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pntrbl
10-27-2009, 01:18 AM
I'm building myself a tapping attachment for the turret on my lathe. I think I got it all figgered out except for the part about holding the tap. Small problem! :D

I see rubber collets are typically used for this but other than pics of the collet itself I haven't a clue how they are held. I imagine some kind of taper with a screw on cap and I see ENCO sells some tapping parts, but there are no pics in the catalog to glean any info from. Purchased parts would be fine but if they can be made by a guy with as little experience as me that'd be fine too.

There will be a 1/2" shaft of whatever appropriate length to work off of the end of.

Thanx for any advice.

SP

gr8life
10-27-2009, 01:37 AM
I posted this just the other day on another site. I do a lot of tapping on the lathe. I have 2 jobs I do a few times a year that involve a lot of tapping and a lot of cutting external threads so I came up with this solution.
First you need to make a shaft with a morse taper to fit your tailstock, mine happens to be a mt3. You can find the taper angle in Machinery’s Handbook or follow some of the posts that show you how to copy a taper.
The shaft is steel, all of the sleeves are aluminum but could be steel. Use what ever you have in your surplus material supply center (the junk box)
The tap holders are Irwin about $20 and hold everything I need from 2-56 for the small one up to 9/16 for the large one.
The smaller one has no lever because I can hole the knurl until it spins in my hand. The large ones, including the die holders have levers but care must be taken when using them. If you get too aggressive you will either break the tap or your hand. I tap in , reverse out then tap in again. When I get near the bottom I use the inch/jog button. I included a picture of how I hole the lever. Should something go wrong the lever pulls thru my fingers and if you are quick you can stop the machine before the tap breaks.
There are 3 size die holders because (guess why) I use 3 different size dies.
Hope this helps someone.
Thanks,
Ed Pictures next reply

gr8life
10-27-2009, 01:38 AM
http://i461.photobucket.com/albums/qq336/gr8lifeLV/TapDieholder002Small.jpg
http://i461.photobucket.com/albums/qq336/gr8lifeLV/TapDieholder003Small.jpg
http://i461.photobucket.com/albums/qq336/gr8lifeLV/TapDieholder005Small.jpg

pntrbl
10-27-2009, 02:52 AM
Thank You for that Ed. Those Irwin tap holders are looking like they could work just fine. How are they attached to your knurled sleeve? Pinned? Setscrew?

SP

JCHannum
10-27-2009, 08:35 AM
The various tapping heads use the tap holders with the Rubberflex style collets or steel collets. The collets serve to center the taps in the holder, not drive them. There is a floating clamp at the rear of the tap holder that does the driving by gripping the flats of the tap.

gr8's tap holders are nicely done, and present an alternate to the tapping head style.

Carld
10-27-2009, 10:10 AM
Maybe I am missing something here but what I see is you modified a standard Irwin T handle tap wrench to clamp into the knurled sleeve you made that fits over the MT shaft.

So if I see it right you made everything except the tap wrench part that holds taps and the holder for the dies, is that right?

I like that method and will roll it around in my mind for my version.

I usually just chuck the tap in my tailstock and power tap with that. If the tap slips in the chuck I either tighten it a little or finish it by hand.

gr8life
10-27-2009, 11:18 AM
The Irwin's are held w/ set screws or any way you want. There is a long thread going now on the PM site under general new.
ed

Carld
10-27-2009, 11:36 AM
I no longer go the the PM site because Don is a major prick so I will not see anything anyone says is there. Don't worry, he hates me as much as I hate him and don't let him tell you otherwise 'cause he would be lying to you.

Jpfalt
10-27-2009, 02:16 PM
Most of the tapping I do on a lathe is done with spiral point taps and I use a standard drill chuck. Where the tap shank is polished and hardened, the tap will spin if it hangs up before the tap breaks.

This may be heresy to some, but it works.

gr8life
10-27-2009, 02:27 PM
If it works for you good. Like pilots say "any landing you can walk away from is a good landing"
ed