How to control/reduce speed of drill press

[LesT]

I've got a Delta 12" drill press (11-990) with a min speed of 620 rpm. I've got a 3 1/2" hole saw that I want to use in the drill press, but it's max speed is 140 rpm. I've called Delta and they don't have any other pulley arrangements that would reduce the speed. I've looked at a router electronic speed control but the info says they work only with motors with brushes - my drill press is a 1/3 hp induction motor without brushes. I don't want to do this job (many holes) using a hand drill - am I just up the creek?

Any suggestions would be greatly appreciated - thanks in advance.

Les

[Morris Dovey]

How deep is the hole? (I'm assuming it's a through-hole.)

[Leon]

Time for an upgrade. I had the same problem with large Forstner bits. Have you checked with a hardware store for replacement pulleys to substitute.

[LesT]

I've looked at the pulley sets, and the one over the motor looks like it can be removed and another pulley put in it's place, but it's the smallest and it doesn't look like a much smaller one could be found. The other pulley set (above the chuck) looks like it is fixed.

Concerning the depth of hole, I'll be drilling hard maple or baltic birch ply

1/2" thick. I'm working on making a wine cabinet and using maple or ply slats with half moons removed to cradle the wine bottles. I had planned to make the half moons by drilling 3 1/2" holes in the 1/2" pieces and then cutting them down the center.

[Morris Dovey]

Have you considered making a template and routing the holes?

[LesT]

so much quicker. What do think about really securing a setup to the table of the drill press into which I can fit the piece to be drilled - how dangerous is operating the hole saw at 620 rpm?

thanks for your help

[Ed Pawlowski]

I have this on my whole house fan motor.

[jo4hn]

I generally run hole saws up to 6" at 480 rpm with no problem. I would think that a 3.5 at 620 would be all right. Just take it easy and lift the saw out of the piece now and then. Keep an eye out for burn marks and ease up if they appear.

Assuming that you don't have a fence, bolt a piece of plywood to the metal table and clamp a straight board to that at the appropriate distance from the center of the chuck. You can also clamp a stop block at the proper distance. That an some hand pressure should do the trick.

mahalo, jo4hn

[Lew Hodgett]

You will never get it centered to get 2 equal pieces.

One piece will always be a tad bigger than the other.

My guess is that existing motor is a 4 pole or 1,800 RPM base speed.

You could replace with a 6 pole or 1,200 RPM motor but that still leaves a 3-1/2" hole saw operating at 400 RPM which is just plain scary.

You could engineer a belt drive reduction ratio and remove the motor to drive it which in turn drives the D/P quill, but pillow blocks, sheaves, belts and a suitable structure aren't free.

Morris has given you the fastest and lowest cost solution.

Make a template and cut ONLY half moon cuts.

1) Faster than any hole saw. BTDT. 2) Every piece will be identical. 3) Eliminates table saw operation. 4) Cost will be minimal compared to other methods.

Cutting lots of holes with a hole saw in a drill press is a TOTAL PITA

BTDT.

As Leon suggests, probably time for a drill press upgrade.

Have fun.

Lew

[Lew Hodgett]

---------------------------------------------------------

If you have a saber saw along with that router, you could really simplify things.

Make two (2) templates, one using posterboard that would allow you to mark a saw cut line maybe 1/4" proud with a pencil for the saber saw and another using 1/4" Plywood for the finish router cut.

Make a simple clamping fixture that will position the part and the template(s) while being held place with a couple of toggle clamps.

Probably trace saw cut line on maybe 100 pieces in less than 30 minutes.

Have fun.

Lew

[d.williams]

The template and router solution sounds good to me for another reason. With a hole saw you might end up wasting a lot of time trying to dislodge the cut out piece from the hole saw. Those cut outs have a way of refusing to backout, you may end up having to take the bit out of the chuck more than you'd care to so that uyou can drill another hole.

[LesT]

Thanks for all the good advice - I'm considering the best solutions given here and other forums and I'll let you know how things work out.

Les

[Leon]

Sure you can, cut the piece in half on a TS then run the waste side through again.

[Robatoy]

1/3 HP and a 3-1/2" hole saw in maple? The second that hole-saw hits the wood, things will come to a dead stop. BTDT. Even a proper 3/4 HP to 1 HP DP with reduction down to 200 RPM would make that a tedious, smoky job. Morris' suggestion is by far the better choice. (As per usual )

[Lee Michaels]

1/3 HP and a 3-1/2" hole saw in maple? The second that hole-saw hits the wood, things will come to a dead stop. BTDT. Even a proper 3/4 HP to 1 HP DP with reduction down to 200 RPM would make that a tedious, smoky job. Morris' suggestion is by far the better choice. (As per usual ) ==============================

Yep, I had to drill lots of holes in metal with a hole saw. The job needed to be done within a day or two and I was on a very short timeline. And the drill was too fast too. My solution was to just squirt lots of lube on the thing and wear a mask with a fan going over the work. It smoked like a chimney. It got the job done. I went out and bought a proper drill press after that job.

We can all make do. But the proper tool can make pleasurable what was total agony before. BTDT

[Morris Dovey]

Well, yes - but I just didn't have enough guts to point out just how quick and easy the hole job would be if LesT would apply the crowbar and bring home a CNC router...

:)

[Robatoy]

saw?? You mean the one that makes elliptical holes?)

[Lew Hodgett]

And neither one will be a full half circle.

Lew

[dpb]

And that's going to bother the wine bottles how??? ( :) )

--

[Leon]

Regardless of where you cut a circle you will not end up with a full circle. A full half circle for a wine bottle is not necessary. 99.5% of a full half circle will work equally as well. The solution for a full half circle is going way way past wasting time for an unnecessary step and will be unnoticeable.