Jacobs Ball Bearing Chuck Rebuild (14N) Done My Way

jbollman said:
10-17-14

Hellow to all: FYI

I apologize for not commenting sooner since i have had 2 major health issues commencing 1 Year ago - however I am now OK & getting
back to doing some machine work. If any one is looking for a top quality drill chuck I would recommend a ROHM chuck - made in Germany (many sizes available) and distributed by ENCO MFG.. I bought one for my drill press and it has been very good. Also ENCO sells a different chuck called a GOOSE. This chuck ( 3/4" max ) I have used it on my Van Norman mill and it is also good. It is made in Taiwan. If you have any questions please list them on the forum. :))

Regards to all,

jbollman
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I purchased a new Jacobs super chuck a couple of years back and the runout is excessive and to make it worse, not repeatable. It is a China chuck. Finally broke down and bought a ROHM ball bearing and it is much better. The only thing I dislike about the ROHM is the barrel is smooth and kind of hard to turn when your hands have any oil on them.

Sandia
 
I've been is contact with the Apex tool group and awaiting an answer on the
question, "when did Jacobs start making their super chucks in Taiwan, yes Taiwan and not China.
Don't know if this is better?
Anyway, I was told that someone will get back to me.
I'll post all replies from Apex here.

As for testing run out, I have some excellent Guhring carbide drills I could use for TIR.
I just need to buy a good Interapid. ( all I have is a crummy Last Word).

On a side note, I wrote to Starrett as well. They wrote that 80% of Starrett tools are
made in the USA, and if I wanted to know which were not, just write and ask.
They were very forthcoming. Thanks again for all the great information and photos!
Outstanding work!
 
Yup, I've also seen some vendors listing COO as Taiwan for these. Not everything Taiwan is "better quality" than China. Yes Taiwan made machining machinery & machining accessories are know to be better quality but I don't find that to be true with other tools such as hand & power tools. Not sure if these Jacobs chucks are falling under the machining accessories category or hand tools category as far as quality. Judging by the complaints I have heard about them I can see why people tend to think they are typical China quality. YMMV & again, as long as you are happy with what you got, who cares.
 
Until I can find a better USA Hartford, Conn. original 14 or 16n SuperChuck w/R8 arbor,
I will use what we have at work. I'm also looking at Albrecht and Rohm keyed chucks with 13 mm cap.
The Taiwanese chuck seems OK, but I know the TIR is beyond spec. Just by looking at the holes.
For my purposes thought, it's fine for now. I'm not fabricating for NASA or BioMed.
I would like to reduce error as much as possible, so I'll invest towards a good height gage, surface plate
and magnifying lenses. ;)

Thanks for the excellent info!

PS
For run out check, what type of base should or can I use for the indicator.?
 
EmilioG said:
what type of base should or can I use for the indicator.?
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Any mag base would/should do the job fine so I would say it's personal preference on what style & quality you want. All my indicator holders are Noga, I love every single one of mine, & there may be very few out there that I would like better, if at all.
 
Got the replacement jaws for the 3rd chuck. Runout wasn't as good as the other two but acceptable considering how bad it was with the original jaws, probably .01" maybe more. About .003" with the new jaws. Updated the 3rd post.
 
darkzero said:
Got the replacement jaws for the 3rd chuck. Runout wasn't as good as the other two but acceptable considering how bad it was with the original jaws, probably .01" maybe more. About .003" with the new jaws. Updated the 3rd post.
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Would it matter if you tried the jaws in different positions considering the main block could have some slight machining irregularities? Or are the jaws exactly the same? On the cheap chuck I repaired it did make a difference which jaw was where.
 
Jacobs are made overseas now? Another great american company lost. :dunno:
 
Cadillac STS said:
Would it matter iin p you tried the jaws in different positions considering the main block could have some slight machining irregularities? Or are the jaws exactly the same? On the cheap chuck I repaired it did make a difference which jaw was where.
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Yep I've already tried that with this last chuck in particular, made no difference on mine. On all 3 of these chucks the jaws were all clocked in the same position according to the markings on the nose. Not sure if it really matters but if they all matched maybe Jacobs had a reason for it so I made sure they all went back in the same way.

I checked runout with no arbor on it in the lathe. Now that I have an arbor on it I'll check run out mounted in the mill. Again this is just an extra one, I have the 2 that I wanted.
 
In several post back, it was mentioned how tight the arbors were seated in the chuck body and the difficulty getting them out.

The first thing I do when I rebuild a chuck, I chuck up gently on the tapered shank, pushing the chuck body against the face of the chuck jaws on the lathe. This generally holds T.I.R. to a minimum. Make sure the jaws are retracted all the up into the chuck. I generally take a 1/2" drill bit or one a little larger and drill out the web in the bore of the chuck to the arbor side of the chuck body. I know a 3/8" drill chuck or smaller you cannot get a 1/2" bit through the chuck. Just use the biggest drill bit you feel comfortable using.

Next, take the largest steel drift punch you can get into the hole and try to drive out. A couple two or three sharp blows should knock the arbor loose. If not, put back in the lathe, go in with the 1/2 drill bit and drill into the arbor. Go about 1" to 1-1/4" deep. This should let the compression stresses relieve them selves in the arbor. Try driving the arbor out. It should come out now. If not, cut off the arbor and bore out the duchman. Do this only if you want to remove the arbor.

I generally remove them. But, that's just my way of doing things.
 
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