Any way to straighten bi-metal hole saws to reduce runout?

[rixtrix1]

I use a lot of hole saws in projects for holes larger than 1" and while most of the holes turn out the proper diameter, runout in the holesaw makes the work vibrate so much it's almost impossible to use a drill press. Any ideas on bending or straightening? Don't really want to bend or pound on them while chucked in the drillpress. I was thinking of getting a grade 8 bolt with the head cut off, nut and washer to replace the arbor, spinning it in the drill press to find the high spot and then moving it to the vice to try some way to straighten it. Comments? Thanks.

[GetMore]

Get a better hole saw? I only give this wiseass comment because I'm not used to seeing much runout on a holesaw. Maybe there's a foreign object stuck in it?

[Bow Tie 67]

Jason may have a valid point, I used a mill to drill large holes and even that had some runout.

[parsonsj]

Mill + holesaw = big vibration, even at very slow speeds. I'd love to have a good solution for it too.

jp

[rixtrix1]

I have Craftman, Ridgid, Milwaukee, Blue Mole and Starrett brands of holesaws, all bi-metal, and they all seem to be this way. I have a 5/8" capacity drillpress that seems quite solid. Guess I'll just play with em and see if I break something or fix the problem. Next phase will be link brackets and a watts propellor in 3/16" and 1/4" mild steel for the 8.5" I've got going. Will be using 3/4", 1-1/4", 1-5/8", 2" and 3" holesaws. Maybe the best thing to do is let the work "float" slightly on a wood backer, rather that try to clamp it down. Next bet is to talk to the kid with the Rhino fabshop next door to where I work and see what he would charge to cut them out with his cnc plasma, but I hate spending money!

[Bryce]

another idea is to replace the pilot drill with a solid drill rod and use an aluminum or steel block on the back side with a hole to fit the drill rod. this may help steady the hole saw. I have done this in the past with good results. If you have a mill the best way to make a hole is the offset boring bars that adjust to obtain the correct radius.

[LowBuckX]

ONly hole saw Ive got to make good holes on the bridgeport was Sandvic brand. Fast cutting also.

[Jim Nilsen]

If you have a Milwaukee hole saw holder with the interchangable saws, the retaining pins keep the saw from bottoming out so it is easier to remove. I had the nut back off far enough one time to let the pins back out and it tightened the saw to drive holder. This stopped a lot of run out and vibration. It also made it damn near impoosible to remove the saw off of the holder. I had to put it in a vise and get out the big pipe wrench to get it off. You can also get saws that are one piece from Lennox that help a bit to stop vibration.

If you are doing very thin aluminum and you can run backwards it will be smoother and not grab and tear the piece, only in aluminum.

I also have placed the piece I want to cut the hole in and have put it between 2 pieces of hard wood and by the time the cutter gets to the piece you are making it will have stabilized. making sure you have a good drill bit in the center that is out long enough to reach the piece before the cutter hits the top board is important. Pre drill the hole so you can center it before you clamp it down. I have to use this method to cut holes in the perforated aluminum so it doesn't grab and tear.

The 3 3/8 hole for my speedo was done with a 3 1/4 saw and only needed a bit of filing to center it up to one side and the 2 5/8 holes will be done with a 2 1/2 saw.

The only and best way to get a perfect hole is with a knockout punch and then you still have to make sure you are perfectly centered, which can take a bit of practice too.

[Jim Nilsen]

ONly hole saw Ive got to make good holes on the bridgeport was Sandvic brand. Fast cutting also.

Sandvic make some of the best saws I have ever used no matter what type. If you can find them they are worth every penny.

[rixtrix1]

I'll try to find the Sandvic brand you mentioned.

[HarleyR]

I hate hole saws.....I broke down and bought every set of Rota Broaches from 5/16 to over 3 inch.... Deep and shallow....Its been very expensive but well worth it....And once you try them you'll feel the same way.

[317millhand]

Im an electrician by trade and use holesaws everyday. We normally use a hydraulic slugbuster by greenlee if you have access to both sides of the metal. Makes a perfect hole everytime.

[Kamikaze Sy]

Check out Blair Hole Cutters. Clean and smooth cutting without run out problems.

[Auto Rod Technologies]

Check out Blair Hole Cutters. Clean and smooth cutting without run out problems.

That's what I was going to say!

[ATOMonkey]

First thing I would do, is mic it to see if it's round. (or calipers if you don't have big enough mics) If it's oval or egg shaped, then yeah, I think putting it in a vise is a great idea. Also, bake it to remove any risidual stresses.

If it's round, you can loosen it up just a little, indicate it on the mill, and then tap it in. Tighten it up again, and spin it a couple of time to make sure it still indicates good.

I'm betting that when it was assembled, it wasn't done on a zero runout jig.

[Syclone892]

Like others have mentioned check out blair hole saws
http://blairequipment.com/holcutters/holcutters.html

I saw these at sema and was amazed because there is finally a solution to the normal crappy hole saw!

I just bought thw set that goes up to 2 1/2 " and have only tried it once and it worked beautifully! The saw I used you can't even tell I used it either not a nick or a scratch on it.

They are kinda pricey but they are worth every penny.

[parsonsj]

I just bought th[e] set that goes up to 2 1/2 " Me too. Mine aren't here yet, but I've got a 2.5" hole to make. I'll report back...

[Van B]

Ever try knockout punches? They worked pretty good for cutting the holes for my A/C vents...

http://www.all-spec.com/products/Tools%7CWire_and_Electrical_Tools%7CTOL-25/