Router Rails - Smooth ANY Surface Completely Flat!

A few years ago I found an excellent design for a router table. It involves using a router that's attached to a square sheet of acrylic plastic that easily slides into a router table. At the time it meant simply being able to see down below in the router canal, allowing me the ability to get a better look at my router bit and the operation. But then I found the advantage that came with being able to remove the router from its fixed location to a handheld unit. It meant, among other things, that I could use the wider router base as leverage.

With this instructable, I want to expand its usage. But let's take it's highly simple, maneuverability nature with us as we do it. Or why do it. Right?

These days there are a lot of people making resin tables with uneven surfaces. They're using logs, slabs and even sticks as the main body before they pour. I'm all for resin and all of its sticky properties, but unless those brave epoxy warriors are planning on doing a complete resin cover as it levels itself, there needs to be a way to level the wood. There also needs to be a way to level it as well, after all it set and cured.

Enter Router Rails.

No, no, this isn't some high speed track where routers rush down train tracks, speeding on bearings. This is a router connected to rails, used to skim the surface with a bit that leverages anything in its path. Let the construction begin!

*Disclaimer: Routers are dangerous as well as any other tool in a workshop. They're not ouchy proof. If you don't know the correct rules that comes with the router or other tools in your workshop, learn them. If you see something that looks dangerous, don't do it. My fingers are actually made out of wood and I have a lathe nearby to *ahem* hand *ahem* craft new ones.

Material List *

• 9" x 9" x 1/2" plywood
• 9" x 9" x 3/16" acrylic square
• (2) 9" x 1 1/2" x 3/4" pieces of wood
• (2) 12" x 7/8" x 5/8" pieces of wood
• (6) 7/8" square dowel rod (cut at 10 1/4")
• (12) #10 x 1" wood screws
• (2) #10 x 3/4" wood screws
• (8) #10 x 1/2" combo pan head screws (domed screws with flat undersides)
• (4) #8 x 1/2" combo pan head screws
• (2) Rubbermaid FastTrack 70" (rail): https://amzn.to/2jZGcRq
• (2) Toggle Clamps (200lb should be more than enough)
• (4) 4" handles (optional but very handy)

• Titebond II wood glue

Tools Used

• Table saw
• measuring stick
• pencil
• tape measure
• awl (optional)
• compass
• 1/8" drill bit (pilot hole)
• 7/32" drill bit (pilot hole)
• Phillips screwdriver or bit (for the drill)
• drill
• drill press
• miter saw
• router
• 1" Forestner bit (optional, see step #3 for more info)
• oscillating spindle sander (optional, see step #3 for more info)
• wrench (for the toggle bolts)

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The rails should be flat. No, need to be flat. Let's keep that in the forefront of our craniums. Buy shelfing rails that are flat and strong. With the "U" style shelf rails that I used, there's a lot of reinforced strength that should keep things straight, that is, of course, unless you choose narrow rails (or have a massive Triton router with the 3 1/4 hp motor. If that's the case, go industrial strength). Make sure of this when buying rails. I went with rails that had a 7/8" section between the top and bottom of the "U". If yours is less, I cannot guarantee it will come out the same.

Let's put this another way, if you choose a different size, godspeed young grasshopper. Throw a comment at the bottom of this and tell us all what you did differently. You'll have to use this instructable as more of a general guide as the sizes will be different. And, in this case, size does matter. We'll need to make absolutely sure that when the base is pressed into the rails that there is a snug fit; NOT a hammer-it-in-with-a-sledgehammer fit, but a nice, solid fit that you can do with your hands. The reason for this is simple: if you wedge it tight in the channel, you're taking a chance that deformation could occur. The bottom lip is not hardened steel and can deform with large amounts of pressure.

So, yeah, find a ruler and measure the inside area if you want this to be absolutely perfect. If you can't find the inside dimensions to be of that size, adjust the overall width (the part that fits into the brackets) to what will work.

Okay, no fancy words. This is the base. Not bass (fishy or instrumental), but base. It is quite literally the heart of this project. This means that we'll need to put a little time in making it to ensure that everything works in tandem. The rails are the arms that connect to the...well, heart. Maybe metaphors aren't my thing. We'll see.

I've put the exact specs that I used with a 7/8" inside diameter rail in a handy sketchup image attached to this step, so pour over it and soak it in. This will definitely be different (and maybe the only thing different) if you either can't find a 7/8" ID rail or go larger. Again, I don't recommend going smaller, so proceed at your own risk.

We'll need to use a 1/2" thick piece of plywood that will be the exact same size (not thickness, just width and length) as our 9" x 9" acrylic sheet that's attached to our router. Connected to that will be 4 pieces of wood. A top and bottom piece measuring 9" x 1 1/2" x 3/4", and two side pieces (those that will fit in the rail) that measure 12" x 7/8" x 5/8".

We'll also want to cut out a viewing hole out of the center that will also allow our router bit to pass through, as well as, well, being able to view what's below. You could get riskier and cut a larger diameter hole out so more viewing can be observed, but that is something you'll have to decide on your own as I have no idea how well it'll work. These are uncharted waters so boldly do as you must in safety.

To make the hole, make diagonals from one corner to the other on adjacent corners. This will form an 'X' in the middle. Simple enough. Use your compass and measure out a radius of 2", set your needle point in the center and sketch out your 4" centered circle. Next, cut out the circle. You can use a scroll saw, a jig saw a coping saw or what I used: a Forestner bit with a oscillating spindle sander to clean out the leftovers.

Building the base, not bass.

First I edge glued all 4 pieces of wood (top, bottom and the sides (being careful to make sure that the 7/8" sides are vertical and glued perpendicularly to the plywood as they are what will be going into the rails) with the 9" x 9" x 1/2" plywood. Those dimensions are in the last step. I clamped it all together and added weight to make sure nothing moved during the drying stage.

I used my Super easy spline jig to add splines to all 4 corners.

Gluing the base...and beyond!

Now let's have a discussion about gluing our base together. I glued all my joints with the weakest joint possible, edge to edge. Is it enough strength for our router base? I have no idea, honestly. Titebond II glue proclaims to be stronger than wood when glued, but I have never done a comparison to see how strong it really is. There are a few options here. You could use my Super Easy Spline Jig, but that means a deep cut to get to the plywood center of the tootsie pop, which it will do easily. If you don't have my spline jig, there may be other spline jigs out there that will allow you the same thing.

You could also use biscuit joints to connect the pieces as well as dowel rods if you have a dowel rod jig. I can't recommend using screws as plywood is not meant to be screwed into the thickness, but it may work somewhat well if you used an appropriate pilot hole.

To recap: I used edge gluing when I glued all 4 pieces of wood (the sizes being in the last step) to my piece of plywood; but I used splines on all 4 corners to reinforce the wood. Gluing may be enough, but that is not what I did. I do not believe there is any danger in gluing alone (especially by the manufacturers description (and let's limit this to titebond II)) except for a damaged project if things head south.

After it's been glued and allowed to cure, I used a belt sander to clean the edges.

Finalizing the edges

Now we'll cut out the rail ties (do you get the play on words here?). The nice thing about these shelf rails is that there are screw holes every 11 1/4" inches. Can you guess how far apart we'll put the rail ties? Yes, 11 1/4" inches apart. We'll cut 6 rail ties at 10 1/4" out of the 7/8" square dowel rods. These ties will be placed one by one inside the rail at each of the 6 screw holes. Yes, there are 7 screw holes in these rails, but the center one will be for the base, so we'll leave that one alone.

With the rail facing up in the air (the bottom of the 'U' facing up), we'll slide the dowels in from underneath until all have been inserted, again lining them up under the screw holes.

OKAY, hopefully that wasn't too much to bite off. When in doubt, watch the video. By the way, clicking on the links in each of these steps will take you directly to the exact place where the step being described is being performed.

Now we'll drill 1/8" pilot holes in each of the 6 ties ends (through the screw holes) before putting a #10 x 1" wood screw in each hole. We'll then insert the base (again, not squeezed in so tight that it deforms the metal. You should be able to lightly press it in). Find the center of the base and match it up with the center of the rails, the 7th hole, which conveniently is the most center hole.

Be careful or you'll do what I did when drilling a hole in the base through the screw holes: I underestimated the width of the wood. Drill a 1/2" deep pilot hole with the 1/8" drill bit and put a #10 x 1/2 wood screw through the rail and into the base.

Once this screw is in we'll flip the rail down on the bench so that the 6 square dowel rods are in the upright, vertical position as well as the base. We'll place the other rail on top, drill our pilots just as we did on the opposite side, and mirror the process from before.

Cutting and install the rail ties

There's really not much to this step. The video will show a better explanation, but I'll break it down. We're going to install two toggle clamps that will hold the router plate to the actual router rails. We'll center both toggle bolts on opposite sides of base and put two screws in each toggle clamp, diagonal on each clamp. You could put screws in each of the 4 holes (8 on both), but it's overkill. The toggle bolt will need to lock in place after it hits the plastic base of the router, so test where that spot sweet spot should be. Squeeze the lever down until it locks in place, then tighten the set bolts that came with the clamp so that it doesn't move. Of course, a little threadlock would work great here or even some locking nuts, but so far I haven't needed to use anything other than what came with the toggle bots.

Toggle it, just a little bit...

Center your handles on the 1st, 3rd, 4th and 6th ties, drill your pilots with your 1/8" bit and put in (8) #10 x 1/2" combo pan head screws (dome top, flat underside). This is an optional part of this step, but it is extremely handy to use.

Oh get a hold of yourself...or not.

This step really has nothing to do with this instructable. Well, kinda. This instructable assumes you have a 9" x 9" x 3/16" piece of acrylic attached to your router. But that's not fair. Why? Because who has a 9" x 9" x 3/16" piece of acrylic attached to their router? Okay, I see a few hands up in the back, but I want this to be universal. I want this very clever way of flattening a surface to be available to anyone and everyone interested.

As each and every router is different, I cannot be more than slightly helpful for this step. Your router should have a base on it already. The best thing that you can do is find the center of a piece of 9" x 9" x 3/16" acrylic, draw a line from corner to corner. Now you'll have an "X" in the center. If you take the base off your old router, you can center up the "X" through the hole in the center of the old router base. You'll find the screw holes that attached the old base and mark them on the acrylic.

This is where it gets tricky. The screw holes need to be sloped as your old screws were recessed in the plastic. You'll have to mimic how your old router base was attached. This will include making pilot holes. Again, each and every router is different, so it wouldn't be fair of me to try to list every router screw for every router. Besides, that would be cruel to me, and I've been nothing but nice to you...haven't I?

Once you've rigged up your acrylic to your router, you'll need to plunge a hole through the plastic...very carefuly. Acrylic is very strong, but it gets picky when it is cut or drilled in to. You'll need to find a good bit, preferably one that you'll use with your Router on Rails, and slowly lower your router into the plastic. Of course, for this method you'll need to have a plunge router. If you don't have one of these, carefully use a forestner bit and drill out the appropriate sized hole in the direct center of the "X".

Okay, another step that's not entirely part of this project, but necessary to make the project work. To flatten a tabletop or a log, or whatever it is that needs flattenin', I recommend using a bowl router bit. Stay far away from the 1/4" diameter shaft as you'll be using every bit of the...bit to route with. My router bit is a bowl bit with a 1/2" shank on it that's about 1 1/4" wide. It's made by Freud and is an excellent tool that I have used many times for projects like this.

Here's a few tips for you.

• Never let your router sit in one spot for too long as it is on or you will burn the wood below the router bit.
• Ease into the material. Don't jam the bit into the wood or start with the bit touching the wood that's about to be removed.
• Take breaks. The bit gets very hot. Tighten the collet as you go. It'll loosen as it gets hot which will damage your work.
• Never use a dull bit, it will run on the wood instead of cutting it and can be dangerous.
• You will need runners on either side of the wood you plan on cutting flat. As each set up is a little different, do a little research on how to add runners next to your project. As the Router Rails is something I concocted for a project many years ago, I don't know how widely used it is. I do know that router sleds are popular. Runners for those should be easy to find and make. These runners are important as they create a flattening plane that you'll want to match your router to.
• The runners you use MUST be longer than the project you plan on cutting as the router bit will need to come to the edge of your project. Remember that the edge of your project still needs to have proper runner space for the 5 1/8" half of your Router Rails.
• Make small passes. Don't try to cut too much at one time.

I do have plans for making runners in the future (something I think is unique), but a pair of 4x4's should work just fine, so long as you plan everything out.

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