Rotary Trimmer Table

Several times recently, I have needed to cut a door or some other square shape into a panel.   Note the large and small trash bin lids.   I tried to bandsaw each side, then coping saw a corner and finish with a smaller bandsaw, then had to trim the door smaller to give proper clearance.   I thought of using a rotary trimmer to do this but thats a lot of clamping to a very narrow strip along the edge of the panel.

I decided to build a table with a fence that held a rotary trimmer underneath in a vertical position.   I made a tile saw table like this and decided thats the way to go.  
Like the tile saw, I needed a 3/4" deck for the tee track, and 1/2" plywood for the rest of the box should work.    

I looked around and found a reasonable ($22.95) rotary trimmer at Harbor Freight that looked like it would fill the bill.   So I bought one, brought it home, dismantled it, and sawed off it's handle to shorten it.  
The trimmer's front collar was almost exactly 1-3/4" in diameter so I made a clamp block to hold it.  
For the fence I routed two tee track slots in the top deck, then used a 1" high by 3/4" wide piece of pine and two tee knobs and bolts.  

I bought this rotary trimmer from Harbor Freight.   Here I've already taken the plastic guide off the front and removed the black side handle.   Also note I disassembled it and re-routed the power wire out the other side.   You can just see the black mark (in the green circle) I made on the lower part of the handle, Just left of the vise, showing where to saw it off.

I sawed off the handle, this thing is about 8" long after the handle is gone.   I measured the diameter of the round shoulder just below the tollet, it is very close to 1-3/4" in diameter.   I'm going to use it vertical and didn't need any extra height.

Power wire rerouted opposite the power switch.

The side handle mounted in the tapped hole (6mm x 1) just behind the shaft lock button.

The table frame in the 12" cauls.   Its 8" high out of 1/2" birch plywood.

I butt joined the corners, not mitered.   I've done this before and it worked OK, as long as you use TiteBond glue.

One of the two pieces of Rockler tee track, I sawed them off to 12" then drilled extra mounting holes near each end, there were already two in the middle.

I counter sunk the new mounting holes.

I made a clamp block, form piece of 1x6, I drilled a 1-3/4" hole in the center then sawed a relief slot from the edge to the center hole.   I drilled a 1/4" hole edgewise, completely through, inserted a 1/4" bolt and nut to form a clamp for the trimmer's neck.   Normally I would use a carriage bolt, but I didn't have one long enough, so I used a 6" hex bolt.

Note the shoulder of the neck of the trimmer is almost exactly flush with the top of the mounting block.

Bottom side of the mounting block with trimmer installed.

For the side mounting block, I used a short piece of 1x2.   Drilled a 1/4" hole for the 6mm x 1 bolt, and screwed this second mounting block to the clamp block.   Note the head of the 1/4" hex bolt on this side of the clamp block.

Top side of the mounting block, note the two screws holding the second mounting block.

Mounting blocks and trimmer mounted to the underside of the deck.

Test fit of top deck onto frame while still in the cauls.

Under side showing mounted trimmer and wiring.

Top deck mounted on frame with tee tracks and fence.

A test, I drilled a 17/64" hole in the support block to line up with the shaft lock button.   Here I'm testing that a 1/4" dowel locks the shaft and moves freely.

Cut a 1/4" dowel and center (ha, ha) drilled some 5/8" dowel pieces.

These will be keepers so the dowel doesn't fall out.

Here I've drilled a #47 (.076" dia) hole so I can pin the keepers in place.   Note the pin material appears stangely like a hardwood toothpick, but it works!

Keepers pinned on the dowel and in place under the trimmer table.

I center drilled another piece of 5/8 dowel and glued it onto the outside end of the 1/4" dowel as a button.

Here I am holding the button, locking the shaft, so I can insert and clamp down on a bit.   It works great.

From the left front quarter.

Whole unit being tested.   It cuts a nice straight line on plywood but 1/2" plywood is a little slow.