How to install the GRS BenchMate

When setting up your bench, installing a good quality bench pin and ring clamp system is something you will appreciate for years to come. It will make your life easier and generally give you much better results. I did a lot of research and concluded that the GRS Benchmate system is the best quality and most versatile system on the market today.  Although it’s a bit of a costly affair, GRS sells a number of “starter kits” that makes it a bit more realistic.

GRS Benchmate Basic Package

Having said that you definitely get what you pay for, this system is SOLID. It just works without any issues and it has clearly been designed by people who sit behind a bench every day.

So despite the cost, choosing the Benchmate system is easy. Getting it installed, however, requires a bit of work and potentially woodworking skills if you (like me) want to have the mounting plate flush with your bench top.

So although there are a couple of different ways to mount the Benchmate system, in this post I’ll concentrate on the installation of the Benchmate fixed mounting plate and hardware which is the foundation for any of the other attachments in the system.

GRS Mounting AdaptorGRS Extra Fixed Mounting plate

I wanted to install the mounting plate bracket flush with the top and front edge of my workbench as opposed to just mounting the bracket directly on the top of the table. Flush mounting the bracket would ensure that I didn’t get those sharp edges on the table top and it would create the perfect support for a small bench block I planned to have sitting on top of the bracket.

Bench drawer and tool storage  GRS Optional Mount installed

Flush mount, as you probably know, involves cutting a slot in the table that matches the shape of the plate perfectly, and obviously the cut would have to be the right depth to make it…well, flush!

There are a couple of different ways to approach this:

You can cut the entire slot by hand

Pros: You have great control. Well assuming that you already have reasonable hand tool skills. If it’s your first job using a chisel, you might want to practice a bit on a scrap piece of timber since you’ll only get one go at this. If the chisel slips you’ll have a painful repair job on hand, or worst case scenario, a trip to the local emergency room because your hand was somewhere where it shouldn’t have been.

Again, with proper tool control you will have great precision by “creeping” up on the cut, i.e. taking a very fine cut until the point where you have the perfect fit.

Cons: It’s slow, hard work if you want to cut out the entire area by hand. You risk making main flat area less than 100% level or flat, thereby creating problems when you get to screwing down the mounting plate.

You can cut the entire slot by machine, i.e. a plunge router or edge trimmer (small version of the plunge router)   

Pros: Fast cut once you have made the template. It’s relatively easy work, easy to get a perfectly flat bottom of the cut out, and gives perfectly straight angles on the edges.

Cons: To do the cut 100% by machine you need to be seriously skilled in controlling the cut along the lines. Alternatively, you need to spend the time creating a cutting template; this is time well spent if you plan to cut slots in other desks but if you only do this one it’s kinda double the work.

Cut out using a combination of machine and hand cut:

Pros: You get the benefit of the fast machine cut (a flat and level bottom of the cut) and you get the precision and control of the hand cut without spending more time than necessary.

Cons: There is some setup required to get the depth perfect, you will need some time to set up the tool alignment support (easily done if you have a couple of straight edge clamps)

As you probably guessed, I used the last method.

Tools Used

For the mechanical cut I used a Bosch Palm Router with a large diameter flat bottom cutting bit. I used a couple of different sizes of chisels to do the clean-up.

So the step-by-step process I followed was:

  • Mark the front edge
  • Cut out the front edge
  • Mark the outline of the mounting plate on the table top
  • Set up the router and cut the straight lines
  • Rough out the center of the cut-out
  • Clean up the rounded corners
  • Fit the plate adjust if needed
  • Repeat until you are happy with the fit.

Mark the front edge

Start by placing the mounting bracket on the table where you want it installed. Then mark  the width of the mounting plate with a 0.5mm pencil so you get as tight a mark as possible. Measure the thickness of the bracket and mark that as the depth of the cut on the table top

Cut out the front edge

Benchmate CutoutCut out the side edges of the front slot using a Japanese or dovetail saw (or whatever saw you are comfortable with). It’s really important that the cut is 90 degrees to the table top and that you cut on the inside of the line. Clean out between the cuts using a chisel, making sure you don’t go deeper than the thickness of the mounting plate.

When cutting the front edge you will need to cut two deeper slots behind the rows of holes on the front part of the plate. The slots are to accommodate the bolts and nuts that are holding the mounting plate to the bracket. What the final cut-out should look like

Mark the outline of the mounting plate on the table top

Lay the mounting plate on top of the table and push it back so it is flush with the table edge. Mark the outline of the mounting plate on the top of the table

Setup the router and cut the straight lines

Router bit setup

Measure the thickness of the plate to get the exact depth of the cut. You can either do that using a caliper or you can place the router base on the mounting plate with the bit outside the plate. You then push the router down until the cutting bit touches the surface underneath the mounting plate. That will set the cutting depth of the bit to be the exact thickness of the plate. Only one word of caution, though: be careful that your cutting bit doesn’t have slightly pointy tips that could dig  into the surface underneath the mounting plate thereby setting the cutting depth a fraction too deep.

Test cut in a piece of scrap to make sure the cutting depth is perfect. I did the test cut with the straight edge mounted. I let the router base follow the straight edge and afterwards measured the distance from the edge of the cut to the straight edge. This gave me the exact distance I would need to set up the straight edge away from the outline of the mounting plate on the tabletop to be sure the cut was just a fraction shy of the line.

Take the first cut along the straight edge, being careful not to cut too far so you cross the back line of the cut-out.

Rough out the centre of the cut-out

Once you have cut all 3 straight cuts you need to rough out the rest of the area where the mounting plate goes. Depending on how large your router base is you may have a situation where the base won’t have sufficient support to maintain a stable, even cut. The best way to avoid that is to mount an auxiliary base that is wide enough to reach across the full cut-out area. Either a piece of ply, thin MDF or a piece of PVC/Plexi will do the trick. Just remember to reset the depth of the cutting bit to be the same as the straight line cuts.

Benchmate installation

The rough cut before cleaning up the corners and cutting the front grooves.

Clean up the rounded corners

Given the router most likely won’t be able to cut the corners precisely in the same arch as the mounting plate, it is safer to clean up the corners by hand using a small, sharp chisel. The only real trick here is to slowly creep up on the line so you don’t over-cut and thereby leave a gap between the edge of the plate and the table top where small parts or stones can roll into and get lost.

Fit the plate adjust if needed.

Once you have cut out the slot you need to file, sand and cut any tight or uneven spots so you end up with a tight, even fit.

Repeat until you are happy with the fit.

Obviously this is an intuitive process, so after you sand a bit try the fit. If it’s not right, sand or file a bit more and try again. As you know, it’s a lot easier to remove a tiny bit of timber each time than it is to put timber back if you over-cut any lines. Although there are always fillers it generally looks accordingly!

So there you have it. Hope it gives you an idea about the install process. Obviously you can do the “quick and dirty” rather than going through the above process, i.e. you just jam the fixed mounting plate directly into the edge of the bench with a couple of nasty big wood screws and Bob’s your uncle! But I’d say if anything is worth doing, it’s worth doing right. No cutting corners!