Shopsmith Forums

Has anyone else had issues with a Shopsmith drill chuck key jamming as you try to turn it? The chuck threads seem to be in decent shape and the chuck rotates smoothly. My problem is that there appears to be some slight mismatch between the key thread and Jacobs chuck thread. The key does not rotate smoothly as you turn it and gets jammed in certain locations. This happens with no drill in the chuck. This is the second chuck key I have tried and both are new from Shopsmith. The chuck came with a Shopsmith I bought used so I am not sure if it ever worked smoothly. Just curious if anyone else has seen this.

That looks like the same chuck that came with my new 510 in 1994. The SS label on yours looks like mine. The problem with mine is that the three holes in the side if the chuck that the key fits in are bigger than the small shaft of the key. When you insert the key in the chuck it can wobble and the gears don't stay fully engaged causing binding. The solution is to keep up pressure on the chuck key to keep the gears fully engaged when tightening.

There is a thread here where I brought up that issue years ago.

John said it

The problem with mine is that the three holes in the side if the chuck that the key fits in are bigger than the small shaft of the key. When you insert the key in the chuck it can wobble and the gears don't stay fully engaged causing binding. The solution is to keep up pressure on the chuck key to keep the gears fully engaged when tightening.

The current and for some time now Shopsmith Drill Chuck has holes that are larger than the Key's pilot. As John said "The solution is to keep up pressure on the chuck key to keep the gears fully engaged when tightening." This is true for all Drill Chucks and their keys. The gears are angled so pressure must be kept on them to remain fully inserted.

Sleeve the holes?

I suppose you could. IMO, it is not worth the trouble. The chuck works fine once you know what is going on.

DavidMcM wrote: ↑Sat Sep 03, 2022 10:34 am Has anyone else had issues with a Shopsmith drill chuck key jamming as you try to turn it? The chuck threads seem to be in decent shape and the chuck rotates smoothly. My problem is that there appears to be some slight mismatch between the key thread and Jacobs chuck thread. The key does not rotate smoothly as you turn it and gets jammed in certain locations. This happens with no drill in the chuck. This is the second chuck key I have tried and both are new from Shopsmith. The chuck came with a Shopsmith I bought used so I am not sure if it ever worked smoothly. Just curious if anyone else has seen this.

Yes. I have a pair of similar SS chucks. Both work smoothly without the key. But when I use the keys, one works very well and the other works poorly. Switching the keys between them, the one that worked well continues to work well and the other continues to work poorly. On closer inspection, I think the one that works poorly is due to the key getting into a bind. The key does not appear to fully engage the chuck at a square angle, while on the other it does. On the bad one, in other words, as I'm inserting the key the teeth engage each other before the key is fully inserted, pushing the key 'upward' (vertical drill press). When fully inserted, the teeth are not engaged square and the key is tight against the top of the hole in the chuck. Pushing the key more firmly into the chuck worsens the bind, while on the good chuck it makes no difference.

I also have an older (50's) Jacobs chuck. It ain't pretty, but things seem a bit more precise. (It also requires a different key.)

- David

I am curious if the one jamming has key pilot holes bored not normal to the axis of rotation. That would be consistent with what you described.

JPG wrote: ↑Mon Sep 05, 2022 11:46 am I am curious if the one jamming has key pilot holes bored not normal to the axis of rotation. That would be consistent with what you described.

It doesn't seem like it, but I will bear that in mind. I can't put my hands on anything that is a great fit for the pilot holes, 17/64" is a bit loose and 9/32" is a nogo. It could be metric or a letter size bore, I have neither. Pilot measures 0.2675", slightly over 17/64" and is also fairly loose, as noted by John and Russ. But the range of wobble of a 17/64" bit seems to be centered on normal to the chuck. Assuming it is essentially same as a Jacobs, I'm wondering if the outer sleeve is not quite pressed on all the way.

- David

Or too far?

I was able to disassemble and reassemble mine primarily using a HF Bearing Separator. Cleaned it up, put it back together making sure the sleeve was fully seated. No difference. On mine the 'ring gear' part of the sleeve is very warn, probably due to the poor fit with the chuck, unless it is causing the poor fit.(?)

I did find that the key for the Jacobs 3326, which has a smaller pilot shaft, works better, though not well, in the bad chuck than a SS key. I don't think I have anything to lose with this chuck, and may try just drilling out the pilot holes to 9/32".

I made a few detailed measurements of the good Vs. bad chucks and found too much inconsistency to be definitive. For this to work, measurements would have to be referenced to an internal point, probably one of the two seats for the split nut. Doing a comparison without knowing the tolerances probably doesn't gain much. Only other thing I can think of is that these could have been made by different suppliers and perhaps require a different key.(?) The SS logo is the only marking I see, and I doubt that SS makes their own chucks.

- David