The sliding mechanism body { font-family: sans-serif; font-size: 100%;} img { margin-right: 12px; margin-top:0px; margin-bottom:4px; border: 0px;} The sliding mechanism The sliding mechanism uses wooden tracks. A square channel on one side ensures proper alignment, while a beveled track on the other side ensures that any play in the square channel is always taken up on the same side when the locking knob is tightened. This will ensure consistency. I started by making a 1:1 printout of various parts from CAD using my BigPrint program. The plans include these printable as individual pages, so you won't need my BigPrint program to print these. However, even the eval version of BigPrint can be used to print the templates The 1:1 printouts are very useful as templates for cutting out the curved parts. But even for rectangular parts, it helps to have a full size printout just to get a better sense of scale and cut down on measurement errors - especially if you are more familiar with inches than Metric measurements. I cut out the square channels by making a series of cuts on the table saw. It's hardly worth putting in the dado blade when making just one of them. By making individual cuts, I could tweak the width of the dado that I cut just by bumping the fence by a tiny amount instead of taking out the dado blades and adding shims. making small adjustments to the fence is easier than it looks. I set the fence by setting my calipers to the right distance, and then set the fence to the calipers. With the square channel cut, checking the amount of lateral play. I had about 0.005" of play (0.12 mm). That was a bit more than I was aiming for, but it is necessary to have a few thou of play just to avoid binding. Just a single coat of varnish on the rails would more than eliminate that amount of play, but I will leave these unvarnished. In my previous router lift, I varnished the rails, and they became too slippery so that it was hard to lock the vertical position effectively. Cutting a groove in the longer of the two panels on my existing router table. The locking bolt will move up and down this groove. This slot doesn't need t be super accurate, so you could just cut it out with a jigsaw or a scroll saw, or even chisel out the area between a series of holes. Now clamping the tracks onto the edges of the pieces. both of these track segments are glued flush to the edge. Next cutting the 35 degree bevel for the beveled track. The 35 degree bevel needs to be cut upright against the fence. It's important that the narrow edge of the bevel still has a bit of support on the table saw table. In retrospect, it would be better to start with a piece 2 cm thick instead of 1.6 cm, then cut the bevel, and after that, mill it down to its final thickness. That way there would be a wider flat part of the work piece on the table saw table for support. With the outer bevel track attached, the tricky part is getting the inner bevel track at exactly the right lateral position so that the two pieces of plywood will be parallel. I made sure the two plywood pieces were parallel, pushed the inner bevel track out as far as I could (the beveled track left of the caliper is not glued yet), and then measured the remaining space between the two tracks. I then made some spacer blocks to hold the inner bevel track at exactly the right position while I glued and clamped it all together. I'm using a threaded rod to push the slider up and down. The end of the threaded rod goes through a small ball bearing in a block of wood at the end of the slide. I'm using a 5/16" threaded rod (about M8) instead of the 3/8" rod I used last time so that the threaded rod will fit through the ball bearings from an old inline roller skate wheels. The bearing fits nicely into a 7/8" diameter hole. The hole is drilled about 15 mm deep (not all the way through), then a smaller 3/4" drill is used to drill the rest of the way through. This gives the bearing a ledge to push against. You can just see the ledge in the hole in this photo. Here's drilling a screw hole for a screw to clamp the bearing in place. A small block of wood with a screw thread in it will be attached to the slider. The threaded rod will pass through a threaded insert in this block. As the threaded rod turns, the threaded insert is screwed up and down, which in turn moves the slider up and down. To make sure I have the alignment just right with this block, I'm inserting a Forstner bit in the hole at the bottom, then pushing the block against it so that the center prong of the Forstner bit will mark the hole location. Next I drilled a hole for the T-nut in the spot marked in the previous step. This block will attach to the sliding part and be driven up and down by the threaded rod. The T-nut provides the thread. But to keep the T-nut's prongs from splitting the hardwood, I start by tapping it onto the wood so the prongs leave a mark. I then use those marks to drill pilot holes for the prongs before pressing the T-nut into the wood. It was tempting to use a different style of insert, but with the insert this close to the edge of the wood, I figured a T-nut was the best option. I used a regular nut in a carved hexagonal cavity on my previous router lift, and that worked fairly well too. I had to file one edge of the T-nut flat as it protruded over the edge of the block. I also filed a notch into it to allow for a screw to hold it down. Adding a screw to hold the T-nut into the block of wood. On my previous router lift, I found that sometimes I forgot to unlock the knob when I cranked it down. This had a tendency to pull the nut out of the wood, so a screw to hold it in is a good idea. With the block prepared, I added some paper to the left and under it, and a thin ruler under it to lift it up a bit, so that when I clamp the sled onto the slider, the block will be firmly pressed against the sled. With the sandwich clamped together, I can drill the screw pilot holes through the sled and into the block. Before drilling, I carefully measured and marked where the block was on the other side, to ensure I drilled the holes in the right location. After drilling the pilot holes, I drill larger (9/64" or 3.5mm) holes in just the plywood of the plywood of the sled so that the screw threads won't engage the plywood. Block now screwed in from the back side. Another block of wood is needed at the end of the track (far end in the photo). This block prevents sawdust form falling into the space between the tracks. Otherwise, that space would soon get clogged with sawdust. Looking at the end of the track, with the threaded rod in place. I wrapped some electrical tape around the threaded rod because I used a hand drill to spin it for a test. A quick test with a drill spinning the rod. Be careful you don't let the sled hit the near end of the track if you do this sort of test. With the gears and locking knob attached. On my first router lift, I varnished the rails. But with such tight tolerances, the thickness of the varnish was far too much, and I had to scrape away most of it. Another problem with varnish that it can be too slippery, but also sticky. So it's best to leave the rails without varnish. I varnished the rest of the router lift, but covered the slides with masking tape. I needed to put a spacer between the knob and the washer to raise the handle far enough to not hit the threaded rod used to lock the angle in place. Another clever Idea I had was to put a lock-nut just behindthe knob, so that the knob is not liable to spin off from vibrations. I found if I tilted the router and forgot to tighten that knob, the knob would end up falling on the floor. I didn't have a lock-nut of the right size handy, so I just drilled a hole slightly smaller than the bolt in a piece of birch plywood, and twisted that onto the threads. I twisted it on far enough so that the knob cannot be fully loosened. That way, it's never lose enough to allow the slider to get loose on the track. There's plenty of mechanical advantage when turning the crank, so the extra bit of friction while raising and lowering isn't even noticeable. Next: Right angle gears Back to index