This weekend I started building a miter jack based on a design by Mario Rodriguez. He published his design in the June 1994 issue of American Woodworker.

The miter jack is a jig that I plan to use for paring 45 degree miters when doing hidden (secret) dove tail joinery. The jig will use both of these blocks. The left block will be in a fixed position. The right block will move left and right, pushed by a acme threaded press screw.



I made the two blocks by gluing up two sets of 3 strips of 31/32" thick solid core cherry faced plywood and then cutting a 45 degree bevel on each of them. A block of black walnut was glued to the mitered face and then re-cut on my table saw. The walnut face is the paring surface. It's set square to the sides and at a 45 degree angle from the bottom.



The faces are co-planer... Trust me that took some tweaking. LOL.

The blocks are 14-7/16" long, 2-29/32" wide and 2-7/8" tall.

I still have to build the frame, a second fixed block to lock in the screw and order the press screw.

Hi Guys

Yeah, I know it's been a while since I gave you an update. But, work has kept me quite busy, but I got off of the Mid Night Shift Thursday morning. Rested most of yesterday and got to work early this morning in the shop.

The first thing I did was cross cut the rails and stiles to length, then using my stacking Dado Blades, I ripped the mortises in the rail stock.

Here is a pic of the dado set up.



It took 8 passes to cut each of the two dados. After making the first cut, I rotated the rail end for end and made a second pass. This kept the dado centered on the rail. The remaining six cuts were made at progressively higher blade settings. Nothing was measured. When they looked deep enough, I stopped cutting.

After that was done, I set up my shop made tenoning jig to make the cheek face cuts.

Here are a couple of pics of the Tenoning Jig with one of the stiles on it.





I use two clamps to keep it tight to the fences.

After cutting the tenon faces, it was time to remove the cheek waste. I set up a stop block on my rip fence, then cross cut them.





With the tenons and cheeks cut, it was time for a dry fit.



Here is a close up of one of the joints.



After lunch I will take everything apart and do the glue up.

FYI, the outside faces will get sheathed in solid walnut and the top surfaces get strips of 31/32" solid core cherry face ply applied.

I might get to milling up the walnut stock tomorrow.

Have fun.

UPDATE: June 2, 2012

Yeah, it's been a while. Get over it!

I had a few hours to spare today and got a lot of work done on the miter jack.

+ Drilled a 1" hole through the side of the block that is the base for the 18" press screw, then used a V gouge cut out slots for ribs on the screw body.

+ Drilled two 3/4" holes, 1-1/2" deep in the the top of the press screw base so that it could be attached to the miter jack base unit. Then drilled a 3/8" holes all the way through the 3/4" holes

+ A 3/4" Brass washer topped with a 3/4" nylon washer were dropped into the holes and the screw base block was attached to the jack frame using 3" cabinet screws. Yes, I pre-drilled for the cabinet screws and used Dr. Dave Pruetts Screw Lube to ease them in.

+ Drilled two 3/4" in the "fixed" miter block (left hand side) and two 3/8" holes through the 3/4" holes, chiseled out the waste to make a slot and attached it to the jack frame, square to, but a little proud of the mitered front edge.

+ Clamped the moving miter block to the fixed box, also a little proud of the front mitered edge.

+ Flushed up the block miters with a block plane.

Tomorrow my plan is to cut and size a block that will be attached to the bottom of the moving miter block. This block will ride between the front and back rails, keeping the moving block"s front edge flush and square to the base front edge. After that I will make a second block that will attach to the bottom of the moving block to keep it from lifting/tilting.

It's been fun.

Bruce,
Looks like you're making great progress on the miter jack.. this is project on my shortlist.. even have a veneer press screw purchased and awaiting.

Thanks Scott,

More work done today. I made some veneer from some left over walnut stock and applied it to the fixed and moving blocks of the Mite Jack. It came out ok, but I screwed up a couple of things. Hopefully I will remember my mistakes the next time I try to make and apply veneer.

I still need to smooth it all, then sand an apply some sort of finish. Howerve, it's usable as is.

Here are a few pics.

It will handle a 13" wide board in its current configuration. I can move the "Fixed block" to the left. If it's moved to the far left end, it will handle an 18" wide board. I left the blocks square and short of the back edge so the jig can be turned around and used to square cut DT tail board shoulders.

You can see a pieces of poplar in it. I had cut a bevel on one end using my SCMS. A few paring swipes is a sharp chisel and the miter was glass smooth. I pulled it out of the jig and checked out the bevel with my combo square. Spot on! Woohoo. It's nice to get lucky!

I'm open to suggestions for a finish.

Bruce

Very nice. I think I asked you this before, have you considered using HMDW plastic for the faces?

No, I did not consider using plastic. I figure if I bugger up the faces, I can detach both blocks and resurface them with wood. Besides, I had all the materials other than the screw in the shop, so the over all cost was pretty low...

And, thanks for your comment. Have fun Rob.

Are the faces glued on?

The HMDW plastic faces wouldn't take well to most glues. I suppose one could countersink for a couple of bolts with matching threaded inserts in the plywood.

Then again, if one uses the fences properly, they should last a LONG, LONG time no mater what material was used.

Yes, the faces are glued on. I figure if I have to, I can cut them off and make new ones easily.

UPDATE:

During the first test run I overtightened the moving block and managed to snap the head off of one of the cabinet bolts used to attach the fixed block. Minor design change ensued. I removed the block, removed the broken cabinet screw and the unbroken screw and then replaced them with 3" hex head TapCon screws. Yeah, I know it's not concrete but those were the screws I had laying about. The repair took about 5 minutes and I was back up in operation.

I did discover another little problem that was easily resolved. My first "test run" also led to the discovery of another issue. IF the work piece is short and does not extend beyond the centerline of the moving block, the moving block has the tendency to skew in on the back end of the piece, leaving a gap at the front edge where the bevels are being made. This was quickly resolved by placing a piece of cut off material the same width of the work piece behind the work piece. Worked like a charm after that. Woohoo.

Looking good my man!.

When it comes time to replace the faces, I'd be tempted to use screws. I'd bet if your reasonably careful it will last for many years.

Hi Bruce.

Here's a suggestion for the next one. Fit the faces with a couple of nice, tight sliding dovetails with a locking peg down from the top to hold them in place. Make a couple of spares so, if you ever do butcher one, you can pull the peg, slide off the old, slide on the new and put the peg back. Hey presto, you're back in business in minutes.

Paul
the little Canadian guy