Shopsmith Forums

I was doing a small face plate turning, about 5 inches in diameter. Speed was set to slow speed on the Mark V (520) when I got a bad catch with the skew. It stopped the quill dead for a second before I could recover. I continued working, and, a few minutes later, I got another bad catch and it happened again. (I was able to make a few design changes to the turning and salvage it.)

Stalling the quill has never happened to me before, so I'm curious:

1. What is happening inside the MV (520) headstock when the quill stalls like that? Polly V slipping?

2. What damage, if any, is this likely to have inflicted (what should I look for)?

3. Is this a sign of some maintenance that I should have done or should do now, like retensioning the polly v?

Thanks,

Al

beeg wrote:WHAT were ya turning? The skew is for spindle use.

I was working on the edge of a small platter.

Most likely the belt is slipping and needs to be tightened. It is also possible the belt is worn out so pull the cover and look at it.

Not likely any new damage occurred from the catches. When the belt is way out of adjustment it is quite easy to stop the quill. That is how I got one of my machines, "basket case" and the PO had the blade mounted backwards and couldn't understand why it wasn't working.... The belt was just so loose nothing would work on it, so I got it out of his hands before he hurt himself.

Ed

Thanks, Ed. I will check the belt out. I've never adjusted belt tension. At the same time, I've never felt I had a reason to. Even today the machine seemed to be working normally. Earlier in the day I had zero trouble boring a couple of 1.75 inch holes through 1.5 inches of ply or cross cutting some 3/4 inch mahogany. But I suppose now's the time to dive into the belt tensioning section of the manual....

A catch on a 5" turning stalling the quill would not surprise me. Now if the motor stalled, I would be concerned.

The poly-v belt may indeed be loose, but that slipping is what it is supposed to do under excessive and sudden torque load conditions.

Put the sanding disk on the quill arbor. Slowly turn the disk to see if any wobble occurs. If none, then check the Poly-V belt tension. I have replaced a few quills that the owner was turning a bowl and caught it with the chisel or the bowl was too far out of balance.

I'm assuming the 5" platter was dry. so weight should not be an issue. I would not suspect any damage at all.

Also assuming you're 520 is a Poly-V and NOT a Gilmer drive.

Before I rebuilt my Gilmer clutch, I did manage to strip a tooth off of a Gilmer belt during a stoppage. So those of us using Gilmer drives need to make sure the clutch is working properly and will absorb the shock of a sudden stoppage. The Poly-V belt design is supposed to slip during sudden stoppages and prevent damage to the machine.

terrydowning wrote:I'm assuming the 5" platter was dry.

Yes, very old, dry African Mahogany

Carry on, you're good.

What speed were you turning and how sharp is the skew?