JT #2-1/2 means exactly that!

According to Norm Dresner :

I don't think that anyone doubted you. We were simply hoping that the drill press spindle was made in such a way as to allow a replaceable arbor, so it would be easy to change to other Jacobs taper sizes. (And some of your earlier terminology suggested that it was so equipped.)

Since there is no such feature, you are stuck with your existing chuck (which, IIRC, was not that bad for a typical drill press chuck) -- especially the ones from China and Taiwan.

It *might* be that the same manufacturer made a version of the drill press with a spindle with a Morse taper socket -- and if so, changing one of those into the drill press might increase your options.

Good Luck, DoN.

According to Norm Dresner :

[ ... ]

O.K. I see where some of the confusion came from. The manual calls the Jacobs taper on the end of the spindle a Morse taper -- which is totally incorrect.

Also -- it is a smaller drill press than I was considering, so a Morse taper in the spindle is quite unlikely. There just is not room for one of reasonable size. My floor-standing one only has a MT-2, and I would prefer a MT-3 in that one. Yours *might* accommodate a MT-1, but that would be too small to be worth the trouble.

Good Luck, DoN.

Actually it could be correct, Don.

According to Jacobs:

"DIN Taper Interchangeability DIN tapered sections are identical to the following Morse tapers:

MT No 1 for tapers B10 and B12 MT No 2 for tapers B16 and B18 MT No 3 for tapers B22 and B24

The length of these tapers is, of course, distinctly less than the overall length of the corresponding Morse taper. Each taper may be regarded as corresponding approximately to that part of the Morse taper nearest the small end(for example: B10), or to the part nearest the large end (for example: B12)"

Tom

[ ... ]

[ ... ]

Intersting information. Of course, it still should not be

*called* a Morse taper, as that leads to the expectation of a socket in the spindle, and a certain length, neither of which is met.

I wonder whether the choice of basing the DIN tapers on the Morse tapers is because there were plenty of precise gauges already around for checking the taper?

And I'm still wondering where that 2-1/2 Jacobs taper came from on the machine's label -- and a taper which appears to be closer to that than anything else, even though there is no mention of a 2-1/2 Jacobs taper in _Machinery's Handbook_ -- at least not in the 25th edition. Just a "No. 2 short taper", which is not truly a half of a #2 taper. :-)

Enjoy, DoN.

Yes, Leon, those are the exact same "models" that I have. I've posted my scan of the "manual" in the dropbox at

the measurements I made in the accompanying text file.

Yes, it certainly appears to be a JT6. Knowing that, I searched Enco

JT6 chucks and came up with 4 ranging from $18 to $84 at so there may be new chucks available after all.

Thanks very much for the info

Norm

Hi Norm,

Is you're press badged as made in Taiwan too (now that you know where to look)? I don't think mine are quite as old as yours, probably bought in the mid to late 70's. They are subtly different too. The slightly newer one doesn't have the nut for removing the chuck, nor any threads for one. The manual that came with that press still pictures it in the parts diagram/list though. Instructions for removing the chuck still tell you to turn the non-existent nut too. This is also the manual that calls it a Jacobs taper. Just eyeballing them though it appears to be the same taper. I only popped off the chuck on the press that has a threaded nut :)

You might want to check how much play there is when you run the quill down and inch or two. As I mentioned, mine are really loose. I don't know what the other readers opinions are, but for drilling tiny holes I don't think this would be a good thing.

Not sure if anyone else posted on this (I'm 2500 posts behind in my reading) but the measurements of the J2-1/2 sure do look the same as the J6 which you don't show.

If they are the same, you can get a J6 chuck...

Regards, Joe Agro, Jr. (800) 871-5022 (908) 542-0244 Automatic / Pneumatic Drills:

Spindle Drills: V8013-R

replying to Norm Dresner, kevin wrote: We're you able to find a replacement for the 2 1/2 in Chuck , too am looking for one

replying to kevin, chris wrote: I replaced my missing chuck that has the the same spindle listed as a JT# 2-1/2 with an Amazon chuck ----->

hope this helps

replying to chris, Elden wrote: Chris, I realize that you posted your response more than 2 years ago, but I would like to ask you a question. Did the chuck you used grip the spindle well or did it ever slip during heavy use? The drill press I have calls for the JT#2 1/2 as well. It has worn to the point that one has difficulty getting it tight enough with the chuck key to prevent slippage on the drill bit.

I realize that the differences are small, but they are the reason for my initial question. I would like to know from someone who has actually put it to a prolonged test whether it is a workable solution.

Thank you for your time, Elden

replying to chris, Elden wrote: Chris, I realize that you posted your response more than 2 years ago, but I would like to ask you a question. Did the chuck you used grip the spindle well or did it ever slip during heavy use? The drill press I have calls for the JT#2 1/2 as well. It has worn to the point that one has difficulty getting it tight enough with the chuck key to prevent slippage on the drill bit. I used an online calculator for finding taper angles

to compare the two Jacob Tapers. Using the specifications for the JT #2 1/2 and for the JT #6 that I found, they were plugged into the calculator. The values obtained were: JT #2 1/2 2.82° cone angle or 4.929% taper; JT#6 2.97° cone angle or 5.191% taper. The differences were 0.15° for the cone angle and 0.262% taper. I realize that the differences are small, but they are the reason for my initial question. I would like to know from someone who has actually put it to a prolonged test whether it is a workable solution.

Thank you for your time, Elden

replying to Elden, Chitty wrote: Revisiting this thread- did anyone verify using a jt6 chuck on the one piece jt

2 1/2 spindle? I?m fighting this same question....

replying to Elden, Chitty wrote: Revisiting this thread- did anyone verify using a jt6 chuck on the one piece jt 2 1/2 spindle? I’m fighting this same question....

replying to Chitty, Elden wrote: Chitty, I have not received any reply to my post except for yours. I was hoping to hear from someone who has actually had used a JT#6 on the JT #2 1/2 spindle and has put it through its paces to make sure it doesn't slip. I guess one will have to take a chance it to see i t will indeed work properly. Have been debating whether to do that or get a different drill press. By watching Craigslist, I think one could get a decent press for $50 to $75 that doesn't have the JT#2 1/2. Elden