Help With Tap Chuck

[hman]

Issues 231 and 232 of Model Engineer's Workshop include a 2-part article entitled "Making a cantilever tool for square tapping," by Morgens Kilde. The article includes plans for a very interesting 4-jaw tap chuck.

Unfortunately, I've misplaced or lost issue 231, which includes key drawings for the chuck body. I've tried to buy a copy of this back issue from the publisher, but they've told me it's no longer available. If anybody on the forum has a copy, I'd sincerely appreciate your letting me know. All I really need is a black-and-white Xerox of Part 1 of the article. I'll be happy to reimburse any expense.

-alternatively-

Does anybody know of a small scroll-type 4-jaw chuck? I'd like to try to adapt one for holding taps.

I'm really tired of tap handles that either don't hold a full range of tap sizes (at least #0 thru ½"), or those that loosen and lose the tap at the slightest disturbance. This whole thing has been a pet peeve of mine for quite some time now! I'd love to find a solution. The chuck in the MEW article looks like it will work ...

Thanks!

 

[RJSakowski]

Chucks used on woodworking braces are designed to hold the square end of a wood bit.

Bob

 

[hman]

Hmmmm ... might be worth considering if I can't find anything else. I used to have a brace and bits, and though the ends of the bits were square, they were also tapered at about 5 degrees. So the chuck probably won't get a solid grip on the straight-sided square section of the tap.

 

[RJSakowski]

Hmmmm ... might be worth considering if I can't find anything else. I used to have a brace and bits, and though the ends of the bits were square, they were also tapered at about 5 degrees. So the chuck probably won't get a solid grip on the straight-sided square section of the tap.]112883[/ATTACH]

John, I took a look at my brace chuck and it appears to do a reasonable job of holding taps from 4-40 to 9/16". The play that I observed was in the direction at a right angle to the jaws and caused by excessive clearance between the jaws and the drive socket. IMO, I would have adequate control of the tap.

If you really want a four jaw, your question was asked in this forum post: http://www.practicalmachinist.com/vb/general/4-jaw-drill-chuck-142151/
Apparently, the Wahlstrom chuck is a four jaw and is still available. http://www.workholding.com/EAGLEROCKPROD.HTM

Bob

 

[hman]

John, I took a look at my brace chuck and it appears to do a reasonable job of holding taps from 4-40 to 9/16". The play that I observed was in the direction at a right angle to the jaws and caused by excessive clearance between the jaws and the drive socket. IMO, I would have adequate control of the tap.

Wow! Thanks, Bob. Guess I'll have to but a bit brace someplace and see if I can adapt it (maybe cut off a short section of the shank, to hold in a collet or regular drill chuck. #4 to 9/16" is definitely a worthwhile range!

If you really want a four jaw, your question was asked in this forum post: http://www.practicalmachinist.com/vb/general/4-jaw-drill-chuck-142151/
Apparently, the Wahlstrom chuck is a four jaw and is still available. http://www.workholding.com/EAGLEROCKPROD.HTM
Bob

Very interesting chucks ... but a bit pricey. I'll keep them in mind, though.
Thanks again!

 

[hman]

Huge THANKS to Savarin, who had the original issue of MEW, scanned the article it for me, and sent it via email!!! I can now proceed with fabricating the tap chuck. Thanks also to RJSakowski ... the bit brace chuck will be my backup plan. This forum is just too great for words!

 

[Eddyde]

Not sure why you need to hold the square part? I have never had a problem holding them by the round section, in in a regular drill chuck.

 

[rock_breaker]

My experience with a drill chuck is difficulty in reading the size of the tap after a few passes with the tap in the drill press chuck.

Have a good day

Ray

 

[hman]

Not sure why you need to hold the square part? I have never had a problem holding them by the round section, in in a regular drill chuck.

I've done that. One of my favorite techniques is to hold the tap in the chuck of a variable speed reversible drill, especially when tapping aluminum. But all too often, especially on the lathe or mill, the chuck just can't hold the tap tightly enough, and the tap spins. As rock-breaker pointed out, this will sometimes rub off the identifying info. If the tap has stamped markings, these will sometimes mar the chuck jaws.

When hand tapping, I've had way too many instances of the tap handle loosening. OK, maybe it's because I've bought cheap (Irwin, among others) tap handles. But this and the fact that they're limited in capacity (usually ¼" or smaller, or ¼" or larger) makes me want to find something better.

I have high hopes for Morgens Kilde's design. Once I've fabricated the chuck, I'll give it a thorough workout and report on my results here.