What bit diameter should I stay under with different routers?

[Rich Engelhardt]

Hello,
I have both a PC 690 and a Freud 1700.
I'd really prefer not to stress either.
Is there a rule of thumb or a guideline I should follow as to what size bits I should limit them to?

[Rob Young]

For me, the bit size limit has more to do with router RPM than "horsepower". Depending on which chart you look at (and if you Google around for router bit size vs RPM charts, you will find a few) some say to reduce RPM at 1", others at 1-1/2". You can spin a pretty big bit in a 1-1/2 HP router if you get the speed right, back off on your feed rate and take multiple small passes.

The next thing I consider is how I'm going to be controlling the router. Hand held, I pretty much limit the bit size to what will fit through the basebplate hole, in my case with a PC 893 that is a little less than 1-1/4 inches. If however the router is going to be mounted in the table, I'm OK with going up to a 3" panel raiser. On skis (for the router, not for me) the largest I've gone with is 1-3/4" but only because it is a bottom cleanout bit and I was using the rig for thicknessing an endgrain glueup.

[Charles McCracken]

Hello,
I have both a PC 690 and a Freud 1700.
I'd really prefer not to stress either.
Is there a rule of thumb or a guideline I should follow as to what size bits I should limit them to?

Rich,

The max for the FT1700 is 3-1/2" diameter when table mounted. Check the manual for the PC and it should be stated.