Jacobs Chuck Question

[Greg Bolton22]

I have a PSI Jacobs chuck that has quite a bit of run-out. The problem seems to be between the chuck and the taper. I have a gift certificate to CSUSA that I need to use and was thinking they would have a decent one. What Jacobs chucks do you guys (and gals) have and recommend? Is it worth a little extra money for a keyless chuck?

Thanks,

Greg

[Michael Mills]

You probably have a Jacobs type, not a Jacobs manufactured (trademark). Here is a one on Amazon, you will need the MT to fit your lathe which I am sure they have also. I don't think the brand of MT is that important.
http://www.amazon.com/Jacobs-Chuck-30602-2-Inch-Keyed/dp/B00002NBJF/ref=pd_sim_sbs_hi_4
Should be able to get the chuck and taper for about the $25 with free shipping. They probably also have the keyless Jacobs manufactured if that is what you want.

If you have a drill press it probably has a 2MT and you can just swap the chuck between the drill press and your lathe as needed.

[Kyle Iwamoto]

I have a PSI Jacobs chuck that has quite a bit of run-out. The problem seems to be between the chuck and the taper.

Can you send it back? I got one from them and it seems fine.

I did not get the keyless, since supposedly, the keyed chucks hold bits much better. IF you tighten all 3 key holes.

[Thom Sturgill]

I did not get the keyless, since supposedly, the keyed chucks hold bits much better. IF you tighten all 3 key holes.

What possible benefit can there be to tighening all three holes. Both the the center where the holes are and the outer ring are single solid pieces. This goes for scroll chucks also. That technique goes back to machinsts independant jawed chucks where it was critical to keep the pressure balanced. On scroll cucks on wood it does give a few seconds time for the wood to compress under the jaws so that you can tighten further. It does also insure that you have changed your grip, but rotating to a new hole does nothing in and of itself as far as I can see.

As to a replacement chuck, I used an $8 one from Harbor Freight for a couple of years until I broke down and bought a MT adapter to fit a keyless Jacobs manufactured chuck I had bought years ago and never used (I bought it for my DP and could not get the old chuck out.) I would not go back after using a better chuck. The HF chuck came with an integral #2 MT. The HF chuck is now on my DP as I never had the proper key for the factory chuck.

[Kyle Iwamoto]

What possible benefit can there be to tighening all three holes.

Try it. You'll probably get key movement on the second keyhole. Usually not the third. It just makes the chuck a little bit tighter. Scroll chucks too. Although there is only 2 keyholes. Habit from years ago.

[Paul Singer]

+1 I agree. I get movement about every time and a tighter grip.

[Bill Bulloch]

Five years ago I bought six #2 MT Jacobs Chucks (one for each of my most used bits) from Harbor Frieght on sale at $6.95 each. I have had no problems with any of them. They are probably a little more expesive now. but should serve you well for lathe work.

[Thom Sturgill]

I didn't say you wouldn't get movement, in fact I stated that you would (in wood for sure). Just that you would get the same movement if you regripped and tightened the same hole after a few seconds. Turning different holes dates back to old style chucks.

[Bernie Weishapl]

I have 3 of these and never had a problem with any of them.

http://www.woodturnerscatalog.com/store/Lathe_Accessories___Drill_Chucks___Key_Chuck___key _chuck?Args=

[Greg Bolton22]

Thanks guys for all of your opinions. Bernie, that is what I was hoping to hear. I will order one with my CSUSA gift card.

Greg

[Scott Hackler]

+1 on the Harbor Freight version. That's what I bought and it's been abused and dropped several times and it still performs great. I bought the keyed version.

[Jon Nuckles]

I don't recall where I bought my keyless chuck (maybe Woodcraft?), but my experience with it and bigger forstner bits makes me wish I had purchased a keyed chuck.

[Wayne Jolly]

Just a couple of thoughts.

I just went through something similar to this. A real Jacobs chuck witha mt#2 that would wobble to beat the band. What I finally found out is that when I inserted the check into my lathe headstock taper, it was the tab at the end of the taper that was holding the chuck and not the actual taper. After grinding the tab back some, and rouonding the corners of it some, it now fits nice and tight and almost all of the runout is gone. So could it just be possible that your taper has a tab that needs to be ground down some or something like that?

Second, I became a firm believer in tightening all three points on a drill chuck, and both holes on my lathe check (it only has two points to tighten it). If you only tighten from a single hole, then the play that is in all of the parts will cause that one jaw to be slightly tighter than the others. As you work, these stresses will all even themselves out resulting in an overall slight loosening of all jaws. I used to only tighten drill bits in my drill press from a single hole and I would get quite a few drill bits spinning in the chuck. Now that I tighten from all three holes, I will still get an occassional spin, but it is now rare and seems to only happen with bigger bits in steel. The only downside that I have noticed is that you may have to visit all three holes to get the bit back out again.

That's my story and I'm stickin' with it.

Wayne