Drill Chuck Key Jams

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DLB
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Re: Drill Chuck Key Jams

Post by DLB »

Temporarily skipping over the details, I'm convinced that there are two or more versions of the look-alike Shopsmith Logo drill chucks and that they may require different, though very similar, chuck keys. Digging through some boxes I located a second chuck that exhibits the jamming I mentioned earlier. The 'key' difference is that this chuck was stored with its key. Here is a picture showing the two key versions:

Chuck Keys.JPG
Chuck Keys.JPG (232.52 KiB) Viewed 871 times

The one on the left works in some SS Logo chucks but is the one that jams in the other. It appears to me to be the same as what the OP obtained from SS. The key on the right is the one I just found, it works in the chucks that exhibited jams and works but is a sloppy fit in the others. Noticeable differences are a smaller gear and a different shape to the thumb pad.

I'm not really able to differentiate between the chucks themselves visually. Therefore, I can't simply look at the OP's post and say definitively that it needs the key on the right. I have one that jams and one that does not disassembled and I'll update here if anything is revealed upon closer examination. Russ mentioned in another thread that there are three versions of the logo itself. Suggesting something. There were no pictures, and I believe the jam/no-jam examples I'm working with have the same logo.

I mentioned earlier that I like the Jacobs better, much more of a quality feel despite being ~twice as old. I will add, though, that the SS Logo chucks close on a smaller diameter. A difference that would be significant for some small bit sizes. Shopsmith says down to 0.020" for the current version. IIRC the Jacobs is a minimum of 5/64", or 0.078".

- David
DLB
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Re: Drill Chuck Key Jams

Post by DLB »

Summary: This post details internal differences between two examples of look-alike Shopsmith Logo drill chucks. The differences, IMO, demonstrate that the chucks are manufactured to different standards, perhaps by different suppliers. And explain why the chuck key currently offered by SS may not be compatible with some of the older look-alike chucks. I'm not confirming that this has anything to do with the problem reported by the OP. I am confirming that yes, I have a couple of chucks that have the same symptoms and am satisfied that I know this is the reason. My conclusion is that there are two or more versions of look-alike Shopsmith logo drill chucks that utilize different keys. The bottom line is that if you buy the current version chuck key, it may or may not work well on a Shopsmith Logo chuck,

The first picture shows the internals of a chuck that jams on the current key. It is fully assembled other than the sleeve being removed. The split nut rides as shown, and bears against the lower (in the picture) seat when snug/tight as shown. The sleeve, which includes the 'ring gear' seats on the split nut. Therefore, the key reference surface for the chuck is the lower (in the picture) seat. So I measured from that reference to a reference point on the chuck key pilot holes. That reference distance varied by 0.062" (roughly 1/16") between the body of Chuck A, that jammed, and Chuck B, that did not. This is a precision part, there is simply no way that this amount of variation could be explained other than two different manufacturing specifications:

IMG_9185 (2).JPG
IMG_9185 (2).JPG (78.88 KiB) Viewed 830 times

Followed by a few pictures of the internals, progressively disassembled, which are similar in function to the Jacobs:
IMG_9186 (2).JPG
IMG_9186 (2).JPG (120.95 KiB) Viewed 830 times
IMG_9188 (2).JPG
IMG_9188 (2).JPG (167.54 KiB) Viewed 830 times
IMG_9192 (2).JPG
IMG_9192 (2).JPG (182.83 KiB) Viewed 830 times

On the last picture of the two bodiesit is difficult to tell the difference. But there is an ~0.062" (~1/16") between the reference surface for the split nut and a reference point on the chuck key holes. The sleeves are also different.

And the two chucks reassembled and shown with their proper keys.

IMG_9196 (2).JPG
IMG_9196 (2).JPG (230.08 KiB) Viewed 830 times

- David
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chapmanruss
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Re: Drill Chuck Key Jams

Post by chapmanruss »

Reading and looking at Davids post above made me curious about the current style Drill Chucks I have. In picture 4 above with the two Drill Chucks disassembled It does appear that the pilot holes are at different distances from the from their split nut's location. There could be a difference in the sleeve to make up for that. In picture 5 above with the two assembled Drill Chucks complete with Keys I noticed the Keys are different. Unfortunately, none of the pictures of the parts or complete Drill Chucks David posted show the actual Shopsmith Logo on them. David mentioned that I stated a previous post that there are 3 different labels for the Shopsmith Drill Chucks since the change from the Cushman Drill Chuck that replaced the Jacobs Drill Chucks. That's all for the Drill Chuck history lesson for today. Below is a picture showing the 3 different labels of the Shopsmith Drill Chucks.

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Current style Drill Chucks - labeled.jpg
Current style Drill Chucks - labeled.jpg (124.69 KiB) Viewed 810 times
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It is the filled in Etched Label that is the current one. On the current one notice the Key is sitting lower in the Chuck. This chuck is open inside all the way through. The other two label version Chucks are not. David showed in picture 5 two different Keys in his Drill Chucks. I have that also and they are shown in the picture below.

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501409 and unknown Drill Chuck Keys - labeled.jpg
501409 and unknown Drill Chuck Keys - labeled.jpg (217.13 KiB) Viewed 810 times
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You can see the difference in the unknown part number Key (which may also be P/N 501419) having the open end on the back end of the gear teeth. The gear teeth themselves are different between the two Keys. I have 5 of the Shopsmith labeled Drill Chucks. Two of the engraved Logo, one of the etched outline Logo, one of the etched filled in Logo and one with the Logo worn off which I believe was the etched filled in Logo. The Chuck with the worn off Logo is also open inside all the way through as noted above about the three different labeled Chucks. I have 4 of the 501409 Keys and 1 of the unknown P/N keys. I do recall ordering sometime in the past a replacement key for one of the Chucks that was missing it. It is one of the four 501419 Keys. As for how well the two different Keys work in the Chucks, the closed end Key works pretty well in all 5 Chucks while the open end Key works a bit rough but still able to do the job. Oddly enough that key is with the Drill Chuck that the Logo is gone and is the Drill Chuck I use the most. Really not that bad at doing the job.

For the ones I have, both types of these Keys have a 17/64" pilot as per my measurements. The outside diameter of the closed end Keys is 49/64" and the open end Key is 47/64" just slightly smaller. I don't believe that makes a difference in their function. I believe what does make a difference in their function is the shape of the gear teeth as can be seen in the picture above. Pushing the open end Key against the pilot hole may be the reason it feels rough during use as those teeth may not mesh as well as the tapered teeth of the closed end Key.

For those with older Drill Chucks these are the current Keys they use.
The Jacobs 33B with adapter and 3326 Drill Chucks use a key with a larger gear diameter and a ¼” pilot, Current Jacobs part # 30251
The Jacobs Multi Craft & Cushman Drill Chucks use a key with a smaller gear diameter and a 9/32” pilot, Current Jacobs part # 30250
Russ

Mark V completely upgraded to Mark 7
Mark V 520
All SPT's & 2 Power Stations
Model 10ER S/N R64000 first one I restored on bench w/ metal ends & retractable casters.
Has Speed Changer, 4E Jointer, Jig Saw with lamp, a complete set of original accessories & much more.
Model 10E's S/N's 1076 & 1077 oldest ones I have restored. Mark 2 S/N 85959 restored. Others to be restored.
DLB
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Re: Drill Chuck Key Jams

Post by DLB »

Both were filled logo before cleaning them up. ;) As near as I can tell, your key labeled "unknown" is the same key that worked significantly better on the chuck on the right in my last picture. I am going mostly by the look of the thumb rest and gear. I think I saw others like both examples on eBay, but it was a couple of weeks ago.

- David
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SteveMaryland
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Re: Drill Chuck Key Jams

Post by SteveMaryland »

For what it is worth, I recently bought a DeWalt corded 1/2" drill for cheap (I think DeWalt/B&D is trying to clear out their corded tools to make way for cordless), and the chuck key that came with the drill is a poor fit. Drill has the old style Jacobs chuck. The stub shaft on the key, which fits into the three radial holes in the chuck, is too small in diameter, and this allows the key gear to not mesh well with the chuck gear. That diametral fit needs to be very close to get smooth action.

The teeth themselves are not mismatched, it is the slop between the key and the chuck which is causing the problem. Key works but due to the sloppy fit it keeps slipping out of mesh when used. Annoying. Maybe a batch of defective keys out there, and Shopsmith got some of them.

I will bet that if someone were to mic the stub shaft diameter on an old good key and these new keys, there will be a difference. I doubt that the problem is with variation in the chuck bore diameter.
Mark V, Model 555510, Serial No. 102689, purchased November 1989. Upgraded to 520
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chapmanruss
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Re: Drill Chuck Key Jams

Post by chapmanruss »

SteveMaryland,

You said,
I will bet that if someone were to mic the stub shaft diameter on an old good key and these new keys, there will be a difference. I doubt that the problem is with variation in the chuck bore diameter.
You called it the "stub shaft" which I believe is what you are calling the Pilot of the Drill Chuck Key. Both of those in my picture in the previous post are 17/64" as measured with a digital caliper. I said one worked better than the other but there was really very little difference and not a scientific test. I think the gear teeth between the two has more to do with that.

I had mentioned the Drill Chuck Keys for the older Chucks as having first 1/4" pilots followed by 9/32" pilots. I just measured both with my digital caliper and found them to be the correct diameter. A 9/32" pilot key fits snug in the current Shopsmith Drill Chucks but has the smaller diameter gear. If a 9/32" pilot with the larger gear could be found that may work better but in checking the Jacobs site, I didn't see one. That 1/64" between a 9/32" and 17/64" pilot does seem to make a difference in the fit on the Shopsmith Drill Chucks.
Russ

Mark V completely upgraded to Mark 7
Mark V 520
All SPT's & 2 Power Stations
Model 10ER S/N R64000 first one I restored on bench w/ metal ends & retractable casters.
Has Speed Changer, 4E Jointer, Jig Saw with lamp, a complete set of original accessories & much more.
Model 10E's S/N's 1076 & 1077 oldest ones I have restored. Mark 2 S/N 85959 restored. Others to be restored.
DLB
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Re: Drill Chuck Key Jams

Post by DLB »

I wouldn't describe any of the fits as snug, but the 'key' difference is the smaller gear. I have two chucks that the 'large gear' key jams in, both work correctly with the 'small gear' key. The large gear prevents the key from remaining square to the chuck when fully inserted, so the pilot ends up at an angle inside the pilot hole and the gear ends up at the wrong angle to the ring gear on the sleeve. One or both of these causes binding. The takeaway is that the current key is a poor fit for some of the look-alike SS logo chucks. I don't know where or if a replacement key is available for the chucks that jam with the current SS key.

The relatively large (.062") difference I measured internal to the chucks confirms that they are different. I'm sure there are thousands of these chucks, and suspect the OP has one. I see them on eBay, or at least I see chucks that come with the small gear keys. Here is a sample, currently available:

SS Drill Chuck.jpg
SS Drill Chuck.jpg (14.76 KiB) Viewed 718 times

- David
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SteveMaryland
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Re: Drill Chuck Key Jams

Post by SteveMaryland »

On my drill I measured the pilot shaft and the chuck bore - they are in fact closer than I thought, about .001" clearance (15/64 nominal dia). But the attached photo shows how much play there is - enough to be a problem each time I use this tool. I suppose it could be attributed to a defect in either the key or the chuck.

I do not see tooth mis-mesh or interference. I will say that my chuck is a knockoff, not a real Jacobs, based on the etching on the chuck. Also I think the key teeth are cast (or forged?), as is typical of chuck keys, and this could introduce much variation. I think the pilot shaft is typically cast also.

Another variable affecting mesh is the distance between the center of the radial chuck bore(s) and the chuck bevel gear.
Attachments
IMG_2482 (3).JPG
IMG_2482 (3).JPG (41.49 KiB) Viewed 698 times
Mark V, Model 555510, Serial No. 102689, purchased November 1989. Upgraded to 520
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chapmanruss
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Re: Drill Chuck Key Jams

Post by chapmanruss »

David and Steve,

I feel I may have introduced some confusion to this discussion. When I referred to smaller and larger gears on the Keys it was not for the two versions of the current key but was including of the two sizes of the keys for the original Jacobs and Cushman Drill Chuck Keys. The picture below shows the 4 different Keys I have for the Drill Chucks used on Shopsmith tools through the years. From left to right, the first is the Key for the Jacobs 33B and 3326 Drill Chucks. The second is for the Jacobs Multi-Craft and Cushman Drill Chucks. It is that key to which I am referring as having the smaller Gear. The third and fourth Keys are the ones we have been discussing in reference to the more current unknown manufacturer(s) of the Shopsmith Drill Chucks. The difference between those two, from my perspective, is the gear on the third having an open back end and the teeth being different than the fourth Key with the back end closed.

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Drill Chuck Keys.jpg
Drill Chuck Keys.jpg (114.26 KiB) Viewed 684 times
.
Is this still clear as mud or did it help?

The second key above which is current Jacobs part # 30250 is a "T" Handle instead of the Thumb Handle (as they are called) shown above.
Russ

Mark V completely upgraded to Mark 7
Mark V 520
All SPT's & 2 Power Stations
Model 10ER S/N R64000 first one I restored on bench w/ metal ends & retractable casters.
Has Speed Changer, 4E Jointer, Jig Saw with lamp, a complete set of original accessories & much more.
Model 10E's S/N's 1076 & 1077 oldest ones I have restored. Mark 2 S/N 85959 restored. Others to be restored.
DLB
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Posts: 1985
Joined: Fri Nov 08, 2019 11:24 am
Location: Joshua Texas

Re: Drill Chuck Key Jams

Post by DLB »

chapmanruss wrote: Sun Oct 02, 2022 5:04 pm Is this still clear as mud or did it help?
It helped. I don't have any Cushman or Multi-Craft, so I've been using 'small' gear in reference to the third chuck in your picture, aka 'unknown,' and only in comparison to the 4th. So yeah, I was thrown off.

Today I'm rebuilding my Jacobs 3326. I decided my best chuck shouldn't be my ugliest chuck. I wish these were still available new, although I know it is a more expensive chuck. Everything, but especially the key, is a much more positive fit.

- David
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