Jig for Lock Mitres

**Auld Bassoon** · 29th April 2006, 07:31 PM

As some of you may have read, I recently had some issues using a lock mitre bit, so I've made this jig.

There's a teflon slider on the back of the vertical jig that runs in the in-feed fence track, so stopping the whole catastrophe from tilting. The fence is already perpendicular to the table, and the handle makes it easier to gently feed the workpiece into the bit, and keep pressure against the fence.

As can be seen, the elements of the jig are just screwed together, so if the vertical (sacrificial) element becomes too daggy, it will be easy to replace it.

For the horizontal cut, I've just made use of the small mitre sled that I already had.

It's pretty important to take small increments of a cut at a time (I'd previously, and mistakenly, thought that it was a "one shot" type of cut. Not sure where that idea sprang from

) as tear-out and crumbling is never far away cutting cross grain.

Anyway, here are a few pics.. As can be seen on these couple of pieces of scrap, the results are fair. With a bit of practice, it might even be possible to make good joints

**dazzler** · 29th April 2006, 07:35 PM

Ayyyyyyyyy leave em loose n call em hand cut!

Cool work!

dazzler

**Auld Bassoon** · 29th April 2006, 07:39 PM

Hey Dazzler!

My hand planed mortices are much better than this

**dai sensei** · 29th April 2006, 08:26 PM

I bought one of those bits at the WWW show last year. Like many things I buy at the show, it's still in the box

. Thanks for the idea, when I eventually get around to using it.

**niki** · 29th April 2006, 08:57 PM

Hi Steve

Very good idea. That’s the kind of jigs that I like, simple, with a few components and you build it “chick-chack” (quickly).

Thank for sharing, it “clicks” some ideas in my head.

niki

**ozwinner** · 29th April 2006, 09:04 PM

Originally Posted by dai sensei

I bought one of those bits at the WWW show last year. Like many things I buy at the show, it's still in the box

.

Me too, I bought one 2 years ago and its still in the box.

Al

**Auld Bassoon** · 29th April 2006, 09:19 PM

Bit of theme happening here, with folks buying these sort of bits, and then not using them.

I'll admit that I bought the lock mitre bit about six months ago, looked at it a few times, but always put it away again as it looked to be too blasted difficult to get good results with.

Well, after trying (and failing) with it, I had a think on why I had failed, and with a bit of research, came up with this. It's simple and it works.

One issue remaining is the cross grain tear out, even with the backing block, so I guess the answer is always make the router mitre cuts before ripping to width.

As well, it does take about 5 ~ 7 minutes per joint, simply because it's a big cut that has to be made in a number of small incremental stages. Having said that, it's a jolly sight faster than hand cutting D/Ts - so for simple joinery, methinks I'll be using this more.

I'd also guess that it's quite a bit stronger than a simple mitre or, possibly, even a keyed mitre. Definitely stronger than a half-lap. It also has the advantage that it's almost automatic that the joint is square.

**McFly** · 29th April 2006, 09:22 PM

Nice work Steve. It's amazing what sort of jig the brain can design to help solve one of the many problems that arise in woodworking.

**ozwinner** · 29th April 2006, 09:27 PM

Originally Posted by Auld Bassoon

As well, it does take about 5 ~ 7 minutes per joint, simply because it's a big cut that has to be made in a number of small incremental stages. .

Wmahahahaha, not for One Pass Al......

Al :eek:

**Auld Bassoon** · 29th April 2006, 10:33 PM

Al,

You should have seen the remnants of wood after I tried a single pass :eek:

One of the lumps went straight through some tarp!

**Bob38S** · 30th April 2006, 11:23 AM

Auld,
Guilty - I also have one of these bits - bought from a catalog - likewise looked at it a number of times and then thought - I'll get to that later.
Thanks for the idea and I'm pleased I haven't tried it yet because I also thought because of its shape that it was a one pass idea.
Regards,
Bob

**tonysa** · 30th April 2006, 10:17 PM

nice idea AB, i too have a bit stored away with plan to use it because triton didn't do bevel cuts. yeah, bought it at WWW show after watching the demo

always a challenge keeping the material correctly positioned when passing across the bit. your jig seems to solve that problem

really need to make proper router table with a couple of T tracks, I'm using triton router top on homemade stand. works ok but really need full surface and more tracks.

wouldn't mind more piccy's of your router table, probably posted here somewhere.

cheers
tony

**Wood Butcher** · 30th April 2006, 10:27 PM

Originally Posted by tonysa

wouldn't mind more piccy's of your router table, probably posted here somewhere.

cheers
tony

Tony, do an advanced search by username (in this case auld bassoon) with posts relating to your topic in mind (ie "router table"). In his case you would come up with this
Shop built router table by Auld Bassoon

**tonysa** · 30th April 2006, 11:12 PM

ahh, so that's how its done, kewl, thanks Wood Butcher.
been drooling over incra bits and pieces for the new router table
nice stuff - added to shopping list ... this list is getting to be as long as a ..... , just need the bank balance to go with it.
cheers
tony

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