Router Table II Homemade Machines & Jigs

My router table has seen a lot of use lately, as I’ve been using it on many of my recent projects. While it is certainly well made and very capable, I thought I could improve a few things. First off, having the raise / lower and locking controls inside the cabinet is a bit annoying. I have to open the front access door (sawdust invariably spills out) and reach inside to make adjustments. I started thinking of ways to put these controls up front and in doing so, eliminate the access door. My first idea was to blank out the opening and make an extension for the crank gear and locking knobs. Threaded rod, some coupling nuts and a new hand wheel would do the trick and in a couple hours the work would be done. Then I got to thinking about the other “;problems”; there are with the table: how heavy it was (that’s good and bad: good for staying put, bad for moving it around), how the top didn’t overhang the base on the front, making it very difficult to clamp on jigs and feather boards. The storage situation was less than ideal as well, as I have run out of space for router bits – I would have to convert one of the side drawers into a bit tray.
So, while I was thinking of these possible upgrades an idea for a new kind of lift mechanism percolated up from my subconscious. I found this idea so compelling, I used it as the excuse I needed to start an all new router table design.

The lift uses an inclined plane to raise and lower the router motor. This is a simple concept and should be quite reliable in operation. Building it should be fairly easy, with no complicated parts. Tolerances need to be tight, but that would be the case for any machine of this type.

It starts with the inclined plane and here I’ve laid out the shape on 1/2″; thick Baltic birch plywood:

layout for a router lift

The dimensions were determined when I modeled it in SketchUp. What I was looking for was a total vertical lift of ~4″; and to get it as close as possible to a 2:1 ratio for the horizontal travel of the inclined plane. My thinking was that 2:1 would be about as steep as it should be, to avoid putting excessive lateral force on the components while it is pushing the motor up. In the end, I wound up with slightly less than 4″; lift for a horizontal run of ~7″;.
To make the action smooth and low friction, sealed bearings are used to ride on the incline, one above and one below.

Cutting the angle:

Cutting the inclined plane

This is about the only thing I use the laser on my mitre saw for: it’s very handy for lining up angles that I haven’t measured.

With the angle cut, I drill holes in the corners:

Drill holes in the cornersRoute between the holes

This is to allow me to use the (old) router table to cut out the centre.
Yes, using a router table to build a router table. These cuts could also be done on the table saw, or with a jigsaw or with hand tools (if you’re into that).

The important part is that the top and bottom edges of the incline be smooth and parallel:

Incline plane finished

A strip of UHMW plastic is fastened to the bottom:

UHMW plastic added to the bottommaking a router lift

This rides in a track. It is free to move forward and back and the UHMW plastic acts as a bearing.

The incline is used to lay out the location of the sealed bearings:

making a router liftmake a router lift

The bearings should be as close to the incline as possible but having a little play here is not a big deal.

I use 3/8″; threaded rod to bolt the bearings in place. The spacing is such that the incline slides easily between the pieces of plywood:

how to make a router liftrouter body holder

The clamp that will hold the router body is made from 1/2″; plywood and solid maple. It is sized for a body diameter of 3.5″;, which is fairly standard.

To guide the router up and down, another layer of plywood is added to the carriage. It has strips of UHMW plastic on its edges, which act as bearings:

how to make a router lift

The motor clamp is notched to allow access to the nut on the bearing shaft:

how to make a router lift

The tracks that the carriage rides in are cut from a piece of solid maple. Here I’ve cut the track long enough to get two, one for each side.

These tracks have a 3/4″; wide dado and are cut to length and fastened to the base:

how to make a router lift

Due to the very low friction of the UHMW plastic, there is little chance of the carriage jamming and the tracks are placed very close to the carriage, to cut down on lateral play.
Also seen, a hardwood strip is made and screwed to the base. The strip holds the incline in the track and prevents it from lifting up.

The motor clamp is then fastened to the carriage:

how to make a router lift

The 1/4″; threaded rod goes through the clamp and carriage, to hold the assembly together. The holes for these rods are slightly oversized, to allow the motor clamp to be moved to adjust router alignment.

The completed lift installed in the cabinet:

how to make a router lift

The cabinet is basically a plywood box, 24″; wide, 14″; high and 20″; deep. In this picture, the front panel is not yet installed. There is extensive bracing for the lift – the two pieces of solid wood run from side to side and plywood panels bridge the lift to the back and front panels. A lesson learned on the first one: make it as rigid as possible.

The lift itself is all screwed together. Glue was not used on any of the joints, making it possible to dismantle for repair or maintenance. Even so, I can’t foresee any issues. The UHMW will last forever and requires no lubrication. The bearings are sealed and are not subject to high speed or excessive side forces, so they should hold up very well.

I made a short video showing the lift in action. It was taken when a little more progress had been done on the table:

With the lift in place, I moved on to the locking mechanism. In this case, it is a short lever on the front panel and by rotating it about a quarter turn, it clamps the carriage of the lift so it will not move. To do this, I used a piece of 1/2″; threaded rod that goes through the two pieces of solid wood bracing that run from side to side. I positioned it as close to the lift as possible, to maximize holding power. One thing to watch for is that it doesn’t interfere with the carriage as it moves up and down.
Here, I’ve drilled 1/2″; holes through the solid wood braces and glued a 1/2″; washer on the front member:how to make a router liftGluing the washer is not strictly necessary, but it doesn’t hurt – it forces wear contact between washer and washer, rather than the washer and wood.On the back member, I cut a piece of 1/2″; plywood to hold the nut. It also has a washer behind it:how to make a router lifthow to make a router lift

The threaded rod cut to length and screwed in.
Jam nuts lock the length, so that when it is turned, it will pull the braces together, clamping the carriage. For this to work properly, the gaps between the carriage and tracks need to be very close. The objective is to adjust the locking lever where just a quarter turn will clamp the lift carriage in place firmly enough that it won’t move. To this end, I used 1/2″; threaded rod to get a smaller teeth-per-inch (tpi), giving more throw per turn. Still, with 13tpi, the movement for a quarter turn is a mere 20 thousandths, therefore the tolerances at the lift need to be very close.

Another 1/2″; threaded rod is used to push and pull the incline back and forth, and it screws into two nuts that are glued into a hardwood block. I cut the groove for a tight fit around the nuts, roughing them up a bit with sandpaper and used polyurethane construction adhesive to secure them:

how to make a router lifthow to make a router lift

The block is then fastened to the incline. The drive screw is cut to length and threaded in part of the way.

I used a 1″; long bronze bushing as a bearing for the rod, and to make up the thickness of the front panel (3/4″; thick), I cut a “;washer”; from 1/4″; plywood:

how to make a router lift

This bearing is tightened to the drive screw and just spins in a 3/4″; hole in the front panel. A sealed bearing would have been better, but I couldn’t get one locally.

I added 1″; x 1″; solid wood cleats (arrow) to the box to screw on the front panel. The front panel is installed and needs to be removable, so only screws were used, no glue:

how to make a router lifthow to make a router lift

The locking lever. Made from 1/2″; plywood and tightened onto the threaded rod. It is adjusted so that in this position (horizontal), the lift carriage is free to move.
The notch is to get a finger in to pull it down, since it is very close to the underside of the top.

The parts for the 7″; hand wheel:

handwheel for router lifthow to make a router table

Made from 3/4″; plywood, it was cut on the band saw and trued to a perfect circle on the disk sander. The 1″; holes are mainly decorative and all of the edges were chamfered. The handle is a length of hardwood dowel with a 1/4″; hole drilled through it.

It operates very well, as demonstrated in this short video:

The legs for this table are made up of 3/4″; stock and I’ve chosen solid pine, mainly because I have a lot of it. Another perfectly acceptable option is 3/4″; plywood or even solid hardwood. Softwood is cheap and readily available, and although it usually isn’t as durable as hardwood, it is certainly strong enough for this purpose.

how to make a router table

The advantages of doing it this way are twofold: First, the parts will be laminated and laminated wood is almost always stronger and more stable than solid wood. Second, it simplifies the joinery and reduces the time required to machine the parts, since all of the parts are just square cut for butt joints.
I start by cutting all of the parts to width and length, then I cut a taper on the lower half of the legs on the table saw using a jig.
This is mainly for aesthetic reasons – the legs will look less bulky if they are tapered.

Starting assembly, the top stretcher is glued and nailed between the legs. I’m using polyurethane adhesive and 2″; airgun nails to fasten the parts together. Screws could be used, but are not really needed and would take longer:

how to make a router tablehow to make a router table

Cleats are added (arrows).
These are for attaching the legs to the main cabinet. Again, these are glued and nailed in place.

The upper parts of the legs are thickened. This laminates the leg and adds glue surface to the top stretcher, effectively creating a rabbet joint:

how to make a router tablehow to make a router table

The lower stretcher is installed.
This is a good time to check if the assembly is square and make any adjustments before the glue sets. With the addition of the bottom stretcher, a cavity is formed and this space will later be used for storage.

The lower half of the legs are doubled:

how to make a router table

Glued and nailed together. This thickening piece creates a dado that the lower stretcher is glued into. Really, no compromise on strong joints when you use butt joints effectively.

The completed set has been sanded smooth and are ready to bolt onto the main cabinet:

how to make a router tablehow to make a router table

Each leg set is fastened to the ends of the main cabinet. I used #10-24 machine screws and t-nuts to make alignment easier and also to increase the strength of the join, since no glue is used here. I want to be able to remove the legs if I ever need to, without destroying the main cabinet.

With the legs on and aligned perfectly on top, a cleat (red arrow) is added to the bottom:

how to make a router table

This helps to support the main cabinet and also closes the gap between the bottom stretcher and the bottom of the main cabinet. This is important, since I want to use the space in the legs for storage.
The black arrow shows how the front panel extends below the bottom of the main cabinet. I did this because the hand wheel is very close to the bottom of the cabinet and it would look better with the panel fully behind it.

The unit assembled:

how to make a router table

Looking a little homely at this early stage, but some paint and other decorations should pretty it up some.

The top on my other router table is 1-1/2″; thick, made up of one layer of plywood and one layer of particle board. At the time, I thought that it would be best to make the top this thick, to ensure it was as flat as possible. What I didn’t consider is that the top needs to be flat on the table, and that it should use the rest of the cabinet to maintain this flatness.
So, with this in mind, I made the top for this table a single piece of 3/4″; Baltic birch plywood. It will be bolted down to the cabinet and the bracing in the cabinet will support the top and keep it flat. This is in the name of sensible and efficient building practice, and not for economy alone.
Another difference is that I just left the edges raw for this top, whereas the edges were banded with solid wood on the other table. Working with a superior material helps: the fine laminations in Baltic birch plywood produce an attractive and durable edge when sanded smooth and finished with clear urethane. Solid wood banding (in this case) would not improve upon this.

With the top cut to size, I lay out the cut for the insert plate. Guides are set up for the router to cut out the 6-1/2″; square hole:

cut a square hole with a router

After the hole is cut through, the guides are moved out 1/2″; and the depth of cut is reset on the router to the approximate thickness of the insert plate. The insert plate I’ll be using is homemade, from 1/8″; thick aluminum and here I’m using a piece of this material to check the cut:

router cuts out a recess at proper depthrouter table top with hole for router plate

With the depth correctly set, I route out the rest of the recess.

To avoid dust collecting in the corners where it will pile up and be difficult to clean, these are routed out a bit deeper:

how to make a router table

I then turn my attention to the insert plate. I carefully cut it to exact size on the table saw using a TCT metal cutting blade (ordinary wood cutting carbide blades can cut aluminum, but have a much sharper rake angle and are not recommended). I then use my disk sander to round the corners.
My experience has shown that a 2-1/4″; hole will be good for 99% of the bits I’ll use and this is the size hole I want in the plate. Making a mark in the centre, a hole saw in a hand held drill is used to cut it out:

aluminum router insert platealuminum router table insert plate

I’m using Windex for lube, simply because it was close at hand. Nearly any liquid will work, with alcohol being about the best choice. Oils are good too, but leave a residue that can be difficult to clean, especially if the part is going to be painted. The plate was securely clamped down for the operation.

Test fit:

aluminum router table insert plate

Snug and perfectly flush with the top. As a bonus, the exhaust from the router doesn’t lift it. This was a problem I solved with a magnet on the other one.

After deburring the edges, lightly sanding with fine paper and cleaning with lacquer thinner, I painted the insert plate black. When this was dry, I put it in the top and sprayed on three coats of satin polyurethane over the whole surface:

how to make a router table

The bottom was given the same finish as the top, to avoid bowing.
As mentioned in my blog entry, I have a new touch-up paint sprayer and this is the first job I’ve used it on. It’s a big improvement over my old one and is really a pleasure to use.
It will be interesting to see how well the finish holds up on the aluminum. I expect it will be fine – the urethane is very tough and is still in great shape on my first router table and the band saw top.

I have to drill and tap the plate for a starting pin – something I meant to have on my other table, but never got around to doing. This is something I should have done before I painted, but I did’t have the pin.

how to make a router table

Dust extraction for this table has to be very good, since there isn’t easy access to the inside of the cabinet. To get it right, I will be doing some tests to check the effectiveness, starting with the minimum and making changes as needed. For now, I have made a single 2-1/2″; hole in the bottom for connection to my shop dust collector through a 2-1/2″; hose, just to see how well it works.
With the cabinet flipped upside down, I first drilled a 1″; hole then used the router with straight cutting bit to get it close to the mark:

how to make a router tabledrum sander in drill to clean up a hole

I then fine tuned the hole with a sanding drum mounted in a hand held drill.

To make it a tight fit for the hose:

dust collection for a router tablehow to make a router table

And from the inside. I located the hole directly below the router body. It’s my belief (hope) that this will adequately clear the dust and chips from the cabinet, but the only way to know for sure is to try it. If I find that the 2-1/2″; outlet is not big enough, I’ll switch to a bigger hose. It was fairly effective in my other router table though, but that cabinet was a bit less cluttered.

The parts for the electrical:

electrical supplies for router table

The orange extension cord will be the power cord. I went looking for just the replaceable plug end to use with some old cord I already had, but found it was more expensive than this 5 metre (16 feet) long cord! Two metal boxes, one for the internal receptacle that the router will plug into and one for the on/off switch on the front panel. Metal covers for both. The metal covers are extremely durable and much better suited for this than plastic ones.

Carefully mark out the location for the front panel switch box and cut it out with a jigsaw:

cut cabinet for an electrical boxinstall a switch

Screw the box in place and wire up the switch.

The internal receptacle is mounted in the front brace panel:

wiring a router tablewiring a router table

Using pieces of the insulation to make wire clamps to hold the cord up out of the way of moving parts.

The power cord exits the cabinet at the back, bottom corner:

wiring a router tableguards added to a switch plate

As I did with my band saw, I’m adding guards to the switch plate. This helps to prevent accidental starts and also protects the switch toggle from damage. The plywood blocks are just glued on with polyurethane construction adhesive and the whole thing will be painted black.

To elevate the router faster, I added another hand wheel that is twice as big as the first one. This larger wheel drives the smaller one at a ratio of ~1:2 – for every turn of the large wheel, the smaller wheel turns approximately two rotations.

how to make a router table

I covered this in some detail in a blog entry.

Starting with a 13″; diameter disk cut from MDF with my circle cutting jig. I laid out the spokes and the inner circle using a piece of wood cut to the right length and a 1/8″; drill bit for the pivot point as a compass to draw the arcs:

how to make a wheelmake a wheel

3/4″; holes in each corner and use the jigsaw to cut out the rest. A chamfer bit on the router table eases the edges after it was sanded smooth.

The large hand wheel is mounted on a pivoting arm that is spring loaded, so it pushes against the smaller wheel. Given the less-than-perfect machining of the parts and relative imprecision of the hardware used, this ensures constant contact with the smaller wheel:

how to make a router tablebig wheel turns small wheel

This works well. The large wheel has a strip of the same rubbery material that I used on my belt sander platform, and this not only improves the grip, it also cushions the contact between the wheels.

I mounted the handle for the large wheel further in from the rim, to better match the feel of the smaller wheel and be less fatiguing to use.

To see how I made the handles for the hand wheels, check out: Making a Hand Wheel Handle in the Shop Tips and Tricks section.

Nothing finishes off a build like a paint job. It brings it all together and makes the completed project look professional and permanent. My band saw is the best looking thing in my shop right now, due mainly to the paint and how “;finished”; it looks.
When it came time to pick the colour, there wasn’t much to think about – I went with white, just like my band saw. I never had much of an affinity for that lawn tractor green that so many stationary tools are splashed with.
To get started, I moved the table outside. Masked out the parts that I didn’t want to paint, covered the top with some scrap OSB and a gallon of paint to weigh it down:

painting a router tablepainting a router table

It takes three coats, sprayed on to get even coverage

how to make a router table

I figured I would let it dry overnight, sand and repaint the next day but found that it was actually very good as it was – smooth as silk. The paint is Tremclad rust paint, flat oil based – in my opinion, the best one-part paint available today.

Having learned a lesson on my other table, I wanted there to be plenty of bit storage in this table. That would be the emphasis, actually – bits only, with no drawers for other junk. The design of the legs left space on each end and I gave some thought as to how I would use this most efficiently. In the end, I came up with a simple racking system.
I cut strips of wood all the same size and length to fit between the legs:

make a router bit holdermake a router bit holder

A 20 degree bevel was cut in a piece of wood to tilt the strips for drilling. Here, I’m doing 1/2″; holes, for 1/2″; bits:

make a router bit holdermake a router bit holder

The reason for the angle is to keep the bits from falling out if the table vibrates.
The spacing is tighter for 1/4″; bits, since the bits are generally smaller in size. There should be ample “;finger room”; between the bits giving a neat, uncluttered storage system.

The spacing of each strip varies, depending on the bit size, with bigger bits at the bottom. The strips are glued and pinned in place:

make a router bit holdermake a router bit holder

The 1/2″; side complete. Storage for 67 bits! Should be adequate.

The 1/4″; side:

make a router bit holder

80 bits fit here. Of my future complaints, bit storage should not be one. Notice I notched the strips around the screws that hold the legs on. I want to be able to dismantle this if needed. With the strips in, I can finish painting the inside.

My original plan was to leave these storage compartments open, figuring doors would be more of a nuisance than anything else. Then I got to thinking about dust and how it would collect inside and how it would be nice to have doors to clean up the appearance and potentially use for more storage – wrenches and other smaller things could be hung on the inside.
To avoid painting, I would use 1/2″; melamine and band it. Here I’ve cut the door panels to size, leaving them a little wide:

white edge bandingedge banding melamine

The edge that the hinges go on is beveled slightly, so as not to bind when closed. I band this this edge and trim off the excess.

The hinges are no-mortise type, left over from a wooden shutter project:

hingeshinges on a door

I figure three are overkill but better to be stronger to give the assembly more durability.

The door is hung to test the fit:

door on a router cabinetmark door to fit opening

Good on the top and bottom, I mark the width. It is then removed and cut. The top, bottom and edge are banded and the door is reinstalled.

A magnetic catch holds it shut:

screw on magnetic catchhow to make a router table

A great fit.

wrench door pulls

For pulls, I made these. Talked about in some detail in this blog entry. Not my usual style, but they look ok and the price was right:

industrial age router table

Starting to take shape. Hand wheels and locking lever are painted, the cabinet is complete. The top is bolted on and I’ve started work on the fence – the part attached to the top on the right is the guide rail for the fence.

Here’s a short video of the table in action:

The fence design of the other router table was very good but there were some things that I would have done differently, if given a second chance. I made a list of features that I would reuse in the new fence design and ones that I wanted to change.

Good:

  • Very solidly made, to clamp fixtures like my pin guide to and not worry about it deflecting.
  • Easy to reposition and a good range of adjustability – it would clamp down tight to the table firmly, without fear of moving.
  • The dust collection arrangement at the fence throat was very good and effective.
  • The high extension above the middle, for clamping feather boards and other fixtures to.

Not-so-good:

  • Not self squaring. Having the fence square to the table makes it easier to use a scale to quickly reposition the fence and makes repeated cuts much more efficiently and accurately.
  • The clamping system was made so that two hand screws would need to be fully removed before the fence could be taken off the table. How many times did I misplace those hand screws? The new fence should have no loose parts.
  • The sliding front pieces for closing the throat opening and for making the router table an edge jointer. In theory, these two features are attractive. In practise, I rarely used either, and never the edge jointer.

Drawing upon these observations, the fence for this table was designed to include the best features of the old fence and incorporate the improvements.

I started on the fence guide rail, which will hold the fence square to the table in a way very similar to how a table saw fence works. It is made up of 1/2″; plywood and hardwood:

how to make a router table fence systemhow to make a router table fence system

It’s bolted to the table, leaving space for the cleat that will be fastened to the bottom of the fence.

Holes for the bolts are countersunk to keep the heads below the table surface:

how to make a router table fence systemhow to make a router table fence system

1/4″; holes are drilled and elongated, to allow the fence rail to be adjusted.

Installed, with 1-1/4″; long 1/4″; bolts, nuts and washers:

how to make a router table fence system

I had to be careful that nothing from the fence system sticks down in the way of the bit storage door opening fully.

The fence is made mainly from plywood, with a piece of solid maple that runs the length of it. The hardwood adds stiffness and continous support across both sides of the fence:

how to make a router table fence systemhow to make a router table fence system

Here I’ve added 1/2″; plywood to form the “;T”; of the fence, that will square it to the table.

All of the parts are just square cut, glued and screwed in place:

how to make a router table fence system

Whenever possible, I like to use simple joinery to speed the machining process and assembly.

To clamp the fence to the guide rail, a simple method was devised. First, a plywood block is notched to hold a 1/4″; carriage bolt:

how to make a router table fence systemhow to make a router table fence system

The head of the bolt is ground flat, to allow the block to sit flush and prevent the bolt from turning.

A second block is added. This clamps against the guide rail by tightening the wing knob:

how to make a router table fence systemhow to make a router table fence system

For dust collection at the throat of the fence, a hole is cut through the table. This is directly behind the insert plate opening. I have to make sure that the hole is in a good place, not too close and not too far and that I’m not drilling into any of the cabinet bracing.

The fence is put back on the table to start work on duct that encloses the throat and connects it to the hole in the table:

how to make a router table fence systemhow to make a router table fence system

The sides of the duct are made from 3/4″; pine.

A 1/2″; plywood back is glued and nailed in place:

how to make a router table fence systemhow to make a router table fence system

The duct is then covered with 1/4″; plywood.

The hole is far enough back to provide some dust collection from above the table for wider stock. This makes a difference, especially for fine dust:

how to make a router table fence systemhow to make a router table fence system

To hold the left side of the fence, a clamp was fashioned that hooks over the edge of the table.

This is secured after the fence is moved and the main clamp is tightened, and stops this end of the fence from moving:

how to make a router table fence systemhow to make a router table fence system

I added a scale and adjustable pointer. Yes, it starts at 70″; and goes down. The tape was a piece left over from my band saw fence (project coming soon) – waste not! What’s important is the gradations, and not the absolute value. At the 70″; mark, the pointer indicates the dead centre of the router bit.

In spite of a light dusting of snow and cold weather, I get 3 coats of finish on the fence:

how to make a router table with fence and dust collection

The trick is to spray it outside, then quickly bring it into the warm to let it dry. Not ideal, but doable and surely beats doing it with a brush.

Fixes

I did some testing of the dust collection and found a couple of trouble spots. The first is at the incline – there is a gap at the top side that can fill with dust and get packed by the sealed bearing that rides on the incline. To fix this, I glued on a thin piece of wood to close the gap (arrow):

how to make a router table with fence and dust collectionhow to make a router table with fence and dust collection

I also drilled 3/4″; holes in each end of the bottom track through the cabinet. This allows air flow up to clear dust when the dust collector is running. I don’t have the dust collection optimized yet – more testing is needed, but it looks like the 2-1/2″; hose will work reasonably well.

Leveling Legs

Another thing lacking on the old router table was that it didn’t have a good way to make it level on an uneven floor. For this table, I’m using the same method I’ve used on some of my other stationary tools. Made from plywood and pine:

leveling legsleveling legs

Slots are cut for the 1/4″; bolt that holds them on and I painted them black. I have some thick rubbery stuff that is used for gym flooring and glued that to the bottom of the levelers.

Bolted on:

leveling legs

Gives nearly 1-1/2″; of adjustment (needed, in my shop). The rubber pads really make for a firm grip on the floor and also cushion the table slightly.

Finished:

how to make a router table with fence and dust collectionhow to make a router table with fence and dust collection

I’m still not in love with the wrench pulls on the doors, but they do the job.

I made a short video showing it in action:

A successful conclusion, the new table is smaller and lighter but doesn’t give up useful storage or capability. An interesting project, well worth the time and effort.

Update

I’ve had a few people ask about using my box joint jig on a router table, so I thought I’d try it. First, though, I had to make a miter slot in my router table top, since I hadn’t done that during the initial build.
To get started, I picked a place to put the slot. Ideally, I would have made it closely match the distance that the slot on my table saw is from the blade, but the mounting bolts for the top are in line with that. So, I moved it out just past those.
I used a piece of MDF as a straight edge clamped on parallel to the front edge of the table. With a 1/2″; straight cutting bit in the router, I made two passes to cut to the full depth of nearly 7/16″;.

cut a slot in the router tablecut a slot in the router table

I then added a strip of 1/8″; thick aluminum as a shim and widened the slot to about 5/8″;. Doing it like this lets me “;sneak up”; on the final size, while cutting the full depth.
For the next pass, I planed a strip of maple 1/4″; thick and used that as the shim. It took a few tries before I had the strip to the right thickness, but found the fit for the bar just a bit too tight. To fine tune, I shimmed the strip with a single layer of paper
and that gave me the exact width that I needed.

tool slot in router tablecut slot in router table

This shows these test cuts at the beginning of the slot and the paper shims. It may seem like I did it the hard way, that I could have moved the MDF to make the final passes, but my experience is that way is more likely to give a slot that is not the same width along it’s length. Likewise cutting the slot with the 3/4″; bit I have – the slot ends up being too wide.

Here’s the final fit:

bar in router tableminor slip

Above right marks where someone entered my shop while I was routing, startling me. No real harm done, just a slight over cut. Tip to all those about to walk into a one-man workshop: wait until the machines have stopped running before going in – please!