I’m returning to woodworking after a long hiatus (like 20 years). I’m trying to make a box with dovetailed corners – something I’ve done before, but it seems I’ve forgotten more than I remember. I’m using a dovetail jig (bench mount, similar to a Rockler) with my router, a 1/2″ dovetail bit and a 7/16″ guide bushing – all as specified in the instructions.
My problem is that the instructions I’m looking at say to set my bit height at 9/16″ from the router base. My bushing stands 1/4″ proud of the router base, so that leaves only 5/16″ maximum cut depth IF I could get the bit set that far inside the bushing, which I can’t. I can switch to a larger bushing, but that doesn’t help my depth of cut, and the larger diameter bushing also makes my cuts narrower because it has less room to move side to side between the fingers of the template.
I have set the bit as close to the base plate as possible without hitting the bushing, but my joints are still nowhere near fitting together, and depth of cut is unacceptably short. Also, I’m using a plunge router, but I can’t move it any lower than it is or the collet rubs the knurled nut holding the guide bushing and unscrews it.
I suspect pilot error, but I just can’t put my finger on it. What am I missing?
Replies
I'm no expert on this so read with caution.
You need to cut the depth you need to cut. For a through dovetail this will be the full thickness of the workpieces. Any less will not work.
5/16 is quite thin stock so may be the minimum thickness you can do.
If your pins are not deep enough to contain the tails then of course the joint will not fit so you need to deepen the cut until it is the full depth required.
It seems you may have a very short shank on your dovetail bit. I have had some success with not inserting the shank fully into the router, but it is much safer to find a bit with a longer shank.
Hopefully this answer will spawn more experienced responses...
I'm not clear what you are saying about your guide bushing being 1/4" proud of the router base. Are you talking about the center "tube" that rides against your dovetail template or are you talking about the surrounding broad "shoulder"? Does it look anything like this:
https://www.rockler.com/guide-bushing-router-plate
If the broad "shoulder" is not flush with the router base, I would say you have the wrong type of bushing for your router.
Thanks for your response. Yes, I'm talking about the center tube. It's 1/4” long. The setup directions I'm reading say the depth of cut should be about 9/16ths, measured from the router base, and specifically say not to measure from the bottom of the guide "tube" as you call it. But that only leaves 5/16ths of bit protruding below the tube, which is not enough for an adequate dovetail. That's my issue.
I'm no expert, either, but if I had that problem I'd clamp a straight edge across the jig to use as a guide and dump the bushing altogether. It's a time-consuming process by it works for me. Then again I hate cutting dovetails.
You don't say if you are trying to cut a half blind joint or a through dovetail. Is it possible that your are doing the latter but reading the instruction for a half blind? I note that the instructions for the Rockler jig says to set the depth of cut to 9/16" for half blind and to workpiece thickness plus template thickness for through dovetails.
If all else fails, maybe ignore the instruction and determine for yourself how deep your cut needs to be and set it accordingly. This may take some trial and error with some scrap wood.
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