Lathe clutch overheating problem

Hello all. Recently purchased a lathe and gave it its first decent run yesterday only to find out that it apparently has an inbuilt smoke machine in the gearbox, otherwise known as a clutch.

What a bargain right?

So my question is what exactly is wrong? Clutch assembly was boiling hot when I stopped the lathe and there was plenty of smoke. How do I fix?

A the risk of being Captain Obvious look for an adjuster of some sort. Also look at the control linkage for wear preventing full engagement. I would hazard a guess the clutch is held engaged by some form of over center system,and if the operating system is not doing that ,that is the first step . Figure out how it works and unless things are totaly worn out you should be able to fix it. If wear is the problem you might make up a dummy spacer plate to get things back into an adjustable area, asuming parts are NLA.

I have a HARRISON 140 Lathe with a lever opiated clutch. When I got it the spring that actuates it was too weak and the clutch was slipping and overheating. Replacing the spring fixed it.

Looks like cup washer clutch. If they have been heated to many times the temper in the cups are gone. Try to do a take up spacer on the end. I've used leather washers between the metal washers before and worked out ok.

emcmike said:

Looks like cup washer clutch. If they have been heated to many times the temper in the cups are gone. Try to do a take up spacer on the end. I've used leather washers between the metal washers before and worked out ok.

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Leather works well. If this is the problem it should help. There are as well flexible friction materials especially formulated for clutches.

billzweig said:

I have a HARRISON 140 Lathe with a lever opiated clutch. \.

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lol.. now I know why those lathes can't cut straight!

If I'm looing at the right part - a multi-plate clutch... are you sure it's not supposed to be oil bathed? And if so... is it just "worn out" or needs adjustment? I have an electro magnetic brake (the part can also be used as a clutch) on my lathe that looks similar -just flat steel plates onto fixed steel... and pressure lubed.

Lakeside53 said:

lol.. now I know why those lathes can't cut straight!

If I'm looing at the right part - a multi-plate clutch... are you sure it's not supposed to be oil bathed? And if so... is it just "worn out" or needs adjustment? I have an electro magnetic brake (the part can also be used as a clutch) on my lathe that looks similar -just flat steel plates onto fixed steel... and pressure lubed.

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The clutch must run dry. I id my repair quite a few years ago, I do not remember all the details. The spring was "set" so it did not provide enough force. I used a die sprig of the correct size. I might have replaced some of the washers too.
T

I may have forgotten a vital piece of information. The clutch overheated when disengaged. The engage lever was pushed down all the way and the break was on

Bryce.R said:

I may have forgotten a vital piece of information. The clutch overheated when disengaged. The engage lever was pushed down all the way and the break was on

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Yup, that might make a difference to the answer!
If the clutch started smoking when it was stopped? (Brake on), then I would assume that there is a lever movement that engages a brake as well as simultaneously dis engaging the clutch. And it is not doing that! I'd say look for an adjustment or maybe something got bent/ broke/ moved when you moved the lathe in

Normally multi plate type clutches are designed to slip when they're not under load. They need a constant supply of oil to keep them cool when they're not driving.

Regards Tyrone.

I think its only splash fed oil. There is an inbuilt oil pump but I think its only for the bearings, not sure.
What's my best plan of action? Pull it appart and have a look? I have never had a clutch driven lathe before hence the noob questions

Check it static first.

Remove power (if not controlled by selenoids)

Put a pipe in the Chuck and turn with pipe wrench and put clutch in and out of gear as well as applying brake.

If it requires power then remove motor belt.

This will allow you to closely watch what is going on regarding loose or out of adjusted linkages.

Bryce, sir
Seems it might be as simple as some form of adjustment ( as other have said ). See if the clutch is in the 'open' position when the brake is applied. Your 'problem' may be as simple as loosening a set screw and adjusting some linkage.
Good luck !
Stay safe
Calvin
PS it's been my experience that it's usually something small adjustment rather than a major fix.. eliminate the small ( read 'simple') things first before tearing the guts out of the thing..

Bryce.R said:

So my question is what exactly is wrong? Clutch assembly was boiling hot when I stopped the lathe and there was plenty of smoke.
View attachment 143070View attachment 143071View attachment 143072View attachment 143073

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That type is a 'wet clutch'. Heat is generated only during engagement, reversing, braking, ect. At full engagement there should be no slip. Roll the clutch over and look for a pin. The pin is a lock for the clutch assembly. When depressed the threaded body can be rotated to take up slack between the clutch plates. Generally the standard check is with a feeler gage inserted between the clutch plates. My way is to take up slack to the point where engagement of the spindle throw is difficult. Then back off till the clutch engages smoothly without forcing.
Clutch plates of this type and country of origin may crack due to heat. Hopefully this is not a problem with your lathe.

A shop I worked for had two 19" 'Select' lathes of similar construction. Tore down one headstock and replaced all but the spindle bearings. Replaced cracked clutch plates.
Quality lathes have three wet clutches, forward, reverse, and braking. Your lathe has the 'asbestos brake band' that tightens around a shaft collar. Simple design=low cost=more maintenance. Check the adjustment. If the operator is using reverse to stop the lathe excessive heat is being generated. Looks like the directed oil splash plumbing was discontinued. There should have been an oil stream directed at the clutch, brake band, and the engagement cradle. Look for the cradle on the clutch shaft. This is connected to the spindle throw located on the apron (if so equipped). This part is subject to wear and shows up as lost motion when engaging the spindle.
The machines I worked on were produced in a country that had 'planned production' and was of typical design. Perhaps the lathe you have now has evolved a bit for the better.
Regards, John

Thanks everyone for the help. The clutch has been hard to engage ever since I got the lathe so im guessing that there is wear and the previous owners have just tightened it all the way up. I will have a look at it in the coming weeks and see how things look.

If it's hard to engage it could be over adjusted. Back it off until it engages with a small click and see how it drives then.

Regards Tyrone

Sorry to restart an old post fellas. I backed the adjustment off and the lathe clutch engages freely however when the clutch is disengaged the plates become too hot to touch. What's the problem? Is the clutch too worn and not disengaging property and therefore heating up?

How's the oil supply ? If the oil supply is poor the idling clutch can still run hot.

Regards Tyrone.

It said right in the picture made in republic of China, there's your problem. Has this site gone pro China or have I missed something.

No oil supply to the clutch directly, only oiled by the splash in the gearbox as far as I can see