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I see a lot of comments about 3/4" and 1/2" thick bases out there, but I happen to have a good size piece 3/8" baltic birch ply sitting around and need a bigger sled for an upcoming project. Any reason not to use the 3/8"? It sits on the saw table so doesn't seem like flex is an issue, and I don't plan to add holddowns or anything else to the base, so just wondered if there's something I'm missing before I cut this one up. I'll still use 8/4 material for the front fence, and probably for the back too since I have some scrap that's been sitting around a long time.
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The question is whether it is dead flat and will remain dead flat.
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(11-21-2020, 12:49 PM)MsNomer Wrote: The question is whether it is dead flat and will remain dead flat.
That's what I think, too. The leading and trailing edge hardwood "spanners" ( I don't know what you call them), combined with the hardwood runners will be key to keeping it all flat and square.
My big sled is 1/2" MDF. I made another, smaller sled last week for cutting box joints. That sled uses 3/4" particle board because that's the scrap I had hanging around.
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Good points. I was thinking the front and back fence, along with runners, would keep it flat.
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Go for it. The front and rear fences are the only thing that keep it flat anyway. Whether it is 3/8 or 3/4, it is actually 0 inches thick where the saw kerf so, so the fences keep in flat. I have gone as thin as 1/4, no problems
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You could make the front and back fence higher to have more assurance it will stay flat side to side. When I made mine, I actually used MDF since I had some. I milled some 2x4s for the fences. So far, so good.
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(11-21-2020, 12:59 PM)WxMan Wrote: That's what I think, too. The leading and trailing edge hardwood "spanners" ( I don't know what you call them), combined with the hardwood runners will be key to keeping it all flat and square.
My big sled is 1/2" MDF. I made another, smaller sled last week for cutting box joints. That sled uses 3/4" particle board because that's the scrap I had hanging around.
I used 3/4" melamine covered particle board. It was (and remains) perfectly flat and it has a good deal of lubricity so it slides more easily than other options. I had it in my scrap bin, so it was what I used. A good choice.
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Thin plywood flexes enough to if it isn't flat, you can make it flat.
That said, if there is a cup, you want it so the fences flatten it, runners aren't going to do much.
FWIW I use 1/2" MDF for most all my sleds.
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(11-23-2020, 08:58 AM)Cooler Wrote: I used 3/4" melamine covered particle board. It was (and remains) perfectly flat and it has a good deal of lubricity so it slides more easily than other options. I had it in my scrap bin, so it was what I used. A good choice.
+1
Steve
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(11-23-2020, 08:58 AM)Cooler Wrote: I used 3/4" melamine covered particle board. It was (and remains) perfectly flat and it has a good deal of lubricity so it slides more easily than other options. I had it in my scrap bin, so it was what I used. A good choice.
Lubricity is an awesome word.
