Rockler has a lock miter bit on sale and I was thinking about getting one because they are usually so expensive. It's a 3/4". My question is how can a bit that is 3/4" tall put a good lock miter on a 3/4" board? I mean, it would have to be set absolutely perfect and if the board was say .760 thick, you'd get a burr. Should I get the bigger bit to do 3/4" stock?

http://www.rockler.com/product.cfm?page=2142

It definitely has to be perfect we keep two dedicated router tables set which are never touched. There's a sign on it that reads touch this and you will get you're pink slip

 

This would suggest 2 differant bits to complete both sides of lock miter. If you're yankin my chain Then LOLLOLLOL, if not I have 1 bit that goes both ways.:laughing:

 

So, should I get the small bit for 3/4" stock?

 

So, should I get the small bit for 3/4" stock?

Yes it will work

 

Do they have a larger/longer one?

This one from Grizzly is 11/16th long according to the specs.
http://www.grizzly.com/products/Corner-Lock-Miter-Bit-1-2-Shank/C1712 and it's $33.00 :thumbsup: bill
or a larger one:http://www.grizzly.com/products/Corner-Lock-Miter-Bit-1-2-Shank/C1331

I see Rockler has the large one at $68 and they have set up jigs:
http://www.rockler.com/product.cfm?page=10247

 

Bud,
There are two incarnations of the bit. The one that is on sale is intended for wood up to about 5/8". That is the bit that is on sale. If you think about how the retail business works, the reason that the bit is on sale is because the bit isn't selling. The larger bit (91722) is selling some what better.

I have used the larger bit. (Amana not Rockler) My experience is that set up is exceptionally difficult. A perfect set up even with a micro adjusting router lift is just not reality. Even using a couple of jigs, set up is just not an easy job and almost never perfect. I don't have the book at hand, but check out pages 130 to 134 (somewhere in that area) of "In The Craftsman Style" for details about the jigs and how to use the router bit.

If you are building a box or cabinet carcass, a simple miter, TiteBond III and squaring jigs will give you just as strong a joint. When you tear apart a miter joint using TB-III glue and clamped long grain to long grain it is the wood fails before the glue. IMHO, TB-III is a stronger wood glue than any of the polyurethane (a.k.a. Gorilla) glues. But I digress. IMHO, the bit is nice in theory but not the most practical when making mitered corners.

 

Hey Bud this one #7849 is $38.50 at MLCS but it's larger 2" wide and 1" tall ( I measured mine) they claim it's 7/8" tall. Either way it's better sized and still not a bad price. They also sell the setup blocks to help with problems that rich talked about.

Here is a video about setting up and using the lock miter.

 

Setup is a bit tricky. You might be better off with using a blind splined miter.

.

 

Rich, Richard and Cabinetman are spot on. They are a bear to set up, even with the set up blocks.
I used mine twice and put it away. IMHO, there are better ways to spend precious shop time.

 

In my opinion it is well worth the effort for set-up but I use mine often (CMT 3/4" & 5/4) they are great for me. I do a lot of box timbers and use tightbond II. As far as the 3/4", I always plane my wood up to 1/32 over. My table is a true ******* router table and not that easy to set up but worth the time IMO. Of course we may be talking about a differant lock miter too, mine is AC/DC.

 

In my opinion it is well worth the effort for set-up but I use mine often (CMT 3/4" & 5/4) they are great for me. I do a lot of box timbers and use tightbond II. As far as the 3/4", I always plane my wood up to 1/32 over. My table is a true ******* router table and not that easy to set up but worth the time IMO. Of course we may be talking about a differant lock miter too, mine is AC/DC.[/QUOTE]


Huh? :huh:

 

Whazzat?

.....Of course we may be talking about a differant lock miter too, mine is AC/DC. HUH? Whachu talkin' bout Willis? :blink: bill

 

We must have been confused at the same time Bill. :laughing:

 

Yup

I donno 'bout you, but I still am. :blink:

 

I never heard of an AC/DC lock miter bit. Mine's straight DC.
Batteries are hard to find, too.

 

This would suggest 2 differant bits to complete both sides of lock miter. If you're yankin my chain Then LOLLOLLOL, if not I have 1 bit that goes both ways.:laughing:

Are set up has a male and a female bit

 

So it is only mitered on outside corner then?

 

Yes that's right

 

Very Sorry for all the confusion . I should Have said two shapers. Two shaper bits a male and a female