# Building a sled, runners from MDF?



## Artemix (Aug 10, 2014)

Hi, I had some "fun" trying to make the sled runners from hardwood, seems like the only way to properly make them is to have a planer/jointer or to make them from plywood/MDF.

I wasted some hardwood trying to make them, with no success, the wood was not perfect enough to allow me to use my fence, however, MDF is perfectly flat and in 2 mins I could make two perfect fit runners.

However, I fear that MDF is not a good material for this job.

Any suggestions?.


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## Stick486 (Jan 4, 2013)

Artemix said:


> Hi, I had some "fun" trying to make the sled runners from hardwood, seems like the only way to properly make them is to have a planer/jointer or to make them from plywood/MDF.
> 
> I wasted some hardwood trying to make them, with no success, the wood was not perfect enough to allow me to use my fence, however, MDF is perfectly flat and in 2 mins I could make two perfect fit runners.
> 
> ...


go with UHMW or similar...

https://en.wikipedia.org/wiki/Ultra-high-molecular-weight_polyethylene

it's the stuff cutting boards are made out of... 
way cheaper as cutting boards too...


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## MAFoElffen (Jun 8, 2012)

Artemix said:


> Hi, I had some "fun" trying to make the sled runners from hardwood, seems like the only way to properly make them is to have a planer/jointer or to make them from plywood/MDF.
> 
> I wasted some hardwood trying to make them, with no success, the wood was not perfect enough to allow me to use my fence, however, MDF is perfectly flat and in 2 mins I could make two perfect fit runners.
> 
> ...


I've made quite a few cross-cut sleds... and I've tried a variety of materials for runners. I'm assuming you are taking about 3/4"x3/8" Miter slots or 5/8"x1/4" slots?

MDF is good left being used as interior panels, carcasses for cabinets, millwork, etc.. If you cut then into thin strips to use as runners, they tend to want to separate and split. When MDF is made, it is pressed together form the sides... and when stress is relieved, as when you cut into thin strips, it wants to come apart in thin paper-like layers. Even if it does stay together, it is not very durable and wears out fast.

I've tried UHMWPE... When cut into strips it wants to flex and bend. When I used that, I cut grooves into the bottom of the sled to mount the miter bars into, to keep them straight. To tell you about the experience, I didn't make any more like it. I have UHMW on me fences and I really like it there, but that is in slots in extrusions, so not the same kind of affair.

Once upon a time (years ago) I thought about plywood... but when you cut plywood into strips, relieving the stress in it, it has a mind of it's own. Very few strips will be even close to being straight. And iif it is off by a smige, a PITA to get down that small amount.

Most of the sleds I still make, I use hardwood or metal bar stock. I've had really good luck with metal key stock... It is durable and I can use nylon set scews to make them adjustable in slots. The metal miter bars are handy, because I can drill and tap the bar stock to screw the sled to the bars. (very strong that way)

But hardwood is cheaper and more readily available. I've had the best luck using scrap pieces of oak and maple hardwood flooring. The best one's I have were made from apitong. (but I had some scrap onhand = too spendy to go out to use just for that...)

Easier with a planer... but not required. Look in my uploads for pic's of one on my TS jointer jigs. I make them in 4' and 8' lengths. I use them as a straight line guide for Circular Saws and a glueup ripping, as a jointer guide or to get a straight cut on rough cut lumber... on my cabinet saw or on my jobsite saws.

Easy to make- A 4 foot long piece of ply wood and a 4 foot long piece of 1x2. Screw the 1x2 to the plywood's factory edge. Take your circular saw, with the wide edge against the edge of the 1x2 and trim the plywood. 

You now have a guide with 2 parallel straight edges. If you put a board on top of that with the bow away from the 1x2, the guide with the 1x3 against your fence. You can get a "straight" quality glue edge rip (on your table saw). 

I use another strip of plywood on top of this guide with a few toggle clamps to hold strips of flooring to cut strips for miter slots. It's just a lot safer to do it that way. You never have to have your hands or fingers near the blade... and it comes out with very nice cuts.

Glue-edge cuts on dense hardwood, I usually use a 10' or 12" glue-edge rip blade, 40 tooth. With dense hard woods, I can sand them to adjust the fit. Then I wax them. I make enough sleds (often enough) that when I have hardwood scraps that look like they would make good sled miter bars, I put them on a hself with my other alike stock. When I get enough of that, I set up my saw and cut a number of them (using the same setup)... That way, I have them on-hand later when I get in the mood to build some new sleds.

I've got a planer and planing jigs, but to tell the truth, I've never used them for making miter bars. On some metal miter bars, I have ground some bars down that were too tight (with a 7" angle grinder.) Not as easy to make them looser.

There's other ways I make them also. I tried thin strip jigs, but thin strip jigs are usually for shorter stock. On longer stock... a challenge. On my panel saw, not a challenge at all though (very easy).

Hoping that info helps. If you have any other questions, just ask.


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## Stick486 (Jan 4, 2013)

some tips for using UHMW...

cut it to fit the slot so that slides easily...
under cut the height/thickness by a fuzz...
use ordinary paper, equal numbers of layers on each side, as shims to hold/center the UHMW to the slot.. shim full length..
two layers to a side for a nice snug fit or three layers to side for a tight fit...
install a layer of quality double stick tape to the UHMW...
set your sled in place...
flip the sled over...
drill *FLAT* bottomed counter sunk holes for truss or pan headed sheet metal screws... K-Laths work really well...
this is what they look like...

Phillips-Truss-Sheet-Metal-Screws-Zinc

if you V bottom the hole, when you install flat headed screws the UHMW expands/spreads/moves and things don't fit right any more.. 
ditch the paper shims...
reset the sled..
slides nicely.. great!!!
if not, side the sled back and forth a few times... 
the table will leave a black mark(s) on the UHMW...
use your shoulder plane laid over to shave one or two thousands and test..
keep at it till your love affair begins..

Veritas® Shoulder Planes - Lee Valley Tools - Woodworking Tools, Gardening Tools, Hardware Supplies


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## Willway (Aug 16, 2012)

I use these UHMW runners. I am quite sure you can find them in Argentina, or have them shipped in. I simply lay coins in the bottom of the miter slot and brad nail the UHMW strips in place. Then turn the sled over and place flat head screws in the UHMW strips. This works very well, and I have never had any trouble with the fit.

UHMW Strip 3/4" X 3/8" X 48" By Peachtree Woodworking - PW1121 - Woodworking Project Kits - Amazon.com 

Dick


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## paduke (Mar 28, 2010)

Ditto on Stick
Cutting boards either UHMW or HDPE
Shoulder plane to kiss the tight spots


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## MikeMa (Jul 27, 2006)

I bought a Incra's runner for my sled. It is adjustable for the slot width, and works very well.


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## Artemix (Aug 10, 2014)

Thank you guys for all the feedback!, I've found this wood that is used in construction sites here a lot, and it's considered semi-hard: saligna, it's cheaper than pine and a lot harder too.

About the UHMW, not many companies here produce it, I'm trying to get in contact with a couple of them, no answer yet.


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## Stick486 (Jan 4, 2013)

Artemix said:


> Thank you guys for all the feedback!, I've found this wood that is used in construction sites here a lot, and it's considered semi-hard: saligna, it's cheaper than pine and a lot harder too.
> 
> About the UHMW, not many companies here produce it, I'm trying to get in contact with a couple of them, no answer yet.


it's those knife resistant plastic cutting boards....
kitchen wares department...


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## Artemix (Aug 10, 2014)

I know that in USA you could probably buy UHMW in any kiosk... but here, it's not like that .


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## Stick486 (Jan 4, 2013)

Artemix said:


> I know that in USA you could probably buy UHMW in any kiosk... but here, it's not like that .


you haven't got any stores that cater to cooks and their kitchens???


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## Artemix (Aug 10, 2014)

Sure, but it's not that easy to find the raw material of those.

No worries, I will find it, eventually, or some nice and flat lapacho lath


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## Cherryville Chuck (Sep 28, 2010)

I would not use Mdf or plywood. Like Mike I tried UHMW PE for runners and I took them off. They were too flexible. I had to go with hardwood, namely white birch which is what I had to work with. I don't know what problem you had with hardwood Artemix but persevere. In my opinion it is the best choice where long runners are required.


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## Artemix (Aug 10, 2014)

The problem I had was that I bought a very twisty piece of wood of 1"x1", it was impossible (for me at least) to get a couple of runners from that, using only a table saw.

So, I bought a new piece of wood of 2x1, and I will build a jig like this one: 

https://www.youtube.com/watch?v=vrYjc3G1vgo

In theory, using that technique, I will get a perfectly squared runner.


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## jw2170 (Jan 24, 2008)

*Back to basics.....*

If using hardwood or even HDPE (UHMW) for runners I would use a small block plane to get the final fit.

No need for planer or jointer....


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## Artemix (Aug 10, 2014)

What would be a block plane and how do you use it to make a perfect fit?.


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## Stick486 (Jan 4, 2013)

Artemix said:


> What would be a block plane and how do you use it to make a perfect fit?.


block plane.... the iron isn't as wide as the body...

Lee Valley Tools - Important Announcement

shoulder plane... the iron is as wide as the body or a fuzz wider...

Lee Valley Tools - Important Announcement

side the sled back and forth a few times...
the table will leave a black mark(s) on the runner...
use your shoulder plane laid over to shave one or two thousands and test at the black marks..
keep at it till your love affair begins..

see post #4 of this thread...

have you considered solid aluminum bar???


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## Artemix (Aug 10, 2014)

Oh I see, it's what we call here "garlopa" .

Aluminium bars, no, I didn't try to find those yet, if the hardwood doesn't work I will have to buy something like that I guess.

I'm so blocked making these sleds (need a 90 and a 45 one) that all my projects are as well stopped, sucks.

I just bought some hardwood again, the previous one was not hardwood, I'll give it another try.


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## Stick486 (Jan 4, 2013)

Artemix said:


> Oh I see, it's what we call here "garlopa" .
> 
> Aluminium bars, no, I didn't try to find those yet, if the hardwood doesn't work I will have to buy something like that I guess.
> 
> ...


a hardwood from the ironwood family would work really well...
Brazilian Ipe is one...


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## Artemix (Aug 10, 2014)

Alright, I desist, this is my third 2x1 I try to use to make the runners.. I just can't do it, for some reason my runner is just.. not flat, not even, I measure at some point and I got 18.9 mms <- perfect fit, but I measure at some other point and I get 18.4 <-there is some play, and I measure other part and I get 19.5 <- doesn't even fit.

However, when I do the same cut with a mdf board, I get a perfect fit.

I suspect that:

1- my table saw skills are.. lackluster.
2- the wood I bought sucks.

I will make the runners for now of MDF, at least until I find a place that sells me something like a perfect flat piece of wood.


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## Stick486 (Jan 4, 2013)

Artemix said:


> Alright, I desist, this is my third 2x1 I try to use to make the runners.. I just can't do it, for some reason my runner is just.. not flat, not even, I measure at some point and I got 18.9 mms <- perfect fit, but I measure at some other point and I get 18.4 <-there is some play, and I measure other part and I get 19.5 <- doesn't even fit.
> 
> However, when I do the same cut with a mdf board, I get a perfect fit.
> 
> ...


suspect the wood you are cutting hasn't a straight edge...
make/dress the edge straight using an edge guide and router w/ a panel bit in it...


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## Artemix (Aug 10, 2014)

Exactly, the wood I'm cutting doesn't have a straight edge.. and even if it has one, the other 3 are not straight witch makes my wood to "fluctuate" when I cut it, making an imperfect cut, and a dangerous one too.


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## Stick486 (Jan 4, 2013)

Artemix said:


> Exactly, the wood I'm cutting doesn't have a straight edge.. and even if it has one, the other 3 are not straight witch makes my wood to "fluctuate" when I cut it, making an imperfect cut, and a dangerous one too.


put an edge guide on it and use the router to cur the edge straight...
no panel bit??? use a straight bit...
the use that straightened edge up against the TS's fence...


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## jw2170 (Jan 24, 2008)

Hi Artemix....

It would help greatly, if you could amend your public profile to let us know tools and experience you have.

You either have to have tools to make your timber square and true, or pay extra and buy it that way.


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## Artemix (Aug 10, 2014)

@Stick I will give it a try using the router technique.

@jw profile updated!.


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## MAFoElffen (Jun 8, 2012)

paduke said:


> Ditto on Stick
> Cutting boards either UHMW or HDPE
> Shoulder plane to kiss the tight spots


+1. 
I picked up cutting boards made from for cheap and cut my own strips. Like I said, If you cut them thick, (like others aid) shim them in the slots and stick the top to it with double sided tape... them I mark the bottom of the sled deck. I then route slots in the bottom of the deck to put the top of the runners into.

The reason I do that is that UHMW runners have some give to them. (Even between the mounting screws.) The slots helps stiffen those up.

I also taper the ends of the runners. It helps to get them in the slots easier.

Big +1 --> With Stick on getting a straight edge. (That's why I originally suggested a straight-edge jig.) Getting a straight edge is going to be the biggest parts of all that no matter what material you use. If you had a router table, you could joint a straight edge with the material you have. If you look at my past posts, there a few jigs that I described and posted pictures on, that I use to joint with a table saw. Getting a straight edge is going to be your biggest "goal" whether you are using Hardwood, metal, UHMWPE or MDF.


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## Artemix (Aug 10, 2014)

The cutting boards are not 60+ cms long... they are too short to work as runners.


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## Stick486 (Jan 4, 2013)

Artemix said:


> The cutting boards are not 60+ cms long... they are too short to work as runners.


use two 30's in line...
the secret is the shims and double stick tape...
then the screws... just make sure they are not flat headed screws...

I've used the stuff for too many years not to have learned it's quirks...


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## Artemix (Aug 10, 2014)

Do you happen to have a video of that?, or maybe someone else's video?


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## Stick486 (Jan 4, 2013)

Artemix said:


> Do you happen to have a video of that?, or maybe someone else's video?


video to what???


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## Artemix (Aug 10, 2014)

Of the tehnique showing hot to build it using 2 strips of uhmw. Nevermind.


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## Stick486 (Jan 4, 2013)

Artemix said:


> Of the tehnique showing hot to build it using 2 strips of uhmw. Nevermind.


butt two 30CM pieces inline to make one 60CM long strip.... i

after DST and screws it won't matter if it's three 20CM pieces...
it need not be one single piece 60CM long...


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## jw2170 (Jan 24, 2008)

This is my post on making a sled, as an example.....

http://www.routerforums.com/jigs-fixtures/17843-my-new-sled.html


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## Stick486 (Jan 4, 2013)

jw2170 said:


> This is my post on making a sled, as an example.....
> 
> http://www.routerforums.com/jigs-fixtures/17843-my-new-sled.html


no I'm not..

Artemix is going to square his saw's fence to the miter slot super accurately...
then he is going to lay his runners in the saw's miter slots...
they are going to fit very nicely... if need be he's going to use two pieces in the slot end to end to get the length he needs...
for mounting purposes he's going to shim the runners so that they are proud of table's surface by a fuzz....
then he's going to put double stick tape on the runners..
using the fence as a guide he'll set his sled into place...
He'll remove the sled and flip it over... at this point he'll discover the DST is holding the runners exactly where they need to be...
no mus... no fuss.. 
then he'll drill FLAT bottomed counter sunk holes for truss or pan headed sheet metal screws... K-Laths work really well for this...
ditch the shims...
reset the sled..
slides nicely.. great!!!
if not, side the sled back and forth a few times...
the table will leave a black mark(s) on the runners...
you'll loan him your shoulder plane to shave one or two thousands off of the sides of the runners at the black marks and test..
you'll make him keep at keep at it till your love affair begins..


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## Artemix (Aug 10, 2014)

Thanks for sharing your experience, a couple of hours ago I've finished the runners and base. Since I couldn't find a perfect fit for the slot, nor I could use a raw and imperfect hardwood to make it perfect and "saw fence ready" to cut my perfect fit.. I decided to follow this method:

https://www.youtube.com/watch?v=8D4APbfSRNY&feature=share&list=UUO39zTYpvWL5jx2q15Ma_Hw

However, I still needed at least one perfectly straight edge, well, turns out that I had 18 mms MDF, finished with the same cover that melamine has, it is like melamine but the center is MDF. So, I made a cut at ~10mms, using the hard part of the MDF to fit tightly to the slot edges.

I glued it with super glue, then I put carefully some screws. It made a very tight fit, zero play, however maybe a little too tight to be comfortable to move.

It is dead easy to do, if you want I can take some pictures, so maybe you can point me out some flaws to the design.

I *think* the MDF used that way (coating touching the edges) sort of works as a hard wood.

I need to make a couple more, I will take some pictures and share them with you.

At least this is a method I know I can do .

(Some day I'd like to know how to take a twisted and imperfect piece of wood and make a perfectly 4 sides squared one)


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## Stick486 (Jan 4, 2013)

Artemix said:


> Thanks for sharing your experience, a couple of hours ago I've finished the runners and base. Since I couldn't find a perfect fit for the slot, nor I could use a raw and imperfect hardwood to make it perfect and "saw fence ready" to cut my perfect fit.. I decided to follow this method:
> 
> https://www.youtube.com/watch?v=8D4APbfSRNY&feature=share&list=UUO39zTYpvWL5jx2q15Ma_Hw
> 
> ...


we love pictures...
and can fix anything....


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## Artemix (Aug 10, 2014)

Cool then!, I will take some pictures and tomorrow I will share them here.


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## jw2170 (Jan 24, 2008)

Stick486 said:


> no I'm not..
> 
> Artemix is going to square his saw's fence to the miter slot super accurately...
> then he is going to lay his runners in the saw's miter slots...
> ...


Must have lost something in translation......:sad:


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## RainMan 2.0 (May 6, 2014)

jw2170 said:


> Must have lost something in translation......:sad:


James it must be your Aussie accent aye


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## MAFoElffen (Jun 8, 2012)

jw2170 said:


> Must have lost something in translation......:sad:


Stick was right. It was not him who suggested that.

It was me. I suggested a slot, to add lateral strength, to keep UHMWPE strips straight.


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## jw2170 (Jan 24, 2008)

MAFoElffen said:


> Stick was right. It was not him who suggested that.
> 
> It was me. I suggested a slot, to add lateral strength, to keep UHMWPE strips straight.


Thanks Mike....


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## jw2170 (Jan 24, 2008)

*My bad.......*



MAFoElffen said:


> Stick was right. It was not him who suggested that.
> 
> It was me. I suggested a slot, to add lateral strength, to keep UHMWPE strips straight.



Thanks Mike.......

Now I will have to wait to see who I need to love....


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## Artemix (Aug 10, 2014)

Sorry for the delay!, I'm a software engineer in my "other" life .

Here are the pictures of my first attempt of a sled.

The runners are made from 1/2" MDF with coating in both sides, that creates a very hard surface.

I've been using this sled for 2 or 3 days, I have zero play, the only thing is that for some reason after the glue and screws it became a little too tight, but I think I need to give it time to get soften.


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## Stick486 (Jan 4, 2013)

Artemix said:


> Sorry for the delay!, I'm a software engineer in my "other" life .
> 
> Here are the pictures of my first attempt of a sled.
> 
> ...


MDF spawls under duress as in when you put in the screws...
look for the rub marks abs dress them w/ your shoulder plane......


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## Artemix (Aug 10, 2014)

I see, I didn't notice the marks yet, but I'll give it a try, thanks for the advice.


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## Stick486 (Jan 4, 2013)

Artemix said:


> I see, I didn't notice the marks yet, but I'll give it a try, thanks for the advice.


waxing the top, miter slots and the bottom of the sled will help a lot...
use plain furniture wax that doesn't have silicone or any other additives in it... 
buff out the wax well...


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## Artemix (Aug 10, 2014)

Great advice with the wax!, I didn't have much faith but.. it worked like a charm.


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