Return to Shop Made Tools





Magical Dovetail Markers






These dovetail markers are rather fun. Also very practical. For some time I’ve been wanting to make a few see-through markers as they obscure less, and make it a little easier to see where your lines are.


These are made of 1/4”-thick Lexan, which is a polycarbonate resin sheet. Fairly cheap, very stable, and fairly resistant to chipping. Although it will scratch if a knife is run along it, I only use a pencil for the initial, marking of the tails. Pins are marked from the tails with a knife.




The sizes here, left-to-right, are 5:1; 6:1; and 7:1. I rarely use 8:1 as it ends up too flat for my liking. My preference for drawers is 7:1, and the other ratios for cases.


To create the chosen angle, you can draw a line 5” on the vertical axis and 1” on the horizontal axis, and then set a sliding square on this. Alternately, you can use a bevel guide, such as this one from Veritas …



We will come back to this in due course.


The first step is to slice up a section of Lexan. The strips are 30mm wide.




Then crosscut into lengths of 70mm (for the angle section) and 40mm (for the square, upper section) …





Once this is done, it is time to fit the parts together, initially as a square.


The first step here is to remove an exact amount of protective film to glue the ends together.


Remove the protective film from the top section (we want an exact thickness), and rest this on the main body. Use a sharp knife to score against the top …




This is what you will have once you peel away the protective film …





The aim will be to glue them together like this …


However, it cannot be done by eye. Everything needs to align exactly.


To do this, place a “fence” or stop block against the end (I’ve used scraps of UHMW, which resists glue). This will locate the top squarely against the edge. Now add a second block to the other side. This will be clamped down to avoid moving position. Ensure that this second block is perfectly square (90 degrees) …





Now we are in a position to glue up.


I used a cyanoacrylate glue, which bonds rapidly and very strongly. It also dries clear.


Place the glue on the surface of the body (where the film was removed). Then add another block to the edge (to aid in aligning the edges) …





Once done, check all is square in all directions …


Time now to create the dovetail angle.


Choose the angle, and transfer it to a sliding bevel.


Now simply wrap the sliding bevel around the top section and scribe the angle on the film …




This is the result with the film waste removed …




The waste can be removed in a few ways: saw and file, a sanding disk or, as I chose, a belt sander …




Work carefully o the lines ..



It is likely that you will have dubbed the sides of the top a smidgeon, so take the gauge to a shooting board, and shoot them flat and square …




Now you are left with a working marker, but the sides are scratched up by the sander. To remove the scratch marks and restore to clear, you have a choice of two methods: the first is to use a flame, and the heat will melt away the scratches. I find this too risky.


My preferred method is to buff them, using a honing compound, and this takes about a minute overall. It is very quick.




While you are at it, make a saddle square 






Regards from Perth


Derek


November 2020