Spindle Speed & Feed Rates - Question

[Moondog]

hello.

I am just in the process of building my router (see project log for specs).

With regard to feed rates etc. I will be mostly cutting timber around 10mm marine ply. Obviously the cutting rate will depend on the cutting bit and power. If I was using a 2400W router and a 2 flute 12mm bit, what would be a reasonable feet rate.

The reason I am asking is I need to work out the gearing for the motors to see what inch/min I will need. The motors RPM is 1750.

What should I aim for in Machine speed with an without load.

For example if I gear down the Y axis 3 to 1 I end up with a feed rate of 100in/min at full motor power.

Another question.

Most router RPM are around 20,000 +/- no load speed. What approx would be the Load speed cutting 10mm ply( assume a reasonable cutting speed).

I have a Felder woodworking machine with a router spindle turning at 6,000 to 9,000 rpms from a 3 HP motor. With a 1/2 inch bit it will handle a very fast feed rate much faster than my hand held router.

Is high speed better, i.e, Router at 20,000 or a spindle around 5000 rpm with heaps of grunt.

I am sure you guys can guide me in the right direction.

cheers

[ger21]

On our commercial router (9HP) I cut about 300ipm at 16000rpm, through 3/4" (19mm) ply. I doubt a 3hp router has the power to do that. Most likely 20000rpm will cause premature tool wear and burning at slower feed speeds. Ideally you want a vaiable speed router (10000 to 20000rpm) and I'd shoot for 150 to 200 ipm. The stiffness of your machine might be a limiting factor as well.

Most variable speed routers compensate under load to try to maintain rpm. Under load you shouldn't see a big difference in rpm.

Bottom line when routing wood, is go as fast as your machine will let you go, and keep the spindle speed as low as you can. The faster the spindle speed and slower the feed, the more heat is generated. This heat is what dulls your tools.

Stay away from the 5000 rpm, most likely you'll need about 10000 and up.