Help! loose chuck

I'm searching for a Taper Chuck, JT33. Specifically, with a 'clamping' action onto the spindle.

A technical drwng would be benefical to help determine - it's hopeful working on my 1" of available spindle?

Could you please aid with this? ... and enlighten me with your suggestions?

"JT" is for Jacobs Taper. A JT33 chuck will have a #33 jacobs taper in the back end. It will fit just perfect on a spindle with a #33 jacobs taper on it.

Won't fit other spindles.

John

I believe that the Jacobs number 33 taper is specifically for drill press spindles, usually the machines that go up to about 1/2 hp, or for drill chucks that have a maximum capacity of 1/2-inch.

This is a somewhat common chuck. Jacobs makes a "model 633" chuck, which is held on only by the friction in the taper.

I'm not sure what you mean by "clamping action," but Jacobs also makes a "model 633C", which additionally has a threaded collar that screws onto a threaded portion of the spindle, which keeps the chuck from falling off if the taper doesn't hold it.

Here is a drill press which uses the model 633C chcuk:
http://cgi.ebay.com/VINTAGE-DURO-16-DRILL-PRESS-IN-IMMACULATE-CONDITION_W0QQitemZ7537224501
You can see the collar just above the body of the chuck, as it is on the threaded part of the spindle.

Most new imported drill presses that you can buy for about $100 at Home Depot use a number 33 Jacobs taper. The imported drill chucks that come on these machines are all crummy and frustrating to use. An old American or European chuck works much more smoothly, and is pleasant to use. You can get a used drill chuck on eBay, or you can buy new from a place like www.use-enco.com.

The jacobs "34-33C" is the more commonly available 1/2" chuck w/ threaded locking collar as used on a long line of Rockwell/Delta drill presses with JT33 spindles. I have never heard of a "633C" but that means nothing.

The locking collar is threaded 1-1/16 - 20 tpi and attaches loosely by a retaining ring on the chuck arbor just inboard of the taper.

If you are having trouble with the chuck holding I suggest using a sharpie marker on the male taper shaft then fit the two as closely as you can and turn (kind of like grinding) them against each other by hand.

Now disassemble and look at the contact...where the sharpie is rubbed off.

Burrs and pimples will definitely affect the contact and prevent proper locking and seating.

I have fixed problems with gentle application of a single cut file and abrasive paper.

The unwanted sharpie marks are removed with rubbing alcohol, which also does a nice job of cleaning the metal tapered surfaces so they will "wring" together somewhat like gage blocks and stick.

A firm deadblow hammer blow will seat it for good.

-Matt

The 633C also uses the locking collar with threads of (1-1/16) - 20tpi, so I guess that model is similar to the 34-33C.

"Supreme" is another brand of American made drill chuck that seems equivalent to Jacobs.