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Just watched the online video on:
Squaring A Crosscut Tablesaw Sled
An indispensable jig that makes accurate miters, crosscuts and tenons a cinch
with Lon Schleining
Found it interesting, however, he recommends making the runners so the grain runs the length of the runner and growth rings are aligned vertically rather than horizontally. He says this is to reduce fluctuation in tightness of fit since the runners will expand and contract less across the grain. Humm, am I missing something? Across the grain is always less stable than any other direction. Also, Beech seems to be more dimensionally stable than Oak. Any comments would be greatly appreciated. Jim
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It may seem counter-intuitive but Lon's right. The wood is more stable in a radial or quartersawn configuration. Movement is less across the growth rings as seen from the end grain.
As to stability, beech moves more than red oak and red oak moves more than white oak. The best choice of the three would be white oak.
Lee
*I used UHMW Plastic for my runners. They are slick as glass and stable.You can had plane it to a very nice fit. The sliding cross cut table is one of the few jigs that I have ever made that I like, because on a whole I hate jigs.
*I'd use the metal runners specifically made for jigs. They have screws to take up the slack from time to time.Grizzly has them in their catalog, or at least they used to.
*I made my sled out of particle board and the runners out of pine. I coated the runners with wax.But it took me a while to figure out how to get the back guide on the sled perpendicular to the blade kerf. Finally, I cut the kerf, THEN applied the back guide. duh!
*My sled uses the Incra expandable metal runners. They work, but not as well as I had expected. They only really expand at two points. "Bulge" better describes what they do. This would be fine except that the bulges line up and half of them leave the miter slots before my workpiece is started or through. With suddenly less guidance, the sled is able to rotate very slightly. Fortunately, I can compensate and get a good feed by pressing lightly sideways while moving the sled.If building this sled again, I would either use regular runners (hardwood, Delrin, or phenolic) or mount the Incra runners staggered so that at least 3 of the 4 bulges are in the slots at all times.FWIW, my sled uses a long fence that rotates around a pivot. It cuts right at 90 degrees when set tight to the back bridge, but can be tilted up to a bit past 45 degrees if needed. The fence extends further than normal to the left, allowing repeat stopped crosscuts up to a little more than 30". I went a little lighter than some folks do - 1/2" plywood instead of 3/4". The sled is easy to manage and a pleasure to use.Hope This Helps, Dave
*Thanks for all the information. I appreciate getting god information before I start the wood butcher process.
*Rob,I like the idea of plastic runners. I am unfamilar with the type you used. could you provide more information and availability.Thanks
*I agree with Dave's observation - the Incra runners are awkward and not as easy to use as the ads suggest. I recently rebuilt my cross cut sled and made my own runners out of quartersawn ash.A tip I picked up is: when making the sled to allow for the cross piece (at the back of the sled that supports the workpiece)to be firmly attached but adjustable. Initially you place it using a just a couple of screws to hold it in place. After cutting the blade slot you can then fine tune it until it is at 90 degrees by placing new screws rather than trying to tweak runners. I found a standard drafting square to be really good for getting the angle correct.Tim
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