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Crosscut sled recommended materials.

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Forum topic by noone posted 05-24-2012 04:34 PM 5659 views 0 times favorited 25 replies Add to Favorites Watch
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noone

410 posts in 1026 days


05-24-2012 04:34 PM

I’m trying to build a crosscut sled and am having some issues. I initially cut a 1/2” birch ply base and then discovered it was bowed. A lot. Then I laminated 2 strips of 3/4” MDF to use as the sled fence and even that is bowed about 1/32”.

I need some recommendations on flat crosscut sled materials.

I was thinking 1/2” MDF for the base and maybe some kiln dried 2×4’s from home depot for the fence?

Recommendations for a perfectly flat fence material?

I also have access to a Woodcraft store.


25 replies so far

View jmos's profile

jmos

681 posts in 1123 days


#1 posted 05-24-2012 04:51 PM

I recently rebuilt my sled (switched to thin kerf blades). I was not really happy with the selection of sheet goods at the home center. I’ve seen a couple of videos calling for 1/2” base, but neither the 1/2” ply or the MDF was flat.

I ended up going with 3/4” ply, just because it was the only thing that was reasonably flat. I used 3/4” for the base, and laminated 3 plys of 3/4” for the front fence and 2 plys for the back rail. I glued them up all together with a top caul and clamped them to my bench to dry. They came out nice and flat on the faces. I jointed the bottoms and verified them with my jointer plane. They helped pull the slight bow out of the base, and the final sled was flat.

-- John

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GregD

637 posts in 1890 days


#2 posted 05-24-2012 05:06 PM

I used 3/4” melamine for my sled base. It seems to me that the melamine on both surfaces help keep the material from acquiring much of any bow, and the material is not so rigid you cannot easily push out whatever little bow it may have.

Incra uses a 1/2 melamine-over-mdf material in its Miter Express and Miter 5000 sleds which is great stuff, but I have no idea where you can get something like that.

Are you planning your sled to extend to both sides of the blade? I see that a lot and even did it myself on my first sled, but I much prefer the sleds that extend to only one side like mine, the Incras, the Dubby, etc.

-- Greg D.

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noone

410 posts in 1026 days


#3 posted 05-24-2012 05:32 PM

I was planning on it taking up the entire space of the table saw with about a foot of it hanging over the left edge.

My primary use for it would be to cut down square panels (up to 24” wide) for cabinets and built ins, with the occasional use to crosscut smaller pieces for doors and drawers that aren’t quite long enough for my miter saw’s stops.

I’m definitely open to any frugal suggestions on materials and design.

View Bill White's profile

Bill White

3589 posts in 2714 days


#4 posted 05-24-2012 05:47 PM

Tuba fours are gonna give ya grief until they fully dry. My sled is 1/2” ply with doubled 3/4” fences. Its flat after I let it sit in the shop and acclimate.
Remember that ya don’t have to go nuts tryin’ to get flat within .0000?
Just tryin’ to ease the pain as well as the cost.
The MDF base will work as well. Melamine will too. Both will degrade on edges or corners if treated roughly.
The well designed fences will certainly help keep the base flat enough.
Bill

-- bill@magraphics.us

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noone

410 posts in 1026 days


#5 posted 05-24-2012 06:21 PM

That Incra Miter 5000 looks interesting, BTW. Tempting…..

I need a flat piece for my fence. Do I have to fork out the bucks for some phenolic plywood from woodcraft?

What can I scrape together from Home Depot? Hmmmmmm…

View NiteWalker's profile

NiteWalker

2710 posts in 1330 days


#6 posted 05-25-2012 02:43 AM

My next one will be entirely MDF.

-- He who dies with the most tools... dies with the emptiest wallet.

View sixstring's profile

sixstring

296 posts in 997 days


#7 posted 05-30-2012 11:49 PM

I used 3/4” mdf for my base and kiln dried 2/4s from HD as my fences. It’s a small sled though, about 24”x12” which really covers about 90% of what normally gets crosscut. It’s more for dados/rabbets and any crosscut I cant do on my 10” mitre saw. Cut a rabbet out of each 2×4 and joined them to the mdf base with glue and screws. The proper rabbet helped a lot with geting everything squared up nice. It’s held up pretty well so far but it’s only been over a month and less than 100 cuts.

-- JC Garcia, Concord, CA : "It's easier to ask forgiveness than permission..."

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noone

410 posts in 1026 days


#8 posted 05-31-2012 04:30 AM

Just finished packing up the Incra 5000 miter sled. I really wanted that beauty to work out for me, but I could not get the miter bar to slide smoothly even after messing with it for 3 hours. I must have adjusted all those nylon washers a million different ways and I still could not get that bar to slide smoothly without “bumping” as the bar entered the slot at each point where the washers were on the bar. Very disappointed.

I could have built a sled with the time I spent f’ing around with this.

I guess I’m back to square 1 where I will use a phenolic flat piece of ply for the fence and either 1/2”mdf or 3/4” melamine for the base.

Or maybe some S4S oak from HD?

View jmos's profile

jmos

681 posts in 1123 days


#9 posted 05-31-2012 12:02 PM

noone, any chance the problem is with your miter slots? Often they are not perfectly uniform along the entire length from the factory. I used a 3/4” block and some sand paper on mine to widen the narrow sport to get any bars to travel cleanly. As I remember the tightest spots were at the beginning and the end. The Incra bars should be pretty darn uniform (not impossible they were machined badly, but not terribly likely), so maybe it’s your slots.

Just a thought.

-- John

View rawdawgs50's profile

rawdawgs50

82 posts in 1771 days


#10 posted 05-31-2012 01:46 PM

John got it right for cleaning up the slots. Use emory sand paper.

For a sled 1/2” is what you want. You want it to be light weight and as little height reduction as possible. For the fence glue up a plywood lamination then joint it flat. I found that the Sandeply at home depot is very good for jigs and would be excellent for this.

Do not beat yourself up on thinking it has to be dead flat. Virtually flat is flat enough. Been doing this along time with jigs and slides that look like they have been to hell and back.

The key is that you fence is perfect a 90 to the blade and that your runner slides tight and smooth. Paste wax works great. Lube up the bottom of the sled and the runner.

Good luck and do not sweat the small stuff.

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noone

410 posts in 1026 days


#11 posted 05-31-2012 02:00 PM

It did seem like the very front of the slot where it begins was tighter. Enough to make it bump so slightly. The only way to keep it from not ‘bumping’ was to make it loose. Too loose to the point it would wiggle slightly. No matter how I adjusted it. I tried expanding one side’s washers more on one part to make it bump less but then it made the other side bump. I played around with it for about 3 hours and finally decided that it wasn’t worth the time and the money when all I really need is a sled that cuts square stock up to 24”. No angles needed here.

Rawdawg-

I totally forgot about that Sandeply stuff at HD. Good call!

I’d love to be able to joint my fence flat, but how do I do that if I don’t have a jointer?

Are you talking about just gluing it up and clamping it to my mdf workbench flat while it dries?

View PurpLev's profile

PurpLev

8476 posts in 2402 days


#12 posted 05-31-2012 02:08 PM

I got a phenolic plywood at rocklers when they were on sale, I think woodcraft sells those as well. they are flat, 3/4” and have super smooth surfaces on both sides which helps with the SLIDING action of the sled.

a day after I bought it I found an INCRA MiterExpress on craigslist that uses similar material (only with MDF as the substrate and not plywood) and have been happily using this ever since… one of the best thing I ever got for the shop.

I was planning on replacing the INCRA factory sled base with the phenolic board I got as it is bigger (for a bigger sled) and I might do that at some point, but for now I don’t see a need as this sled just does everything I need and is not ‘broken’ so no need to fix.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View jmos's profile

jmos

681 posts in 1123 days


#13 posted 05-31-2012 02:15 PM

If the bar was only binding in certain places, it was most definitely your slots. If you have a caliper you should be able to measure the narrow spots. Another method is cut a block an inch or two long that barely fits in the slot (could also use a narrower pieces with a screw in it to allow easier adjustment) and run it up and back in your slots; areas where it binds are narrow and need attention. Do some light sanding (don’t go crazy, you can remove metal faster than you might think) and keep testing. Once you get a uniformly tight fit you should be good. And I’ll be those Incra bars will work great.

This is something that should really be done to all table saws as part of the initial setup and tuning. Once it’s done you should never have to worry about it again.

-- John

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noone

410 posts in 1026 days


#14 posted 05-31-2012 02:37 PM

Hmmmm. The sled is still packed up in my car ready to go to UPS. Maybe i’ll pull it out and give it another try. I measured the width of the slot with my digital caliper and it was .755” wide. I measured it in several spots along the slot, but I did not measure the very front where the slot first starts.

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jmos

681 posts in 1123 days


#15 posted 05-31-2012 02:41 PM

If you liked the Incra enough to buy it, I’d try it again. Even if you cut your own hardwood runners you’ll have the same problem if the slot is not uniform. You’ll have to either accept sloppy runners, or tune up your slots. No good way of getting around it.

If you decide again to send it back, it only cost you some tape, right?

-- John

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