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South Bend Heavy 10 Cam Clutch not engaging

Dan1900

Aluminum
Joined
Jul 29, 2017
I picked up a cam clutch for my heavy 10 last week to replace the star knob.

I installed it and re-assembled the carriage, but when I went to activate the power feeds, none of them worked. Half nuts worked fine, and the tumblers were engaged / leadscrew was spinning.

So I took the apron off again and re-installed the star knob. Tightened it, and everything works as intended.

So here are a few details with the apron dissassembled:

- when I install the cam clutch and pull up on the lever to apply pressure, I can feel the handwheel and/or cross slide gear tighten up.

- however, when I spin the worm gear, the smaller transfer gear inside kind of stays in place

- when the star knob is installed and tightened, I can rotate the knob and see all the gears transferring power as they should

So I am thinking the problem may be the clutch is not locking up / tightening up enough? The entire clutch was disassembled and cleaned, then properly installed per the SB instruction manual.

Could it have something to do with the keyed bushing / collar?

I've kind of hit a wall on this and am not sure what is wrong, so I appreciate the input.
 
He's right you know. It's there for a reason. Make one using your old clutch or just do it without a clutch. I was looking at another clutch the other day and the Bushing on it isn't spoiled, it's the same diameter across the entire length.
 
You guys mean the keyed bushing? Because if so I reached out to the seller and he found the bushing and shipped it separately.

I am having these issues even with the bushing installed.
 
I was talking about the Bushing but if it's not that then you need to totally take the clutch apart and make sure you have all the pieces. There might be a missing spring, clutch plate, etc.

It's easy to take apart, just knock out the little pin under the Bushing.
 
I was talking about the Bushing but if it's not that then you need to totally take the clutch apart and make sure you have all the pieces. There might be a missing spring, clutch plate, etc.

It's easy to take apart, just knock out the little pin under the Bushing.


The clutch has been disassembled a few times for the cleaning / painting process. I attached a pic of the assembly. Not pictured is the washer that circulates oil. Inside the clutch gear are all the plates as well as a spring.

To help make it a little more clear what my issue is, if you see in the picture the clutch is engaged and tight. However, when gear #1 moves, gear #2 does not. Problem is, when this is assembled, the worm gear would turn gear#1 which should also cause gear#2 to turn, in order to operate the power feeds.



IMG_3964.jpg
 
ah, I *think* I know what's up....when the lever is straight out like that you have gone past the cam action.. It should be adjusted to where it locks up at approximately 45 degrees or so.

IOW- straight out is the same as straight down...which is disengaged(ok, bit of an exaggeration)
 
Straight out is okay, that's how mine is adjusted and it's fine.

Dan, I answered your PM before I saw this update. gears 1 and 2 do turn together, but I can force them to turn separately with some force. This is the same whether or not the clutch is engaged or disengaged.
 
I'm going to reply through here in hopes more people see it and might have an idea.

When I engage the clutch, gear #1 turns by itself. Gear #2 locks up and doesn't want to turn on the shaft. If I apply some more force to turn gear #2, it will turn gear #1 as well.
 
That mechanism is a slip clutch - at a certain torgue, slip between the two gears will occur. With the lever being able to go straight out, the slip torque cannot be increased. The adjustment must be made as per the manual so that the lever can compress the clutch discs before reaching horizontal. I believe as the radius of the cam follows a constant radius as you near the horizontal. Power is transmitted when both gears are clutched together.
 
just for shits and giggles try adjusting it so it begins to grab at about 45 degrees...the SB literature I have seems to indicate the the lever should not be straight out before it starts to grab and if it is you are out of adjustment and need to replace discs.

That's all I got, if that doesn't work or help to isolate the problem,all I can suggest is to check with Ted...he will certainly know.

Hope you get it figured.
 
Another thing I was going to try was adding some shims inside where the plates go, and maybe outside at the thrust washer, to see if that may work. When I engage the clutch lever, there is a little bit of front to back play between the parts, leading me to think the clutch is not fully engaging because of wear in the plates...will investigate tonight.
 
just for shits and giggles try adjusting it so it begins to grab at about 45 degrees...the SB literature I have seems to indicate the the lever should not be straight out before it starts to grab and if it is you are out of adjustment and need to replace discs.

That's all I got, if that doesn't work or help to isolate the problem,all I can suggest is to check with Ted...he will certainly know.

Hope you get it figured.

Does your literature specify a thickness tolerance for the plates? I'd be curious for my own edification.

Thanks.
 
i don't have that.

To be clear, you are right that pointing straight out is fine if that is the way you like it...the way I take it though(it's kind of vague) lock up should begin at some point before, for sure some speculation of their intent on my part, and I never owned a cam clutch SB.

I bet Ted has technical info on plates.
 
It's kinda hard to tell from the picture but if you look at the curve on the handle it is not quite at dead center, meaning I can't tighten the handle up any more unless maybe I put it in a vise and used a hammer. So I don't think the issue stems from the handle not engaging but somewhere else.

i don't have that.

To be clear, you are right that pointing straight out is fine if that is the way you like it...the way I take it though(it's kind of vague) lock up should begin at some point before, for sure some speculation of their intent on my part, and I never owned a cam clutch SB.

I bet Ted has technical info on plates.
 
I figured it out...I am going to update this in case someone down the line stumbles upon the same issue. I just had the thrust bearing washer installed backwards. It's deceiving because the hollow portion of the washer seems like a perfect fit with the thrust washer...but when you install it this way and you engage the clutch, instead of pulling up against the plates, it just bumps against the end of the clutch inner mechanism. One of those things that's easier to explain if you see it:



IMG_3966.jpgIMG_3965.jpg
 
I figured it out...I am going to update this in case someone down the line stumbles upon the same issue. I just had the thrust bearing washer installed backwards. It's deceiving because the hollow portion of the washer seems like a perfect fit with the thrust washer...but when you install it this way and you engage the clutch, instead of pulling up against the plates, it just bumps against the end of the clutch inner mechanism. One of those things that's easier to explain if you see it:



View attachment 215266View attachment 215267

Thanks for the update. It took me 6 months to finally get around to fixing the clutch feed not working after I rebuilt lathe and moved it into the shop. I just putter around mostly so not having auto feed wasn't an issue but now I am getting into some projects and wanted it working.

Such a simple fix, I am sure others have made this error as it seems like the counterbore is there to fit the thrust bearing and it isn't.
 








 
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