O/T Tapping speed and feed survey

[Code_Breaker]

What is the concensus of tapping speeds and feeds?

 

SFM vs. a set RPM, namely 100 RPM across the board.

 

I am mostly concerned with H13, S7, 420ss:

 

I am not voicing the reason, just that it is operator related.

 

 

Code_Breaker

[chip]

For steels I usually never go past 300 R.P.M.'s. I also never go too deep 1/2 .500 or so. For aluminum I was playing with that the other day, I was running 2000 R.P.M. Building molds I tend to be conservitive with certin operations.

A friend of mine programs production, It's unbelivable some of the numbers you can run without breaking a tap. There also running form tools that drill-tap-c'sink-c'bore all in one tool/opp!

Some machine companies are running that peck tap routine that's cool.

[robk]

I agree with Chip about never going past 300 R.P.M.'s in steel. All we run is 420ss in here and the taps last forever.

 

+1 on the peck tapping routine also. Just tried it out for the first time today, and it's pretty cool.

[TREV]

i for one have always used 200 rpm. dont ask me why ,it just works ......for me anyhow

trevor

[chris m]

I usually run 1/2 the 'middle' SFM suggested by the manufacturer [they say 40-80 I run 30] with great success. I don't typically run over 1200 RPM or so if I can help it. Some of our older machines don't reverse well or overshoot massively at higher RPMs so you need to take that into consideration

 

C

[Tim Johnson]

In steels I usually run middle to top sfm at 1 1/2*dia depth and cut the sfm by 1/3 for every added dia depth. A 1/4-20 at 3/8" deep at 60 sfm would be 917 rpm. At 3/4" deep it would be 408 rpm. (917*.66666*.66666)

[Hardmill]

quote:

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I am not voicing the reason, just that it is operator related.

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Hey Code,

Tell stuart to crank that thing up.

And tell him steve says "HEY"

 

PEACE

[crazy^millman]

Guess I am just crazy then because I tap at 2000 rpm in Aluminum max I can get away with and tap at 500 rpms with a 1/2 tap in cold rolled steel. With harder materials I do slow it down alot but use recommidations a sart not a middle for doing things. I use inserts as normally 25% to 75% over the high SFM called out by the Manufacture. I look at it this way if doing production or quanites of part as if I make time to pay for the burning effect you get doing things at warp speed.

 

One job I did years ago the manufacture of the inserts said 350 to 600 sfm in Carbon steel. The inserts were $10 dollars an piece using 6 with 8 sides. The job at the middle of 475 sfm was taken 5 hours to machine down and 1 corner. We did 8 to 10 of these plates at a time. I would do them at 1350 sfm and would get them done in 1-1/2 hours and 3 corners. I knocked 3-1/2 hours of the job at an insert cost of $22.50 with a total time saving in dollars of $2275 per run to spend and extra $225 on inserts but here is the kicker I really saved double that becuase I had that time ot put on another job so I really made $4550 spending an extra $225 on inserts. Point is for every minute wasted going slow or being safe you do not lose that minute you lose doulbe that minute becuse that is tiem you can not put on soemthing esle.

 

Anohter exmaple use ot make 330 rings at a time with 30 tapped holes along the diameter. I would tap them at MAX rpm on the machine. It took the guy before me 6 hours to do these parts at 200 rpms 10 at a time in a 4th axis I was doing them at 2000 rpms and losing about 3 parts with about $12.00 in time and material in them and 3 taps about another $15.00 each to them in 55 min for 10. That was 33 runs of this set-up. I knocked 155 hours off the job at $65 hour shop rate was $10075 more we made on the job than before. It is all realtive but time is money and money is time and the peeny wise get the chepaest tooling and the cheapest things will only give you results in that area. I know tooling and new machine are expensive but the more we sit back and do nothing and not imporve the more work goes abroad where they don't have to do it better just cheaper. WE not only have ot do the work better and cheaper but faster and bring it back.

 

Sorry guys will get off the soapbox. Just my humble opinion guys.

 

This is no way was a put down on where I work or directed at the owners of my company. Here is their email incase anyone feels I am out of line.

 

[email protected]

[email protected]

[email protected]

[mayday]

quote:

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This is no way was a put down on where I work or directed at the owners of my company. Here is their email incase anyone feels I am out of line.

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Ron, nice nondiscriminatory addition to your post.

[crazy^millman]

Yeah well now I have to be very careful in expressing my opinions or views since it was reported that I go off on where I work every week on here and since this was a general statement about helping and giving my humble opinion about some of my thoughts I just want that commnet to go along with the email to the link of this thread.

[Jack Mitchell]

Code Breaker,

 

This has always worked for me through the last 25 years or so.

 

Base the rpm on surface feet per minute or call this cutting speed, which amounts to the same thing. Mild steel is always considered the standard which is based on 100.

If drilling a ½” hole then 4 times cutting speed divided by diameter

(In this application then the rpm for drilling this diameter in this material would be 800rpm).

Tapping a 1/2-13 would be 200rpm as follows.

 

For tapping: then use 25% of the drilling rpm as your base for determining rpm for form cutters;

This applies to taps, corner rounding end mills, tapered cutters, dovetail and T-slot cutters as well.

To simply program all tapping speeds at 100rpm and letting the operator adjust based on his knowledge or experience is fair if you feel comfortable with it; personally, I wouldn’t since it would leave the opportunity open to say that “hey, I didn’t write the program” or “it’s taking so long – because” It has been my experience that if you give the operator an inch then you will simply end up bent over taking the rest of it.

 

 

Regards, Jack