Rail & Stile Router Bit Question

[Marty Tippin]

I recently bought a used Porter-Cable rail & stile router bit set (part no. 43560 & 43561) and have found that the width of the tongue on the rail and the width of the groove on the stile differ by nearly 1/32" - the tongue is thinner than the groove, which seems like it's going to make for a sloppy joint.

Is this to be expected or did I buy a set of junk bits? These do not appear to be adjustable bits, so I don't think there are any shims that I could take out to improve the fit.

[Steve Roxberg]

You can generally add spacers between the top and bottom of the bit to make the tongue thicker or thinner. Remove the not on the top and the top bearing, and cutter. Place shims (thin washers) in and put it back together.

A little initial tweaking or tweaking for different woods is not unusual.

[Peter Quinn]

If I'm seeing the set right in pics, then groove cutter is fixed, its part of the sticking cutter, the tongue is adjustable by adding shims between the bearing on the cope cutter and one of the other two cutters. If you didn't get that appropriate shims you can buy them from a router bit source like infinity, eagle america, woodcraft, or you can buy "precision washers" from master carr that have the same ID as your router bit and will function as shims, just that they list them as "precision washers". Either way I'm pretty sure that stack is in fact able to be shimmed, it has a nut on top of the shaft of so the cutters can be sharpened, that means it can and often must be shimmed post sharpening.

[Marty Tippin]

Total operator error on this one... the stile I was test-fitting against was a piece I had run through the bit twice after making an adjustment...

I cut a new set of test pieces and they fit just fine.

For the record, I did take the bit apart but didn't find any spare shims - there's a washer under the nut on top of the rail bit, but it's way too thick to be considered a shim.

[Peter Quinn]

Total operator error on this one... the stile I was test-fitting against was a piece I had run through the bit twice after making an adjustment...

I cut a new set of test pieces and they fit just fine.

For the record, I did take the bit apart but didn't find any spare shims - there's a washer under the nut on top of the rail bit, but it's way too thick to be considered a shim.

Should it become necessary you can add shims, they are not expensive, I got a lifetime supply for around $10 from Master Carr.