# How not to service a Jacobs chuck



## mattthemuppet2 (Sep 8, 2014)

1. Don't do it late at night when you want to do something else

2. Don't do no. 1 after already fixing a different Jacobs chuck, as that will make you think you somehow know what you're doing

3. Don't use PVC pipe as a standoff to press the sleeve off as that is very very stupid and you will end up with a chuck inside a PVC pipe

4. Just stop there, further attempts will just end up in tears/ swearing/ both

5. If you ignore 4., for goodness sake don't keep cranking on the press handle when it won't come out all the way. It's probably come out cocked and if you keep pressing you'll just bugger it up.

6. If, after hours of work you managed to fix all the screw ups you've just caused, you manage to get it back together and working well DON'T GIVE IT ANOTHER LITTLE TWEEK ON THE PRESS as it will then no longer work and you'll have to take it apart _again
_




It's now fixed and opens/ closes freely other than a couple of slightly tight spots. If I'd known then what I know now, I would have happily put up with it being a bit sticky..


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## 12bolts (Sep 8, 2014)

So what are you doing about the cracks in the casing?

Cheers Phil


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## mattthemuppet2 (Sep 8, 2014)

pretending it doesn't exist 

I'll chuck up the truest bit of rod I can find later if I can grab some garage hours and see if the runout is reasonable (0.005?). If it is, then I'll leave it as is. If not, I'll have to wait for payday and get a replacement.


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## Chucketn (Sep 8, 2014)

Matt, I have a very old Jacobs chuck, I believe it's a 1A, that was in my Dad's Kennedy. It has an obvious weld repair to the outer sleve. It opens and closes a dream and when mounted on it's threaded arbor, has .0005 runout. I wonder if Dad learned the same lesson you just described, and a friend that was a good welder helped him out?

Chuck


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## mattthemuppet2 (Sep 9, 2014)

could be. I can't logically see a way in which an out-of-round sleeve at the taper end would affect accuracy, so hopefully it's still fine. Didn't get a chance to test it last night as I was working and I think I'm making grape juice tonight..


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## middle.road (Sep 9, 2014)

mattthemuppet said:


> pretending it doesn't exist
> 
> I'll chuck up the truest bit of rod I can find later if I can grab some garage hours and see if the runout is reasonable (0.005?). If it is, then I'll leave it as is. If not, I'll have to wait for payday and get a replacement.



Well, I'm thinking I can send you mine for repair, since you now have the experience. :biggrin:
I've got a No.34 still in a ziploc from when I attempted repairs to it sometime in the late 90's, and a couple of 14N's that need a look at.

_Dan


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## mattthemuppet2 (Sep 9, 2014)

middle.road said:


> Well, I'm thinking I can send you mine for repair, since you now have the experience. :biggrin:
> I've got a No.34 still in a ziploc from when I attempted repairs to it sometime in the late 90's, and a couple of 14N's that need a look at.
> 
> _Dan



one learns by doing, right? I'd be happy to have a crack at 'em, but you may have to wait a similar amount of time to get them back again  The 2 other ones I did were rescues from an eBay auction - $12 for 3 chucks, one of which has been fixed and working on my lathe for at least a year and the other is waiting for me to make a new arbor for it.


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## Pat of TN (Sep 9, 2014)

I feel like I've read this somewhere else. Hehe.You gave it a good shot! At least it most likely won't affect anything important. I went through something similar today. Nothing specifically related, but the upshot of this is - when you start to get tired, or frustrated, it's time to quit for a little while. Like after breaking a 4-40 tap.


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## george wilson (Sep 10, 2014)

Matt,do be careful with that chuck. Those special Jacobs with the safety collar are rather rare,and cost a good bit if you buy them new. It might cost more than your drill press did.

And now,Jacobs are made in China. The new ones might not be very good.

I am wondering if it would be possible to take a SIMILAR 1/2" Jacobs chuck without the collar,and just fit your collar parts to it? I have no idea if the bodies would be the same,but just without the collar.

Now that you have the collet chuck though,it is not really a necessity to have the locking collar on your chuck. You shouldn't be putting sideways pressure on it to make it come loose from the #33 taper. You could just get a regular 1/2" chuck that is more common,with the 33 taper hole in the top,and use that,if worse comes to worse. And,try to buy an old MADE IN USA Jacobs in good shape. I can't advise buying a Chinese Jacobs. I just do not know if they are good or not. Perhaps Jacobs has them made to the proper tolerances,and of GOOD metal. I have no idea.


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## mattthemuppet2 (Sep 10, 2014)

Pat of TN said:


> I feel like I've read this somewhere else. Hehe.You gave it a good shot! At least it most likely won't affect anything important. I went through something similar today. Nothing specifically related, but the upshot of this is - when you start to get tired, or frustrated, it's time to quit for a little while. Like after breaking a 4-40 tap.



agree with you 100%! I'm getting better at realising when I should stop, but sheer cussedness sometimes gets in the way.



george wilson said:


> Matt,do be careful with that chuck. Those special Jacobs with the safety collar are rather rare,and cost a good bit if you buy them new. It might cost more than your drill press did.
> 
> And now,Jacobs are made in China. The new ones might not be very good.
> 
> ...



It looks like a safety collar chuck, but it's actually a normal chuck that has a separate release collar threaded on to the spindle above it. Doesn't do anything to hold the chuck on, but a quick twist (now) pops it off for when I need to put that collet chuck on. Speaking of which, I used 3 different end mills and 2 different collets in it last night


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## george wilson (Sep 10, 2014)

I  had forgotten about that. Lucky the collet fit!!

Anyway,finding a used 1/2" Jacobs with a 33 taper on ebay shouldn't be difficult,then. They are EL MUCHO more common than the safety collar types.


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## mattthemuppet2 (Sep 11, 2014)

yep, I'm a lucky guy  So much so, that another generous member of this site is sending me one of his spare 33JT taper chucks as a replacement. Then I can use this one that I've "fixed" to hold a countersink or hole finder to cut down on swapping things in and out of the chuck.

Finished my second milling project last night, I'll post pictures up in the POTD thread when I get a chance. Getting better each time, although I now need to fit my digital caliper scales to the vise and quill as eyeballing it just isn't accurate enough!


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## middle.road (Sep 11, 2014)

george wilson said:


> Matt,do be careful with that chuck. Those special Jacobs with the safety collar are rather rare,and cost a good bit if you buy them new. It might cost more than your drill press did.
> 
> And now,Jacobs are made in China. The new ones might not be very good.
> 
> ...



And there I go again learning something new, I did NOT know that was a 'safety' collar. I took one off a 33. 
Where's the jackass emoticon?...

_Dan


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## george wilson (Sep 17, 2014)

Matt,glad someone sent you a chuck. I was going to see if I had a spare one.


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## mattthemuppet2 (Sep 17, 2014)

thanks George on both counts. I consider myself very lucky to be part of this community! Now, if you could find me some extra time in the day so I can get out to the shop, _that_ would be even more appreciated!


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## Tozguy (Sep 26, 2014)

mattthemuppet said:


> pretending it doesn't exist
> 
> I'll chuck up the truest bit of rod I can find later if I can grab some garage hours and see if the runout is reasonable (0.005?). If it is, then I'll leave it as is. If not, I'll have to wait for payday and get a replacement.



Seems to me that a steel collar with a shrink fit would close up the crack some and at least give some peace of mind.


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