I have made a sled like yours, but put the "stop block" on the end in to the planer FIRST. I tried putting it in last like you suggested, but my planer wheels (not the cutter) grabbed the top board and slid it forward off of the sled. So at least in my experience, your planer wheels manage keeping the board from coming back at you, just like they do with any piece of wood you put in there; and the stop block keeps the sled and board from moving independently.
Makes me wonder how thin you can build a torsion box before it stops working. There is probably a ratio of the thickness to the space between the cross members that needs to be followed to maintain stiffness and flatness.
I did a lot of reading up on torsion boxes before making this one, and the consensus seems to be that the thinner the skins, the closer the interior supports should be spaced. If you were to use 1/4" plywood for the interior supports and the skins, I'm sure it could be problematic. That would be an interesting video to make, testing torsion boxes to see at what point they no longer work.
@@MurphysCreations Your supports are already relatively close to one another, and are much thicker than 1/4". From what I can tell, such thickness should be able to afford you a 12" spacing
Quick explanation of a torsion box: It converts bending into compression. For the top face to bend, the bottom face needs to compress. Wood can bend, but not compress
Did you run into trouble using sleds made of plywood/MDF? I totally get why this works and it's a good idea, just curious if you had some specific issues with the usual method to share.
I originally had one made from melamine. It warped over time. A big part of that is that it was stored in an unconditioned space. I plan to insulate my shop this year, but until then, this won't warp on me.
@@MurphysCreationsI feel that - my "workshop" is just my uninsulated garage. Hopefully sometime in the near future we can insulate it, but for now, the MN winters are a real problem.
From my research, short ways is all that necessary in this application. I've seen much larger torsion boxes where they run both ways. In this application, the sled is so narrow, having a spine run down the middle won't really do anything. If you used thinner plywood for the skins, maybe it would make sense.
![เปิด อาณาจักร หมื่นล้าน "สาระตั้ม" l [Nickynachat]](http://i.ytimg.com/vi/3XE0nPF4YkQ/mqdefault.jpg)
I have made a sled like yours, but put the "stop block" on the end in to the planer FIRST. I tried putting it in last like you suggested, but my planer wheels (not the cutter) grabbed the top board and slid it forward off of the sled. So at least in my experience, your planer wheels manage keeping the board from coming back at you, just like they do with any piece of wood you put in there; and the stop block keeps the sled and board from moving independently.
Makes me wonder how thin you can build a torsion box before it stops working. There is probably a ratio of the thickness to the space between the cross members that needs to be followed to maintain stiffness and flatness.
I did a lot of reading up on torsion boxes before making this one, and the consensus seems to be that the thinner the skins, the closer the interior supports should be spaced. If you were to use 1/4" plywood for the interior supports and the skins, I'm sure it could be problematic. That would be an interesting video to make, testing torsion boxes to see at what point they no longer work.
@@MurphysCreations Your supports are already relatively close to one another, and are much thicker than 1/4". From what I can tell, such thickness should be able to afford you a 12" spacing
important point about the number of vertical supports: Remember that your planer pushes down HARD. The thinner the skin, the more bowing can occur
Quick explanation of a torsion box: It converts bending into compression. For the top face to bend, the bottom face needs to compress. Wood can bend, but not compress
This is going to be my next sled. I have a sled. It was good when I made it, but it warped on me
Well done! Solid presentation.
Thank you, I am glad you enjoyed it!
Did you run into trouble using sleds made of plywood/MDF? I totally get why this works and it's a good idea, just curious if you had some specific issues with the usual method to share.
I originally had one made from melamine. It warped over time. A big part of that is that it was stored in an unconditioned space. I plan to insulate my shop this year, but until then, this won't warp on me.
@@MurphysCreationsI feel that - my "workshop" is just my uninsulated garage. Hopefully sometime in the near future we can insulate it, but for now, the MN winters are a real problem.
is it important that the rungs run the short-way instead of the long-way? or is that just a coincidence?
From my research, short ways is all that necessary in this application. I've seen much larger torsion boxes where they run both ways. In this application, the sled is so narrow, having a spine run down the middle won't really do anything. If you used thinner plywood for the skins, maybe it would make sense.
@@MurphysCreations How did you come up with all the sizes? rule of thumb? or did you find a calculator somewhere?
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