Do we really need another video on how to make a table saw crosscut sled ? YES !

[Steven Woodward]

My 30 year old sleds did not fit new table saw due to spacing of miter slots. Gave my old sleds to the guy who bought the old saw, and set out to make new sleds. Did some research on best practices in table saw sled construction and found the following great two ideas that were new to me and perhaps others:


Alan Turner in FWW July/August issue 2012, squeezes the two halves of the sled together with a clamp, before gluing the rails in place. This eliminates play in the miter rail guides. Eliminating an annoying source of variation. See my photo below.
William Ng demonstrated in a YouTube video the 5 cut method to very accurately measure the perpendicular error between blade and fence and then calculate how much to move one end of the fence. Difficult to explain this method so I refer you to his video if you are interested. Just search YouTube for “5 Cuts to a "Perfect" Cross-Cut Sled”

To gain more control in adjusting the fence perpendicular, I glued a sacrificial fence in place, and clamped the final fence to the sacrificial fence. Then using the 5 cut method to determine how much the fence should move at one end, I selected a shim of that thickness to place between the sacrificial fence the final fence at one end. In a single adjustment this produced “perfect” perpendicular with no fiddling. Fence could then be screwed to bace and sacrificial fence cut off. See Photo below

Here is a video showing all the construction steps https://youtu.be/twEc6LZHlJQ (https://youtu.be/twEc6LZHlJQ?fbclid=IwAR1AHL3q88pH6-bEaKy0u2EhQAmuzsu5bWdezOP9OidZOrXXP0WHGt3ErEs)

Now researching for design of a precise 45 degree miter sled for picture frames and for frame and panel doors with miter corners. If you have any suggestions please share.
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[Richard Coers]

We need a new video? Who's we? After 48 years of woodworking, I'm pretty comfortable with not having another video. LOL But I do admit that's a clever way to market for more youtube subscribers.

[Rod Wolfy]

Nice video, Steven. Thank you.

[Bruce King]

Great video! Love the part where you sawed it in half.

[Michael Drew]

Dangit..... You're two weeks too late. Loved the method you used to snug up the miter bars. I spent a couple hours filing down some aluminum bars after gluing mine to the base with S-glue, and not taking enough time to make sure they were snug - before securing them. I like the sacrificial fence idea too. That would have saved me a bunch of time as well.....

[Dan Cameron]

Steven has deminstated the ONLY potential advantage of using two runners on a sled, and that is the fit can be "adjusted" by setting the distance between the two runners. However this scheme overlooks the potential problem of the fit becoming too loose or too tight as humidity changes cause the plywood or mdf base to grow or shrink. If mother nature controls the humidity in your shop, seriously consider a single width-adjustable runner. It is just as stable and strong. Yeah, I know I have harped on this perhaps too often, but my intentions are honorable.

[Bruce Wrenn]

Now researching for design of a precise 45 degree miter sled for picture frames and for frame and panel doors with miter corners. If you have any suggestions please share.
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449093Find a video on the DUBBY. I only have one regret with my Dubby, I waited too long to buy one. Deadly accurate on miters. I watched Jerry Cole demonstrate the Dubby for years before buying one.

[Michael W. Clark]

I really like your sacrificial fence approach, thanks for sharing that.

My current sled is similar to yours. I’m considering adding a track to the fence for a movable stop to be adjusted more easily. Did you consider that?

[Steven Woodward]

Steven has deminstated the ONLY potential advantage of using two runners on a sled, and that is the fit can be "adjusted" by setting the distance between the two runners. However this scheme overlooks the potential problem of the fit becoming too loose or too tight as humidity changes cause the plywood or mdf base to grow or shrink. If mother nature controls the humidity in your shop, seriously consider a single width-adjustable runner. It is just as stable and strong. Yeah, I know I have harped on this perhaps too often, but my intentions are honorable.

I had not thought about that humidity thing. Will see how it goes when the warmer humid weather comes. My shop does not have HVAC. My hope is that sheet material, like plywood and MDF only change dimension in thickness, not in length and width. But the proof will be in the pudding. Good or bad I will follow up in 6 month or so.

[Steven Woodward]

I really like your sacrificial fence approach, thanks for sharing that.

My current sled is similar to yours. I’m considering adding a track to the fence for a movable stop to be adjusted more easily. Did you consider that?

I'm considering it now :)

[Dan Cameron]

I had not thought about that humidity thing. Will see how it goes when the warmer humid weather comes. My shop does not have HVAC. My hope is that sheet material, like plywood and MDF only change dimension in thickness, not in length and width. But the proof will be in the pudding. Good or bad I will follow up in 6 month or so.

Sorry Steven, but the facts are that plywood and mdf do change dimensions with humidity changes. If you are putting down underlayment, for example, the building codes insist that you leave a gap between sheets. Your sled could become too tight to use or too loose to meet your accuracy requirements depending on how much humidity change occurs and in which direction. My mantra should be "stamp out dual runner sled videos"

[Frank Pratt]

Sorry Steven, but the facts are that plywood and mdf do change dimensions with humidity changes. If you are putting down underlayment, for example, the building codes insist that you leave a gap between sheets. Your sled could become too tight to use or too loose to meet your accuracy requirements depending on how much humidity change occurs and in which direction. My mantra should be "stamp out dual runner sled videos"

It does change with humidity, but not near as much as solid wood. Plywood changes about the same as solid wood does along the grain.

[Dan Cameron]

It does change with humidity, but not near as much as solid wood. Plywood changes about the same as solid wood does along the grain.

It is true that plywood changes less than solid wood's changes across the grain (radial and tangential), but it changes MORE than solid wood's longitudinal changes. The alternating layers fight one another but reach a comprimise.

[Steven Woodward]

Steven has deminstated the ONLY potential advantage of using two runners on a sled, and that is the fit can be "adjusted" by setting the distance between the two runners. However this scheme overlooks the potential problem of the fit becoming too loose or too tight as humidity changes cause the plywood or mdf base to grow or shrink. If mother nature controls the humidity in your shop, seriously consider a single width-adjustable runner. It is just as stable and strong. Yeah, I know I have harped on this perhaps too often, but my intentions are honorable.

Built my new Miter Sled with a single snug fit UHMW runner. It feels good - smooth sliding and play. Thanks to Dan for that. I am now a true believer in the single runner.

Here is post on new Miter Sled: https://sawmillcreek.org/showthread.php?289990-A-versatile-and-precise-miter-sled&p=3102612#post3102612

[Steven Woodward]

I had not thought about that humidity thing. Will see how it goes when the warmer humid weather comes. My shop does not have HVAC. My hope is that sheet material, like plywood and MDF only change dimension in thickness, not in length and width. But the proof will be in the pudding. Good or bad I will follow up in 6 month or so.

UPDATE: One year later.
As shown in the video, the sled is made with two runners and the runners do not have to fit snug in the table saw miter slots. One year later, having gone through the four seasons of humidity, I find the sled is a little loose in the runners. Other sleds I made with a single snug fitting runner have not become loose. My conclusion is that one runner is better than two, as long as the single runner can be made to fit snug in the miter slot. Here is a video showing how to cut snug fitting runners: https://youtu.be/MZu0JvW1g3k

[Warren Lake]

the old guys sled was loose for likely 30 years. When I asked how he cuts square he said he just holds it to one side and its bang on.

[Kris Cook]

Just saw this for the first time. Your video is excellent. Good presentation.

[Rick Potter]

I noticed the screws in the face of your fence in the video. Did you have to shim the fence to get it flat? I notice my like fence is a bit off of straight.

Thanks,

[Minh Tran]

Remember to put finish on your sled! I built one two years ago in my unfinished garage that witnesses ~80% RH and temperature swings 0-85 deg F (New England). The base has warped and it's all but junk.

I'm due for another one and somethings I'd like to do differently:
1. Aluminum adjustable miter bars (runners). They're pricey but won't weather. They can be reused.
2. Baltic birch plywood base. Waterbased Poly finish.
3. (4) T-Tracks, parallel to the miter bars, two inside two outside, on the the base to allow the back fence to be adjusted for squareness. The inner tracks can host clamps. T-bolt to thread from underside with tightening knobs on top. Hole cut in the front fence for clamp removal.

#3 is a new technique for me because it's awkward to get underneath the sled to nudge it into place. If it isn't square, you also have to offset your screws.

[Howard Rosenberg]

Steven,

Fabulous video! You're an excellent communicator and you made a lot of disparate info super-clear.

Also - it was great seeing a Toronto Public Library card being put to such good use! And where are you from originally in the Maritimes?

And - never need to apologize - keep em coming!

Many thanks.

[Steve Demuth]

1. Aluminum adjustable miter bars (runners). They're pricey but won't weather. They can be reused.


I build all my sleds and jigs with HDPE runners. Easy to machine, and if you mount it with a countersunk conical head screw, you can adjust it for a perfect fit simply by changing the tension on the screw. Much less expensive than aluminum ($40 will get you enough to make 24" runners at Rockers, e.g.), and simpler to work with.

[Steve Demuth]

It is true that plywood changes less than solid wood's changes across the grain (radial and tangential), but it changes MORE than solid wood's longitudinal changes. The alternating layers fight one another but reach a comprimise.

In my experience, the actual change at the scale relevant for sleds is minimal. The US Forest Product's Laboratory reckons it's about 0.0002" per inch per 10 percentage point of relative humidity change. The figures up to less than 0.004" over the course of season change across the span of the two miter slots on my table saw, and it's consistent with my experience - my favorite crosscut sled with two runners works winter, spring, summer and fall in my shop with no climate control.

I make most jigs with only a single runner, but plywood movement isn't the reason. Two runners simply aren't necessary, and are work to get calibrated.