Powermatic Shaper

[Bill Leonard]

I ran across a Powermatic PM 26 shaper at auction recently with 1/2 inch, 1/4inch router collets as well as the standard 3/4 inch spindle. It also had a reverse. My question to you shaper users: What is the purpose of reversing either a router or shaper bit? I am surely missing something obvious here, but!!

[Nate Carey]

A single cutter head may offer more than one profile by flipping it on the spindle. Also proper "registration" of a work piece may require the cutter head to be flipped if multiple passes are being made. There should be a groove in the spindle; this groove accepts a unique washer that, when properly installed, prevents the spindle nut from backing off when running in reverse.

Another valuable (perhaps more so than the motor reverse) feature of some machines is a tilting arbor.

Router bits are designed to run in one direction only.

[J.R. Rutter]

Just so it is clear - Registration of the part in relation to the cut controls a critical dimension.

If you need a 1/4 round (the negative space) that is exactly to size, you would run it with the cutter below the part so that the table and fence reference the cut.

If you need an exact lip thickness (positive space) on the edge of that same 1/4 round (to fit in a groove, etc.) then you would trap the part between the cutter and the table so that any small thickness variation would not affect the fit.

The same cutter can be used either way, but when you flip it, you need to reverse the rotation and feed direction.

[Frank Drew]

Bill,

There's also a 1" spindle available for that machine that comes attached to its own bearing cartridge, and only takes a minute or so to swap out.

[Rod Sheridan]

Bill. one other use of reverse is so that you can flip the cutter over and go with the grain, for example when trimming parts to size using a template.

Double spindle shapers exist for that very reason, the spindles rotate in opposite directions, so with 2 cutters you can simply move your template from one spindle to the other to prevent tearout.

Regards, Rod.

[Jamie Smith]

Doesn't it also allow for climb cuts with a feeder?

[Rod Sheridan]

Doesn't it also allow for climb cuts with a feeder?

Not really, a climb cut refers to the feed direction.

In a climb cut you are feeding the wood in the same direction the cutter is turning.

It's only possible with a stock feeder as you have noted.

Regards, Rod.

[J.R. Rutter]

Bill,

There's also a 1" spindle available for that machine that comes attached to its own bearing cartridge, and only takes a minute or so to swap out.

You can also get the 1-1/4" spindle for it. Same exact part as the PM #27.

[Frank Drew]

I didn't know that, JR, thanks.

[Bill Leonard]

Thanks for the info guys. What a great web site. I now own the critter and need to figure out how to use it. I'm sure I'll be asking for more knowledge. In the short term it is going to replace my router table, and eventually I hope to expand its use to its original intent. I'm replacing the 3 phase motor with a 3hp single phase. I'm getting conflicting comments from "experts" on rather I will be able to reverse the single phase motor. Any advice here would be appreciated.
Bill

[Philip Johnson]

Bill I am no expert on electrical stuff but looking thru my manual for the powermatic pm 2700 shaper there is a different part number for the 3 phase and single phase magnetic switch and the forward and reverse switch. Would you be better off and cheaper to consider a phase converter.

[Bill Leonard]

I considered a phase converter, but several electrician friends as well as a motor rewind guy recommended a motor swap. The switch on the shaper is compatible with single phase and is rated for a 3hp single phase, so no problem there, and the cost of a converter is about the same as a new motor.