Help with tapping

[jspangler]

Hi

I need a good baseline for tapping through holes in .375 thick 1018 Cold roll. The tap size is 4 mm, and the drilled size is .1299 (3.3mm?). I'm using my Tree VMC, with rigid tapping. The control figures out the feed based off the spindle RPM, so what would be a safe RPM for that small of a tap? It taps 10mm all day long with no problems.

 

Thanks

 

John

[chris m]

20 SFM would probably be a good baseline [485 RPM] for that job

[crazy^millman]

I would also look at TIN coated and no coolant with some tap fluid. TiAln Coated would do very well also and could problay get away with a few drops of tapping fluid. If you already got the taps then would look at the Tap fluid if not coated gives a better looking thread.

 

HTH

[Mike Whitten CAD/CAM Contractors]

jspangler,

 

I don't have a handbook at home here but I always drill to the absolute max on the minor dia if you are using a cut tap of course.

 

I would also make sure to use a spiral pointed plug cut tap, coated if posible. OSG is always the best choice for the money.

 

The best speed to start would be as Chris stated 20sfm. If you have problems, just roll em. It is OK to roll through threads if you have to.

 

Mike

 

[ 06-04-2004, 12:29 AM: Message edited by: Michael Whitten ]

[chris m]

Ron, in my experience TiAlN doesn't work as well in CD steel as TiN; I think TiN has more lubricity to it. I hate tapping oil, though, I'll stick with my VNT800 wherever I can.

 

+10 on the roll tap; OSG Hy-Pro NRT [TiN] roll taps are the nuts and not very expensive at all [the ExoTaps are huge $$ though, use 'em only if you NEED 'em]

 

Run at least 50% more RPM with the roll taps if you run them

 

C

[Mike Whitten CAD/CAM Contractors]

We switched to OSG Hy-Pro NRT 1.5pi on everything. That way we have the correct tap in stock for steel if needed.

 

They are great!

[Mike Whitten CAD/CAM Contractors]

John,

 

Are you from Claremont, CA ?

[crazy^millman]

Well I am thinking along the lines of the Exo taps we use to use in Harden Wear plate for the Paper Mills. A regular tap about 5 holes and A TIN tap about 12 holes the Exo-Taps about 50 to 60 holes. Yeah I hate oil but found without it that stuff nothing lasted very long. I am thinking you need to be up at like 1000 rpms also but that is just crazy talk I know.

 

You have got some great advice from the other guys see where it takes you.

[jspangler]

HI

Thanks. The only taps I can find here are 4 flute uncoated, so I'll just run these by hand, and order some good ones for the machine. I hate pulling broken taps oout of parts!!

 

Thanks for the input.

 

John

 

PS I'm from Rosemead, about 30 minutes West of Claremont.

[Mike Whitten CAD/CAM Contractors]

John,

 

That is a coincidence, I grew up in Claremont and I had a friend whose name was John Spangler. I think he would of been older than you though. It was in about 1970-1971.

 

We were only about 9yrs old at the time.

 

Thanks

[?Mark]

It's 1018 so there is no need for fancy taps. Anything will work...

We use cheap roll taps very often on this type of material in blind holes, works great. RPM at about 500 or so.

 

Regards, Mark