Finally, a better sled runner

[Andrew Joiner]

I'm a fan of single-runner sleds too. Just as an experiment I made one with a 3/8''x 3/4'' UHMW runner. It crosscuts 36". It's lightweight because the body is only 3/16" thick. It's still accurate 8 years later. It's my favorite sled cause it's light and stores right under my cabinet saw.

[Bob Wingard]

Since your #1 criteria was that you didn't want something that expends/contract with the seasons, I think you will be sorely disappointed with this stuff over time.

I used to carry armloads of it home from work, hoping to use it for runners & jig parts ... UNTIL I found how much it moved with heat/cold ... I see you've made provisions for adjustment on your ... that is a good idea, because you will use that feature more than you'd like.

These guys provide all the technical properties of the stuff, in case you're interested ... ... ...

http://www.polytechindustrial.com/pr...w-polyethylene

[Alan Schaffter]

Since your #1 criteria was that you didn't want something that expends/contract with the seasons, I think you will be sorely disappointed with this stuff over time.

I used to carry armloads of it home from work, hoping to use it for runners & jig parts ... UNTIL I found how much it moved with heat/cold ... I see you've made provisions for adjustment on your ... that is a good idea, because you will use that feature more than you'd like.

These guys provide all the technical properties of the stuff, in case you're interested ... ... ...

http://www.polytechindustrial.com/pr...w-polyethylene

I may be wrong, but I think you will find like nylon, UHMW PE also absorbs moisture! As I said in the original thread, I like 3/4" X 3/8" cold rolled steel for my miter bars. I think it slides easier than any of the plastics.

[Phil Thien]

Since your #1 criteria was that you didn't want something that expends/contract with the seasons, I think you will be sorely disappointed with this stuff over time.

This thread got bumped because a spammer posted a link to what I assume is his plastics reselling outfit. The spammer had three posts over several years, all of them links to his plastics outfit.

The thread was started approx. four years ago, and I have not noticed any seasonal problems whatsoever in that time.

I looked up the coefficient of thermal expansion for UHMW plastic: x 10-5 in./in./°F (http://www.jjorly.com/uhmw_technical_data_sheet.htm).

It would appear that in order to see a change of .001" across the .75" width of the runner, I'd need a change in temperature of approx. 12.12 degrees (F).

Absolutely a ton more than (for example) aluminum. Probably a ton less than what you'd expect from seasonal changes for wood.

My shop is climate controlled, so it really doesn't matter for me.

[Phil Thien]

I may be wrong, but I think you will find like nylon, UHMW PE also absorbs moisture! As I said in the original thread, I like 3/4" X 3/8" cold rolled steel for my miter bars. I think it slides easier than any of the plastics.

Water absorption over 24-hours is stated as NIL:

http://www.jjorly.com/uhmw_technical_data_sheet.htm

[Alan Schaffter]

Water absorption over 24-hours is stated as NIL:

http://www.jjorly.com/uhmw_technical_data_sheet.htm

Thanks, so it is not like nylon.

[Andrew Howe]

I do know Peachtree offers runners they claim are .75", and other runners designed for Craftsman slots that are .744". The .75" runners I got are a little shy of .75", though. It would be interesting to know the actual size of the Lee Valley units you returned.

I do know that a year or so ago I tried some .75" UHMW plastic at Rockler in a chunk of the miter channel from Incra that I had. At that time I felt they were a poor match, the UHMW plastic had too much play.

Knowing what I do now, I think it would have worked fine had I either used the prongless t-nuts or used the screws from the bottom like others have suggested. The little bulge in the UHMW plastic is really all it takes to firm the fit up.

I bought some.from mcmasters and it was too big for my saw slot. Bought cold rolled steel.and it fits perfect with one runner. My sled is big 33" capacity for the workshop cabinets I am making.

[Anthony Diodati]

I wonder if there is somewhere local to get the cold rolled steel. There is some reasonable on e bay, but then the shipping kills it IMO.
Maybe I will check with lowes. Tractor supply had some aluminum and cold rolled, but it was only about 1/8" thick.

[Jacob Reverb]

I wonder if there is somewhere local to get the cold rolled steel.

Markup on metals at the Borgs is probably 5000%. Google or Yellow pages "steel service" or "steel service centers" in your area...they may have short offcut remnants ("drops") they may sell you cheaply (most sticks are sold in 20' lengths). Check also for local welding and metal fabrication shops.

I think I bought my cold-rolled steel for runners at use-enco.com ... look for items marked down and you can do all right. They also have regular specials (20% off, free shipping, that kind of thing) if you get on their mailing list or Google around for Enco coupons.

I do metal fab as well as woodworking, and I have been very happy with their prices/service/shipping speed.

[glenn bradley]

Good stuff Phil. I have runners of wood, aluminum and UHMW. Where I live all perform well but, I do use the trick of tightening the UHMW screws just a bit to tailor the fit. The aluminum has adjustments built in (Incra) but, the wood had to be planed/scraped for a tailored fit.

[Phil Thien]

Markup on metals at the Borgs is probably 5000%. Google or Yellow pages "steel service" or "steel service centers" in your area...they may have short offcut remnants ("drops") they may sell you cheaply (most sticks are sold in 20' lengths). Check also for local welding and metal fabrication shops.

I think I bought my cold-rolled steel for runners at use-enco.com ... look for items marked down and you can do all right. They also have regular specials (20% off, free shipping, that kind of thing) if you get on their mailing list or Google around for Enco coupons.

I do metal fab as well as woodworking, and I have been very happy with their prices/service/shipping speed.

I think every decent-sized town has a place to get the stuff. Here in the Milwaukee area I'd probably go to Speedy Metals. Get the phone book and start calling anyone in there and ask them if there is a local source for cold rolled.

[Alan Schaffter]

It is good to see my suggestion for using cold rolled steel for miter bars is still a good one

As I went back through this thread one other idea popped into my head when some folks talked about the weight of their sleds. I haven't done it but plan to take a hint from metal aircraft manufacturers (and other metal fabricators)- I'm going to add lightening holes to my sled.

If your sled is made from decent Baltic or other good birch ply, you can cut holes in it to reduce the weight. It can actually have more holes than structure and still do the job its intended job just fine. Grab a fly cutter and have at it!

[Anthony Diodati]

It is good to see my suggestion for using cold rolled steel for miter bars is still a good one

Well, I went to Lowes anyways to see what they had. 3/4" wide, but only 1/4" thick, X 3 feet long, but it should be OK. It was normally $7.00 something, on clearance for $5.74 each.
I didn't think that was too bad, so I got 2 of them.
Was worried they might be a little loose, but they are actually too tight, but I think I can knock them down with a file a little bit. I think 1/4" thickness will be alright.

[Phil Thien]

Well, I went to Lowes anyways to see what they had. 3/4" wide, but only 1/4" thick, X 3 feet long, but it should be OK. It was normally $7.00 something, on clearance for $5.74 each.
I didn't think that was too bad, so I got 2 of them.
Was worried they might be a little loose, but they are actually too tight, but I think I can knock them down with a file a little bit. I think 1/4" thickness will be alright.

1/4" will be fine.

Let us know how they work out.

[Anthony Diodati]

OK, what is the best way to line up the steel runners once I get them sized?
A have a $25.00 piece of phenolic plywood that I don't want to ruin. Should I drill my holes in the runners, then shim the bottom of my runners in the slots, and use carpet tape on the runners, and lay my board/base on the runners, remove it and screw it down?
I was thinking I want to use 2 runners, not one.