Making A Dowel Joiner Homemade Machines & Jigs

I bought a cordless trim router a little over a year ago especially for this project. Yes, it sometimes (often) takes that long to get around to it. But I did make good use of the router in the meantime and it has completely replaced the corded one I had.
The project is a dowel joinery machine, very much like a biscuit joiner. Or domino joiner, but without the high price tag.

Even though I had a full year to prepare and plan, this is a prototype that I built on the fly. I did a quick drawing in SketchUp to get started and figured out the details as I went. The idea is to make this and see if I like using it before I commit the time to a more polished version.

I started with a box that fits around the body of the router:

I thought that would be the easiest, most accurate way to hold the router.

Inner tube rubber was double sided taped to the inside of the lid to grip the router body:

Coming up with the quickest and easiest methods that don’t involve a lot of messing around is how you build a prototype. You want it to work properly, but it doesn’t have to look pretty or have all the bells and whistles.

I made the bottom panel of the box 1/4″ wider on each side to fit in grooves in the rails:

The rails guide the router back and forth to make the plunge cuts. There’s a number of different ways to do this and I picked the one, you guessed it, that was quick and easy. It’s also very accurate and should be durable enough that it doesn’t loosen up after using it a bunch of times.

A return spring is not strictly necessary, but it’s a feature I’d want on a final version so I added it here.

The question is will it work properly on one side, or do I need two? That was quickly answered: one is enough. Notable that I didn’t have a compression springs big enough for this, so I stretched out a tension spring to make one.

The spring happens to fit perfectly around a 1/2″ dowel and that keeps it from deflecting outwards while compressing it. The dowel also acts as a means to hold the router box on the tracks so that it doesn’t just slip out of the end:

A washer and screw on the end of the dowel does that and makes it easy to take apart.

The fence is simple as well, just a piece of 3/4″ plywood for the vertical part. It has grooves and slots for the screws that hold it onto the rails and also allow it to be adjusted up and down:

Knobs would be more convenient, but again this is a prototype so it’s basic function above all else.

The horizontal part of the fence is 1/2″ ply that has the clear plastic indicator:

The indicator is adjustable to line it up accurately with the centre of the router bit. Once again I made this as quickly as possible, but it does work well.

I was most indecisive over how I would hold the tool while using it. Originally I thought I could use it like my biscuit joiner, just holding the body of the machine. But this is a bit too chunky to hold onto securely so I made a simple handle that’s attached to the top panel:

You can see I also replace the top panel. That’s my one concession to appearance – I didn’t like the look of the 1/4″ plywood.

Ready for a test cut:

The video above shows more, but here’s the first after I had the tool lined up properly:

Two 1/4″ dowels and the joint is perfectly flush and lined up.

I did make one change, and that was to partially fill the large hole where the bit comes through:

I found it difficult to hold the tool on the end of narrow stock when most of the end was not up against anything. The patch is 1/4″ plywood, so it still allows the collet of the router to come forward.

Here it is finished and outdoors to get a good picture:

The joiner should also work with 3/8″ dowels and I’ll try it when I get a (sharp) bit. And my early impressions are very positive. In fact I’m thinking that I should buy a second router like this and leave this one in the tool. There were several times over the last year where I could have used this.