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post #1 of 16 (permalink) Old 05-18-2014, 05:04 PM Thread Starter
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Default crosscut sled question

I built my crosscut sled about a year ago and it has worked pretty well so far. But now the runners have shrunk a little bit and will need to be replaced.

Question is... how deep should the runners sit in the miter groove of the table? If I am correct, sled itself should sit flat on the table. That means there should be a gap between the bottom of the runners and the miter groove.

How should I go about this?
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post #2 of 16 (permalink) Old 05-18-2014, 06:50 PM
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Originally Posted by mikeoleary View Post
I built my crosscut sled about a year ago and it has worked pretty well so far. But now the runners have shrunk a little bit and will need to be replaced.

Question is... how deep should the runners sit in the miter groove of the table? If I am correct, sled itself should sit flat on the table. That means there should be a gap between the bottom of the runners and the miter groove.

How should I go about this?
Why don't you check with Incra and see if you can buy the runners that they use on their Express Sled, they should not be very expenisive, are not mad of wood, and are adjustable as to width to fit in the miter slots in the table. Just an idea and seems like it would eliminate a lot fussing around with making your own out of wood.

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post #3 of 16 (permalink) Old 05-18-2014, 08:28 PM
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Mike it would be best if the sled sits flat on the saw table. Otherwise you risk having it tilt under a long load to one end which would cause an off square cut.

Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.
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post #4 of 16 (permalink) Old 05-19-2014, 01:56 PM
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Mike I use UHMW runners exclusively. I also use thin UHMW tape on the bottom of the sled. The runners are 3/4" wide, X 3/8" thick. This will leave about 1/32+" above the bottom of the miter slots. Most miter bars are 3/8 inch thick. I hope this helps.

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post #5 of 16 (permalink) Old 05-19-2014, 03:54 PM
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Mike I use UHMW runners exclusively. I also use thin UHMW tape on the bottom of the sled. The runners are 3/4" wide, X 3/8" thick. This will leave about 1/32+" above the bottom of the miter slots. Most miter bars are 3/8 inch thick. I hope this helps.

dick
Dick, what is UHMW. I used to use a Teflon tape on my sand bags when shooting benchrest. The slick Teflon insured to some degree that the rifle would recoil the same way from shot to shot. If anybody has any interest in shooting, and I know that few if any readers of this forum care about such things, but it is a myth that the bullet leaves the barrel before the rifle begins to recoil, therefore controlling recoll from shot to is extremely important if you are trying to get shot after shot to go through the same hole. Is UHMW anything like Teflon tape?

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post #6 of 16 (permalink) Old 05-19-2014, 04:56 PM Thread Starter
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Thanks for the input guys. I am currently leaning toward the incra miter sliders because I don't have the right tools to get UHMW down to the right dimension. I have a DeWalt contractor's saw and they put this terrible rough coating on the table and miter slots. I had pretty good luck sanding it off, but it slightly changed the miter slot dimension.

Jerry I can give an answer on what UHMW is technically. It is ultra high molecular weight plastic. I believe this type if plastic is very strong due to the length of it's molecular chain. It also has low friction coefficient. I work on a supertanker, and all the fenders at the docks we go to are made from UHMW plastic. It is a very useful material.

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post #7 of 16 (permalink) Old 05-19-2014, 05:11 PM
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Dick, what is UHMW. I used to use a Teflon tape on my sand bags when shooting benchrest. The slick Teflon insured to some degree that the rifle would recoil the same way from shot to shot. If anybody has any interest in shooting, and I know that few if any readers of this forum care about such things, but it is a myth that the bullet leaves the barrel before the rifle begins to recoil, therefore controlling recoll from shot to is extremely important if you are trying to get shot after shot to go through the same hole. Is UHMW anything like Teflon tape?

Jerry
Jerry UHMW is a very slick semi rigid plastic. They claim this stuff wares better than steel. The surface is almost as slick as ball bearings. As a matter of fact they use it as bearings in some machinery. We put it on the sides of our table saw fence, 1/2" thick on each side. it is actually slicker and wares better than Teflon. It is a little pricy at $20.99 for a piece 1/2x4x48 inch. The tape for the bottom of sleds and jigs is much less expensive. I think I got mine from Peachtree woodworking through amazon.com. You can see what is available, and read the reviews at,

Amazon.com: UHMW: Tools & Home Improvement

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post #8 of 16 (permalink) Old 05-19-2014, 08:00 PM
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Originally Posted by mikeoleary View Post
I built my crosscut sled about a year ago and it has worked pretty well so far. But now the runners have shrunk a little bit and will need to be replaced.

Question is... how deep should the runners sit in the miter groove of the table? If I am correct, sled itself should sit flat on the table. That means there should be a gap between the bottom of the runners and the miter groove.

How should I go about this?
If you install runners using something like maple they can be initially set up in this manner
1. Place a series of washers or coins in the slot. This will raise the finished strips about 1 mm from the bottom.
2. Use double sided tape on the top of the strips. When you place the sled being sure it is lined up square the tape will hold the strips temporarily in place.
3. Slide the sled and tape held runners back far enough you can run a screw in from the bottom.
4. Slide the unit forward to do the same at the front.
5. Lift the sled off and remove the spacers
6. Test the sled's slide and if you're pleased finish screwing the runners to the base
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post #9 of 16 (permalink) Old 05-19-2014, 08:23 PM
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I tried UHMW PE ultra high molecular weight poly ethylene (the full name which you can Wiki for more info) on my sled. Lee Valley sells strips of it 3/8 by 3/4 for this purpose. I removed it shortly after and went with hardwood. Using hardwood allow allows me to stick the runners 10 to 12" out the front and back of the sled which insures a straighter cut and the ability to use the sled for wider cuts since the runners are well established in the slots by the time the sled reaches the table. The UHMW was not stiff or strong enough to allow this.

Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.
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post #10 of 16 (permalink) Old 05-20-2014, 12:03 PM
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Originally Posted by mikeoleary View Post
Thanks for the input guys. I am currently leaning toward the incra miter sliders because I don't have the right tools to get UHMW down to the right dimension. I have a DeWalt contractor's saw and they put this terrible rough coating on the table and miter slots. I had pretty good luck sanding it off, but it slightly changed the miter slot dimension.

Jerry I can give an answer on what UHMW is technically. It is ultra high molecular weight plastic. I believe this type if plastic is very strong due to the length of it's molecular chain. It also has low friction coefficient. I work on a supertanker, and all the fenders at the docks we go to are made from UHMW plastic. It is a very useful material.
I have a question, what is the best form or tool to cut UHMW??
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