Cutting the Tongues on the Workbench Top

With the breadboard ends made and the side-boards that will dovetail into the ends cut, it is time to cut the tongues that the breadboard ends will fit over.

In my last post, Cutting the Dovetails on the Workbench Sides, I mentioned how the length of the side boards would determine the length of the workbench top from one rabbet shoulder to the other.

To form the tongue at each end, I planned to cut a rabbet on the top of the bench top and then cut a corresponding rabbet on the underside.  My main concern in this step is making sure that the shoulders of each rabbet are perfectly lined up.  If they are not, then the breadboard ends won’t fit properly.

To line up the rabbets I decided to build a quick jig.  I cut a piece of 2 x material to be about 1/16th of an inch wider than the thickness of the bench top.  I took two pieces of  ¾” plywood and ripped them to the same width.  I then screwed them onto the 2 x material at a 90° angle.  I did this by putting both pieces of ply on their edge on a flat reference surface and sandwiching the 2 x material between them.  A machinist’s square sitting on the reference surface helped me to square up the 2 x material.

All of this ensures that once the jig is clamped to the workbench top, I can route along one plywood edge guide, flip the bench top over, and route along the other plywood guide, and the rabbet will be in line.

My plunge router and the jig I built to line up the shoulders on the top and bottom.

I didn’t have a spiral up-cut bit for my router and looked online for one.  The solid carbide ones are quite expensive, some are $100, and I didn’t want to spend that much.  I read on one of the forums where someone had used a HSS milling machine bit with great success.  A little more research lead me to a couple of websites, McMaster-Carr and Enco.  I ended up purchasing a ½” spiral bit from Enco.  It was the best deal and I paid about $12.  I also purchased a ¾” spiral bit that I might use for starting the dog holes in the bench top when I get to that step.  I paid $15 for the ¾” bit.  There are hundreds and hundreds of these bits on the two websites I just mentioned, and it can be a little overwhelming trying to find exactly what you need.  Make sure that you get one that is listed as “center cutting” or it won’t be able to plunge into the workpiece.

Spiral up-cut bit mounted in the router.

When I first started to route the rabbet, I set the router to a depth of about ¼” and since the rabbet is so wide, had to take multiple passes to remove all the material.  I then deepened the cut and repeated the multiple passes.  I continued this until I got to the final desired depth, but this took a long time.

To clean up the cut, I had two planes that I thought might be useful.

My Veritas large shoulder plane.

My Stanley No. 78 Rabbet Plane.

The shoulder plane wasn’t cutting very well until I opened up the mouth a little.  After that, it worked great!  I also tried to use my Stanley No. 78 Rabbet Plane.  I only met with frustration with this tool.  It was cutting too deep on one side and was making a mess of the bottom of the rabbet.  No matter how I tried to adjust it, I just couldn’t get it going.

I then had to turn the bench top over and route the other side.  This is becoming no easy task.  The bench top must be in the 200-300 pound range and I needed help to flip it.  Once the bench top was turned over, the jig performed as planned and the rabbet shoulders lined up well.

With the other side routed I tested the fit of the breadboard end.  Damm!  I cut the rabbet a hair too deep and the fit was a little lose.  I ironed on a strip of birch edge banding to the bottom of the rabbet and re-tested the fit.  This was a lucky save and the fit was, to use one of my granddad’s sayings, “Tight as a cork up a monkey’s…”

When it was time to repeat this whole process on the other end of the bench, I thought I would change my method  little.  Instead of routing away all the material, I only routed along the shoulder line and went almost, but no quite, to final depth.

Routing the shoulder only.

I ran my wheel marking gauge along the end grain to show where to chisel away the waste.

A quickly scribed line to indicate where to chisel.

I wasn’t going to use my any of  my nicer chisels for this, but my trusty 1″ blue chip Marples made short work of the job.

A mallet and chisel to quickly remove the waste material.

I went along the line pretty quickly and removed all of the excess material.

This is way quicker than routing all the wood away.

The rabbet being cleaned up.

Once I had chiseled away the waste, I set the router to the final depth and cleaned up the rabbet.

Routed to final depth.

Here’s how it looked with the first side done:

One side done, now for the other.

Time to flip the benchtop again.  I’ll be glad when the bench is in its final location and doesn’t need moving again.  I’m along way from that point though.

After cutting the tongue on the other end of the bench too thin and having to add the birch banding to thicken it, I made sure to leave the tongue on this end of the bench a little thick.

My earlier frustration with the No. 78 plane wasn’t going to get the best of me and I spent some time figuring out what was going wrong.  There is not too much room for lateral adjustment on these planes and I couldn’t skew the iron enough that it was cutting evenly on each side.  I removed the iron and discovered that the previous owner had sharpened it in such a way that the cutting edge was not square to the side.  This was causing the uneven cut.  I mounted the iron in my Veritas Mk. II honing guide and re-ground the bevel at 30° and square to the edge.  I polished the edge up to 8000 on my water-stones and then put the iron back in the plane.

With the new squared up cutting edge, I was able to tweak the lateral adjustment so that I was getting an even depth of cut on each side of the iron.  I also adjusted the iron to that it projected beyond the side of the plane by just a hair.  I set it for a light cut.

Wow… so this is how it is supposed to work!  It made nice even shavings and cut beautifully.  I glad I spent the time fussing with it.  It made it very easy to accurately adjust the thickness of the tongue and sneak up on a nice friction fit for the breadboard end.

Finally I set it up right!

It’s cutting like a dream.

Here you can see the tongue finished and properly sized for the breadboard end:

I planed down the tongue until the breadboard end fit just right.

And here it is with the end in place:

And the end fits nice and snug.

Both ends on and ready for the sides to be fitted.

Starting to get a feel for how it is going to look.

With the breadboard ends fitted, the next step will be to cut the half-blind pins in the breadboard ends.  As I previously wrote, I have cut the tails on the sides already.

Also, I think that I need to cut ½” off of each side of the tongues so that the tongue does not completely fill the recess in the breadboard end.  As I wrote earlier, I’m not expecting a lot of wood movement, but it would be silly to no allow for any at all.

As always, any comments or questions are welcome.  Though I’m not sure anyone is reading these.

More to come.  (When my World Cup viewing schedule allows)