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Problems with MT2-JT33 Chuck and Arbor

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Forum topic by Redoak49 posted 07-22-2019 10:20 PM 194 views 0 times favorited 8 replies Add to Favorites Watch
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Redoak49

4102 posts in 2439 days


07-22-2019 10:20 PM

Topic tags/keywords: drill press chuck arbor

I recently bought a keyless chuck for my drill press and it uses a MT2 – JT33 chuck arbor. The MT2 stays up in the drill press fine but the JT33 going into the chuck keeps coming loose. I have cleaned the arbor and chuck and made certain nothing was there. However, after a little use, the arbor to chuck connection comes loose.

I have pressed it up in tightly and also tapped it pretty hard with a dead blow hammer but still am having a problem.

Does someone have suggestions on what to try at this point?


8 replies so far

View Delete's profile

Delete

439 posts in 822 days


#1 posted 07-23-2019 12:34 AM

This is a problem that has become quite consistent since the advent of Asian machines, if it is not the MT tapers its the JT33 chuck mounts. Metalworking machines have drawbars which help. But general purpose drill presses and woodworking equipment do not.

One thing you can try is rubbing the finest grinding compound you can find, (buffing compound might work but I have never tried it) on the JT33 taper, with it inserted into the chuck, and starting with light pressure, rotate using the MT taper as a handle, increase pressure and continue rotating. when it starts to get real tight clean it up and try it out. If it still drops out you may repeat but if you still can’t get it to stay tight, you may have to inquire with a machinist to see if he has the equipment to grind an accurate taper. You might want him to check the chuck as well, one of them isn’t right. It might be cheaper to just buy better quality.

Price really counts here, the cheaper you buy the more chance you will not get a good fit.

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Woodknack

12870 posts in 2830 days


#2 posted 07-23-2019 03:59 AM

Send it back and if it was a cheap part, buy a better brand like Rohm or Jacobs.

-- Rick M, http://thewoodknack.blogspot.com/

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Redoak49

4102 posts in 2439 days


#3 posted 07-23-2019 11:14 AM

Yes, I could buy a Rohm or Jacobs Chuck and arbor for $300+. Hoping to find a more reasonable solution.

View HokieKen's profile

HokieKen

10276 posts in 1589 days


#4 posted 07-23-2019 12:45 PM

I would do as Carlos suggests and see if a quick lapping helps. If not, it should, at a minimum, let you know how far off the fit is and in what area. If it’s close, put your arbor in the freezer overnight and insert it into the chuck with a couple of good whacks the next morning. The cold will cause it to shrink slightly then when it expands, you should essentially have an interference fit. As long as the fit is pretty close to begin with, this should take up any slop.

-- Kenny, SW VA, Go Hokies!!!

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Redoak49

4102 posts in 2439 days


#5 posted 07-23-2019 01:24 PM

I will try the lapping and see what happens. It is the JT33 arbor to chuck that is coming off.

Part of the problem may be that I am running the drill press at 2500-3000 rpm.

View HokieKen's profile

HokieKen

10276 posts in 1589 days


#6 posted 07-23-2019 01:50 PM

I don’t think your speed is really a problem. Honestly, with JT fits, I usually consider it permanent. More often than not I haven’t been able to release it even with wedges once it’s firmly seated.

Another possibility is that you aren’t seating it fully. Open the chuck so the jaws are fully retracted and sit the face on a piece of scrap wood. Then hold another piece of scrap on the butt end of the MT and whack the crap out of it with a big, solid hammer. You ain’t gonna bend anything. And if you do, you didn’t really want it to begin with…

-- Kenny, SW VA, Go Hokies!!!

View Nubsnstubs's profile

Nubsnstubs

1588 posts in 2180 days


#7 posted 07-23-2019 02:03 PM

Do what Ken said, but after it’s stuck onto the arbor, pick it up and then start beating the crap out of it at the tail of the MT2. i don’t know why, but the shock of the blow will drive the chuck upwards. A couple good hits, and it should be seated until you pry it off with a set of wedges…......... Jerry (in Tucson)

-- Jerry (in Tucson) www.woodturnerstools.com

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MrRon

5625 posts in 3694 days


#8 posted 07-23-2019 08:02 PM

Get some machinist’s blueing and paint it onto the JT taper. Insert the chuck and rotate it a couple of turns. Then remove the chuck and observe the blueing pattern. It should be completely blue all over, but if there are bare spots, that will tell you the taper is not perfect on either the shank or the chuck or both. That will at least tell you what the problem is. There isn’t much you can do about it other than to replace it with a better chuck, MT2/JT33. I don’t recommend beating the s**t out of it; you will just damage the bearings of the DP.

If you were a machinist with the right tools, it could be fixed, but as a woodworker, no way.

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