T. Jost
Cast Iron
- Joined
- Jan 28, 2007
- Location
- Hillsboro, Kansas USA
The title says it all. Anyone got recommendations for surface speed for sawing 3-1/2" holes in 1/2" A36?
Todd
Todd
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Hole saw SFM in mild steel
- Thread starter T. Jost
- Start date
- Replies 6
- Views 2,408
matt_isserstedt
Diamond
- Joined
- Dec 15, 2003
- Location
- suburbs of Ann Arbor, MI, USA
I would go SLOW, like 100rpms or less, most "smaller" drill presses will not be able to go that slow. Key would be to drill a couple chip evacuation holes (say 1/4" dia) thru the material in the kerf for the holesaw. Use cutting lube. I have holesawed 1" thick CRS before.
T. Jost
Cast Iron
- Joined
- Jan 28, 2007
- Location
- Hillsboro, Kansas USA
I'll be sawing these under the radial drill. Goes down to 44 rpm.
T. Jost
Cast Iron
- Joined
- Jan 28, 2007
- Location
- Hillsboro, Kansas USA
Thanks for looking guys, but I think I've got it sorted out.
Matt, I can't use the chip evacuation holes because it is the 3.3+/-" plugs of 1/2" material that I need, but that would be handy if I was just trying to make big holes. I only need 24 so the idea of buying a 20 foot bar of 3.375 steel for 12" would put a big dent in this jobs profit margin.
77 rpm, dry, with compressed air blowing in the slot to keep the chips from binding between the kerf and the saw. Seems to be working well.
Matt, I can't use the chip evacuation holes because it is the 3.3+/-" plugs of 1/2" material that I need, but that would be handy if I was just trying to make big holes. I only need 24 so the idea of buying a 20 foot bar of 3.375 steel for 12" would put a big dent in this jobs profit margin.
77 rpm, dry, with compressed air blowing in the slot to keep the chips from binding between the kerf and the saw. Seems to be working well.
matt_isserstedt
Diamond
- Joined
- Dec 15, 2003
- Location
- suburbs of Ann Arbor, MI, USA
Think you could invert the idea for your app and use drill the chip thru-hole in the outer side of the circumference. That said, it needs to be pretty closely spaced as far as a tolerance...kind of like need a mill to put in the evac hole, spaced out from the center hole, then shift over to the hole saw.
Compressed air is good too, whatever it takes to get the chips from packing up the gullets on the holesaw.
Compressed air is good too, whatever it takes to get the chips from packing up the gullets on the holesaw.
Cyclotronguy
Stainless
- Joined
- Sep 21, 2005
- Location
- Northern California
Forget hole saws...... grab a rota-broach and put it in a 3/4" tool holder. Run the broach at 100 sfm and give it some serious feed with coolant. Chips will come flying up the flutes of the rota-broach.
T. Jost
Cast Iron
- Joined
- Jan 28, 2007
- Location
- Hillsboro, Kansas USA
I don't have a 3.75" rota-broach. I do have a couple of these Lenox hole saws.
With one in reserve I decided to do a little experiment. 154 rpm (which comes out about 140 sfm) is doing an even better job. Chips are still mostly grey. Saw is staying cool enough that the paint isn't smoking off of it and that part of the job is done and I still have an unused saw!
This is a small part of a big job that was originally quoted with these pucks being plasma cut, which didn't happen in a timely manner so I had to improvise. After lunch I'll slap them in the lathe for a bushing hole and later weld them into the pivot arms. The fun never ends.
Todd
With one in reserve I decided to do a little experiment. 154 rpm (which comes out about 140 sfm) is doing an even better job. Chips are still mostly grey. Saw is staying cool enough that the paint isn't smoking off of it and that part of the job is done and I still have an unused saw!
This is a small part of a big job that was originally quoted with these pucks being plasma cut, which didn't happen in a timely manner so I had to improvise. After lunch I'll slap them in the lathe for a bushing hole and later weld them into the pivot arms. The fun never ends.
Todd
