Miter Key Slot-cutting Jig

I decided to use the Box Swap as an excuse to make a more rugged version of my miter key slot cutting jig. First I apply a little "what-if" work in Sketch Up:



I take one of the horizontals and drill a couple 5/16" holes that I will connect with the router table and some stop blocks:



Without changing the fence or stop positions, swap bits and cut the trough for the t-bolt that will secure the clamping block. I use the same bit to make the large rabbet that will accept the ZCI:



I want to be able to replace parts as they get worn out so I join the two horizontals with a spline. I center the height on the thinner part and reference the surface of the mating part so that things line up. The stacked featherboards help keep the piece run through on edge stable and safe:



When I make things like replaceable inserts, ZCI's or custom backer boards, I always make a few extra. It takes only a few minutes longer than making one. This way when the item I am using fails at the worst possible moment (like there's a good one?) I just grab one of the ready-mades and get back to work:



Just a few more . . . .

Here is what it looks like assembled:



And here it is in the 'use' position. I can safely cut (without finding any screws that is) up to 2" which more than covers anything I might use this for.



I cannot show you a sample of it in action as (queue mysterious music) the Box Swap box must remain a secret till it is delivered to whoever it is that is getting it .

nice tutorial glenn,, and i need to get my sled set up for replacable inserts like yu have there..

Glenn i just love your tutorials and explanations.

Can i confirm that i have my understanding correct. Given the blade is entering from the front and cutting through the corner of whatever is having the spline inserted, there is only need to cater for replaceable inserts on the outgoing side to prevent the dreaded tearout correct?

Thanks man that was on my to do list.

Rob Keeble said:

there is only need to cater for replaceable inserts on the outgoing side to prevent the dreaded tearout correct?

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Exactly correct. I did use the spline so that I could eventually replace the front piece but, it would have to be pretty chewed up before I would. The spline would need replacing as well.

Rob Keeble said:

Thanks man that was on my to do list.

Click to expand...

This is one of those things that I put off for quite awhile. I had been using this



for I don't remember how long (that's the third backer board double stick taped to this poor little thing). I don't know why I am content to wait so long on some things. I guess if it ain't broke . . . It literally took about an hour to make the new one; eight screws and some scrap. There isn't even any gluing involved.

Hmmm, I better double the amount of time this took. I swear I fooled with this little clamp block longer than it took me to build the jig

I roughed the shape on the router table and planed to final fit:



It looks like so:



And gos here:



This is really an optional item that makes it quick to turn and re-secure the box. I never had one before. We'll see if it turns out to be a big help or just something I spent some time on