# bit speeds, something to think about



## reible (Sep 10, 2004)

We have talked about router speeds (rpm) in relationship to cutter diameter before but I thought I would do a spreadsheet and do a few speeds and post them here. This is the speed of the edge of the bit at the stated diameter at the rpm listed (in rounded mph):

3” bit at 10000 rpm = 89 mph

3” bit at 12000 rpm = 107 mph

3” bit at 15000 rpm = 134 mph

3” bit at 18000 rpm = 161 mph

3” bit at 21000 rpm = 187 mph

3” bit at 23000 rpm = 205 mph

3” bit at 28000 rpm = 250 mph



So you can see why you need to slow the rpm for the bigger cutters. As reference here are a few more:

1” bit at 18000 rpm = 54 mph

1” bit at 22000 rpm = 65 mph

1” bit at 28000 rpm = 83 mph



¼” bit at 28000 rpm = 21 mph



This all came up when I was posting some questions for points about a month ago and was going to ask this as a question. Then I saw a mention of speed in a recent magazine and thought of it again.


1 mile = 1.609344 Km for those who need to know.




Ed


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