dovetail router bit question

[Allan Daskam]

Hello i would like to know if i can use a dovetail bit with a bearing on it in my porter-cable jig it is a 4210 the one for use with a 5/8" o.d. bushing is a 17/32 with a 7 degree cut. I will be making half-blind dovetails in 3/4" stock. Will the freud 22-5505 or any other one.

thanks
Allan

[Bruce Wrenn]

First, I'm no expert as I just opened my 4212 last night. I think the bushing for the half blind dovetails is 0.750 (3/4"). Why would you want to use a bearing instead of a bushing? From Amazon, I ordered an extra bit, Freud item 22-115.

[Allan Daskam]

yes you are right it is 3/4" bushing don't know where i came up with 5/8". I had read on that that you could get better resultes with a bearing bit because the the bit is in the exact center of the bearing and to get a bit in the exact center of the bushing is harder to do. the jig does work well, but some of my fits could be a little better.

[Charles Lent]

Allan,

If you keep your router oriented the same way during all of your dovetail cuts, router bushing concentricity isn't really a problem. Get the bushing as centered as you can, but then make all of the dovetail cuts with the router facing in the same direction. I put a black mark on the base of my router and always point that side of the router toward the jig. An offset router bushing is only a problem if you rout some of the dovetail cuts and then change the bushing offset by turning the router or the bushing. As long as the offset is the same throughout the cutting process it's error will not be seen in the joint. Make sure that the router bushing is tight so that it can't turn or move during your cuts. Peachtree Supply www.ptree.com has some thin wavy spring washers to put under the bushing nut to keep it from loosening, or you could find some O-rings that fit under the bushing nut to use for this purpose.

Charley