Squealing clutch motor

[Matt S]

Please forgive me if this topic has been covered elsewhere but I couldn't find any other references to it. I know there's fewer clutch motors being operated these days but they're still useful. I am posting under the sewing machine section 

I have a clutch motor on my bell skiver, a 1/2HP 1400RPM Hoover. Looks like it dates to a time when Pontius was a pilot, with an exposed clutch. It's recently developed the "curious quirk" of screaming like I'm banging a sack of randy tomcats against a wall whenever the clutch warms up, which in practice means under a minute of use. Doesn't occur running the machine without load.

Two polar opposite causes and fixes occur to me but I don't know enough about clutches to know which is appropriate:

(1) The clutch pads are sticking and need a lubricant.

(2) The clutch pads are glazed, so not gripping against each other and need deglazing, perhaps with a solvent, or the application of spray-on belt-grip.

The obvious fix would probably be to replace the clutch pads but I think this motor went out of production about the same time as the Brown Bess. I could replace the motor but this handily hangs off the frame of the table rather than bolting through the wooden top, which is convenient.

Do any fixes for the current motor spring to mind?

[Albob]

My opinion and worth every penny you paid for it is since you're not sure if it's glazed pads or sticking pads the first step is take it apart and check it out. 

I'm not in the know on skivers but if the clutch motor hangs maybe a better option would be a servo conversion. I replaced clutch motor on my old Singer 111W155 and never looked back. I bought the motor from Bob over at Toledo Sewing, for 150 bones I was up and running smooth and quietly,

[Constabulary]

if you need a good new clutch motor check with College Sewing, they sell the remaining stock of 1/2 HP clutch motors for 28 GBP + tax and shipping but hey are 440V units. A friend installed one of these on his Adler 4 and he is happy with it. He runs it on 230V one phase with a capacitor. He could not find cheaper motors in Germany. I have tested it and I´m quite impressed how well the clutch works.

Edited August 29, 2018 by Constabulary

[Matt S]

I stripped the motor last night and pulled the pulley wheel. I found that the clutch on Methuselah's motor has a friction ring made of cork pressed into a deep groove. It was pretty glazed and dry. Worrying about being able to get an off-the-shelf replacement I thought I'd try turning it over and using the other side. TLDR it worked, though I lost a tiny bit of material tapping it home.

After taking the opportunity to replace the mastodon grease in the sleeve bearings everything went together just fine, with no spare parts left over. No squeaking this time and the pedal is far more responsive, which is great. We'll have to wait a few months for the damp weather to see if the stuck pig impression returns though.

[Matt S]

Here's some photos for your collective enjoyments. Notice the clutch plate, completely unguarded for convenience/maiming. Those two square bits the motor's hanging off? 30mm square steel bar. Solid, not tube. Running half the depth of the table. Let's just say nobody's going to pick this thing up and run away with it.

Just in case anyone else is insane/cheap enough to still be running a similar motor I found that the lever assembly had to be removed from the bottom of the motor to allow enough access to remove the pulley wheel.

Here's the innards of the pulley motor, after I flipped the friction ring and reseated it with judicious use of the thumb detector. Tiny bits of cork got shaved off but c'est la vie. Should be good for a few more centuries now.

Edited August 31, 2018 by Matt S

[Northmount]

There are other threads about greasing cork clutch pads so they don't grab.  If you search for them, you should be able to find the type of grease recommended.

Tom

[gottaknow]

6 hours ago, Northmount said:

There are other threads about greasing cork clutch pads so they don't grab.  If you search for them, you should be able to find the type of grease recommended.

Tom

I’ve always used white lithium on cork clutch surfaces after deglazing them with some 220 emery cloth.