Tapping Acme Threads

[TexasRotorHead]

Im sorry for the simple question, but I am having a small difficulty with this problem I am having.

Basically, I need to tap a blind 5/8-8 hole into an aluminum piece I have made.

Almost all of the taps I have found are tandem, so I cannot use them. There are also roughing and finishing sets, but they are a little out of my budget.

Are there any companies that sell cheap acme taps for a blind hole or types of machine shops that cut alot of acme threads?

Thanks.

 

[berkshire]

Buy two and cut the lower taper off one to make a plug tap.
B.E.

 

[MikeHalloran]

A CNC machine shop can mill the threads.
You'll probably have to buy the thread milling tool they'll need.
For a few pieces, you might get away with a severely modified tap.



Mike Halloran
Pembroke Pines, FL, USA

 

[11echo]

berkshire (Aeronautics)
..."Buy two and cut the lower taper off one to make a plug tap."

"Plug tap" ..OR Bottoming tap?

 

[mfgenggear]

TexasRotoHead

what do you mean by this statement,
"Almost all of the taps I have found are tandem, so I cannot use them".

The three styles of Taps are Taper (Starting), Plug & Bottoming.
if one looks at the the three types of taps in the machinist handbook it explains the three style of taps.

acme taps are made in sets starting/roughing, second roughing/sem-finishing & a final finishing.
The Taps are diffrent geomtry for hand Tapping Vs Machine
Tapping.

if the hole is a blind hole the a bottoming taps will be required.
I would recommend having these taps made for your requirement. if it is not off the self Item.

while mill threading the internal acme is possible, In my opinion, it is much easier to tap.

HTH
MfgEngGear

 

[BillPSU]

Acme threads are usually not used in a blind hole. They were predominantly used as a feed screw application. The amount of thread depth and width requires the tandem tap to produce the thread. If you really need an blind acme thread have it thread milled.

 

[saberblue]

You might want to see if there is a used machinery dealer in your area -- you might be able to find the taps you want for pennies on the dollar -- use them to make the parts you want and then sell the tools back -- the other alternative is E Bay

A.R. "Andy" Nelson
Engineering Consultant
anelson@arnengineering.com

 

[ornerynorsk]

The tandem tap that you mentioned is the industry standard and getting ahold of bottoming taps is not going to be a stock solution. You can modify a woodruff cutter, if you have any toolgrinding ability, to make a passable improvised acme thread mill, but you can't get very deep into a hole with it. Making an improvised weld-in insert from a stock acme aluminum nut is going to be your best solution, if you have the space or design allowance in your part to do so.