locking miter bit/joints

[david bolf]

hi, i am a new member and novice woodworker. i am currenty converting attached garage into a shop and have bought some tools. i bought the new jet supersaw with 30" fence, made a table extension to hold my Jessem master lift with bosch 1617 router. i am planning to make a jewerly box and humidor. i purchased a freud locking miter bit. with some scrap 3/4" stock i have been practicing to get a tight fit on the joint. i have centered the height of the bit for the 3/4" stock and have moved the fence about 1/4" at a time. i also have feather boards holding the stock against the fence and the table top.

my problem is that the first pass rides against the fence fine after that the edge drifts across the fence and the result is a wavy cut. any advice on bit setup, technique, and # of passes required to accomplish this joint would be helpful. i have read that once you get the bit set you can pass both the vertical and horizontal cuts without making any adjustments. is this true?

thanks

[Ted Shrader]

David -

First, welcome to the Creek. It is a friendly place to hang out and dangle your feet.


i have read that once you get the bit set you can pass both the vertical and horizontal cuts without making any adjustments. is this true? That is the way it is designed to work. After proper adjustment, your cuts will align perfectly.


Any advice on bit setup, technique, and # of passes required to accomplish this joint would be helpful.
I have cut a miter with the table saw to take off material up to where the tongue is. This still leaves a small flat edge to bear against the fence/table to guide your cut. (Sometimes I just run them through in a single pass.) The idea is to get the bit height and fence position just right so the cut is perfect. The angle of the tongue makes it so you can't "sneak" up on it.

Try laying out the material so you make a horizontal cut on one edge then a vertical cut on the other. (Vice horizontal on both sides of two pieces and vertical on both sides of the other two pieces.) Obviously, for this technique, the arrangement of the pieces is critical.

Additionally, the dimensions of your pieces are critical. All must be exactly the same width.

Please continue your use of feather boards, push sticks, etc. As you are aware, that is a lot of exposed metal spinning around.

Good luck and welcome,
Ted

ps More info <a href="http://www.jesada.com/instructions/lock_miter.html">here</a>.

[David Rose]

David, I agree with Ted. I'm writing this from work so if anything is confusing please ask, I'm kind of rushing.

What it sounds like to me is that you are cutting slightly too deeply on the final cut. If there is not a tiny bit of flat left on the edge of the board there is no support for what has passed the cutter. Once the piece has passed the cutter you have nothing to control the depth of the cut. Does this make sense? I've done this more than once with your results.

The way around this is to use a sled instead of the fence to control the depth of cut. I actually use both. The fence controls the setting for depth and is fine for the initial cuts. The last cut is where you need the sled. If the support is controlled by the sled instead of the fence you get support before *and* after the cut. Of course this is only good for end cuts or fairly short pieces. If you use the miter lock for legs or something longer then I leave a tiny flat on the final cut.

David

[david bolf]

thanks for the replies. i think you both hit it on the nose what my problems were. i dont have a sled or miter track setup yet on my table extension. this table is kinda temporary, for i am gathering info to build a router table/station like the jointech system. like everything practice will make perfect.

[Mark Stutz]

I haven't used this particular bit, so I can't speak from experience. My router fence has movable, replaceable faces to make a "zero clearance" fence. Would that work for this particular bit?

[david bolf]

i can certainly see how a zero clearance insert would help my problem. as i stated early i am new to this and time and experience will pay off for future projects. thanks again

[Wendell Wilkerson]

I haven't tried to use a lock miter bit yet, but I have found a website with a very detailed description of using one.

Wood Shop Demos - Lock Miter Demo (http://www.woodshopdemos.com/cmt-lm1.htm)

Actually, this site has all kinds of good info that is well documented with pictures. Good Luck.

Wendell