Power tapping with mill

[kmanuele]

I am able to power tap aluminum, up to 1/4-20 so far, on my PM728. I tested 3/8-16 on steel, but it struggles and stalls.

It occurred to me that this would be a perfect application for a planetary gear reducer to increase output torque. But I don't see any marketed for this purpose.

Thoughts, ideas ?

thx

K

 

[woodchucker]

make your own.

Tapping Head

I saw a video , I think doubleboost, maybe someone else. They used a Speeder (English for reducer). The English ones are way nicer than the American units. But I'm too cheap to get one and ship it over. At the price I could buy a tapmatic. I bought this one on ebay for $6 a few months ago...

www.hobby-machinist.com

Tapping Head

I saw a video , I think doubleboost, maybe someone else. They used a Speeder (English for reducer). The English ones are way nicer than the American units. But I'm too cheap to get one and ship it over. At the price I could buy a tapmatic. I bought this one on ebay for $6 a few months ago...

www.hobby-machinist.com

 

[finsruskw]

Use spirol taps
Works for me, at least up to and including 5/8" so far

 

[Jim F]

I am able to power tap aluminum, up to 1/4-20 so far, on my PM728. I tested 3/8-16 on steel, but it struggles and stalls.

It occurred to me that this would be a perfect application for a planetary gear reducer to increase output torque. But I don't see any marketed for this purpose.

Thoughts, ideas ?

thx

K

You might need more machine......

 

[Dabbler]

@kmanuele When I power tap in steel, I go for a 65% thread instead of a 75%. This significantly reduces the torque required to do the cutting, and results in fewer broken taps. By increasing your torque through a planetary reducer, you might be risking broken-tap-in-hole problem...

 

[woodchucker]

You might need more machine......

or like he said, a planetary reducer.. it will increase the torque, ad least doing it without much fuss.

 

[projectnut]

There's definitely something wrong with either the mill or the tap. I've tapped 3/8-16 holes in 1/2" and 3/4" mild steel with a hand drill and spiral point tap. You shouldn't be having trouble with a 1 hp mill (if it really puts out 1 hp) and a sharp HSS spiral point tap. Make sure you're using a machine tap i.e., spiral point for through holes, or spiral flute for blind holes. Standard hand taps have to be reversed every 1/4 to 1/2 turn to break the chips and allow them to collect in the flute. They will jam and break if attempting to continuously turn them in the forward direction.

I've tapped 5/8-11 holes with my 1 1/2 hp Bridgeport running on a static phase converter. The converter reduces the available hp by about 1/3 which would put it in the 1 hp range. I do admit that I run the mill at around 90 rpm and use a drill chuck and only tighten it to the point that the tap will slip if it hits a hard spot. So far minimal slippage and no breakage. Also, I use only name brand taps like Bosch, Greenfield, Cleveland, OSG, Champion, and more recently YG1.

 

[kmanuele]

There's definitely something wrong with either the mill or the tap. I've tapped 3/8-16 holes in 1/2" and 3/4" mild steel with a hand drill and spiral point tap. You shouldn't be having trouble with a 1 hp mill (if it really puts out 1 hp) and a sharp HSS spiral point tap. Make sure you're using a machine tap i.e., spiral point for through holes, or spiral flute for blind holes. Standard hand taps have to be reversed every 1/4 to 1/2 turn to break the chips and allow them to collect in the flute. They will jam and break if attempting to continuously turn them in the forward direction.

I've tapped 5/8-11 holes with my 1 1/2 hp Bridgeport running on a static phase converter. The converter reduces the available hp by about 1/3 which would put it in the 1 hp range. I do admit that I run the mill at around 90 rpm and use a drill chuck and only tighten it to the point that the tap will slip if it hits a hard spot. So far minimal slippage and no breakage. Also, I use only name brand taps like Bosch, Greenfield, Cleveland, OSG, Champion, and more recently YG1.

1 HP BLDC motor so it should be able to deliver full torque at low speed. It doesn't struggle when milling steel.

I tapped several M12x1.75 holes by hand in steel a while back (with a spiral flute tap). It went ok but a bit hard on the hands and shoulders with my standard tap wrench. So I thought my mill should be able to do up to 1/2, or close to it.

I only tried it once as a test with a straight tap, and it stalled. So maybe it was the tap as you suggest. I'll get some proper machine taps and see how it goes.

Thanks

K

 

[Batmanacw]

1 HP BLDC motor so it should be able to deliver full torque at low speed. It doesn't struggle when milling steel.

I tapped several M12x1.75 holes by hand in steel a while back (with a spiral flute tap). It went ok but a bit hard on the hands and shoulders with my standard tap wrench. So I thought my mill should be able to do up to 1/2, or close to it.

I only tried it once as a test with a straight tap, and it stalled. So maybe it was the tap as you suggest. I'll get some proper machine taps and see how it goes.

Thanks

K

Are you using quality sharp taps or chinesium or worse, carbon steel hardware store taps?

 

[Winegrower]

Look around for tapping heads like Tapmatic or Procunier. You can find eBay deals. They have a built in clutch to prevent disaster, and a 2X auto reversing function that is extremely nice. I made an array of 1/2-13 threads in a 1.5" setup plate, aluminum, but good result in steel too, about as fast as you could work the handwheels and the quill feed. Spiral flute taps exclusively, prefer YG1 these days.