Building the pantorouter XL pantographAlso availble in French
Why the pantorouter XL?
A frequently asked question from readers wanting to build
the pantorouter is where to get that style of router. This style
of router, with a motor that pulls out of interchangeable bases
(like this one)
is hard to find outside of North America. This
is probably because other countries require that the router turn off when you
let go of the handle, and that necessitates putting the switch on the handles,
and that's difficult to do with the motor detaching from the base and handles.
Outside of Canada and USA, except for a few brands and models, routers are plunge routers, with the body and handles often consisting of one piece. This type of router is too bulky to fit into the pantograph mechanism of my original pantorouter design.
Building the pantograph
I printed out my plans, including a sheet (pasted together from many pages)
with a lot of the parts in full size
using my BigPrint program.
The links will pivot on some 3/16" (5 mm) steel rod. Getting holes of just the right fit is important. I drilled some test holes with different 3/16" brad point bits, but these all drilled slightly oversized, resulting in a fit that had a tiny amount of play in it.
I ended up drilling the holes at 11/64 (1/64" or 0.4 mm smaller than I needed), and then drilling the holes to final size using a regular (not brad-point) drill bit.
This resulted in a very tight fit with the rod, which is what I was aiming for.
Freshly applied glue is very slippery, so to keep parts aligned, I clamp on one of the long pieces to the plywood without any glue, then apply glue to the thinner bottom layer...
Next I glue on the other long piece of hardwood.
I wanted to remove that first piece of hardwood, otherwise, the glue that squeezed out from gluing on the plywood would have made it very difficult to remove later.
It's very important that the pieces align laterally. Here, I'm checking that alignment with a square.
The holes are not necessarily perfectly aligned with each other, so I take the reamer, push it through the hole on one side, and then into the hole on the other side. I do this coming in from both sides to get both holes into alignment.
A number of people have "improved" on my design by drilling larger holes and using bronze bushings in the holes. But that means you can't use this trick to get the holes fully aligned. The bronze bushings do last longer. A steel rod in a wooden hole might wear out after cutting as few as ten thousand joints. But if you are at all concerned about wear, put oil in the holes and polish the rods, and it should last much longer.
But then I realized, in my design, the pantograph only needs to tilt by 30 degrees off square. Here I added some blocks of wood below the router mount to limit the tilt to just over 30 degrees off right angle.
The pantograph needs to be mounted on a base, and the base has two corners cut away to fit in the machine, as designed. I mostly cut these on the table saw, then finished the corner cuts on the bandsaw.
These need to be very square. To compensate for any non-square-ness that my drill press may have, I drill the hole about 5 mm in then rotate the block 180 degrees (around the axis of the drill bit) and drill another 5 mm, repeating until I'm all the way through. If the drill press table has any tilt error, every 180-degree rotation effectively reverses that.
But one of the holes was still not quite square. The piece did not lie flush against the pantograph link once it was on the shaft. So I drilled another hole, and another, and by the fourth hole, I had one that was sufficiently square. I think the grain of the wood, running diagonally, pulled the drill to the side a little.
A pencil mark, directly below the hole, on the link, allows me to line it up.
I then mark the hole locations by inserting screws in the holes, and tapping them down with a hammer. The point of the screws makes a divot in the wood to mark where to drill the pilot holes.
Getting the location for the front mount. I used two scraps of 18 mm birch plywood as spacers behind and in front of the pantograph to leave sufficient room for the spring cams that will help compensate for the weight of the router later.
Most people mount routers in jigs by screwing the base to a piece of plywood. This method would work for this mount as well, but I'd lose a little bit of depth of cut. So instead, I'm mounting it by two metal rods. Nearly all router bases have holes for two metal rods, for use with various jigs.
After that, I slice off part of the blocks, so that I have about 0.5 mm of the hole cut away.
I used a compass to mark the same distance from each hole to make sure I had the center between the two holes, then lined that up with a center line on the front mount. This will ensure that the router's collet will end up on the center line between the two pivot points.
I put screws in the screw holes, tapped them with a hammer, then used the divots from that to drill pilot holes for the screws in the plywood.
This mounts the router securely to the front part of the mount, but I need support to keep the front from pivoting. So I made some pieces of plywood that reach around the router's handles. With this router, I could have just unscrewed the handles as well.
It turns out, the pieces of plywood to link the front and back hit the pantograph links, and I couldn't quite tilt it 30 degrees off-square. But I was only a little bit off, so just chamfering the edges of the plywood pieces that hit the links allowed me to get 30 degrees tilt again.
I'm still missing the template holder, stock holding table, plunge mechanism, and other bits. But the pantograph is the core of the machine, and I was keen on trying it out. So I used some wooden boxes to hold the template and stock.
I used a follower and template that I made earlier.