Monday, January 5, 2015

Building The La Forge Royale Miter Jack- Part 6


We're on the home stretch now. All the hard work and meticulous joinery is going to pay off real soon. Marking for the garter screws with a Vix bit. A transfer punch is useless here due to the countersink.


Remove the moving jaw from body and drill pilot holes. You'll find it much easier to install the garter screws with the nut block removed from the body.


Note that I had still not driven the groove pin into the screw's tenon. The garter pin is still loose. The groove pin will get installed later after the jack is finished.


Finally its time to cut the miter on the front of the body. I set the blade to dead on 45. If you're unsure of your setting, make some test cuts and check the mating pieces with a square. Also make sure that the bottom of the body and the top are coplanar. No sense in making the 45 deg side accurate with the bottom if its not parallel with the inside where you'll be placing your workpiece. 



Next, mark, predrill, and drive the four screws that hold the fixed jaw and the nut block. You don't technically need the nut block attached for this next step, but it does make a nice handle.


Also attach the moving jaw and the half miter jaw. Cinch down on the retaining blocks so they keep the jaws from moving about. Also, and this is important, the short end of the half miter jaw will need to be planed flush before the next step, so the base will run flat against the table saw fence.


With the same fence setting, run the base through the saw. This will create a small flat on the bottom of the jaw that's exactly in line with the beveled edge of the base.

 


Place a straight edge on the bevel and mark the sides of the three jaws.


Cut close to the line, but not to it. You'll plane the rest off by hand.


While the blocks are off the base, hand plane the bevel with precise strokes to remove the table saw marks. This buys you one more guide for planing the blocks to a precise 45.



The runners at the fixed jaw end need to be trimmed flush. Wow, do I need a fresh blade on my bandsaw.


Cut close with a saw and break off the little waste pieces.


Pare the end grain from above and then along the ledge. I need to sharpen my chisel. That's pitiful.


Plane the protruding ends flush.


The setup for planing the 45 degree faces.


I start with a jointer plane for its mass, since I need to remove a fair amount of material. Look close. You can see a gap under the plane's toe. This is the amount of material I need to remove from jaw face. So when you bandsaw, get close. This is hard work.


Check constantly to make sure you're keeping the jaws square to the outside faces (which reflect the inside of the jaws if you've made them correctly) in both directions, and at 45 to the body's edge. I use the same techniques as before when planing the 90 degree ends of the jaws. Use stop cuts and again, constantly check your progress with your square.


If you've cut a consistent distance from the pencil line on the bandsaw, you should be able to simply take repeated shavings from the entire surface until its flush with the body's edge. I apparently cut a little off square on my moving jaw. You can see the low spot above, along the inside face of the jaw. I had to plane all the surrounding wood away before the marks were removed. Doing this with a hand plane is really the only way to get this right. You can get the jaws dead flat and right on the money angle-wise. If you have a belt sander that starts looking really attractive, don't be a fool. Those things can't make flat.


Again, gauge from the bottom of the jack, but only if its dead parallel with the inside surface.


The inside corner of the moving jaw out at the tip didn't quite clean up. I didn't want to take the surfaces down any further after getting them dead on. Also, my brother stopped in the shop earlier today and while checking out the vise, broke off that corner. I made him fix it before he left, but when he pulled out a carton of Durham's Rock-Hard I told him to hit the road.


So I chiseled it flat.


Then cut a little piece with the same grain direction.


Glued it on with CA and accelerator.


 Sawed the big piece off, and planed the rest flush.

 




The 90 degree face was flushed up and trued by simply planing the back edge of the body flush (remember the blue tape at the table saw?) The end grain did need just a smidge of planing to get it dead flush.


I looked close at the end grain of the half miter jaw and the grain flows nearly perfectly between it and the fixed jaw. I'm still trying to figure out how this can even happen. Even if I cut it from the same section of the tree, it should not match this close. It nearly the same at the front too (see a few pics up). Incredible. I should have bought a lottery ticket today.


Last thing I did today was trim the splines flush and break the corners with 220. The main part of the jack is complete. I need to get back on my deadline project before I completely finish this. So it may be a couple weeks or so before I get a chance to make the screw handle and base. Those bits have no moving parts, and do not need to be so precise. Man am I looking forward to making them after all this!


5 comments:

  1. I'm exhausted just reading it all, Jameel!

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  2. Beautiful work. Remember the small mysterious peg on the original, protruding from the end of the fixed jaw? I think it could be a little foot, so that the whole apparatus can sit on the floor, screw handle up, with the peg's length equaling the proud end of the base so that the whole thing will sit level. Does that make sense? -John Vernier

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    Replies
    1. Thanks for the reminder. I had spaced out that part. And that indeed is its purpose.

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  3. Are you using a carbide blade in your bandsaw?

    One thing I don't like about the Lenox carbide blades is that the tooth spacing is perfectly uniform, which means that the blade vibrates at its resonance frequency, which means that you get the kind of ripple marks that are visible in your photos.

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  4. No, just regular old steel. The blades are good, my laziness is the problem. I have used the laguna blades, but never liked them.

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