Pantorouter plunge controls and router springs

Making the plunge lever

Having built the pantograph, plunge sled with drawer glides, table, and template holder, the pantorouter XL is basically operational, but it's not very convenient to use.

The shape of the lever is simple enough that I can transfer the measurements onto a piece of wood rather than paste the template on.

I made the cuts parallel with the wood on the table saw, then cut the rest on the bandsaw.

A series of holes needs to be drilled in the end of the lever, to allow me to mount it slightly further out if I want to later.

I just mark the holes off the 1:1 drawing, then drill and countersink them on the drill press.

Next the operating handle. I round the edges of the handle part of the lever. The other end needs to have a notch cut out of it to couple with the link I just built.

The operating lever couples to the link as shown. For the lever's main pivot, I'm using a #10 wood screw, which screws into the template holder.

The hinge with the link could be a piece of steel rod or a wood screw. I'm using part of a knock-down fastener screw. I like the large head on it, and the smooth shank will make a nice pivot.

I cut the screw to length, then chamfer the ends to make it easier to screw into a slightly undersized hole.

The screw threads end up engaging only the other side of the operating lever, allowing the link in the middle to pivot freely around the smooth part of the screw's shank.

The lever and link mount on the pantorouter right here, but I will leave them off for now so I can work on the plunge depth stops.

Making the plunge depth stops

The depth stop mechanism is made from four blocks of wood. I cut the basic rectangular shape of these on the table saw, and here I'm checking the size against the 1:1 drawings.

Three of the blocks get a hole the same size as the shaft, but the largest gets a hole slightly larger so that the shaft will slide freely in the hole.

The holes get a slot cut into them to allow the block to clamp down on the shaft. Also, a few other bits are cut off to shape the blocks

This is how the plunge stops fit on the pantorouter. The block at left secures the shaft to the sled. The large block at right is screwed to the table, and the two small blocks clamp onto the shaft to provide depth stops.

In the plans, I have a 1/4" (M6) carriage bolt and threaded knob to clamp the blocks onto the shaft, similar to the one shown at left.

But I have these screw knobs that I have been meaning to use for something. They are a bit too short to use with a nut on the other side, but a T-nut extends them enough to be just right.

Unfortunately, the knobs have an M6 thread, and the closest I have is 1/4" T-nuts. The T-nut almost fits. So I ran an M6 thread tap into the T-nuts, and now the metric threaded knob screws in just fine.

I place the T-nut over the hole, then tap it with a hammer to mark where the prongs end up, then drill holes for the prongs, large enough for the prongs to loosely fit into.

T-nut and knob mounted on the block.

The block that holds the shaft is screwed to the plunge sled, and the other block to the table. The hole in this block is larger so that the shaft can slide freely.

The small blocks are then clamped to the shaft to serve as stops.

And the plunge lever can now be mounted right above the depth stops.

Router weight compensation

Gravity always pulls the router down. Though the operating lever provides a 2:1 advantage, lifting up the router by the operating lever is still tiring over time. To help lift the router up, I'll be adding springs that push the two pantograph links up, which in turn lifts up the router.

Two cam-shapes for a string to wrap around are cut from Baltic birch, using 1:1 templates, on the bandsaw.

A screw on the inside corner of these will allow a loop of string to hook onto them.

One of these spring cams mounts to the front. It goes on the main shaft and also screws onto the long link.

The other cam just slides onto the shafts of the pantograph. The holes in the cams are slightly arger than the shafts to let them slide on easily.

The springs I bought at Lowes are slightly too long, so instead of using the loops at the end, I'm bending the last loop to the side on the vise, using a piece of wood and a hammer, then cutting off the original end loop.

The sideways-bent loop screws to the edge of the plywood.

And some string (sash cord) ties the spring to the screw on the cam.

With the link pivoted all the way to the other side, the spring has quite a bit of stretch to it. Imagine the long link held in a fixed position, this spring will effectively pull the short link to lift up the router.

The other spring cam is on the front. The spring needs to go under the shaft for the plunge depth stops. I hadn't drawn how the spring attaches on that end yet, and the spring is long enough that it needs to go under this shaft.

I had to carve out a notch to make room for it. I moved the shaft for the depth stops a bit higher in the plans, so you shouldn't need to carve a notch to make room for the spring.

The springs aren't strong enough to counteract the full weight of the router. Even though it's a smaller router, it probably isn't any lighter than the motor-only unit of a full-sized interchangeable base router that I used on my other machine.

And another minor touch, a piece of dowel as an operator handle.

Ready for some more testing. Here cutting a tenon. A sizable tenon for such a small router, but I can take it in steps.

And the corresponding mortise cut. Makes a nice pop when the tenon is pulled out of the mortise quickly.

Next: Adjusting for accuracy

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