Miter Lock Joint

[Kris Cook]

I just received a miter lock bit and was wondering about others experience before I use it.

I did get the Infinity bit with setup jig so that part I think I am good with.

My questions:

In 3/4" stock have you seen the need to make multiple passes?

How great is the risk of breaking the fine edge without a backup piece of wood to support the edge?

Thank you.

[Mel Fulks]

It’s been years since I used those. Several times here I posted my method…now out of the biz….I don’t remember all my steps. But a
“back fence “ is the best way to run them . Rounding off the inside corner ,and leaving a small flat at outside corner stops most tear out.

ONE pass ,with medium speed or more , when you start getting tear-out get them sharpened

[Stan Calow]

I tried three different brands. I would buy one, try to get it to work, but ended up throwing it in the lake. Then I would get determined and got another, with same result. I was not patient or skilled enough, even with using the set-up blocks specific to each brand. All my problem, Im sure others get them to work fine.

Getting that vertical piece was the hardest, and yes breaking the fine edge was a problem. Also I kept getting the middle tongue to break off. Multiple passes seemed to make the cuts too loose. I would only try again if I had a horizontal router setup.

[Carl Beckett]

The knife edge was a weak link to me - since you need to be able to hold the reference against the fence on the outfeed side as you complete the cut. So double taping a guide piece on top of it provides that surface to guide against.

Agree on the single pass - unless your stock is perfect.

And agree on setting up so it leaves a 'small' flat instead of the knife edge.

It took a bit of practice, but in the end I was able to get satisfactory results (for me).

Now.... another option might be ripping a 45 on the table saw, or even non locking 45 on the router table. Some say this is as strong (if not end grain). Then on a recent box I was making I put the 45 on the table saw then added some Dominos across the joint for alignment and extra holding. That was much more straightforward than the locking miter. Its not obvious to me I will keep using the miterlock.

[Kris Cook]

Thanks all.

I did get the cuts made with good results. I was using walnut that was very straight. I also used feather boards on the table only.

I did consider a 45 degree joint but would probably have used a spline which complicates things a bit.

Very impressed with this joint. I know it may be old hat to production furniture makers but now that I have a actual router table with fence that is easy to set up I will be exploring more uses.