Router Arbor to Accept Shaper Cutters?

To solve a one-time problem, a woodworker looks for a way to mount a shaper cutter on a router. February 14, 2010

I have a Triton 3.25 router mounted on a cast iron table. The insert is a 3/8 aluminum plate. It's a pretty stout table. There is a shaper cutter profile that I need but I can't seem to find in a router bit. I understand there's a reason for that and I understand that shaper cutters require a lot more power to turn than a router can provide, but if I took small passes, I feel that the router would have enough power to do it. However, I need to find a way to mount it in the collet. I was wondering if anyone has heard of a shaper arbor that can be installed into the router? Rather than pay to have the bit custom made, I would prefer to just buy an arbor.

Forum Responses
(Solid Wood Machining Forum)
From contributor P:
Several manufacturers such as Amana make arbors that accept side grooving cutters. They also have the arbors that are used with cope and stick door cutter tooling. Technically, they are just very small shaper cutters mounted on a small arbor with a guide bearing. You could adapt one of these arbors easily. Obviously, this is a proceed at your own risk setup. The cutter dia should be run as slow as possible and the dia kept under 3 inches.

From contributor L:
Most shaper cutters are rated at or below 10,000 RPM. Most routers can only go down to 12,000 RPM. If the shaper cutter is small (2 5/8" OD) I think it could work. Any bigger than this would be scary. If you do try this, I would recommend using an extension cord, a long one, and plugging the router in with it on at a distance and letting it run for a while to make sure it's not going to do something funny.

From contributor J:
Grizzly has one for 1/2 inch bore. #G4820, $14.95.

I personally would not sanction the use of it, but it would probably work for some light duty work.

From contributor N:
For very small shaper cutters that have a 1/2" bore, Grizzly (and others, I think) offers an arbor that can be grabbed by a router collet. I've never tried one.

From contributor D:
I'm not the squeamish type, and often my cavalier attitude gets chided, but I think that's getting pretty scary. At least I hope you have a variable speed router turned all the way down, that the cutter is the lightest and best balanced you can find, and you build a hefty fence around it just in case something starts to come loose. Otherwise that's a good way to get killed. I'm not saying that with an attitude; it seriously gives me chills.

From the original questioner:
Thanks for all the help. I got one from Grizzly on order. I should be able to get a shaper within the year, so this would only be a temporary situation. I won't be using any shaper cutters over 3 inches and my Triton can go as slow as 8k rpm, so I think I'll be okay.

From contributor L:
10,000 rpm should be fine.