# lock miter bit



## stripper (Nov 27, 2012)

Hi; I'm new to using a router table,and I'm having trouble with a lock miter bit.
The problem is when I try the vertical cut it goes about an inch then jumps. Everything seems to be in the right place. It's like it just dose not like end grain.

I'm trying to make small boxes out of walnut.

Any help would be helpful.

Thanks Joel


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## Cherryville Chuck (Sep 28, 2010)

Are you going the right direction? You should be working from right to left. If you are still having problems there is a jig you could make which would help. Make a sled out of a vertical piece and a horizontal piece of ply or solid wood. Attach another piece of wood or ply that will sit over the fence. You can clamp your workpiece to the arm that rides over the fence and this will make the setup more solid. This is a similar idea to a tenoning jig that would work on a table saw. The back of the jig will also help prevent blowout when the bit gets to the end of your board.


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## Quillman (Aug 16, 2010)

Don't blame yourself. This is one, if not the worst of all router bits.
It should never have been miniturized from shaper stock.
But alas, you & many others have them.
What to do? Work out a plan to take the cut in ~ 5 stages, ending up with a 10 - .020" finish cut. Perhaps a set of thin panels removing one/pass.
Like this.


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## mgmine (Jan 16, 2012)

Are you using a feather board to hold the wood down? You will also need a sled as mentioned or a miter gauge to keep things straight. You might want to reconsider the bit and make a simple miter spline joint which can be done on the table saw.


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## cagenuts (May 8, 2010)

Quillman said:


> What to do? Work out a plan to take the cut in ~ 5 stages, ending up with a 10 - .020" finish cut. Perhaps a set of thin panels removing one/pass.
> Like this.


Except in this case the thin panels need to be vertical and not as shown on PW's site.

OP, are you using the correct size of lock mitre bit?


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## harrysin (Jan 15, 2007)

stripper said:


> Hi; I'm new to using a router table,and I'm having trouble with a lock miter bit.
> The problem is when I try the vertical cut it goes about an inch then jumps. Everything seems to be in the right place. It's like it just dose not like end grain.
> 
> I'm trying to make small boxes out of walnut.
> ...


I never thought that the day would dawn that I would question anything that Pat. has said, however, the difficulty that woodworkers have in setting up the lock mitre bit is getting the height of the bit and the position of the fence spot on so I have difficulty in visualising moving the fence several times for the vertical and the horizontal cuts. Many of my boxes used these joints and I used wood between about 3/8" and 3/4" (I have three sizes of bits) and never had problems making the joints in a single cut, and that includes Jarrah which is a very hard wood. It's important that once a test joint is perfect, to make a pair of set-up pieces for a quick set-up the next time that same thickness of wood is used.
I'm sorry for the poor shot of the joint in the Jarrah box.


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## stripper (Nov 27, 2012)

Thanks for all the advice, all of it was helpful. I took everything apart and over, much better they second time. I used a block clamped to the back of the vertical piece to ride on the fence, and a push block to hold it to the fence. I just glued up two of the four boxex I am making, so we will see how they come out. I think with a little sanding on the belt sander I should be fine.

I'm sure I'll be back with more ?????

Thanks Joel


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