Tap turning

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Sunami

Member
Joined
Sep 17, 2015
Messages
40
Location
Baltimore, MD
What do you all use to turn the taps on your lathes? I got to that part of my project and realized I really didn't know how to turn it. I took it out of the lathe and did it by hand and wrench.
 
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bobleibo

Member
Joined
Mar 15, 2007
Messages
2,130
Location
Utah
Stick the tap in the tailstock and slowly turn the headstock with the blank mounted in it by hand while advancing your tailstock in unison or let it float free if it will cooperate. Pretty much like drilling blanks on the lathe.
 

jalbert

Member
Joined
May 17, 2015
Messages
993
Location
Louisville, KY
I use one of these guys to turn the part while threading:
https://littlemachineshop.com/products/product_view.php?ProductID=3897&category=

Seriously one of the best accessory purchases I've made for my lathe.

My approach to threading on the lathe is as follows:

1.UNPLUG lathe
2. Insert crank in the back of the headstock spindle and tighten
3. Insert tap or die holder in tailstock Jacob's chuck.
4. Make sure tailstock is not locked down, and can slide freely.
5. Gently butt tap or die up against piece to be threaded, and turn crank counter clockwise a few times to make sure the tap or die is nicely centered up on the workpiece.
6. Turn crank clockwise and thread the work piece, while simultaneously applying enough pressure to move the tailstock forward as the tap or die gets pulled into the work piece. Back off the tap or die off a bit after every couple of turns to break the chips loose.

This has worked very well for me. The key is to move the tailstock with your right hand while threading. Don't let the movement of the work piece pulling in the tap or die move the tailstock, or that could potentially lead to some nasty breakages.

-John
 

duncsuss

Member
Joined
Jun 29, 2012
Messages
2,161
Location
Wilmington, MA
What I do: "this works for me", YMMV, etc, etc.

I put the tap into my MT2 Jacob's (drill-bit) chuck and slide it into the tailstock, just a little loose so that I can rotate it by hand but not so loose that it wobbles.

The tap has to be pushed in far enough that the chuck grips on the round part of the shank (beyond the squared-off part).

I lock the headstock and slide the tailstock up so the nose of the tap is touching the hole, then simply grab hold of the chuck and turn the tap into the part.

I don't worry about the back end of the Morse taper sliding out of the tailstock, by the time it's moved far enough to where it could begin to tilt, enough threads have been cut to keep things running true. (And I'm holding the chuck anyway, I don't let it drop.)
 
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