What tap for tool steel?

[orionstarman]

At my shop we had been using Hanson-Whitney taps, for A2 and D2 tool steels, but our local supplier told us that they went belly up and he can not get them any more. The taps he recommended turned out to be junk. Can someone recommend a good replacement?

Also, at my shop it has been standard practice to only tap holes .300" to .400" deep max, in the CNC mill, and then finish off by hand. This is not so bad when your just doing a couple of holes in a couple of parts but when you have 4 or 5 holes in a couple of dozen parts it gets old fast. Is this the standard practice at other tool and die shops?

What kind of tapping oil do you use? I worked at one shop that used a thick, black and smelly oil. I think they called it Huber's oil... not sure but it worked great.

Thanks

[HuFlungDung]

I do believe in step tapping holes that are more than twice the diameter of the tap deep. I've tapped enough holes by hand to get the feel for about how far I can turn a tap in before it begins to get "dry" and to need another application of cutting fluid.

I'm very cautious, because I don't have a tap burner I have no trouble doing this repeat tapping with rigid tapping in my Haas VF3, nor did I have trouble doing step tapping with a floating tap holder in my older non-rigid cnc mills.

I use sulferized cutting oils to tap threads in steels. I've found that I get much longer tap life that way, and that results in better quality threads for more holes. I brush the fluid on the tap. I also make use of a skimmer to get that oil back out of the coolant.

BTW, Kennametal makes good taps for the tough jobs, but there are several other good makes. Don't buy the cheapest ones

[dertsap]

kennametal and yamawa are both good taps ,though personally i lean more toward the yamawa

[pepo]

A cordless drill with an adjustable clutch is an awsome tool for "hand tapping" right to the bottom of a hole. I got a lot of raised eyebrows a year ago when I brought one into the shop. Now half the guys have them and the other half is borrowing them. In tooling I power tap a few turns deep on a mill to keep things straight then finish on the bench with the drill. Takes 5 seconds to do what use to take me 2 minutes. Its not for every situation but sure has saved me a lot of work.

[NC Cams]

Emuge makes some pretty good high end taps. We had some airfreighted in overnight. Nice guys to work with.

The taps worked great, until we stuck/broke them...... Although their special hard ones are supposed to be able to cut Hrc 50, don't count on it. Use EDM when you get that hard.....

[5th-axis]

I have had great luck with Emuge taps. At my previous job I used to tap holes in 52100 bearing steel. I would tap approx. 300 holes before I changed the taps. The steel was green and not heat treated, but was pretty gummy. I just used flood coolant and kept my speed down around 200 RPM. On blind holes, I used a spiral fluted tap. On through holes, I used gun taps. On hardened material I used carbide taps. They were costly, but worth it.

[KENNETH BROWN]

My Shop Gave Up On Emuge Now Use Osg Taps. We Tap Everything(a2,d2 4140 Per Hard,1018 And Cast Iron) With Them(ridgid And Floating Head),and They Are Cheaper Than The Emuge's,use To Do The Same Thing Only Tap A Few Threads Down And Finish By Hand But With The Switch To Osg We Tap Complete.we Still Break A Tap Once In Awhile, But A Lot Better Than What We Had.

[orionstarman]

Originally Posted by HuFlungDung I do believe in step tapping holes that are more than twice the diameter of the tap deep.

What do you mean by step tapping? How do you do it?

Originally Posted by HuFlungDung I use sulferized cutting oils to tap threads in steels. I've found that I get much longer tap life that way, and that results in better quality threads for more holes. I brush the fluid on the tap. I also make use of a skimmer to get that oil back out of the coolant.

What it the name of the sulferized cutting oil that you use?

[HuFlungDung]

Step tapping: program sequential G84's calling different depths at the same hole position.

Rigid dark thread cutting oil would be one type of sulferized oil.

[cnc-king]

Originally Posted by HuFlungDung Step tapping: program sequential G84's calling different depths at the same hole position. Rigid dark thread cutting oil would be one type of sulferized oil.

you can also add a Q value to your G84 line so you don't have to rewrite the G84 line. G98 will bring you back to the initial plane to start the next peck.