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I have finally built a nice router table with a Milwaukee 5625 3HP Router in it. It has a veriable speed so I am wondering if anyone knows of what speeds would work better for the different woods with respect to burning. I am guessing a little slower speeds would be better for hardwoods then soft woods. But maybe wood reacts differently the metal. If I knew I wouldn't be asking.

Chris

In my experience, the only wood I ever have trouble with burning is maple so I make sure there's a lot more clearance on it or I take lighter cuts. It's a combination of speed vs feed, so if you're burning something then you need to push it through faster or slow down the router.

In the case of CNC I optimize my feed to catch up to my highest spindle speed, but in the case of hand work it's totally dependent on how fast you're comfortable feeding the work!

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Speed of the router has more to do with diameter of your cutters. Big, honkin' 1/2" shank cutters for making raised panels require slower speed than cutters under 3/4" diameter. Amana tools has their catalog online and they state the max rpm for all their cutters, which you could extrapolate to similar cutters by different manufacturers.

Any cutter under 1 inch diameter can run full speed, 20-25K rpm. You will likely burn wood by using either a dull or dirty resined bit, or like Bob says, feeding the stock too slow. Some woods are just more prone to burn as well, maple and cherry are two prime examples.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Thomas also reminded me of something I missed: All things being equal (RPM, torque, cutter geometry,etc), both your depth of cut and your feed rate scale linearly with the diameter of the cutter. So, if your cutter is half the diameter of another then you feed it at half the speed and half as deep per pass. This also works for RPM, so half the RPM=half the feed rate (though this can bottom out when your cutter's edge isn't moving fast enough to slice cleanly through the material you're cutting).

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

So are you then saying that if I am burning because my feed rate is too slow then instead of speeding my feed rate then I can compensate by reducing the RPM? If so that would probably be a better solution for me since sometimes it is easier to keep my feed rate where it is and it may be at a rate that I'm more at ease with depending on what I'm cutting. I was hoping to be able of using RPM changes to my benifit. It's like when routing a binding channel, Im not one for just ripping around the edge.

Yep, you got it.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

So speed and feed behaves the same for wood as it does for metal. I suppose it's the same in regard to hardness too. I wasn't sure if wood would be any different then metal. Sometimes things react differently then what we might assume so I figured I ask to make sure.
Bob, buy the way if I use a spiral downcut... never mind.

The only difference is that wood will compress and crush off instead of cutting and shearing off if the cutting edge isn't hitting it fast enough, so chips form differently. This puts a minimum usable RPM on a cutter based on its sharpness and readius.

And the spiral bit thing...

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services