How to control/reduce speed of drill press

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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
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LesT wrote:

How deep is the hole? (I'm assuming it's a through-hole.)
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Morris Dovey
DeSoto Solar
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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.
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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.
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LesT wrote:

Have you considered making a template and routing the holes?
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Morris Dovey
DeSoto Solar
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Yes, that has crossed my mind, but the hole saw would be 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
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LesT wrote:

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
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"LesT" wrote:

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
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Update: Some more thoughts. -------------------------------------------------------- "Lew Hodgett" wrote:

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

And neither one will be a full half circle.
Lew
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Lew Hodgett wrote:

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

You half to ask a wine snob.
Somebody is going to feel left out if their bottle was deprived of a full half circle support.
I'm from the Two Buck Chuck crowd.
Lew
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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.
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"Leon" wrote:

Not if you don't try to reinvent the wheel.
As stated in a previous post, cut a half circle with a router and a template and the T/S goes away.
You also eliminate the necesssity of cleaning up saw cut surfaces.
Whether a full half circle is necessary is academic.
Trying to do this job with a hole saw is another kettle of fish IMHO.
Lew
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Lew Hodgett wrote:

If your saw cut surfaces need more cleaning up than your routed ones your saw has a serious problem.
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"J. Clarke" wrote

T/S blade, Yes HoleSaw, No
No matter how you cut it, a hole saw is not a finishing tool.
Lew
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Understatement Of The Week goes to...........
Those hole-saws are CRUDE! I have bought the best, cheapest, staggered teeth, bi-metal, Swiss-made custom ground...... no matter. Drill-press or not.. they do not leave a finished hole. A router, properly used with proper bit, does leave a very nice hole...if it isn't too small.
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Robatoy wrote:

I don't understand "if it isn't too small" - what's "it"?
I routinely cut large holes with small bits. For fun, I uploaded a drawing showing the toolpath for a (large) blind hole "drilled" with a "small" bit to
http://www.iedu.com/DeSoto/Misc/spiral.gif
You might find it interesting that the toolpath (red, starts at center of hole) consists only of straight line moves, marked by a circle the size of the bit at each end, and the finished hole (green) is good to about +/- 0.001"
I'm not sure there is a "too small" :)
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Morris Dovey
DeSoto Solar
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On 8/13/2009 8:55 PM Morris Dovey spake thus:

Yeah, yeah, you've got yourself a CNC machine. We get it.
--
Found--the gene that causes belief in genetic determinism

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