Help with 6-32 Form tapping in cnc

ApolloSpeed

Plastic

Joined

Aug 28, 2007

Location

texas

• May 1, 2015

• #1

We are having some issues putting 6-32 taps about about .400" deep into 6061 aluminum.

So we just bought a few Greenfield HSGH3BOTT Trulede FE 6-32 form taps. Was planning to drill with .125" drill about .750" deep, and form tap about .400". I don't have ridge tapping on our fanuc cnc, but I do have a floating tap holder. Will be using blauser coolant and programming in mastercam x8.

What RPM?
Do I program it just like I would a regular tap in Mastercam?

I've never done form tapping, so any advice would be appreciated before I commence to breaking more taps! lol

 

drewboyer

Stainless

Joined

Apr 7, 2009

Location

Odessa, TX

• May 1, 2015

• #2

Just run it like you would a normal tap. I have rigid tapping on my mill but I run it at about 1300 rpm in 1018 in a .122" hole

 

Nerdlinger

Stainless

Joined

Aug 10, 2013

Location

Chicago, IL

• May 1, 2015

• #3

The only thing I've learned with form tapping is that the pre-tapped hole diameter is critical - too small and the tap breaks, too big and the thread doesn't form up all the way and you end up with what looks like a double thread. My machines have rigid tapping but I would think you can program it just like you would a cut tap in your floating holder. Is there an SFM recommendation on their website? I always just call the tech guys and get their recommendation...usually send helpful.

 

J

Jorgo

Hot Rolled

Joined

May 11, 2008

Location

Sechelt BC

• May 1, 2015

• #4

6-32 was my nemesis before discovering form taps. I would break them like they were free. Since I started form tapping I haven't broken one. I run them exactly the same speeds as cut taps with coolant. I use DoAll kool tool semi synthetic coolant.
Jordy

 

K

kevin66

Aluminum

Joined

Apr 1, 2015

• May 2, 2015

• #5

You didn't say if you were tapping a blind hole but I assume that you are. We have both floating and rigid tapping machines. We have found that in blind holes we only will use roll form taps that have an oil groove. The taps that don't always have a higher probability of breaking due to the hydraulic pressure that it takes to displace the oil/coolant that is in the bottom of the hole.

 

Metalcutter

Titanium

Joined

Sep 14, 2005

Location

San Diego

• May 2, 2015

• #6

It's a FORMING Not cutting tap. A couple of drops of way lube will be better. Cutting oil with 80% water, you may find galling.

Regards,

Stan-

 

G

gustafson

Diamond

Joined

Sep 4, 2002

Location

People's Republic

• May 3, 2015

• #7

I use a 3.1 mm drill[.122 as noted above] as .125 usually ends up too large

 

G

gdgambler

Hot Rolled

Joined

Oct 1, 2006

Location

K. Falls, Oregon

• May 5, 2015

• #8

With a floating holder I make sure the feed is alittle slower feeding in and the pullout is alittle faster so the tap will for sure be floating in and out otherwise the feed could over pressure the tap and break it or on the pullout could be the same way.

 

Mike1974

Diamond

Joined

Nov 5, 2014

Location

Tampa area

• May 6, 2015

• #9

Jorgo said:

6-32 was my nemesis before discovering form taps. I would break them like they were free. Since I started form tapping I haven't broken one. I run them exactly the same speeds as cut taps with coolant. I use DoAll kool tool semi synthetic coolant.
Jordy

Click to expand...

I have a part I form tap a 1-64, lucky me. have not broken any yet (JINX!)I also run parts with cut and form taps for 2-56. The form is especially hairy since I am running it to within about .003 of the bottom of the hole (the hole is milled to flat bottom), and I had to grind off about 1 to 1.5 of the lead to get the depth in a blind hole... stupid engineers!

Metalcutter said:

It's a FORMING Not cutting tap. A couple of drops of way lube will be better. Cutting oil with 80% water, you may find galling.

Regards,

Stan-

Click to expand...

I have been form and cut tapping with our Hysol MB50 with no problems. I run between 8-10% concentration. Oil is fine for tapping, but unless you have a setup, the minimal lube system or whatever, it is quite the pain to reach into the machine and dab some oil on the tap/part for every hole.

 

D

dksoba

Hot Rolled

Joined

Apr 8, 2011

Location

San Diego

• May 6, 2015

• #10

Jorgo said:

6-32 was my nemesis before discovering form taps. I would break them like they were free. Since I started form tapping I haven't broken one. I run them exactly the same speeds as cut taps with coolant. I use DoAll kool tool semi synthetic coolant.
Jordy

Click to expand...

Me too, exactly the same story. Form taps are sweet. Also, if I don't have a 6-32 form tap on hand, I discovered that increasing the minor diameter (The range is 0.104 to 0.114" according to thread pal for a class 2B fit) helps a lot. And, if you insist on using the 0.1065" (#36) drill peck tapping can get the job done beautifully.

Now, back to the op: I'd start at a low RPM not knowing the type of machine you have, say 200 to 500rpm, and program just like a regular tap. Program it to start/end above your hole by a good amount (say 0.5"), so that for sure it gets out of the hole. After you get that working, you can go down from there. I think I'd also be using a 3.1mm drill. Blaser coolant should be good, but make sure your concentration is up there (8% or more is what I like, but YMMV).

Matt