Tool Rest Arm Rotation

foxtrapper · Post by **foxtrapper** » Thu Mar 17, 2011 11:33 am

algale wrote:Hmm. What about a series of closely spaced through-holes, just large enough to accept the thread]

Threaded through holes aren't very good. You lose the clamping force entirely, and you have to space the holes further apart on the shaft.

But look at this image.

See how the set screws are tapered at the tip? If the piece they screw into has a tapered hole to match, the screws lock in place. When new, the set screws effectively cut a grove to lock themselves into. After a few uses, they lose that ability and don't hold nearly as well in a new location.

Interesting. Not sure that this would necessarily work since you still have a rotational force.

Having a welded nut in the tube won't eliminate rotational force at all. That's true. But it gives you much greater clamping forces to the shaft and larger contact surface. You can really reef down on a bolt going through a welded in nut there. To the point you could easily break the aluminum casting.

pennview · Post by **pennview** » Thu Mar 17, 2011 2:16 pm

I see from the part numbers, you are using those lever-locks to clamp the horizontal arm to the upright, not the regular setscrews. I don't have any lever-locks so I don't know what the tip looks like, but I took a look at the setscrew on my 510 and it indeed is one of those with a serrated end. It's also likely that these setscrews grip better than the lever-locks because you can apply more torque with the long allen wrench.

JPG · Post by **JPG** » Thu Mar 17, 2011 2:48 pm

Serrated, cupped - IMHO both bad. A domed end will grip very securely without scarring the tube(much).

Earlier versions had more of them and very few cupped/serrated screws.

IMHO the biting type are ok for seldom loosened/tightened uses, but where repetitive adjusting is done, the softer ends are mandatory. The quill shaft is the most obvious, the tool rest a much less obvious one.

algale · Post by **algale** » Thu Mar 17, 2011 5:22 pm

pennview wrote:I see from the part numbers, you are using those lever-locks to clamp the horizontal arm to the upright, not the regular setscrews. I don't have any lever-locks so I don't know what the tip looks like, but I took a look at the setscrew on my 510 and it indeed is one of those with a serrated end. It's also likely that these setscrews grip better than the lever-locks because you can apply more torque with the long allen wrench.

Actually, my arm must have been made during the transition between set screws and lever locks; it came with the set screws installed and the lever arms in a bag as an upgrade. Thinking the set screws might work better, I've tried both and found no difference in terms of arm rotation whether I am using the lever locks or the set screws.

damagi · Post by **damagi** » Thu Mar 17, 2011 10:40 pm

algale wrote:YIKES! You sound fortunate not to have been injured. I hate to say it, but if Shopsmith knows this is an issue with the design of the tool rest they are really asking for another products liability suit someday.

I agree...not terribly happy about it. I ended up getting a UTR because of the issue, though I think its pretty sad overall. I have had it happen on a number of different shopsmiths, so I know its not just one. However, all were used so I don't really have any recourse I guess.

swampgator · Post by **swampgator** » Thu Mar 17, 2011 11:03 pm

You gents have just scared the pants off me.

Here I was reading up and watching videos on turning with all the safety items to consider. Now, I read this. Will be looking into my systems to see what I can do. Will also be watching to see what solutions you propose and trying to adapt. Thanks for this thread.

beeg · Post by **beeg** » Thu Mar 17, 2011 11:11 pm

Have ya cleaned the top of #293? To clean off any oil or wax.

JPG · Post by **JPG** » Thu Mar 17, 2011 11:34 pm

damagi wrote:I agree...not terribly happy about it. I ended up getting a UTR because of the issue, though I think its pretty sad overall. I have had it happen on a number of different shopsmiths, so I know its not just one. However, all were used so I don't really have any recourse I guess.

A What??????

beeg · Post by **beeg** » Fri Mar 18, 2011 12:07 am

Universal Tool Rest.

JPG · Post by **JPG** » Fri Mar 18, 2011 12:10 am

beeg wrote:Universal Tool Rest.

Ahhhhh So!