Hole Saws for Plywood?

[Doug White]

I need to drill about fifty 1 1/2" holes in 5/8" plywood. The last time I did this, I use a plain carbon steel hole saw, and it was a pretty miserable experience. The saw teeth clogged quickly, it overheated a lot, the plugs were hard to remove, etc.

I was planning on using a bi-metal saw this time, but I don't see that they've done much to improve the basic design. None of the ones I've seen appear to have changed anything to keep the teeth from clogging, for example. I have seen some that have a plug-ejection device that works by reversing the drill, but the drill I will be using isn't reversable.

I've searched the archives & the last threads that had much on the topic are a couple years old. I'm hoping someone has discovered something useful in the meantime.

Thanks!

Doug White

[Doug Miller]

Try a brad point or Forstner drill bit instead of the hole saw.

-- Doug Miller (alphageek at milmac dot com)

How come we choose from just two people to run for president and 50 for Miss America?

[Secret Squirrel]

[e-mail] (Doug White) wrote in news: [e-mail]:

Perhaps a Fortner or Sawtooth drill bit would be easier?

[Jerry Gilreath]

Along those same lines, I too need to drill some 1 1/2 in holes but I need the *wheels* that come from them. My question is, what would be a safe way to round over the edges of the said *wheels*?

[B a r r y B u r k e J r .]

Why not use a forstner bit or one of it's clones?

Barry

[Chris Merrill]

I've heard a recommendation to drill a hole with a regular drill bit (maybe 1/4"?) _just_ inside the perimeter of the circle you will be drilling with the holesaw. This will give a 'dust relief' area where dust can be ejected from the teeth. Maybe more than one hole would help more?

disclaimer: I've never tried this myself...

[Joe Gorman]

I've done this, but with relatively green live oak. It took several holes around the circle to allow me to cut 1" thick disks. Having the edge of the disk on an edge also helped. Still a PITA so I haven't tried lately. kind of wonder if trying to fill the notches between the teeth with chalk or baby powder would help clear the sawdust. Joe

[nospam]

if you need holes that are 'pretty good'- a little chipping and fuzz is no problem, and you need to drill a bunch of them quickly- the hole saw is probably a good way to go. you will need a drill with plenty of power and a high quality hole saw. to keep from clogging with sawdust back the hole saw out and blow off the dust frequently. if the hole saw is sharp it'll make more like shavings than dust anyway.

if you don't care what the backside of the sheet looks like, or you can back it up with a block of 2x4 or something, you can use a spade bit. the hole quality will be ok, as long as you keep the bit (and especially the spurs) sharp. these bits are easy to sharpen with a file.

if you want a nice smooth wall cut, use a forstner bit. backing it up with something is a good idea here too. these bits are more complicated to sharpen, but not too bad.

if you need a real clean accurate hole, try a template and plunge router. Bridger

[jo4hn]

[Jerry Gilreath]

Mahalo jo4hn, I never thought about the drill press thing. I was going for the router table, but your idea should work. I'll give it a try after while. They aren't really a wheel, they're going to be feet for a couple cutting boards. So, in that respect, the carriage bolt will work fine. Glue the hinky side up and nobody'll ever know. You truly are akamai! Mahalo once again!

[Robert Bonomi]

Okay, you wanna be difficult, don't you?

Taking it as given that you're actually making _wheels_, you'll eventually have something down the center for an axle.

Thus, a 'small' hole in the center of the piece isn't going to hurt anything.

Therefore, make a jig.

a simple flat piece of wood, with a screw-hole in the middle of it.

position the wheel-to-be with the center of the circle at the screw-hole, and hold it down (temporarily) with double-sided masking tape.

Turn the jig over, and run a screw through the hole, into the wheel-to-be. till the screw is _tightly_ holding the piece in place.

Turn the jig back right-side up, and use a bottom-bearing round-over bit.

Voila!

[Ron Magen]

Jerry, If you are going to spin them on a DP, I've got a 'trick' that may help with the hole saw cutting.

I had a number of large holes to cut, and my Radial Drill Press won't turn slower than 500rpm . . . about twice what is 'recommended. I was cutting

3/4" ply - 'regular' and PT. I had to make the 'bits' last and get out the 'plugs' so I couldn't just 'burn' my way through.

What I finally did was set-up to go just a hair LESS than HALF-WAY through !!. First cut from one side, withdrawing the saw frequently to get rid of chips and for cooling. Then the same on the other side. Most of the time the 'second pass' left slivers of wood holding the 'wheel' in place . . . you can 'feel' what is happening. Sometimes they came out on the saw {but you has something to grab on to}, and sometimes they had to be lightly 'tapped' out.

Whatever . . . the job went fairly quick, a simple 'swirl' with some 60grit paper cleaned up the hole . . . and the same could have cleaned up the 'center lip' on the 'plugs'.

Regards & Good Luck, Ron Magen Backyard Boatshop

[Trent©]

They sell an adjustable hole cutter, Doug. The center of the hole...to steady the cutter...is a regular drill bit. The outside cutter is a metal cutter piece...and the diameter of the cut is set with an Allen screw.

They're probably about $10-15 max at most hardwares.

Wishing you and yours a happy holiday season...

Trent

Proud member of the Roy Rogers fan club!

[Sweet Sawdust]

After having cut a few thousand 2 1/4 inch "wheels" from 1/4 to 3/4 stock I use the belt sander to smooth the edges. Take an old Philips screwdriver of the right diameter and put it through the holes, (as many wheels as will fit on the screwdriver) place the loaded screwdriver parallel to the belt of the sander, apply LIGHT pressure to the wheels and turn the screwdriver to the angle where the wheels start to turn slowly on their own. hold wheels on screwdriver with fingers, its going to fast when fingers starts to burn. When sides are clean take a trim router and round over edges using a router mat to hold the wheels in place. It goes fast and gives a very clean edge.

[oakman]

I've used a carborundum toothed hole saw whereas the cutout wasn't clogging and hard to remove from the inside of the bit... its all in the set of the teeth which retains that cutout inside the hollow of a hole saw.

[Jerry Gilreath]

Many thanks all! The job of making all the little wheels are done. I tried all the suggestions on different sets. Sweet sawdust, when them little boogers get to spinning on the sander, it does generate some heat!!! Don't have to worry about playing the piano for a while. Oh wait, never could to begin with! Again, many thanks to you all, they kept my fingers out of the spinning router bit on the router table.