Hand Tap Recommendations

[robk]

I need to tap a few 1 1/8"-7 blind holes in 420ss. Anybody have any recommendations for manufacturers of hand taps that size?

 

It's been a long time since I hand tapped anything, yet alone that big. As a matter of fact this will be the biggest hand tap I have ever used.

[crazy^millman]

Hand tap huh. Might look to Widell or someone like that if it is a special. If standard anyone should carry one.

 

HTH

 

www.widell.com

[Charlie Pierson]

www.emuge.com

 

 

cp

[b_daddy]

I'm with Ron, Widell has been good for the specials.

[Mgrenier]

Robk,

 

Why use a hand tap? Can you use a spiral fluted tap that will evacuate the chip out of the hole? That would help since hand tapping these sizes a not a small job. Wouldn't want to be the person doing it.

 

Just my 2 cents,

[Gary]

We do alot of bigger stuff like that and TAP MAGIC makes all the differance on thread quality on bigger taps. If you have a strong machine make a driver for your tap and drive it that way. Beats a big handle or cresent wrench.

[Chris Rizzo]

If it's something that you can't get in a machine, mag drill presses are great for tapping big holes. They have reverse and pretty good torque. You'll have to clamp a steel plate to the stainless material though for the magnet to grab. I've snapped a 7/8" tap with a Miwaukie mag press in 304l stainless. Switched to a tin-coated spiral flute tap and ran a few dozen holes no problem from there. I don't really like running sprial fluter's by hand though, (meaning in a tap handle). They are pretty unforgiving.

 

hth

[Kevangel]

I put a spring loaded center in tap and a 4' peice of pipe on the end of an adjustable wrench and use Butterfield drilling and tapping fluid in SS. fluid really makes a diff. Flatten pipe with wrench inside and "weld with duct tape"

[MIKE_B]

quote:

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Flatten pipe with wrench inside and "weld with duct tape"

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We like to use molly D here for ss tapping

[P_Scott]

robk,

 

Why not use the Thread Mill cycle with a single point boring tool? Mcam X MR1 included roughing passes for Thread Milling. Large diameter threads are usually much easier with the thread mill op. Then you wouldn't have to look into buying a specific size tap and hand working it. HTH

[heavychevy2155]

im with peter on this one.

[robk]

Thanks guys... I ended up ordering a tep from Greenfield. My catalog wasn't up to date.

Anyway thanks for the different suggestions. Can't thread mill because part will not fit on machine.

It will fit in our radial drill, but it will most likely be cheaper to use a tap wrench instead of getting a tap holder. Thanks again.