Clutch acting weird, HELP

[alita589]

Hi all, Im new here and in need of help and problem solving with the clutch on an old Sebastian lathe with power cross feed. The clutch is a cone style (see pics)




This is the problem i am experiencing: (see videos)
1. With the clutch nut loss the hand wheel turns freely and the clutch spins mostly freely.
2. With the clutch nut tightened the hand wheel turns mostly freely in one directing but gets stuck in the other direction causing the clutch to slip.


View attachment loose clutch.movView attachment tight clutch.mov

I'm not sure if this is normal but it seams like there is something wrong. I tried cleaning everything out as best as i could but i can hot remove the outer part of the cone because the knob was welded in place preventing me from removing it and inspecting and cleaning the bore. I would like to avoid taking this apart if i can. The inside cone, shaft and bore was cleaned and and inspected to make sure there are not burs or other obstructions.

I would welcome any advise on what I should try doing to fix the sticking issues?

Thank you, Emily

 

[RJSakowski]

A difference in torque is most likely caused by play in a thrust bearing coupled with improper friction. Many low end lathes use a washer for a bearing which can cause this. Replacing the washer with a needle thrust bearing should solve this. I'd try the lubrication first though. A washer with a lower coefficient of friction like Turcite will help too.

 

[alita589]

@RJSakowski are you saying that adding a thrust bearing to where the nut tightens down on the knob?
I hope so because I'm not sure where else it could go.

 

[alita589]

Unfortunately adding a better bearing surface didn't work. i still have the same issue of it sticking when going in one direction.
Should I try taking it apart and inspect it?

 

[sdelivery]

Look at your cross slide screw and nut.......

 

[woodchucker]

My first thought was your nut is tightening in one direction.. if this is a left hand thread. But that's a weak thought..
My SouthBend has it's clutch in an oil bath, is yours similar and just not completed?
Is there any play in your shafts? If there is, when reversing is the gear moving in too close and jaming against the other gear... you may want to reverse the apron in the vise so you can carefully watch it .. maybe even record it on video slo mo.

 

[alita589]

thank you for all your recommendations. here is what the I have done and where I'm at. FYI I attached 2 videos to the post above.

• the outer shaft seams to be sticking in one direction more than the other when the clutch nut is tightened.
• the nut doesn't tighten or loosen when the clutch slips or any other time.
• i tried using a bronze bushing and thrust bearing on the clutch nut but it hand no effect or the issue.
• i checked the gears and there is no binding when the nut is tightened or loosened.
• i suspect the issues is in the outer shaft and bore in the casting. maybe a piece of metal catching in the oil grove channel, not sure. I can't take this apart because someone welded the star handle to the outer shaft. at this point i think ill have to drill out the weld so i can remove and inspect the outer shaft and bore.

should i take it apart? or try something else?

 

[woodchucker]

thank you for all your recommendations. here is what the I have done and where I'm at. FYI I attached 2 videos to the post above.

• the outer shaft seams to be sticking in one direction more than the other when the clutch nut is tightened.
• the nut doesn't tighten or loosen when the clutch slips or any other time.
• i tried using a bronze bushing and thrust bearing on the clutch nut but it hand no effect or the issue.
• i checked the gears and there is no binding when the nut is tightened or loosened.
• i suspect the issues is in the outer shaft and bore in the casting. maybe a piece of metal catching in the oil grove channel, not sure. I can't take this apart because someone welded the star handle to the outer shaft. at this point i think ill have to drill out the weld so i can remove and inspect the outer shaft and bore.

should i take it apart? or try something else?

yes, take it apart. it's not usable the way it is.
but before you do, study if there is another way of removing it.
if you remove everything and it has a problem turning one way, I think you have no choice but to remove it.

 

[alita589]

yes, take it apart. it's not usable the way it is.
but before you do, study if there is another way of removing it.
if you remove everything and it has a problem turning one way, I think you have no choice but to remove it.

how do your recommend I take it apart? this is what i am working with...

 

[Winegrower]

Reading this thread, I’m confused, perhaps somebody can help me out. The way my lathes have worked, when the clutch is engaged, the apron is locked to the feed mechanism…in the case of my Logan, it’s locked to the lead screw key way, (not the lead screw threads) and in the case of the Takisawa, it’s locked to a separate feed rod. In either case, you can’t turn the hand wheel because it’s locked to the feed mechanism.

Perhaps the hand wheel should not move even when the apron is off the lathe, because there may be a gear train, a worm or such, that prevents movement in any case when clutch is engaged.