Thread: Lock miters and plain miters - hold downs for routing vertically

With a plain 45 degree bit you don't have to do it upright, flat on the table is exactly the same.

Lock mitres are good if you have to do lots at a time, getting them set up properly is a massive headache and just not worth it for small runs

The table saw is the better option for cutting mitre joints. With a saw, you can change the tilt angle of cut to suit any irregularity's.

If you use a router table, the table has to be flat. The spindle has to be perpendicular to the table. And the bit has to be 45°. And after all of that, you can't run the joint up to a sharp 45° point because that point is referencing off the fence, so you need to leave it with a 0.2mm flat.

that vertical jig looks like just another gadget designed to prey on the inexperienced. Holding a piece vertical against a fence is no different to doing it on a jointer. It is actually a little easier because the cutting action of a router bit pulls the timber into the fence and all you need to do is dampen the vibration/chatter with pressure.

depending on what type of tearout you are talking about, with a router table you can make a zero clearance sacrificial fence which will prevent tearout on the face of board.
Preventing tearout as the bit exits the piece on end grain (spelching) is done by butting up a sacrificial behind the workpiece to support the fibers.

Originally Posted by elanjacobs

With a plain 45 degree bit you don't have to do it upright, flat on the table is exactly the same.

But aren't you removing an entire edge and therefore the outfeed fence will be back to far? Holding it vertically solves that problem.

No it doesn't; if you're removing the reference edge working vertically, your table will be too low on the outfeed end and that's much harder to deal with than adjusting the outfeed fence.

In addition to Kuffy's comment, routers don't work as well on end grain as edge grain and your bits will dull faster and give you furry ends. If it was me, I'd be sticking to the saw.

For locking mitre joints I use a similar looking jig taken from Roy Sutton's "Jig making for the router". It's shown on the bottom left of the book cover and is quick and easy to use... once you've got the tool set up sorted . I only ever use this joint on drawers and utilitarian boxes.

As for ordinary mitre cutting I'd agree with the above posts; stick with a saw not the router. If I ever get into fancy box making I'd refine that statement further by saying use a table saw; and follow up with a shooting board or guillotine.

Originally Posted by elanjacobs

No it doesn't; if you're removing the reference edge working vertically, your table will be too low on the outfeed end and that's much harder to deal with than adjusting the outfeed fence.

I'll stick with the table saw as everyone has suggested but I'm curious to see what the router table can offer. As for routing vertically the piece is referenced off the fence. See this video
https://www.youtube.com/watch?v=HRGtcihAVuE

You can add a false reference edge with sticky tape, but that gets tiring very quickly.

notice how in the video he uses MDF in the vertical jig. If he used solid timber, that back edge would have be blown to pieces.

I guess a sacrificial backing board could be used but I take your point. Like in this video https://www.youtube.com/watch?v=AijVPt9VFiM

Those box makers who swear by lock miters must use some sort of vertical attachment for narrower boards. That's what I was curious to hear about.