Jacobs keyless chuck loosens when starting mill

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frbauer
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Jacobs keyless chuck loosens when starting mill

Post by frbauer » Sun Aug 12, 2018 2:14 pm

I have recently been having a problem with my Jacobs JKP-130-J6 keyless chuck loosening when I start my Bridgeport. It has thrown the drills when I see they have come loose and turn off the mill. Has anyone else experienced this issue? Can the issue be resolved by disassembly and cleaning of the chuck? Any suggestions??

pete
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Re: Jacobs keyless chuck loosens when starting mill

Post by pete » Tue Aug 14, 2018 12:19 am

I don't own one nor have had that problem. Still not enough information to help though. Exactly how old is that chuck. For example is it old enough to still be stamped Made in America? If so? It's my understanding only from reading the Practical Machinist forum that the current parts kits Jacob now sell to rebuild there chucks is no longer correct for the original American made Jacobs chucks. If that's so then finding a NOS parts kit on places like Ebay is the next step. There's a few videos on Youtube about rebuilding Albrecht chucks, so I'd assume there would be ones about the Jacobs as well.

Second question, have you ever been using the 1/2" shank Silver & Deming type drills in it? Those can and do kill keyless chucks because the higher torque requirements for the larger drills will cause the keyless internals to self tighten to the point of over stressing the parts. If you have then the whole chuck might be non rebuildable. Sorry I can't be more helpful.

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BadDog
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Re: Jacobs keyless chuck loosens when starting mill

Post by BadDog » Tue Aug 14, 2018 1:28 am

You are not supposed to oil keyless chucks. Or so says Albrecht, I assume Jacobs and other chucks of the same design are similarly supposed to remain devoid of oil.
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frbauer
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Re: Jacobs keyless chuck loosens when starting mill

Post by frbauer » Tue Aug 14, 2018 5:55 am

Pete: The chuck is about 15 years old. Yes, I have from time to time used Silver & Demming type drills, up to about 1", however, progressing up to that diameter gradually in steps. That may indeed be the issue. As far as country of manufacture, I can only find "Spain" stamped into the top of the fixed ring. Thank you for your reply. It is very helpful.

pete
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Re: Jacobs keyless chuck loosens when starting mill

Post by pete » Tue Aug 14, 2018 6:37 pm

Well Badog might have nailed the problem down better than I have if you've oiled it. If so then maybe a simple disassembly, cleaning and regreasing where it's required just might do it.

You might take this as only information that was correct at the time I bought them or not since I've no idea just what there actual quality is today. Maybe 8-9 years ago I bought 3 of Glacern Tools integral shank 1/64" - 1/2" keyless chucks. Two in R8 and one in MT 3 to use on my lathe. At that time they were running about $100 a piece. I also made a point of checking there runouts as soon as I got them. All 3 would do .001" - .0015" which matches pretty well what the one Albrecht chuck I have does. My guess is there durability would be a bit less than the Albrecht's. But there still a pretty fair chuck for a home shop. Or at least they were back then. Today I think they run about $150. It might be tough to figure out what exact rebuild kit you might need if the cleaning doesn't work. Rohm is another good make, but there roughly about what the Albrechts run and from what I've seen they do make some cheap chucks roll stamped with there logo. A home consumer grade that looks and works no better than anything else from China that's cheap so I think that's where there made. A midrange line that seems ok for the one I bought. And the one's at the Albrecht price level. I try to pay attention to what's mentioned on the PM forum about the quality of tools as those guys know what there talking about and use what there buying all the time so accuracy and durability is important. I can't recall one post there where anyone was impressed with the current Chinese made Jacobs chucks, and Jacobs sure hasn't dropped there prices. If your going to be paying roughly what a real Albrecht costs then it's accuracy and quality should be equal to them. That's apparently not true today.

It sounds like you might need or want a good keyed and keyless chuck. If you could find an older American made NOS keyed Jacobs ball bearing super chuck that's still in the box on Ebay then it would be worth it. Golden Goose I think are made in China but are supposed to be pretty good. I've never used one so can't verify that. Llambrich is another that's supposed to be very good. And many on the PM forums seem to like the keyless chucks Mari Tools are selling at a pretty decent price point. If it were me I think I'd try the disassembly and cleaning first even if you haven't oiled it. Sooner or later all drill chucks need that anyway.

It depends on what you have for tooling on your mill. But one of the reasons I bought a set of ER 40s for my mill was I'd then have the ability to hold up to 1" shanked drills. Those ER's hold drills very noticably better than any drill chuck I've used. I do the same with the 1/2" shank S & D drills as well and have never had a drill slip if the collet nut is torqued down properly. Below that 1/2" then I just use the keyless chucks. I did forget to mention that power tapping with keyless chucks will kill them even faster than the larger drills will and for the same reasons. I limit my keyless to maybe 3/8ths tap sizes at the most. They can still open when reversing unless real small taps are being used. Over 3/8ths they go in an ER.

frbauer
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Re: Jacobs keyless chuck loosens when starting mill

Post by frbauer » Tue Aug 14, 2018 7:02 pm

Hi, Pete,
Thank you very much for providing all that info. I have never oiled the chuck or disassembled it. I recently downloaded the disassembly instructions and will give it a good cleaning in the next week or so, and see how it behaves after that. In the meantime, I will do some prospecting on ebay and see what might turn up in the NOS category. Thanks, again. This is very helpful.

pete
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Re: Jacobs keyless chuck loosens when starting mill

Post by pete » Tue Aug 14, 2018 7:33 pm

Glad some of that might help and I hope you post if that cleaning works or not. It could be useful information for someone else in the future. Also a review on any new chucks you end up buying. At one time if you wanted a good keyed or keyless it was safe to just pick up what Jacobs was making. Now you have to do a lot more digging to find anything that's under $300 and still decent.

Without knowing for sure what rebuild kit may or may not fit what you already have then I'd be real careful when you press that chuck apart. It's real easy to have the ball bearings bouncing around the shop if your not. The last one I did I pressed it apart while it was inside a clear plasic bag. It was a pita to do it that way but it worked. Tom Lipton on Youtube did a good video awhile ago about rebuilding an Albrecht that had some good techniques in it that should work for almost any brand of keyless while reassembling them.

frbauer
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Re: Jacobs keyless chuck loosens when starting mill

Post by frbauer » Tue Aug 14, 2018 8:16 pm

Thank you, Pete. Sounds somewhat akin to taking a watch apart. One can create some junk if they're not careful enough and not quite sure about what comes next. I appreciate the hints. I'll see if I can find Tom Lipton's video and get as much insight as I can before tearing into it. Also, I will certainly pass on any info I have in working towards a resolution on this issue.

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NP317
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Re: Jacobs keyless chuck loosens when starting mill

Post by NP317 » Tue Aug 14, 2018 9:12 pm

I suggest that Jacobs-type chucks can be cleaned by squirting brake cleaner up into them, while held vertically so they can drain out.
Give it a try.
~RN

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SteveHGraham
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Re: Jacobs keyless chuck loosens when starting mill

Post by SteveHGraham » Tue Aug 14, 2018 9:37 pm

Golden Goose is Taiwanese. Supposedly, Vertex chucks are made by the same people.
Every hard-fried egg began life sunny-side up.

frbauer
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Re: Jacobs keyless chuck loosens when starting mill

Post by frbauer » Tue Aug 14, 2018 10:41 pm

RN, thank you. That would be very quick and easy to try before getting into it any deeper. I'l see if it resolves the problem. I'll let you know how it goes...

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Bill Shields
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Re: Jacobs keyless chuck loosens when starting mill

Post by Bill Shields » Wed Aug 15, 2018 6:19 am

I second the comment about 'DO NOT OIL'

I ordered one from a fellow a while back & it arrived all nicely cleaned and lubed

I cannot say that it 'threw' drills, but certainly would not stay tight.

as opposed to brake cleaner, I dunked it in a jar of acetone overnight to cure it of this propensity.

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