Miters...how do you do?

Re: Miters...how do you do?

William Duffield, on the Cohansey

>All of the above, but ultimately, plastic wood. :^)

Really, it depends strongly on the application (e.g., fine furniture vs. finish carpentry, vs. boat, bright finish vs. paint) and the location (e.g., shop, customer's kitchen, at the dock in a Noreaster). What I use most often is a backsaw in a miterbox, and trim to fit with a #7 on a shooting board with a 45° fence attached.

Re: Miters...how do you do?

Luke Herzberg

>Call me a dunderhead, but a MITER box for cutting MITERS didn't even cross my mind. When I first started woodworking a few years ago I thought they were the cat's meow, but eventually figured that since I still had to clean up the joint a little, why not just saw to a line? The miter box I used was a fairly clunky old Craftsman with a very heavy saw...not real user friendly, so maybe I just got a bad taste for them.

When the angle is on a long face, such as picture frames, I can pare or plane them up fairly nice. When the angle is on the short face, like molding, I seem to have a tougher time keeping the mitered surface flat, square, sharp and all those good things.

And as far as application, I guess this would be specific to a fit and finish where you desired a seamless look...the invisible line miter.

Thanks,

Luke

Re: Miters...how do you do?

William Duffield, on the Cohansey

>For small moldings, especially if you are away from the shop, you can even use a three board miter box, with a pair of 45° kerfs in it. If you build your own, just saw the kerfs with your big, clunky miter box. The added complexity of SCMS's aren't necessary, even for large cove moldings. just turn the molding upside down, with the back of the molding against the fence and the top of the molding against the table, and cut straight down using the 45° kerf as a guide. If the molding wants to slide back and up, tack a fence to the table and push down and against the fence.

Oh, and I missed one of your questions: For the shooting board, I prefer a couple of sheets of cabinet grade plywood, and a couple more for the fences and hook. 1" works well for the base, and 1/2" for the working surface and side of the chute. Fancy hardwood shootboards look good, but the plywood is strong and sturdy and doesn't move with changes in humidity, so your fences stay square. When you are cutting the blade relief in the side of the ramp the first time, the glue in the ply will dull the blade pretty quick, but subsequent uses will not, as long as you keep the same blade depth. Just make sure that whatever plane you use has sides that are perpendicular to the sole. The extra mass of a heavy shootboard turns out to be an advantage for on-site work, even though it is a pain to haul around, because it tends to move around a lot less on wobbly sawhorses, etc. when you are pushing the jointer along it. Any kind of shootboard or miter box, especially one you are going to take away from your workbench, needs a lip along the bottom front edge, that you can hang over the front of whatever you set it on.

Re: Miters...how do you do?

Ed Mulligan, Cape Cod

>Luke -

The donkey's ear works great for trimming miters. I'm posting a couple of images of one I use for 22.5 degree miters. For scale, it is made out of 3/4" plywood.

Ed

Pic #2 

Ed Mulligan, Cape Cod

>

Re: Miters...how do you do? *LINK*

Ted Shuck, Centennial, CO

>I'm just coming into this thread very late, but would like to offer a couple of suggestions. I think that Sir William is right on target using processed woods for a shooting board. I used MDF for the base of mine and it has stayed stable. I used hard maple for the running board for the plane and a glued a thin strip of hard maple to the edge of the base where the sole of the plane runs. This avoids the glue planing that William mentioned and gives a smoother surface as well.

I have recently received a strip of 1/4" thick UHMW plastic that I plan to use to cover the running board on my shooting board. I have waxed my running board area and/or the side of my shooting plane to reduce friction, but find that wood dust gets into the wax and leaves sticky globs on the shooting board. This affects the squareness of the surfaces, so I am going to a permanently slick solution that I hope will stay flat and square.

I included a link to the UHMW strip that I bought from Lee Valley. While there, I found that they sell UHMW tape, which might be a better solution...

Regards,

Ted


UHMW strip from Lee Valley

contemplating materials for jigs and fixtures

William Duffield, on the Cohansey

>One small warning about UHMW. It moves. It deforms under repeated stress, like a very, very slow, wet noodle. You have to be conscious, when designing a precision jig that would incorporate it, to back it up and fence it in with something stiff. For example, I would not recommend it, all by its lonesome, for the runner in a tablesaw slot where you need to maintain parallel or perpendicular. I've tried, and spent way too much time adding and subtracting BugBear's cigarette papers, or the equivalent, trying to keep the jig square. It is a very seductive material, but I think I prefer using lignum vitae or teak or even maple and a can of Johnson's Paste Wax at hand to keep everything slippery. I also like purpleheat for sliding surfaces of jigs. It is stiff and hard, and it takes a very fine surface polish.

Oh man! I thought our ply shooting board was already more than heavy enough. MDF is even heavier, and I'm not getting any younger or any stronger :^) Other than that, yours a very good recommendation to use MDF for building jigs, etc. Note also that they make MDF (but not all of it, IIRC) with waterproof bonding agents, so if you face it with maple, you should be able to use hide glue to bond the maple to the MDF, so you can replace the maple when it wears.

At the other end of the glue scale, thin wooden bearing surfaces bonded to a substrate with epoxy can be persuaded to release with a heat gun. Epoxy just loses all control at elevated temperatures. However, I do not know where the epoxy breakdown temperature is in relation to MDF's breakdown temperature or the temperature at which MDF begins to release toxic fumes. This might be worth further study. OTOH, it's really easy to build a new shooting board, should you wear out your old one :^)

Donkeys ear completed

Luke Herzberg

>After my original post on the donkey's ear, I've whooped up this plywood monstrosity. It is constructed as a box with 3 plywood ribs making the 45 degree angle. Hollow on the bottom, it clamps to the end of the bench. I used oak plywood and also oak fences. I figured I could take the fences off for a 45 degree clamping jig too.

Works great as well! I was amazed at how clean of a miter I could produce. Next up I'll have to build a horse's hoof and then maybe an entire hindquarter of a mule.

- Luke

Re: contemplating materials for jigs and fixtures

Ted Shuck, Centennial, CO

>Thanks for the warning about UHMW moving. I had not anticipated that.

I think I will go ahead and try using it for the running board anyway and see if it stays square in this application.

Ted