I'm trying to make mortises using a router, but I want to use pre-made Domino tenons. I'm working with 1-inch thick white oak and was thinking that the 8mm domino tenon would fit. Can anyone advise me on the proper type and size of router bit (with a 1/4 inch shank) to achieve a loose fit for the Domino tenons?
5 Answers
Check out Lee Valley or similar places for true metric bits with a 1/4" shank. Just beware of some stores selling bits that claim to be imperial but are actually mis-marked metric. Real annoying, trust me on that!
You’ll want to match your router bit to the size of the domino. For example, an 8mm domino fits in an 8mm hole. The dominos actually swell from the glue moisture and create a tight fit, which you need to consider while aligning your pieces. For routing, spiral upcut bits are the way to go!
Mixing metric and imperial can get tricky! Make sure you're using true dimensions—like for 1-by stock, that's actually 3/4" thick. If you're making your own dominos, just remember that the Domino tool has a bit that can adjust a bit on its own. I'd go with a standard 3/8" bit and just slightly oversize it for better fitting.
If you want a more tailored fit, consider grabbing bits specifically for dominos from Woodpeckers. The loose fit depends more on the slot width than the thickness, so focus on getting that right. You could also use 5 or 6mm bits based on your needs, and I had great results with loose tenons in my projects before switching tools.
Since you're using metric Dominoes, I'd recommend going for a spiral router bit; they work best for this kind of job. You might have a tough time finding an imperial bit that fits perfectly with the domino dimensions. It might actually be easier to start with the right bit size and make your own loose tenons to fit into it.
Nice tip! Should the mortises be a little loose both side to side and up and down?
Trend does make an 8mm router bit with a 1/4 shank, but double-check if it’ll match the 8mm domino size.
I’m joining true 4/4 stock. The idea is to use pre-made dominos but cut the mortises myself. Do you know if the domino tool makes an exact 8mm hole, or are the tenons slightly undersized?