Router speed

[SBH]

Is there a general guide to determine what router speed is best for different types of wood or using different bits? Or is it trial and error?

I was using a brand new Rockler carbide 1/4" x 1" w/ 1/2 shank to cut slots all the way through a 3/4" thick select pine and after about 12 cuts the bit broke. The good news is, I received a new one from Rockler at no charge. I was experimenting with different speeds and haven't really noticed a difference with higher speeds or lower. But the bit broke at a lower speed. Therefore, I don't know if this was the cause of the break or did I just have a faulty bit.

Thanks for any help

[Jim]

The general rule is the smaller the bit, the higher the speed. Your problem was most likely taking too deep of a cut with such a small bit. Three or four passes would be more reasonable. Jim

[Stoutman]

The smaller the diameter of the bit, the faster you have to spin it. The wider the bit the faster the carbide is spinning at the edge therefore the slower in needs to turn. For a 1/4" bit you want to spin it at the fastest setting.

It could be that you were routing out too much wood at one time. Take more passes with less depth of cut.

[Nova]

See the article written by the late Patrick Spielman listed below. Note the section under "Don't try to cut too much!".

[CW]

There is a lot more to it than speed. In the case of a 1/4" bit, run it at full speed. Slotting, or cutting the full diameter, is the hardest cut you can do with a router bit. General rule of thumb for cutting depth is 1 to

1.5 diameters deep. This means 1/4 to 3/8 deep per pass and feed no faster than chips will clear the cut. Chips packing in the cut will load up the cutter.

[Leon]

Typically on bits up to 1" in diameter it is safe to run the router wide open. But like every one has pointed out, take shallower and multiple passes. 1/4" is about as much as you want to remove at one time.