o/t acme thrd bars?

[Gary]

I am wondering who all of you guys use for acme threading bars? I have some 7/8-8 nuts to make out of 360 brass. They are about an 1.5 long. i need to thrd these on a lathe because of the odd pitch They should cut like butter but i need a source for hss and/or carbide tools. I checked on getting a tap made but was 182.00 bucks and boss just gave me the look. Any info would be great.

Thanks

Gary

[betts]

Sorry I can't help you decide on a thread tool, but it really does beg the question, why aren't they using 7/8-6?

 

Customer is always right.

 

How many do you have to do?

[Bzwak]

Hey There,

"ph HORN ph" out of Germany makes the carbide bar BU111.0500.03 That we are using to do a 3/4-6

ACME in 6061. It takes a ton of passes and low SFM, but it comes out Great.

[Gary]

Small quanity order so i am going to shelf some. Yeah the original supplier uses odd ball sizes so they could sell the replacements $$.

[crazy^millman]

Well I made my own. I took a piece of O1 toolsteel made the relief for the area I wanted then had it heat treated. I then cut them with no problem. I have done a 2" 4 tpi acme nut on the CNC this way in 12L14 and it worked very well.

 

HTH

[MCam Newbie]

Internal Tool makes several sweet solid carbide tools for Acme threads. Most insert type lathe tool suppliers offer that type threading insert as well. Try Vargus or Sandvik. All of the above mentioned have websites.

[Philcott]

As I am sure Gary has found out, the problem is trying to find a bar that will fit into a minimum bore of between .7 and .73 and still hold an acme insert. I would either do as Ron has mentioned and grind up your own bar or go the tap route. Unless this is a through hole and cut from blanks I would think you will need to run the tap as a 2nd operation. I have not heard of Bzwak's bar from Germany but I will, for interest sake try to have a look at it.

 

Phil