Router Improvement - Add-on

I have repaired my old Makita Plunge Router and added a very useful add-on to give me fine plunge adjustment - something it could never do.

As a small router it had a fitting on the side which you could set to stop the plunge at a given point but, it was always difficult to precisely set the length of the router cutting tip.

The finished add-on might look like a steampunk aircraft but it's now a far more useful tool.

4x M12 x 220mm hex head bolts / 8 nuts and washers

2x M10 Rivet nuts (insert nuts)

1x M10 x 90mm stainless steel hex head bolt

3x M5 x 50mm bolt

1x M6 x 50mm bolt

10mm MDF pieces

Some years ago I bought a table saw and a router table extension. I made a 2mm steel plate adapter to fit the router which would bolt into the supplied holes under the table. As the router never had a facility to adjust the depth of the plunge it was always difficult to set the length of the cutting bit height above the table - you had to manually try to hold the router in place and use the clamp to keep it positioned - meanwhile the spring loading would make a fine adjustment difficult. The router worked well on the table until a chip of wood was pulled into the air itake on the sides of the router. You can see these slots in the router sides on an image above. The fan inside then scarred the windings and cut through two of the outer wires. I discovered this when I opened it and was able to do a solder bridge repair to the two wires and get the tool working again. I will be making a guard to prevent this happening again further down in this project.

As you can see from the previous images, there are 4 threaded holes in the base plate of the router. 3 of these holes are M5 threads which are intended to clamp the original router fence fittings. The 4th hole is a M6 thread used for the router's original plunge depth stop.

I worked out that I needed 4 standoffs which would support a plate which would carry an adjusting thread bolt and handwheel (knob). This would screw in to push against the router's spring loading to extend the cutting bit, and when unscrewed the spring loading would retract the cutting tip. Once set the router's clamping lever would be used to secure the position.

The standoffs probably don't need to be thicker than 8mm. I have used M12 (12mm) bolts, which is a total overkill, but they already have a thread on one end. I chose to flatten off the bolt markings on the hex head and then to centre drill and tap 3 of the hex ends for a M5 bolt - to a depth of about 15mm. The 4th bolt I drilled and tapped for a M6 bolt, also to about 15mm depth. These 4 inserts then screwed into the base plate holes and provided good standoffs to accommodate a 10mm piece of MDF to form the new back plate.

I measured the original hole distances in the routers back plate and marked them out on a piece of 10mm MDF. I drilled these out to 12mm for the 4 standoff bolts. I also marked the centre and drilled a 13mm hole to take one of the rivet nuts. The so called 13mm drill bit I have measures 12.94mm so it gave a very nice tight fit for the rivet nut.

Note: I inserted the rivet nut from the underneath side so it won't push out in the future.

I also flattened off the marking of the 10mm stainless steel hex bolt to give it a more smooth turn when pressing on the back of the router casing ( I'm thinking that I should really glue a brass disc to the middle back of the router casing so that it gives a better wearing, and smoother, surface for the bolt head).

Fit 4 of the 12mm nuts and washers on the standoffs. The 10mm bolt is then screwed through the new base plate rivet nut and the whole back plate dropped over the standoffs. Level it off by adjusting the nuts and then add the last washes and nuts to tighten on the back plate.

Any wheel, crank, etc could be used to raise and lower the router in the standoffs, but as I have a pile of MDF scraps I chose to use some of this. I will probably polyurethane the handwheel later to make it last longer.

I used the 2nd rivet nut and a locking (M10) nut and washer to fasten the handwheel on the end of the thread. Because the rivet nut is 13mm long and the MDF is 10mm thick I glued a small square of to the middle and when the rivet nut was inserted I then drilled down using a forstner bit till it touched on the rivet nut.

Fit the new handwheel.

I decided to make a thin aluminium cover guard for the cutting end of the router. I have a roll of 1.5mm flashing which I cut this from. When it fitted without the spinning spindle and the two plunge columns touching (scraping) I used a glue gun to secure it to the router body.

Then it's just a matter of getting it all put together and fitted back under the router table.

It's so much easier now to set the cutting depth.

The table extension for the router on my saw table doesn't lend itself to cutting angles etc so plans are being made to build a proper and versatile routing bench/table.

The project I've shared here is specific for the model of router I'm using but the concept can very easily be adjusted and adapted to suit other models.

Hope this is of help to someone.

Think, plan and measure - and again and again. One can usually come up with a good idea to improve a tool etc.

Have fun.