DP Speeds?

[Russ Filtz]

Anyone have tips on what speeds to use on the DP? I know that wood is supposed to take higher speeds than metal, but what about different bit sizes and forstner, etc.? I was using a 2" forstner on some cherry and kept stalling the motor. Bit was a bit dull and sharpening helped some, but still had to take it real slow. Should I have bumped the speed a bit? Not sure the exact setting, but I believe it is pretty much in the middle on a JET 17MF. Do the bigger bits need higher speeds to keep spinning?

[Kent Cori]

Russ,

This is a guide that I found and use.

http://www.woodmagazine.com/wood/story.jhtml?storyid=/templatedata/wood/story/data/85.xml

[Chris Padilla]

My Delta DP came with a guide for drill speeds; it isn't quite as extensive as the list I just printed out that Kent posted, however. :D

Thanks, Kent.

[Rob Russell]

Anyone have tips on what speeds to use on the DP? I know that wood is supposed to take higher speeds than metal, but what about different bit sizes and forstner, etc.? I was using a 2" forstner on some cherry and kept stalling the motor. Bit was a bit dull and sharpening helped some, but still had to take it real slow. Should I have bumped the speed a bit? Not sure the exact setting, but I believe it is pretty much in the middle on a JET 17MF. Do the bigger bits need higher speeds to keep spinning?

On the 2" bit, you should have dropped the speed as low as your DP would go. The ideal range for a woodworking DP is 250-3000 RPM, if you check that chart in the link Kent posted. I have a 3-phase motor and VFD so I can get my old Clausing down to that sort of RPM.

[Chris Padilla]

Rob,

I think we should start calling you "3-phase" as it fits nicely! :D

[Rob Russell]

I said I have - not that it's assembled and working! :D

Most people don't realize what 3-phase can do for you. The Clausing DP I have is a floor model honker from the late 60's, 6" quill travel etc., that I picked up a a tag sale cheap (like $150). It's a great DP, but it's slowest speed is only 400 RPM or so. I knew I needed slower after I'd used a 2"+ forstner bit in my benchtop DP at 500 rpm and had to bounce the bit into the workpiece to drill the hole. Re-pulleying the DP isn't the best solution, so I picked up a good used 1HP 3-phase motor at a local motor shop and snagged a VFD on Ebay. The VFD will allow me to run the 1HP motor down to 250 RPM and still have a full 1/2 HP. You just can't do that on single phase.

[Chris Padilla]

What is an obvious reason why 3-phase isn't considered residential? I don't think many homes have 3-phase available as a rule. If it is so great, why don't we have it in our homes?

[Greg Mann]

Rob,

I think we should start calling you "3-phase" as it fits nicely! :D
Chris, after reading Rob's electrical dissertations on Frank's workshop thread I don't think "Mr. Edison" would be unwarranted. I learned more about workshop wiring from Rob's posts than a couple 'Home Wiring' books I have and his explanations were easier to follow. He gave us the why as well as the how. Great Work, Rob.

BTW, Russ, the basic characteristics of power transmission are the slower the speeds the more the torque, as long as the motor speed is constant anyway. Holds true for everything, I think. Of course now that I've said that someone will give an example where it's not true.:)

Greg

[Russ Filtz]

I realize the torque/speed argument, but what about cutter head momentum? Isn't this why the router runs at XX thousand RPM so the cutter doesn't bog down? Otherwise we'd be running router bits at 2rpm and chewing the wood out!

Guess I'll try it both ways next time I have a problem and see what works best. Good old experimentation. Just wish my DP had a high/low switch like my hand drill!