On the left is the stock throat plate that came with my Craftsman saw. I only use it with sanding belts, and when I'm cutting really large parts. I made the one on the right out of 1/8" MDF. The stock throat plate creates several problems, one is small parts want to drop down into the saw's base, and the second thing is the tear out on the bottom of most pieces that you cut due to the lack of support underneath. You can remedy this problem by using zero-clearance inserts, or at least an opening that more approximates the size of the blade that you are using. These can be made out of many materials, including scraps of plywood, MDF, tempered hardboard, acrylic sheet, etc.
They are very simple to make. The one above was made by stack cutting several pieces of 1/8" MDF that were secured with double sided tape in between, then trace around the original throat plate and cut outside of the line to make them a tiny bit over size, you make them fit tightly by sanding around the edges (if you make them to loose add a thin piece of tape around the edge & trim).
If you are lucky enough to have a throat plate that is a standard size of a hole saw blade, you could cut them out with a hole saw in your drill or drill press. The only drawback to this method is that you are limited to the 1/4" hole left by the bit in the center of the hole saw, however you could cover the the hole with tape or card stock when done and make the appropriate sized hole with an awl or small drill bit.
One other consideration in the final fit, the one that I made above sits just shy of flush with the table top, so it needed to be shimmed up to make it flush. You can use paper, index card, cereal box, the back of a writing tablet(paste board), tape, or whatever else that you can glue to the back to make it fit flush with your table top, remember these are disposable. If you can't find a combination that makes it fit flush, make it sit just proud of the table and then sandit down a little until its just right.
What if my saw doesn't use a table insert? We'll cover that in the next post.
Tuesday, April 15, 2008
Zero Clearence Inserts - Reduce Tearout & Chipping
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I took out the stock insert as soon as I got the saw, but after experiencing gouges on the back of whatever I was working on due to tiny little granules between the wood and the metal base, I attached a self-stick linoleum square to the work surface. I cut it to the shape of the scrollsaw base. It works great- very smooth surface now with nary a scratch and it actually make the saw look pretty spiffy. I used fake-wood linoleum. Anyway, I cut out a fairly large hole around the blade, but you could just as easily leave it as a pinprick, just big enough for the blade to come through. Really easy, inexpensive, and no clamps- just the adhesive the 12"x12" linoleum tile comes with.
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