come off because
the lathe spindle shoulder is actually bigger than the hole in this
cover. (Not like the diagram.)

2) Loosen the lock nuts one the back end of the spindle and remove them,
the gear, and the spacer. I could remove the Spindle rear cover, but not
sure I really need to.

3) Loosen the set screw on the spacer inside the headstock on the back
end.

4) Tap on the back of the spindle to free it toward the chuck end.


Am I on the right track? Should I expect the shaft to slide inside the
bearings without lots of effort? How about the key on the big gear; is
that likely to slide out easily too.

I think I see how to get the other shafts apart, so I am not worried
about that yet.

Thanks for any guidance on my approach or what to watch for.

I could post my parts picture in the drop box too, if that would be
useful, either now of after I get the job done.

-Rex

The lathe may have been operated when there was no oil in the resevoir.
That will damage the seals for sure. The next time you put oil in it
some of it will leak out through the seals and ya just gotta replace
them eventually. Usually you will notice it if its coming out of the
seals. Oil on the drive belt will make it spongy and soft as well as
make it slip under a heavy load. Oil on the outboard side will just
coat your gears. But you should see it somewhere. Unless you have a
void in the casting that is eating it. I have seen that. Couldn't see
the porosity in the bearing seat (headstock end in this case) but a
liberal dopping of blue ATV before reassembly seemed to make it stop
loosing oil. We did find oil inside the head stock resting on the chip
pan. Didn't find any stream down to that point... I hope you don't have
to go to that extent as the link belts are so much easier to deal with
your other problem.
Good luck,
Doug

Great information. A comment from my Voest manual on pre-setting the
bearings - "Readjustment of the bearing should be done with the
greatest care. It should still be possible to turn the main spindle by
hand rather easily. The best method to check the correct adjustment of
the main spindle is to have it run about 1/4 of an hour at maximum
speed. Afterwards the front as well as the rear main spindle bearing
should just be about handwarm. When the bearings become very hot, the
adjustment should be loosened. However, if no increase of temperature
is observed, the bearing adjustment should be tightened, since a
closely adjusted bearing is an advantage for work with the parting tool
or when fly-turning." BTW, these are Timken tapered rolling bearings.
Good luck.