HAAS MINIMILL USERS Q'

[Mike@Dive Lab Inc.]

hey guys, any mini mill users ever had any problems with tapping stainless or similar metals. I was tapping a 1/2-20 hole in s.s.316 with a good tap @ 100rpm plenty of coolant .400 deep the hole is .950 deep plenty of room. I guess it cought a chip and the cat40 holder pulled out of the spindle on the reverse and chewed up the pullstud and messed up the balls that grab the stud. I always threadmill anything over a 1/2" just curious what you guys do and if you have had any problems tapping before.

 

thanks

 

mike

[?Mark]

quote:

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holder pulled out of the spindle on the reverse

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assuming your code looks good I'd think there is not enough tourqe at 100rpm on a mini mill to do 1/2-20 in 316ss...

[PGW Steve]

That doesn't sound right. Since it is strictly a rotational torque, the load should all be on the dogs on the spindle. There shouldn't be enough of an axial load to pull it out if everything is syncronized. I did something like that once but I had a G81 instead of G84.

[Rick Henrickson The Boeing Co.]

there is no way that has enough torque to tap 1/2 - 20

[MattW]

At the risk of stating the obvious, rigid tapping is an option on the MiniMill. If your speed and feed are in synch, having this option turned off would do it...

[PeterM]

P.S. on MattW Hass are usually shipped with some non purchaced options activated on a temporary code. After one to three months these options become disabled without warning, it happened to our tool room mill, scrapped some parts too! We have tapped 1/2-20 successfully on our mini's but not .960 deep. We have also had tool carosel problems that would allow a tool to clamp non oriented, I would give that a peek, because it could result in the damage that you got. Peter

Mx-Mr2 mill level 3

[Mike@Dive Lab Inc.]

All the code&options are good it has every option, I just got off the phone with HAAS and they said luckily I was at a 100 rpm or it could of done much more damage. I do have the ridig tapping option and it has worked fine for hundreds/thousands of holes alomost 2 years, mostly in brass and plastics.Peter, I was only tapping .400 deep, the drilled hole is .950 deep. I've done 12 parts before the problem and they tapped great. Anyways, it looks like I need a new drawbar, luckily I don't think it messed anything else in the spindle

[Lars Christensen]

I would never have the balls to tap 1/2 in our Minimill, I do not even drill anything in steel over 1/2.

[88Matt]

Where u able to take the tap out and look at the threads? sounds like the tap may have slipped alittle and tried to cut threads coming out or as u said caught a chip.

have u ever peck tapped with the rigged tapping option?

[savagkd]

I'm with Lars. We thread mill 1/2 in. and up on our Mini.

[Kelly Burns]

Check your code, I like to slip in the occasional G83 on a tap and its not cool. As for as being able to tap past a 1/2" in a mini, Ill tap up to 7/8 regularly, you just have to give it some rpm to work with or it will stall. 7-1/2 horse motor on most of ours, I dont know about the older ones though.

[Randy Morton @ Clem Industrial]

Another option would be peck tapping instead of just plowing it right to depth.

 

G0Z.25

G99 G84 Z-.075 R.25 Fxx.xxxx

G99 G84 Z-.15 R.25 Fxx.xxxx

G99 G84 Z-.225 R.25 Fxx.xxxx

G99 G84 Z-.30 R.25 Fxx.xxxx

 

I think you get the point....anyways, this may work better, and be easier on the machine from the torque perspective. Smaller cuts, less power required.

[Thee Dragracer1951]

I've peck tapped in my Mini Mill as well nad I've done 1/2-13's and 1/2-20's too in 304...

I thread mill all the bigger stuff

[Chris Rizzo]

We run a production line in our Mini mill of parts tapping m12 and m14 spiral flute bottoming taps in 303L stainless. About 300 parts per month, easy. Just yesterday I had a holder pull out of the spindle and gouge the crap out of the spindle. I've probably tapped 10,000 holes and this is the first problem I've had. However I know my draw bar in that machine is waaay below minimum spec, so I had a disaster waiting to happen.

 

I also think my operator did'nt tighten the m12 tap enough, and it could have walked out of the collet too, causing the chain of events.

 

p.s. those holes are tapped over 1.25 deep. Never knew the mini mill could'nt do m14 (over 1/2") until I read all the doubting thomas' here.

 

[ 07-18-2006, 08:50 PM: Message edited by: Chris Rizzo (Italian' stylin') ]

[Mike@Dive Lab Inc.]

Thanks for the info, the thing that got me was the tap is in perfect condition, not so much as a chipped flute. I would of thought the tap would of broke or spun in the collet before it yanked it out of the spindle. For you guys that do tap what rpm would you suggest for a 1/2-20, I'll see if I can find the torque to rpm specs for the mini mill. If it has enough power to pull the holder out of the spindle at that rpm, youd think it would have enough to tap. I think i'll threadmill from now on 1/2" and under.

 

Thanks

[Joel Walker]

It's the material,316 s.s is really gummy, when the tap stops to reverse, thats when it's gonna give you a problem, I suggest that if the quantity of the run is not to many just start the hole with 1-2 threads then tap them buy hand the rest of the way, use chroma-tap tapping fluid, I have to tap 1/8-27 npt into 316 alot and it's a nightmare.

 

Good luck!!

[Mike@Dive Lab Inc.]

I'll give it a try, I do a ton to npt 1/8,1/4, with a skip tooth in 316 on the mini mill and it always worked great

 

thanks

[?Mark]

quote:

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If it has enough power to pull the holder out of the spindle at that rpm, youd think it would have enough to tap

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I'm thinking you might've stalled the spindle while z axis was still moving, but I was wrong before...

[PGW Steve]

another question is what are you using for tapping fluid? I've given up using coolant and now put a drop of some kind of specific tap lube on each hole.

[race 10]

We Have tapped up to 3/4-16 in our mini mills and have been sucessful. I think that the haas machines all have a setting that you can change to make the tap reverse and come out up to 4 times as fast as programmed to go in. I myself do not like to bring the tap out any faster then it goes in incase it does catch a chip or something. this might be something to look into. I always set this parameter to "0"

[Gary]

I have stalled are vf-5 on 1/2-13's before. Machine only has like 70'lbs of torque. The tap don't break (not enough power.) It will do the job but I have to run the tap at 500 or more rpm to get it to work. Spiral taps have helped alot might want to go that rought.

[Guest]

I roll formed an M29 tap x 60 mm deep

 

in 1018

 

Oh sorry that was a gear head Matsuura 760

 

 

[Rick Henrickson The Boeing Co.]

John you funny guy!

thats like a yugo vs humve

[S.Hall]

If you use a g81 as apposed to a g84 you will miss the (M42) code that you need when threading, witch gives you torque control with the spindle. On a Haas this is the High gear override. Good post.

[Thee Dragracer1951]

Ain't no gearbox on a minimill....