Six Inch Hole Saw Drill Speed Question

[Rich Riddle]

I am about to use a 6" hole saw to cut 3/4" MDF. At what speed should the drill press be set?

[Bill Huber]

The slowest......

The big problem is the hole saw will build up with MDF and want to get hot and not cut very well.
I had a bunch to cut and after a few tries with the hole saw I went to a fly cutter or what ever they call it.
http://www.eagleamerica.com/product/301-0110/gifts_under_25

[glenn bradley]

I'd go about 250 and check the temp often but, for MDF I too would grab a circle cutter.

[Jamie Buxton]

Bill's right: the bigger issue is the sawdust. It stays in the kerf, and the saw essentially rides on a bed of dust rather than hitting the MDF. Unlike a drill bit, the saw doesn't have a spiral shaft to pull the dust out of the hole. You'll be able to cut perhaps an eighth of an inch before the saw starts cutting poorly because of the dust. Pull the saw out, vacuum out the kerf, then cut another eighth, then vacuum, etc.

[Jerome Stanek]

I use a brass brush to keep the teeth clean just back it off and hit the teeth while it is spinning and the slower the better

[Rod Sheridan]

I am about to use a 6" hole saw to cut 3/4" MDF. At what speed should the drill press be set?

use 250 RPM and drill a dust relief hole all the way through, just inside of where the hole saw will cut.

That way the swarf goes into the hole and doesn't overheat the saw..........Rod.

[Rich Riddle]

Thanks for the input folks. I went with the fly cutter as suggested by many of you. Will let you know how it works out.

[Art Mann]

use 250 RPM and drill a dust relief hole all the way through, just inside of where the hole saw will cut.

That way the swarf goes into the hole and doesn't overheat the saw..........Rod.

Hmmm. That is something I never thought about trying. Like Bill, I just bought a fly cutter for use on MDF. Forstner bits will also pack up with MDF dust under the cutter and cause slow cutting and overheating. I will have to try the hole technique.

I agree with everyone else that for that size hole, just use the slowest speed available. Take it easy and watch for overheating.

[Bill Huber]

Thanks for the input folks. I went with the fly cutter as suggested by many of you. Will let you know how it works out.

Not to be a smarty pants but you do know there are 2 way to set the cutter.....

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[ian maybury]

A related one to watch for is to ensure that the side of the cutter to the outside diameter of the cut has enough angle ground on it to ensure that it properly clears the cut surface...

Guess the other issue that can crop up if we're unlucky during low speed large diameter boring jobs in the less than high quality/high stiffness/well toleranced drill presses many of use is chatter of one sort or another. Which can on occasion have the less than ideal effect of causing the chuck to drop out of the morse taper socket in the spindle, or cause enough vibration at the cutter to mess up the finish and even the dimensions.

It's worth making sure the chuck is well driven home in the taper. After that it's definitely advisable to make a test hole or two. Speed changes are generally the first option in finding a way to move away from chatter...

[Chris Padilla]

Not to be a smarty pants but....

We don't need no smarty pants mods, eh?! ;) Oh wait.... :D

[Lee Schierer]

Be sure to watch your fingers when you swing that fly cutter around. They are famous for banging up knuckles and fingers.

[Rich Riddle]

Not to be a smarty pants but you do know there are 2 way to set the cutter.....

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So should I cut the hole in the table? Ponders for a moment or two. What would Chris advise?

[Mort Stevens]

The big problem is the hole saw will build up with MDF and want to get hot and not cut very well.

I used to have poor luck with hole saw until someone showed me a trick to give the saw dust some place to buildup--remove every 6th tooth, just grind it away completely. After I did that I've never had anymore problems with hole saws or heat buildup.

[Bill Huber]

I used to have poor luck with hole saw until someone showed me a trick to give the saw dust some place to buildup--remove every 6th tooth, just grind it away completely. After I did that I've never had anymore problems with hole saws or heat buildup.

Good idea, I will have to try that the next time.

Thanks..

[Ole Anderson]

Using a fly cutter on my mini-mill to cut a 4" hole in 1-1/8" particle board for a duct support. Flipped it at halfway.

https://www.youtube.com/watch?v=q5ORwZJ3ErE&feature=youtu.be

[Myk Rian]

So should I cut the hole in the table? Ponders for a moment or two. What would Chris advise?
In the table? Uh, no. Put a piece of ply under it, and clamp everything down tight. Especially for a 6" circle. As soon as it cuts through, raise the quill.