# miter lock router bit



## Clutchcargo (Apr 9, 2007)

I picked up a large lock miter router bit to miter together some columns into 5/4 pvc. This will be my first project using a router. This bit is difficult to set up because it's basically just trial and error until you get it right. My question is, what speed should this bit be turning at?


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## Tippy (Oct 5, 2007)

The speed of a router bit is a fxn of its diameter. The guideline I use is not to exceed a tip speed of about 75 mph. You can go up to 100 mph if you feel the application really calls for it. So, a 3" bit will run 8000 rpm (roughly 71 mph) and a .5" bit will run the full 22,000 rpm of the router (roughly 33 mph). 

Anyways, this is just a guidline I use. Routers and their bits are designed to run at high rpm's, as opposed to shaper cutters. So you can be a little north of my 75 mph threshold to get a little cleaner cut. However, as I said, I don't exceed 100 mph, it can lead to bit failure.


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## TexasTimbers (Oct 17, 2006)

Trial and error is it with a miter lock bit. At least that has been my experience. As to the RPM all I know is mine works best at the #3 setting on my big Porter Cable. :smile: At least for most woods. 

But Tippy sounds like he knows what he is talking about I'd take his advice. I never thought about converting RPM to MPH.

Okay I just looked at my router and the #3 setting is 16,000.


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## Clutchcargo (Apr 9, 2007)

It seems like 8000 RPM is far to slow, it causes the workpiece to chatter\. I find that 16-20000 seems to work better. I'm cutting 5/4 PVC boards.


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