Need Advice for Carriage on Clausing 4900

[Robotwizard]

Hello,
Can't find any specs on what the vertical freeplay on the carriage should be for the Clausing 4900. I measure approx .020 with magnetic base and dial indicator. I removed shims on rear but not enough. I did the trick of tightening carriage lock until slight drag, but don't have any tight spots along bed. Should I find a surface grinder and take the bed clamps down a bit or should I look for another good carriage? and also a good bed? thanks

[Carm]

I am not following you, my apologies.
What is the problem you are having?

[Robotwizard]

The carriage on this lathe has a lot of up and down movement.

[wlw-19958]

Hi There,

I think you should shorten the saddle "hold downs." These are
relatively cheap and easy to modify. Also, if you take too much
off, you can add shims between the hold down and the underside
of the saddle. Clausing (as you already know) put shims in there
to be removed as the bed and saddle wear.

If you screw up, the parts are cheap and you can fabricate them
yourself if you need to. I don't think you need to have the parts
surface ground but it won't hurt either.

Good Luck!
-Blue Chips-
Webb

[Robotwizard]

Thanks Webb! Does it sound like the wear is mostly in the saddle then? This model does have a flame hardened bed so is it more likely the saddle would wear before bed? This one came from a school, so it seems to suffer more from neglect and abuse from inexperienced operators than from a lot of use. Might have a lead on a used saddle and bed, so I'm tempted to get both if reasonable enough. Would I be opening up another can of worms getting different parts as far as realignment and adjustment tho?

[wlw-19958]

Hi There,

Thanks Webb! Does it sound like the wear is mostly in the saddle then? This model does have a flame hardened bed so is it more likely the saddle would wear before bed? This one came from a school, so it seems to suffer more from neglect and abuse from inexperienced operators than from a lot of use. Might have a lead on a used saddle and bed, so I'm tempted to get both if reasonable enough. Would I be opening up another can of worms getting different parts as far as realignment and adjustment tho?

I hesitate to say. Even tough the bed is "Flame Hardened,"
the bed can wear too. If abrasives get in between the saddle
and the bed, they will embed into the softer cast iron of the
saddle and act as a lap and wear the bed down.

You say your bed has even wear over the length of the bed.
This is kind of unusual. Usually, the wear is more prominent
near the headstock where most of the work takes place.

You said that your lathe is an ex-school lathe. If the school
system in question is anything like the ones I am familiar with,
machines are taken apart and cleaned and painted every few
years and they were not always very particular on which part
got put back on what machine. This might be the case with
your lathe.

Swapping parts from another machine may not improve things.
I think your original idea of re-working the hold downs is a good
one for the reasons I already mentioned before. If the bed and
saddle from the other machine are in better condition, that might
be a reason to go for it.

Anyway, Good Luck!
-Blue Chips-
Webb