Rigid Tapping

Jim at Gentex · June 15, 2022, 05:01 AM

I hardly ever use rigid tapping, so this may sound like a dumb question.

Should I use the same speed / feed parameters for a 4-40 Heli-Coil tap as I would for a regular 4-40?
I think the pitch is the same, but this is the first time I have ever had to rigid tap for a Heli-Coil.

Yeah, go ahead, feel free to pile on the n00b...

JParis · June 15, 2022, 05:14 AM

In rigid tapping, most machines rely upon the pitch...it links the spinde and feed to that number....you can run the speed as you like...the pitch will handle the feed....may need to see how fast you can get it on your equipment...we "generally" run ours around 2000/2500 rpm...doesn't actually hit that number but the time to tap eack hole is quick

Jeff · June 15, 2022, 05:26 AM

Quote from: Jim at Gentex on June 15, 2022, 05:01 AMYeah, go ahead, feel free to pile on the n00b..

lol I'll go easy on ya.
Yes use the exact same speed and feed for a #4-40 as you would a #4-40 helicoil tap. It's just a tad larger and you should be using SFPM anyway, so size does not matter. (or so I've been told

)

I've changed all of my posts to spit out a G95 for tapping. So now if the operator needs to change the rpm for any reason like flame hardening got a little too close to the holes, etc... they can just change the rpm without having to worry about matching the feedrate.

We tap about 10,000 #4-40 helicoil holes per year in one of our vmc's if not more.

Jim at Gentex · June 15, 2022, 06:54 AM

OK thanks for the input, guys.

We have 4x very shallow holes (only 0.3" deep) in a small plastic part, so it should be an adventure!
The fixture holds 12x parts per cycle, so drill & tap 48 holes each run.

Jeff · June 15, 2022, 07:26 AM

Gravy!

CNCAppsJames · June 21, 2022, 07:23 AM

When tapping you REALLY can't beat switching to UPR (G95). Then you can put away the calculator and just adjust your speed to suit the material/conditions.

JM2CFWIW

TSmcam · June 21, 2022, 01:12 PM

Quote from: CNCAppsJames on June 21, 2022, 07:23 AMWhen tapping you REALLY can't beat switching to UPR (G95). Then you can put away the calculator and just adjust your speed to suit the material/conditions.

JM2CFWIW

Totally agree. G95 all the way. Using G94 and used Tap Pitch x RPM is throwing back to the days of compensating to the centre of the radius of a ball nose cutter