Need info re spindle taper and stuck chuck on Craftsman 150 drill press

I bought this old drill press the other day -- it's from the 50's I
believe. Model number is 103.24520.
Bad story is this... the headstock was off center and I wanted to
center it. I had a friend to help (who has a dozen drill presses at
his shop). I started to tell him what I wanted to do and before I
could stop him he just reached up and released the headstock lock. The
headstock came down instantly onto the table (about a 12" drop).
Fortunately, no hands were down there.
Before this happened, I had measured under .003 runout below the
chuck. Now I measure about twice that. So I figure I'll remove the
chuck (Jacobs) . It took a lot of work to get the thrust collar loose,
but I cannot get the chuck off. I fear the force of about 50 or more
pounds of headstock falling 12" on the chuck might have really stuck
it in.
Anyway, I don't know what the taper is and would appreciate any help
in figuring out how to get that chuck off. There is no slot on the
spindle for the drift. I have a manual for a slightly older version of
this drill press, and it says "be sure the taper on the chuck and on
the spindle are clean", so I know it is a taper, and there is a "chuck
removal wedge" in the parts list, but I don't have it.
Any advice would be most welcome.
Thanks.
-Bruno
Reply to
Bruno
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Ouch!, anyway -- even if nobody was hurt. Why didn't he at least look for a stop collar below the headstock -- and check that it was solid?
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Some drill presses have a solid spindle, with a male Jacobs taper on the end to accept the chuck. The wedges (they come in pairs) are available from places like MSC, and probably most other serious tool supply places. However, you need to determine what the taper is, first. If the chuck is a Jacobs, copy all the information on it, which should encode the Jacobs taper (among other things). Perhaps a JT-6, perhaps a JT-3, perhaps a JT-33, perhaps something else.
Most sizes use a single pair of wedges, but some require half of two different size wedges. Visit Jacob's web site, and you should find the sizes documented. Try a google search for Jacobs and see what it does for you. I can't seem to find the bookmark which I had for their site at the moment.
Having the male Jacobs taper a permanent part of the spindle removes one of the chances for fixing it more easily -- replacing the arbor which adapts the Jacobs taper in the chuck to the Morse taper in the spindle.
Good Luck, DoN.
Reply to
DoN. Nichols
Well, I finally got the chuck off late last night after a lot of muscle on the thrust collar.
The chuck is a Jacobs model 633C and I knew it had a Jacobs 33 taper. I looked all over the net and could find nothing about this specific model of chuck (other than which key fits). I assumed an arbor with maybe an MT2 on the other end.
Turns out DoN, that you were right on the nose. The drill press spindle has a JT33 taper and is threaded above that. The chuck has a built in threaded thrust collar that draws up the chuck on the taper. I'd never seen one of those before, and I assumed they would be separate pieces, but the collar was on the chuck with no obvious way to remove it.
With the chuck off, I cleaned it all up and took new measurements. The spindle runout measured between .0020 and .0025. WIth the chuck on and a piece of drill rod chucked in, the runout is about .0035. I think that's as good as I'm going to get and as good as one could expect from a 50 year old machine. I'm happy enough with it.
I think a new project will be to make a stop collar for the headstock.
-Bruno
Reply to
Bruno

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