Cut Tap for 1215 LCS ?

Ox · Dec 29, 2018

3/8-16
1.06 through
1/2" round stock
in the sub-spindle

I have been using the Mod Btm Sp/Fl taps, but 1215 just aint stringy enough to make it work, and it's just too deep that it loads the flutes up.
I went through 2 or 3 taps in 300 pcs. Then tried a Sp/Pt tap, but that packs the sub collet and stripper up post haste!

I make the same part in 5/16 and 1/4" threads as well. None of them run much volume.
The 1/4" I would form and be done with it.
Possibly the same for the 5/16, but I'm not even sure if we've ever made the 5/16 version.

But forming 3/8-16 in 1/2" round - in the sub-spindle no less, just aint a good plan.
It could (should?) spin.
It could crack.

I tried to get a std Sp/Fl tap the other day, but they didn't have any of those in stock locally.

So I just tore that job out (I have <200 for stock at this point anyhow) but wonder if anyone has a GO-TO tap for jobs like this?
I find these type jobs to be about the worst for finding taps for these days.

Machine does NOT have rigid tapping, so don't want to peck it.

So, what cut tap doo we like for this?

-----------------

Think Snow Eh!
Ox

DDoug · Dec 29, 2018

Properly aimed piece of 3/32 brake line tubing with compressed air ?

If you get it real close, could it evacuate the chips ? (with the first tap
that packed the chips)

Or with the spiral tap packing the collet, could a clamp on chamfer
ring be used like an old time clamp on chip breaker ?

Shop Supply Guru · Dec 29, 2018

You could threadmill it. You could get a coolant through bottoming tap. Usually modified bottoming taps have 2-4 threads chamfered. I would be curious to see if you got a spiral flute bottoming tap with 1-2 threads chamfered if that would break the chips better.

What RPM are you running?
What helix angle is the tap?

litlerob1 · Dec 29, 2018

You have Y on there right? I would look at Thread-milling.

Are said Modified Bottoming style, so I assume you mean these;;

Hopefully not these, they grab on chips that are supposed to be coming out.

Have you tried these ones?;;

Not sure if one is better than the other one. Honestly, I'd at least try Rolling them, 1215 is about as easy as you get without Lead.

R

Hazzert · Dec 30, 2018

Peck tap it, it shouldn’t add much to the cycle.

Whysosharp · Dec 30, 2018

I second the form tap. Just shoot for 55-60% thread in steel I wouldn’t even be concerned.

litlerob1 · Dec 30, 2018

Hazzert said:
Peck tap it, it shouldn’t add much to the cycle.

Can't, no Rigid Tapping.

adama · Dec 30, 2018

Don't know, would also like to know, have never found spiral flute reliable past about 2D deep.

cnctoolcat · Dec 30, 2018

Maybe try some high-dollar, exotic-coated, “slow spiral fluted” taps by OSG, Greenfield, or Emuge...?

guest · Dec 30, 2018

I would be in the form tap camp. At least until I knew it didn't work.

HY PRO NRT Taps - OSG

Whysosharp · Dec 30, 2018

What’s your stick out like if your deep enough in the sub spindle I can’t imagine any issue

Ox · Dec 30, 2018

Whysosharp said:
What’s your stick out like if your deep enough in the sub spindle I can’t imagine any issue

What?

Shop Supply Guru said:
You could threadmill it. You could get a coolant through bottoming tap. Usually modified bottoming taps have 2-4 threads chamfered. I would be curious to see if you got a spiral flute bottoming tap with 1-2 threads chamfered if that would break the chips better.

What RPM are you running?
What helix angle is the tap?

200 - 400 RPM.

I'm not milling them.
I could secondary opp (hand chuck) them if it came to that.
We have opened up a bunch of 1/4-20's that we had in stock this year to the 3/8-16, and that's no trouble.
Not sure what we used, but prolly a SP/Pt tap on that and just filled the main spindle with chips.
Trying to find a better way.

I don't think that this is the only job that this scenario comes up, but also - I can't say what other jobs it does.... Just does occassionally.

litlerob1 said:
You have Y on there right? I would look at Thread-milling.

Well, I have Y on others, but not this one. I have rigid elsewhere too, but other than finding the right tap, this machine is best suited.

Actually - yeah, that's what I had in mind. I haven't used those very often, but usually in alum I think?
I am wondering if the faster helix would let the [broken] chips roll around in there, and fill a longer section of flute than the slower helix?
Maybe not - but that's what I wanted to try - and my thought process behind it.

-----------------------

Think Snow Eh!
Ox

litlerob1 · Dec 30, 2018

I dunno, you'll need to wait for a Tap expert.

I haven't tried these ones. But they are spiral flute, with a bunch of room behind the flutes???

rklopp · Dec 30, 2018

Shop Supply Guru said:
You could get a coolant through bottoming tap.

Aside from form tapping, TSC is the best idea I've seen so far in terms of confidence that it would work. (If it doesn't, get a bigger pump.

) What are the odds TSC is available on your machine?

Ox · Dec 30, 2018

"Through the spindle" - could be done if a full time job prolly. I could inject coolant through the rotary coupling of the sub-spindle, but not sure the volume would be enough to help. Maybe...

"Through the tool" would Shirley be doo-able if it was rigid tapped. I have used "through the tool coolant" on my own made ( not made at home) tapping type units before, but jf you put too much juice to it, you will overpower the return springs. A small hole in a tap to flush chips would require more pressure that would be recommended for the tens/comp feature.

This is a small job. Not lookin' to git quite that involved.

----------

Think Snow Eh!
Ox

Shop Supply Guru · Dec 30, 2018

I sell these units they run about $800
Rego-Fix Recool
https://m.youtube.com/watch?v=VXMZWdKGbWA&t=32s

I have a guy in Delta, Ohio that runs them if you want to take a look.

I would suggest that and a tap with a 15* helix like the ones mentioned above. I sell in Northwest Ohio let me know if you want a sample tool.

Ox · Dec 30, 2018

Shop Supply Guru said:
I sell these units they run about $800
Rego-Fix Recool
https://m.youtube.com/watch?v=VXMZWdKGbWA&t=32s

I have a guy in Delta, Ohio that runs them if you want to take a look.

I would suggest that and a tap with a 15* helix like the ones mentioned above. I sell in Northwest Ohio let me know if you want a sample tool.

I have seen those advertised and I think that I looked at the at The Tool Show too.
Those are very cool, but I hadn't recalled a price on them before.
Either way, this machine doesn't have live ER collets, and this is not a live tool app anyhow.

I will try to keep you in mind for those if that day comes sometime tho.

---------------------

Think Snow Eh!
Ox

Shop Supply Guru · Dec 30, 2018

Just so you know it works for live or static tools.

Nerdlinger · Dec 30, 2018

Ox said:
But forming 3/8-16 in 1/2" round - in the sub-spindle no less, just aint a good plan.
It could (should?) spin.
It could crack.

Think Snow Eh!
Ox

If the O.D. surface finish doesn’t need to be perfect “Carbinite Metal Coatings” will grit up the inside of your sub collet and the part will NOT spin. You WOULD have to buy an oversized collet so that it would be 1/2” after the coating but the stuff works and holds up.

Don’t know about the cracking, though??

(I think this is my ?third? plug for that company this week haha)

http://www.carbinite.com

litlerob1 · Dec 30, 2018

I realize, you probably don't want to commit the time to it Ox. BUT what's your resistance to Single pointing it? You would still be packing chips to the back of the part if you did it conventionally. Or you could Thread it from inside-out, after all, it's a through hole right.

It's probably a 2m cycle. Load to Unload.

Cut Tap for 1215 LCS ?

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