Cross Cut Sled Questions

[Teresa Jones]

How can such a simple concept be so difficult to execute??

I machined two runners out of mahogany to fit both miter slots. I then cut a piece of 1/2 inch baltic birch plywood to the dimensions of the table top (48 inches side to side and 28 front to back).

With the runners in the miter slot, I applied double-sided tape to the top sides of the runners and then placed the plywood on top of the saw, aligning all the edges.

Removing the assembly, I proceeded to drill pilot holes for the screws to attach the runners to the plywood. The first runner attached without any problems. The second one split in two different places.

Now, the sled would not slide, because the split runner is binding in the miter slot. No problem, I removed the runner, ran it through the jointer and reattached. OK, now we get a nice smooth slide all the way through.

This morning, getting in the truck, heading for work, I notice that the plywood base is now warped at both far ends - arrrghhh!!

I need your helpful suggestions and I am willing to start all over again.

Things I am considering - using UHMW plastic for the runners and 1/4 inch MDF for the base. I think 1/2 inch MDF is too heavy?? Should the sled be smaller dimensions?

If you made it this far, bless you!!

Thanks,

TJ

[Rob Russell]

Teresa (or do you prefer TJ?),

Do you have a bridge across the end of the plywood that warped? If so, it's possible that movement in the wood pulled your plywood into a warp.

If you don't have a bridge, consider that as soon as you run the sled through your saw, you'll have 2 halves of a sled.

Here's an article that shows some different versions of crosscut sleds.

http://benchmark.20m.com/articles/CrosscutSleds/CrosscutSledArticle.pdf

Rob

[Ted Shrader]

Teresa -

Like Rob says, you need additional support. Mine has a single layer of plywood on the "front" side of the sled (side that hits the blade first). The "back" side has a double layer with a T track embedded. Handy for attaching a stop block for repeatability of cuts.

One other suggestion - different runners. Mahogay is kind of soft and prone to splitting (as you found). The runners won't last as long as some made from a harder wood - say maple. Also, there are UHMW plastic runners available, but I think most of the friction comes from the bottom of the sled. (I use maple.)

The runners on the "front" of my sled extend beyond the sled about 3" and are tapered for about 1½". Makes putting the sled on the saw very easy.

With a little fine tuning, you will find this to be one of the handiest tools you own!

Good luck,
Ted

[Dick Parr]

The first sled I built I used the plastic runners. DON"T

They expand when you put screws into them and then they don't run in the slots. I spent half a day fighting this. I used oak runners and had a garbage can full of plastic. :mad:

When I built the next one, a miter sled. I went out and got the metal ones that are already drilled and can be adjusted. Piece of cake. :D

Good luck.

[Jim Hill 2]

Sorry your having so many problems. I made mine out of 1/4" birch plywood with Red Oak Runners. I ran about a 5" bridge over the front and back edges and screwed them from under the plywood. I made pilot holes in the red oak runners and counter sinked them. I like your idea of double sided tape, but at the time I just shemed the runners and used super glue then screwed it to each end. The only suggestion I would give is not to put screws near the blade. I eventually decided to use mine as a jig for cutting finger joints and the screws had to be removed to avoid the blades hitting them. Good Luck!

[Teresa Jones]

Thank you all for your comments.

I have plenty of red oak in the scrap pile, so I will start with new runners. I made mine the length of the miter slot. I think I will add the extra length as suggested.

Should I add the front and rear support bridges before I attach the runners? I was planning on using a milled down 2x6 for that application.

Thanks for the advice about the plastic, I will steer clear!!

I was surprised the baltic birch warped, but maybe with the added weight of the bridge it will do better.

Thanks again, everyone!!

TJ

P.S. - My nickname is TJ and I do prefer it, but I answer to just about anything!!!!

[Todd Burch]

Teresa, I have a 1/2" baltic birch sled that is 6 years old. I love it. The ply was a little "warpy" when I started, but once it is screwed to my 1" fences, and was cut in the middle into two pieces, it's pretty flat. And, what flat is is not, when I set it on the saw, it flattens out.

I used white oak for the runners - it's what I had in the scrap bin that was hard. Mahogany, walnut and cherry would be too soft wearing.

For the rear fence, I used a piece of red oak, a full 1" thick, 5½" tall (or so) and the width of my sled. There is no requirement to make the sled the same size of your table, it can be bigger or smaller. I have two sleds, a big one and a small one. With the big one, I can cross cut a piece 26" wide, which handles most cabinet case parts (23¼"). Also, no need to sweat making the 1/2" ply square to the table - just make sure your runners slide nice, are not snug but not too loose, don't bind anywhere front to back, and your rear fence (if that is your registration fence) is dead on square to the blade. The front fence, or non-registering fence, can be on sideways for all that matters - there is no requirement to have it square - I just eyeballed mine, which is 1" thick yellow pine.

Todd.

[Kent Cori]

TJ,

My experience with the UHMW runners mirrors Rick's. I finally scraped them down far enough to work but I could have bought several adjustable metal slides for the effort I put into the scraping.

[Bruce Page]

I guess I'll be the rebel again... I used UHMW for the runners on my large sled and I’ve been happy with it. I used several screws in each one so that I only had to snug them and not over tighten. I have zero play, they are unaffected by humidity, and they slide like greased lightning.

[Lars Thomas]

Well Bruce,that's gotta be the prettiest cut-off sled I've seen. That's better looking then the stuff I take out of my shop. Impressive.

[Todd Burch]

Boy Bruce - what a fancy sled!! Mine does not have the rails that span the distance from the rear fence to the front fence, and, I don't think I would like them either, as they would interfere with removing cut-off stock, especially on the right side of the blade.

I like your blade guard to the back - I don't have one. I do have them on my finger joint jigs though.

Todd

[John Miliunas]

I guess I'll be the rebel again... I used UHMW for the runners on my large sled and I’ve been happy with it. I used several screws in each one so that I only had to snug them and not over tighten. I have zero play, they are unaffected by humidity, and they slide like greased lightning.

Hey Bruce, really nice looking sled you got! Question: What is that brassy looking bushing or whatever over on the left side of the sled? I see it both, from the top and backside of the sled table. :cool:

[Bob Lasley]

TJ,

I have to agree with Dick on the metal runners. I like the Incra Miter Sliders. They are not cheap, but I think the adjustment feature makes them worth the money. I have several on various sleds and jigs.

Bruce,

Woweee! That is about the fanciest sled I've ever seen. If I had something that fancy in my shop, SWMBO would be hauling it into the living room for a piece of furniture!

Bob

[Dick Parr]

Bruce, very nice looking sled. I was thinking of putting the same type of runners on mine except they would be to secure a piece of plexyglass to keep the chips from flying back into the face. Is that brace piece on the bottom a stop?

[Bruce Page]

Thanks guys,

The sled is straight out of AWW, I no longer have the issue but it was the cover story 3 or 4 years ago.

John, the brass piece on the sled is a stop. If you look closely at the first pic you’ll see a brass stop on the side of the wing, it stops the sled before the blade hits the plexiglas guard.

Todd, yep you're right, the cross braces are sometimes a real PIA! I store this thing under the crosscut table and it is heavy, the braces save my back.

[Steven Wilson]

Here's the sled I made a couple of years ago. Overall the panel cutter is 42" wide and 36" front to back. That's enough to cut a 30" wide panel. The design is a combination of ideas I got from the Incra and Woodhaven web sites. The track material is from Incra and the miter runners are from Woodhaven. The base of the panel cutter is 1/2" Baltic Birch plywood with a piece of Formica laminated on the bottom. The horizontal supports are 1 1/2" x 2" pieces of hard maple. Both horizontal supports have T-track in them for mounting clamping jigs and guards.

[Todd Burch]

Steve, what flavor of overarm blade guard is that? Todd.

[Adan Madrid]

Teresa (or do you prefer TJ?),

Do you have a bridge across the end of the plywood that warped? If so, it's possible that movement in the wood pulled your plywood into a warp.

If you don't have a bridge, consider that as soon as you run the sled through your saw, you'll have 2 halves of a sled.

Here's an article that shows some different versions of crosscut sleds.

http://benchmark.20m.com/articles/CrosscutSleds/CrosscutSledArticle.pdf

Rob

Rob,

Good article. I agree with the author's recommendation. For $300-$800 you are better off buying a sliding table attachment if you have the floor space.

[Adan Madrid]

Here's the sled I made a couple of years ago. Overall the panel cutter is 42" wide and 36" front to back. That's enough to cut a 30" wide panel. The design is a combination of ideas I got from the Incra and Woodhaven web sites. The track material is from Incra and the miter runners are from Woodhaven. The base of the panel cutter is 1/2" Baltic Birch plywood with a piece of Formica laminated on the bottom. The horizontal supports are 1 1/2" x 2" pieces of hard maple. Both horizontal supports have T-track in them for mounting clamping jigs and guards.

Steve,

Nice Ride! Good job on that sled!

Adan

[Steven Wilson]

Steve, what flavor of overarm blade guard is that? Todd.
That's the one from Exaktor (www. exaktortools.com), works like a champ.

[Dale Critchlow]

Teresa -

"Mine has a single layer of plywood on the "front" side of the sled (side that hits the blade first). The "back" side has a double layer with a T track embedded. Handy for attaching a stop block for repeatability of cuts."

Ted: From you description it sounds like the "bridge" is simply two layers of plywood at the rear of the sled. Is this correct?

If my understanding is correct, what is the dimension of the uncut plywood at the read end of the sled? Also, what are the thicknesses of two pieces of plywood?

I have been thinking about building a very low profile sled. I have a homebuilt blade guard with a 4" dust collector hose. My present sled is several inches tall so the blade guard must be set high which makes the dust collection less effective. Your design sounds like it just what I need. My plan is to put a removeable stop in the miter slot to prevent me from pushing the sled too far into the blade.


Dale Critchlow

[Ted Shrader]

[QUOTE=Ted Shrader]
"Mine has a single layer of plywood on the "front" side of the sled (side that hits the blade first). The "back" side has a double layer with a T track embedded. Handy for attaching a stop block for repeatability of cuts."

Ted: From you description it sounds like the "bridge" is simply two layers of plywood at the rear of the sled. Is this correct?True. Two layers of ¾" baltic birch laminated together. Then a dado was ploughed out deep enough for an aluminum T-track.


If my understanding is correct, what is the dimension of the uncut plywood at the read end of the sled? Also, what are the thicknesses of two pieces of plywood? The front and rear fences are the same profile and run the entire width of the sled. They are 3" high at the ends and 5¾" high in the middle. The middle section is about 10" wide. The distance from the top of the saw cut and the top of the fence(s) is 3".


I have been thinking about building a very low profile sled. I have a homebuilt blade guard with a 4" dust collector hose. My present sled is several inches tall so the blade guard must be set high which makes the dust collection less effective. Your design sounds like it just what I need. My plan is to put a removeable stop in the miter slot to prevent me from pushing the sled too far into the blade. Dale CritchlowI have a Brett Guard overarm saw guard. I move it out of the way when using the sled. I don't have dust collection (yet) so hadn't considered that a problem - until now.

Your idea sounds like a good one. Instead of a stop in the miter slot, how about extending the rear of the sled base a little farther. Enough to add one layer of plywood (or whatever) under the sled to act as a stop when it hits the table top? Then, put another layer on the top of the sled to act as the fence. The fence piece will have to extend far enough forward to get to the blade. The low profile fence would, as you say, fit under the guard and still allow dust collection.

Sorry for the delay in reply.

Regards,
Ted

[mike malone]

using UHMW plastic for the runners and 1/4 inch MDF for the base. I think 1/2 inch MDF is too heavy?? Should the sled be smaller dimensions?
If you made it this far, bless you!!
Thanks,TJhi TJ
if you do get that sled going, you may want to check out these video tips on sleds at FWW:

http://www.taunton.com/finewoodworking/pages/wvt002.asp

http://www.taunton.com/finewoodworking/pages/wvt003.asp

regards
mike

[Teresa Jones]

Thanks, again, all.

I cut some runners out of oak and attached the bridges and I am in business!! Not as fancy as Bruce, but the design is very close.

You all are the best!!

TJ

[Alan Turner]

Looks like I am too late, but . . .

I took a piece of 3/4" mdf,, put the mpale runners in the slot, and some glue. Then, shot them on from the top down. Tested the slide; fine. Then flipped it and drilled and screwed the runners in place. Then, put it on the saw, cut it to about 6" from the rear, and squared the rear fence to teh blade. clamped it, and glued and screwed from the bottom. Then, same with the front. Works well, low cost, of course. A bit of wax and I'm off to the cross cutting races.

[Fred Voorhees]

I am envious of all of the great crosscut sleds pictured within this thread. I built mine from 3/4"MDF and a slab of hard maple with a red oak runner. It wasn't very difficult at all and produces some darned nice square cuts. All of the pics have certainly given me ideas to incorporate into a new sled and it might not be to far in the distant future that finds me attempting a second sled.

Fred Voorhees

[Jim Jones 35]

I guess I'll be the rebel again... I used UHMW for the runners on my large sled and I’ve been happy with it. I used several screws in each one so that I only had to snug them and not over tighten. I have zero play, they are unaffected by humidity, and they slide like greased lightning.
Bruce, What a nice looking sled.Mine is simular but I used 1/2" baltic birch for the bottom and two pcs.3/4 laminated for the front and rear bridges,I also used the UHMH for the runners and put 1/8"dado for them to keep them from warping.Had to play with the screws holding them so they didnt spred the plastic.Yours was made by a craftsman mine was made by a tinkerer.Very nice . Jim Jones

[Bruce Page]

Bruce, What a nice looking sled.Mine is simular but I used 1/2" baltic birch for the bottom and two pcs.3/4 laminated for the front and rear bridges,I also used the UHMH for the runners and put 1/8"dado for them to keep them from warping.Had to play with the screws holding them so they didnt spred the plastic.Yours was made by a craftsman mine was made by a tinkerer.Very nice . Jim Jones

Thanks for the compliments Jim, I don’t know about the craftsman part tho…:confused: I wish I had used ½” Baltic berch instead of the ¾” melamine coated particle board. The sled is heavier than it needs to be.

[Jeff Skory]

Thanks for all the ideas and links everyone. I made a crosscut sled from a magazine article. It is made out of 3/4" MDF with three pieces on the back so that it won't tip off the end of the table. Man is that thing heavy.

It is getting a little sticky in the last few days.

After viewing the video on the Taunton site I wonder if my runners have the grain running in the wrong direction. And I think my sled is just a wee bit off from 90 degrees. I like the tip they gave of testing it out while the glue is still wet and using a clamp for fine tuning. I will definitely use both of these tips in my next sled which I will be building soon.