peck ridgid tap/2

[fuzzyracing1967]

Hi guys,was keeping an eye on the first thread about this,but making it work wasn't a question for me.I am more interested in when you think it is called for.The code that you all put up is for holes taped .75 deep,I'm doing holes over 1.25 deep with just strait tapping with no poblem.Was wondering what the benefit is that you see by pecking? Is it becouse of mateiral,depth,or something else?

[rrossey]

I posted a new thread for help about the rigid tapping. As you are tapping these depths in one shot, can you suggest the right parameters?
Thanks,
R. Rossey

[bishb25]

I use peck tapping for 6-32 taps in steel 3/4" deep. If I don't, the tap will almost always break. Check setting #133 "repeat rigid tap" ( if your machine has this setting) and set it to "ON" for peck tapping.
That's the only job I've had to peck tap.

[fuzzyracing1967]

6-32 in steel 3/4 deep,yeah I can see that you would want to peck.I just don't see having the need to peck once you get above 1/4-20,unless the the material calls for it.I just don't see where it can help in most apps,I mean I have a 30 year old cinn millacron machine tapping 1/2-13 holes 2.5 inches deep in 4140 with no problem.Forgive me but I'm looking at this as,(how is this saving money),ok a little easer on the tap,but nothing else.

[Geof]

Originally Posted by fuzzyracing1967 .....I mean I have a 30 year old cinn millacron machine tapping 1/2-13 holes 2.5 inches deep in 4140 with no problem......

What is your tap drill size/thread percentage?

Certainly with 1/2-13 pecking is less necessary because chips clear better and the tap is stronger. Also in 4140 I believe the chips curl very nicely out of a spiral flute tap.

I have sometimes encountered problems in HRS using a tapdrill size for a 75% thread because the chips do not clear nicely but going to a 65% thread with a large tapdrill means pecking is rarely needed.

[fuzzyracing1967]

(What is your tap drill size/thread percentage?

Certainly with 1/2-13 pecking is less necessary because chips clear better and the tap is stronger. Also in 4140 I believe the chips curl very nicely out of a spiral flute tap.)

Well this is partly why I asked this question in the first place,I'm using a 27/64 drill going to a dpeth of 3.5 inches,and tapping with a gun tap.Granted we put oil on this ,but still no need to peck,even if we could with this antique.
I so hate this machine,I swear I could do things faster by hand,lol
so I'm still wondering why peck?

[Donkey Hotey]

How many holes have you tapped by hand where they went full depth without binding up with chips? I've had taps get stuck in a deep hole from that very problem.

The chips get bound up in there, then at the point where you stopped cutting, there are little burrs. The bundle snags and your tap ain't coming out without some wiggling. The mill doesn't know when to do that 'wiggling' so your only alternative is to peck tap.

I'm a recent 'form tap' convert. I ain't cutting threads again unless I have to.

[fuzzyracing1967]

Well thats why I ask,if I was tapping by hand i would be reliving the tap as I go,reguardless of the depth or the tap itself.I just don't see a reason to be pecking with the machine,maybe with the exception of tapping alum/bronze.
Maybe I'm missing somthing here,but I just don't see a reason to be pecking.

[Donkey Hotey]

Wait...so you say that you'd peck the tap by hand (relieving it) but you don't know why you'd want the machine to do it? Now I'm confused.

Hmmm...I just went back and reread your original post. I still don't understand why you don't understand. If you're doing 1000 holes a day and don't have time to stand over the machine, you can't afford to nurse it through every cycle. Pecking ensures that it's going to pull out and get a good rinse and lube before it goes back in for another go at the material.

The first 367 holes might go great, then sometime around 10:00 AM, you hear the 'snap' come from the cabinet...if you're lucky enough to hear it. Maybe it's one hole per part and you can afford to throw it away. Maybe it's a tooling plate with 200 holes and you just broke a tap inside one of them. EDM or scrap pile: here I come.

[PBMW]

I have a couple of jobs that when I run them I tap wlell over a thousand holes a day. I don't peck tap. I got no time to stick a tool in there twice or three times.
I run a 1/4-28 roll form tap in 1018 at 1200rpm in my Mini. .700 deep.
In and out. Keep an eye on the tap, keep track of how many holes it's done and be inspecting every ten or so parts with a plug gage...
The only time I would EVER even THINK about peck tapping would be when the machine runs out of power to turn the tap. But then, I'd have the job on the wrong machine, wouldn't I?

If you are thinking about pecking because of chips, You're using the wrong tap.
Spirol tips for through holes, spirol flute for blind holes, form taps for both.

[fuzzyracing1967]

Donkey Hotey now there you bring up a reason for useing it,I don't do parts with anything near that many holes,most parts under say 5. See the reason I asked about this is from a time stand point,just like pbmw says he doesn't have the time to go back in holes all day,but I can see it if it made the differance between making a good part or scrap.Don't get me wrong I can see using pecking,but I just don't have a need for it right now,I hope in the future I have parts where it came in handy though.