Genos 560 tapping RPM

I’ve got some M-3 tapped holes in copper and aluminum coming up. I found a good DLC coated tap that is supposed to work well with both materials. The minimum recommended speed puts me at 2,200 rpm. That makes me nervous thinking about the balls in the spindle bearings changing direction that fast. The fastest I’ve gone is 550 rigid tapping.

It’s crazy to think about a 30 hp spindle driving a tap that fast and then hogging stainless on the next job but that’s life. My goal for this machine is longevity and not replacing spindles. I’m only making a few parts at a time so tapping cycle time is the least of my concerns.

What sort of tapping speeds are all of you maxing out at?

MCritchley said:

I’ve got some M-3 tapped holes in copper and aluminum coming up. I found a good DLC coated tap that is supposed to work well with both materials. The minimum recommended speed puts me at 2,200 rpm. That makes me nervous thinking about the balls in the spindle bearings changing direction that fast. The fastest I’ve gone is 550 rigid tapping.

It’s crazy to think about a 30 hp spindle driving a tap that fast and then hogging stainless on the next job but that’s life. My goal for this machine is longevity and not replacing spindles. I’m only making a few parts at a time so tapping cycle time is the least of my concerns.

What sort of tapping speeds are all of you maxing out at?

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.
machine that can do synchronize tapping that is a spindle slowing down slide or tap travels in sync. then rigid tap
holder can be used rather than extension compression tap holder
.
many machines not in sync you can see tap turn extra as spindle slows down. certain rpm in certain gear ratios
this turning extra can be a lot. if tap screws itself extra into hole obvious hitting the hole bottom and tap
breaking can be a issue. some machines you might avoid the highest rpm that still in low gear as it might have
more problems.
.
programmer needs to not tap hole close to bottom of drilled hole. its possible a tap can screw in a extra 0.100"
than its programmed to.
.
obviously some machines can handle tapping over 1000 rpm and other machines its not a good ideal. big tap offers higher
resistance to turning thus turns less extra. M8 or smaller turns so easy its more a problem

I usually tap at 250 or 500rpm. Your machine isn’t going to reach 2200rpm.
It has to accelerate while moving in Z

In reality, it will reach the programmed depth before it ever reaches 2200rpm.

I form tap around 2000RPM all the time with the Genos. Agreed it probably won't get there - but it might get close on a deep hole.

I only leave about .010in on the bottom of the hole.

Probably tapped over 100k holes in the <M4 range.

I've been up to 4000rpm in my M560. It wasn't much of a time save over 3000rpm so we ran it at 3k. Yes it actually hit the target rpm. No issues at all and we've tapped a lot of holes in that machine.

Do note that there are separate tap cycles for a rigid holder vs tension compression. On top of that, you can set a parameter to allow you to use either with G84. If it's not set to rigid it will under feed. If you have a rigid holder in the machine at the time, you'll likely lose the tap.

Set it up for your holder and run the rpm it needs to run. You'll be fine.

SMT said:

I've been up to 4000rpm in my M560. It wasn't much of a time save over 3000rpm so we ran it at 3k. Yes it actually hit the target rpm. No issues at all and we've tapped a lot of holes in that machine.

Do note that there are separate tap cycles for a rigid holder vs tension compression. On top of that, you can set a parameter to allow you to use either with G84. If it's not set to rigid it will under feed. If you have a rigid holder in the machine at the time, you'll likely lose the tap.

Set it up for your holder and run the rpm it needs to run. You'll be fine.

Click to expand...

Good info there thanks! I've been running the M3 tap at 1600 revs and everything is going well. Its probably still a bit slower than the coating would like. The next part with that tap is worth about ten grand so I was proving our the cycle before feeling comfortable with a small tap in a VMC.

MCritchley said:

Good info there thanks! I've been running the M3 tap at 1600 revs and everything is going well. Its probably still a bit slower than the coating would like. The next part with that tap is worth about ten grand so I was proving our the cycle before feeling comfortable with a small tap in a VMC.

Click to expand...

I'd be doing the same thing!

I tap a lot of holes on my 560s, 4-40 to 1/4-20 and normally run 2500 to 3000 rpm though timewise I can't tell much of a difference. On the Brother I normally tap at 4000 to 6000 rpm and can't tell much difference there either.

I've programmed small taps at max speed (5k) on my 560 but never watched them or paid attention to cycle time or actual RPM.

When I tap I hit the button and walk away so I won't hear the crunch. LOL