Inlay Tools #3: Straight Line Cutter
The next tool up is the straight line cutter. This looked at lot more straightforward than the radius cutter, but it does still require a nice uniform mortise to hold the cutter support beam. I used Cherry on the first tool, but I decided to go for some scrap Sipo (afraican mahogany) I had left over from another project, since I wanted to make the tool nice and thick.
Like the first tool, all I had was a resized and pixelated image from the L-N website, the cutter, and some thin brass bar stock from Speedy Metals.
I trimmed an 8/4 block to size, and then used the offcut to give myself a nice 4/4 square crossbar. I also selected the 3/32″ x 3/4″ brass stock. 360 Brass is an extremely workable material, and it doesn’t rust, which makes it an excellent metal for integrating into your woodworking tools.
I laid out the general shape of my final tool, and marked where I’d like the various mortise and rub strip to be located at.
The hardest part would be to keep the mortise walls perpendicular, so that the beam that supports the cutter will remain in line with the work. You don’t want your inlay skewed into the workpiece sideways, and if the radius cutter’s teeth don’t run in a straight line, the width of your inlay will be the wrong size for the work. First, I bored out most of the waste.
Then I used my marking knife (made from a kit from Czeck Edge) and a backer block to edge a nice straight line from corner to corner. I then lightly chiseled and relieved the edge, to give myself a nice reference surface.
Here’s my in-action shot, of truing up the sides of the mortise all around.
The bar drops in, and remains almost dead perpendicular.
Given I did it with hand tools, the mortise is probably as dead true as I’m going to be able to make it.
If you’d like to cheat, then I suggest you hog out the hole with an undersize forstner bit, make a template, and slowly remove the side wall waste with a flush pattern trim bit on your router table, and only do the final corner bits by hand, so you’ll have 4 large surfaces to reference against.
Next I cut the overhang area, where the brass wear strip will be mounted, and that the tool will ride on.
I did this in a 2-cut pass on the tablesaw, with no trapped waste. It was just just shy of perfect, so that the ATB blade I had loaded would not leave an unsightly groove. I cleaned out the small nib with a rabbet block plane.
With that cleaned up, I cut the brass stock to size with a hacksaw, and taped it in place so that I could predrill the screw holes into my stock. You’ll notice that the whole piece is fastened in place pretty well. I find when working with metal, this is worth the few extra seconds.
I got the holes drilled out, and just barely let the countersink touch them.
This is why I hate multi-flute countersinks. Inevetible chatter.
I have to pick up a single flute job for this particular brass screw. On the todo list! I removed the screws and began to clean up the holes by hand with the multi-flute as best I could.
I mounted the wear strip, and screwed it in. You’ll notice the screw heads do protrude a tiny bit. Yes, this is on purpose! I find if you leave them a bit proud, that after you file them down, you get a much tighter fit than if you set them in all the way, since the screw’s lip is rounded, and the countersink is a straight wall.
Then I filed it flush with the bottom of the body of the tool.
Looking good so far.
I probably should have taken this step earlier, since I’m not balancing the tool on a half-side, hence the elaborate clamping, so lesson learned! So much easier to make a mistake like this once you’ve got a good aftermarket drill press table! The hole is for the 1/4-20 threaded insert which will hold the knurled bolt that retains the cutter bar’s distance from the work.
This is my favorite way to install a threaded insert. The only thing I would also have done is to put a washer in place between the first nut and the threaded insert, but I needed this insert to sit slightly below the level of the wood to hide it. I never use the flats cut into the threaded insert, as they almost always leave some thin shavings in the well of the threaded insert, which eat up the brass threads. I probably should have used an actual brass insert, but I didn’t have any, and these were included with a Rockler T-Track make-your-own kit I got, so I used them!
With brass knurled knob installed!
With the retaining knob out of the way, I moved back to the wear strip, and my effort to pretty it up. I got my very fine bastard file, and went to town. I followed it up with some 320grit to give it a slightly better polish. I don’t take it any higher than that on a work surface like this. It isn’t jewelry, its a tool!
Some quick work at the bandsaw, followed by the belt/OSS sander, and we’ve got a shape pleasing to my fat hands. Although the tool is a bit oversized, I find I get a good comfortable grip on it. Perhaps a I’ll eventually “Krenov” it to fit my hand, once I try it out some.
Last up, I’ve got to prep the cutter bar to hold the cutter. Quick eyeball layout.
Pre-drilled hole looks good.
And we’re good to go!
It cuts beautifully.
Next up, Slicing Gauge!
Thanks for providing such a nice piece on inlay tool making. Your photos and process explanations are great and very helpful.
Wonderful write-up. I will be trying to make these soon and am looking forward to the inlay slicer. One comment on the edge tool. It is not set up to score at a distance less than the width of your bottom inset. You will have need to score for an inlay pretty close to the edge.
Looking at the picture of the Lie-Nielsen, it seems the bottom part of the diamond shape mortise is cut back some to allow the cutter to move closer to the fence and allow for a line to be cut in as little as 1/8″ from the edge.
I’m sure it is an easy correction, but I am not as clever as you and need to have an example in front of me.
Please keep up the wonderful work.
Rick