Introduction: The Ski Sled

Picture of The Ski Sled

If you were raised sufficiently far north I'm sure you can relate to the joy of waking up to snow covering the ground. My favorite thing about the white stuff is the way it decreases the coefficient of friction between the ground and an object sliding over it. In other words, I love sledding! More than likely this love was inherited from my dad, who one year took an old runner sled and fastened some old skis along the bottoms of the runners. When everyone would get together, this "ski sled" was the fastest sled down the hill, but the addition of the skis kept the runners from flexing - meaning it only went in a very straight line.

Ski Sled 1

Several years later, my dad and I tore apart the ski sled and rebuilt it. This second ski sled had a rudimentary steering system, which worked by flexing the fronts of the skis. Although this system allowed for some steering, it was far from perfect. Then two years ago, I took this sled down an extremely bumpy no winter maintenance road. By the bottom of the mile-long hill, virtually every board on the sled was shattered.

Ski Sled 2

Although, this second ski sled was dead, I knew that one day I would build its successor.

Step 1: Design

Immediately after destroying the second ski sled, I began designing the new sled. I had four main design objectives for this new sled. First, its frame would be made from aluminum to ensure that it would be durable, while keeping its weight as low as possible. Secondly, it should turn better than the previous sled. Third, it would have to be relatively easy to build (In other words, I didn't want to have to weld aluminum tubes together). Finally, riding a sled 1 mile down a bumpy road had me intrigued by the idea of adding suspension. Not only would the suspension make the ride more comfortable, but could also improve control through the rough bits.

I designed the sled in Sketchup around these 4 design criteria. For steering, the skis would pivot along their entire length. Tie rods connected between the handlebar and brackets attached to the skis would tip the skis left or right as the handlebar was turned. Although simply tipping the skis will not cause the sled to turn, it was assumed that with my body weight primarily on the rear of the skis, they would twist along their length, introducing a turning action.Steering

For the suspension, it was decided that two control arms would be used to connect each ski to the central frame of the sled. This frame would consist of a central box tube running the length of the sled, with three smaller box tubes protruding from its sides. The suspension control arms would be attached to the front and rear protruding tubes at points close to the central tube. Small, bicycle shocks would be placed between the ends of the control arms and the ends of the protruding box tubes.

Suspension Design

I decided to use wood for the decking and handlebar. There were two reasons for this. First, using wood made the construction of the deck relatively easy. Secondly, I wanted the finished sled to have a classic look (think an old-time Flexible Flyer sled).

Design

I can't stress how important a full 3D model was to the success of this project. Not only did it eliminated all of the guesswork in knowing if the suspension and steering would freely move through their entire range of motion, but it provided an accurate guide for fabricating each part of the sled.

Step 2: Preparing the Center Box Tube

The core of the frame was constructed from a 3' long 1.25" x 2.5" aluminum box tube of 1/8" in thickness. Several holes were cut in this box for mounting of the handlebar and the perpendicular protruding box tubes.

After drilling a 1/2" hole for the handlebar pivot bolt, a notch for the handlebar to rest in was cut from the end of the box. I cut the sides of this notch using a hacksaw and then drilled closely-spaced holes along the bottom edge, which allowed me to easily break out the notches on both sides of the box tube. Once these aluminum pieces were broken away, the notch was smoothed and squared up using a file.

Cut Handlebar Notch

Smooth Handlebar Knotch

The trickiest holes were the three square holes which needed to be cut through both sides of the box. The perpendicular box tubes would be slid through these holes and bolted into place. I drilled two large (~3/8") holes in adjacent corners of each of the marked squares. By dropping a jigsaw into these holes, I was able to connect the holes and roughly cut out the squares. A file was critical to smoothing out these rough squares so that they would perfectly fit the 1" x 1" box tubes, which would be slid through them.

Cut Square Hole

File Square Hole

Step 3: The Perpendicular Box Tubes

The perpendicular box tubes protruding from the sides of the central box were made from 1" x 1" aluminum box. I recommend using a stronger alloy of aluminum (I used Al 6061, vs. the more commonly available Al 6063), as there is considerable stress where these boxes pass through the central box.

After cutting these tubes to length, 1/4" holes were drilled vertically through all three boxes for mounting the decking. 5/16" holes were also drilled in the sides of the front and rear box tubes for mounting the control arms and tops of the shocks.

Finish Holes in Box Tubes

To allow the shocks to attach to the ends of these box tubes, a small notch was cut from the bottom ends of each box.

Notch Ends of Box Tubes

After cutting these notches, the bottom edges of the sides of the boxes (adjacent to the notch) were beveled slightly by cutting away the corners with a cutoff disk.

Bevels on Ends of Box Tubes

Step 4: The Control Arms

The control arms were made from a 1" x 1.5" aluminum box tube. Since the top of each control arm needs to be open to allow it to attach to both the frame and shock without interference, 1/4" was cut off the top of each box to form a 3/4" x 1.5" U-channel. Ideally I would have purchased a 3/4" x 1.5" U-channel, but this was not available from my metal suppliers. I drilled the 5/16" holes for mounting the control arms to the frame and shocks before cutting the top off the box tube to ensure the aluminum did not bend during drilling.

Start to Cut Off Top of Control Arm Box

Finish Cutting Off Top of Control Arm Box

With the top of the box removed, the next step was to cut deep notches in the ends of each control arm. These notches allow the control arm to mount to both sides of the perpendicular box tube at one end, while straddling the width of the shock at the other end. After cutting the sides of each notch with the hacksaw, the bottoms were cut using a cutoff disk.

Cut Notches in Control Arms

Four identical control arms were prepared and are presented along with their associated mounting hardware in the image below.

Finish Control Arms

Step 5: The Shoes

Four small shoes were prepared for mounting the frame to the skis. These shoes were made from some 2" x 2" aluminum box tube that my father-in-law had left over from a fencing project. After the shape of the shoes was cut from the box, 5/16" holes were carefully drilled through them from mounting to the lower ends of the shocks and control arms.

Box Tube for Shoes

Large Hole in Shoes

Smaller holes were also drilled in the bottoms of the shoes for mounting to the skis. Note that three screw holes were made in the rear shoes, while only two screw holes were put in the front ones. Since the skis are considerably thinner at the location where the rear shoes attach, the extra screw was added to ensure a secure connection.

Step 6: Assembling the Frame

With all of the frame components prepared, I was ready to assemble them. The frame was assembled according to the sketchup design presented below.

Assembled Frame

Once all of the aluminum bits were sanded to smooth out any surface imperfections, I slid the 1" x 1" box tubes through the square holes prepared for them in the sides of the central box tube.

Slide Tubes into Center Box

When I prepared these 1" x 1" boxes I did not drill holes in them for mounting to the central box. I wanted to first align them in the central box and then use the holes in this box as guides for drilling these holes. By measuring side to side, and using a speed square, I was able to ensure the 1" x 1" boxes were perpendicular and centered relative to the central box. Once I had this position nailed down, I drilled the 1/4" mounting holes through the 1" x 1" boxes.

Drill Box Tubes Through Center Box

After bolting the perpendicular boxes to the central box, I proceeded to bolt the tops of the shocks to the frame. I used shoulder screws for these connections as well as all of the other suspension connections, which are required to pivot freely.

Fasten Tops of Shocks

With the tops of all four shocks mounted, I mounted the control arms to the frame. Once again, shoulder screws were used. Washers were used to fill the gap between the sides of the control arms and the 1" x 1" boxes. I just kept adding washers until there was minimal side to side play.

Attach Control Arms to Frame

With the control arms and shocks bolted to the frame, their bottom ends were jointed to the shoes for mounting to the skis. Once again, shoulder screws and washers were used for these connections. It should be noted that I applied a small layer of grease to the shaft of each shoulder screw to help lubricate each pivot point.

Connect Shoes

Step 7: Prepare the Wood

The handlebar for the sled was made from a piece of 1" thick cherry. After planing the cherry to the correct thickness, I cut out the shape of the handlebar using a jigsaw. The edges of the handlebar were smoothed using a 1/4" round-over router bit.

Cut Wood for Handebar

Two pieces of 1/16" thick aluminum were cut to fit the top and bottom of the handlebar. These aluminum plates add strength to the handlebar where it attaches to the sled and also provide a smooth surface for where the handlebar pivots inside of the central box tube.

Cut Aluminum Plates for Handlebar

Holes were drilled through these aluminum plates for both mounting to the handlebar (the 1/4" holes) as well as for the 1/2" pivot bolt.

Drill Holes in Aluminum

A vise was used to hold the plates in place over the handlebar and these holes were continued through the wood.

Drill Holes Through Wood

With the holes drilled completely through the handlebar, the plates were bolted to it using two 1/4" screws. Next, two angled holes were drilled for the bolts, which would be used to support the tie rods used to tip the skis. Previously-drilled holes near the ends of the aluminum plates were used as guides for the location of these holes on both sides of the handlebar. I began by drilling the angled holes approximately half-way through the handlebar from the one side. Then, I flipped the handlebar and completed the holes from the other side. This method ensured that the completed holes were at the correct angle through the handlebar.

Drill First Side of Angled Hole

Finished Angled Holes

With all of the holes drilled, the completed handlebar was mounted to the frame using a 1 1/4" long shoulder screw. As with all of the other pivot points, the shaft of this screw was greased. I also applied some grease to the surfaces of the aluminum plates so that they would slide smoothly inside of the notch in the central box tube.

Mount Handlebar to Frame

Step 8: The Deck

The decking was made from a single 1" thick board of cherry, which was cut in half to form two thinner boards. A table saw was used to cut half-way through the board vertically. Then the board was flipped and cut again to create the two thin boards.

Cut Board in Half

Although this method resulted in two remarkably smooth boards, both boards were still planned to around 3/8" to remove any surface imperfections.

Plane Deck Boards

Next, the deck boards were cut to length with the ends being angled slightly. At the rear of the sled the central box is slightly longer than the side rails. This angle on the ends of the deck boards creates a nice transition between the side rails and the end of the central box.

Cut Angles on Deck Boards

With the deck boards cut, they were aligned on the frame and the position of the mounting holes were transferred to them using a hand drill. I then used my friend's drill press to finish up all of these holes in the deck boards. With these holes drilled, both deck boards were bolted to the frame using 1/4" screws.

Drill Holes in Deck Boards

Two 1" x 1" side rails were also ripped from a 1" piece of cherry. After rounding the edges of these rails with a router, I aligned them onto the frame, marked the location of their mounting holes, and drilled these holes through the rails.

Prepare Side Rails

Drill Holes in Side Rails

All of the wood on the sled - including the handlebar - was finished using danish oil. I initially was going to use a finish like polyurethane, but given time restraints I decided to use oil instead. In the end I think this was a better option as the wood will be exposed to a lot of moisture, which could work its way under a hard finish. The oil may not hold up as long, but I can easily re-apply oil at any point in the future.

Step 9: Mount the Skis

My friend found some old 135cm skis in his shed. Not only were these skis the perfect length for my sled, but they had a sidecut to them, which I thought would help with the steering. I positioned the skis under the shoes on the frame and marked the location of the mounting holes onto them.

Position Frame on Skis

Next, I drilled pilot holes in the skis for the mounting screws to thread into. I wanted these holes to be as deep as possible without drilling through the bottom of the skis. To make sure I didn't drill too deep, I wrapped a piece of masking tape around the drill bit at the correct depth. Once the masking tap began brushing the surface of the ski, I knew the hole was the correct depth and I stopped drilling

Drill Holes in Skis

With the skis prepared for mounting, I painted them red. I like red skis as it reminds me of old-time flexible flyer sleds. You'll notice that I also painted a set of straight 135cm skis that I have - although I have yet to try them on the sled.

Paint Skis

After the paint dried, I cut the mounting screws (I used #14 stainless wood screws) to length and attached the skis to the frame.

Attach Skis to Frame

Step 10: The Steering

With the skis attached to the sled, it was time to finish up the steering system. First, I cut the two brackets for mounting to the skis from a sheet of 1/16" aluminum. I drilled a 1/4" hole through each of these pieces close to their one end.

Cut Aluminum for Steering Brackets

Next, I used my bending brake to bend this sheet into the final u-shaped bracket. As you can see, I was barely able to make the second bend with my brake. Notice that I've also drilled two small holes in the bottom of the bracket for mounting to the skis.

Bend Steering Brackets

Once the brackets were bent, I used the hole in the one end of each bracket as a guide to drill the hole in the second side of each bracket. Obviously a drill press would be ideal for this, but I don't currently have one at home so I did it carefully by hand.

Drill Second Holes

These steering brackets were mounted to the front of the skis using the same technique and screws that I used for mounting the skis to the frame.

Attach Steering Bracket to Skis

Moving to the handlebar, I inserted two 3" long 1/4" screws through the angled holes. I used countersunk washers and screws with countersunk oval heads to account for the angle where the screw heads contact the handlebar. Inverted lock nuts and countersunk washers were used to fasten the bolts into the holes on the top side of the handlebar. Additional inverted lock nuts were added close to the ends of the screws. These nuts would be used to fasten the inner tie rod ends.

Install Angled Screws

I fastened tie rod ends to both of the steering brackets using a 1/4" bolt and many washers. These tie rod ends have a 1/4" female fine thread socket for attaching to the tie rods.

Fasten Tie Rod Ends to Brackets

With the tie rod ends attached to the brackets, the tie rods were threaded into them, the inner tie rod ends were attached to the rods, and then these rod ends were slid over and bolted to the tilted bolts.

Install Tie Rod

Step 11: It's Testing Time!

With the sled finally finished, I took it out to some no winter maintenance roads in Pennsylvania and Vermont. On our first day of testing, we learned that the skis had a tendency to flip up-side-down during turning.

Flipped Ski

To fix this, we made some small aluminum stops, which would prevent the skis from tipping beyond approximately 30 degrees.

Stops

This worked well for a few runs, but eventually the stops ended up bending and breaking the very thin control arms they were attached to. I re-built the control arms out of thicker aluminum and with integrated stops to prevent ski flipping.

Broken Control Arms

With the control arms fixed, my wife and I made the 6 hour drive to Lincoln Gap in Vermont. This time everything held together beautifully and I was able to record a maximum speed of 34 mph! However, the sled had a tendency to catch the edge of the outside ski when coming out of a corner. I felt like it was trying to toss me off the side - although it was never successful. I determined if I could always keep the skis in a negative camber configuration this situation would be avoided.

Negative Camber

After receiving a final late winter snow storm, I tested this negative camber configuration on a mountain close to home. It worked as expected; I did not catch an edge and the sled still turned acceptably. The steering is still not quite as sharp and responsive as I would like, but that gives me something to work on for next year. Be sure to follow me here on Instructables or on Youtube if you want to find out how I end up improving this sled in the future.

Comments

Gadget Man 656 (author)2017-03-27

Could you provide measurements of your sled, and pictures of the build as you go. Where did you get the springs at, and what is the strength of them

makjosher (author)Gadget Man 6562017-04-04

At this point I haven't put together detailed drawings - although I hope to be able to provide that for future designs. I would recommend downloading the sketchup file and looking at that if you are interested in the dimensions I used (of course you'll have to download sketchup, which is free: https://www.sketchup.com/download) I purchased the springs on eBay for around $8 a piece. They are just cheap rear bicycle "shocks" from China (400 lb/in spring rate). I say "shocks" because there really is no damping, just a spring. I would have liked a slightly lower spring rate, but this was as low as I could find. I'd love to use air shocks in the future - assuming I can afford them :-)

clintg20 (author)2017-04-04

MATE YOU HAVE PUT SOME WORK INTO IT

makjosher (author)clintg202017-04-04

Thanks! As many of my projects are - the idea is simple but the execution is much more difficult. That's a bummer that you don't have snow though.

clintg20 (author)2017-04-04

I AM FROM AUSTRALIA
NO SNOW

SCHLEPIC (author)2017-03-31

Well done! It looks like a wicked good time.

makjosher (author)SCHLEPIC2017-04-01

Haha. It is! I just wish I had some steeper hills closer to home.

yaşara7 (author)2017-03-29

it s really nice but i m concerned about the ropes ?

makjosher (author)yaşara72017-04-01

Thanks, but please elaborate?

MTKapp27 (author)2017-03-28

Incredible!!! Amazing Instructable. I did not read this whole instructable yet, but i did not see a break.

makjosher (author)MTKapp272017-04-01

Thanks man!

Lardo (author)2017-03-27

Why won't the PDF open? I click on the PDF "download" button, and get nothing.

makjosher (author)Lardo2017-03-27

I'm guessing you mean the skp file? If you don't have sketchup you probably will not be able to open the design file. You can download sketchup for free at: https://www.sketchup.com

Lardo (author)makjosher2017-03-27

Nope. The SketchUp file I got. It's the PDF of the instructions that won't download.

makjosher (author)Lardo2017-03-27

Ok, I see what you mean now. The pdf downloaded fine for me, but hardly any of the pictures came with it. The reason for that has to do with the way I formatted this Instructable. Since I embedded most of the pictures from another site, they aren't showing up in the Instructable pdf download. I would recommend using a pdf printer to print the Instructable to a pdf file.

schreib (author)2017-03-26

Fantastic Job. other comments ably do justice lauding you for your stature as a designer and presenter. Something new possibly:
-- keep in mind you gotta stop, especially when going fast towards an oak tree! Suggest a knife type drag keel actuated down into the snow at heels of runners. plus wear a helmet!
-- It has been years since I downhill skied but as I recall to make a turn . . . it is a process by which one lifts up the entire body a tiny amount to allow pivoting both skiis just above the snow to re-orient them to a new angle. Doing so will be very hard with a platform under your torso where you have no ability to use your body to significantly create a downward force. You can't take the weight off the sled like you can by flexing your legs or hopping a bit with normal skiis. However, What comes to mind is a way to momentarily press some object down into the snow while a mechanism allows a central pivoting action. It would require very quick action and very minor angle adjustment in order to prevent excessive drag and loss of control.
-- an alternative to this is reconsider the entire flat runner idea. It started out good through your Dad's initial design and your latest work but to advance you may have to AGAIN think out of the box. What comes to mind is going back to flexible runners but with wider bases(ski like) and made of carbon fiber or some composite. Remember, money is no object here! You may even consider going to your local university's mechanical engineering dept and ask them for free consulting assistance. Offering them an opportunity to turn this into an undergrad design class project etc.
-- It would be nice to know what you think of Sketchup vs traditional CAD. I still use an OLD version of Vectorworks on my OLD MacBook. Been looking for replacement for years that is less than $1000.

makjosher (author)schreib2017-03-27

Thank you for the comment and the suggestions. I'm intrigued by your "hopping" sled. :-) Interestingly, there are actually sleds used in the German-speaking parts of the world, where you actually press on the snow with your hand to apply more weight on your outside runner, which forces a sharper turn. I know that's a different configuration than what you are talking about, but you're idea isn't perhaps as out there as you'd think.

As for Sketchup vs traditional CAD software. I have used Autocad as well as Solidworks and I will say that traditional CAD software is far superior to Sketchup when it comes to easily creating accurate, tool-ready designs. Where Sketchup excels is for more basic geometries (think houses or cabinets instead of machined parts). Sketchup is easier to learn than most CAD programs and you can still create complex geometries, but it will be more difficult to create them. Basically, if you're drawing houses or bookshelves I'd recommend Sketchup. For something mechanical (like this sled) I would recommend a traditional CAD program. Hopefully that helps. As an alternative, I'd recommend checking out Autodesk Fusion 360. It's free for hobbyists and is supposed to be more robust than Sketchup. I have it, but haven't taken the time to learn it yet.

theojt (author)2017-03-26

Very cool design, but I feel obligated to recommend some tweaks. Having been an adventurous type in my youth, I have hit more than one tree while sledding down as fairly steep grade through the woods near our home. Don't assume everyone will be sledding out in open fields.

Future iterations should (as already noted below) move the control mechanisms under the top plate so no screws or hardware can protrude. If possible, go with lower profile brackets to mount the controls arms. Use roundhead bolts with no slots wherever possible. All square corners on the aluminum parts should be rounded minimally, and reduced in height if possible. Basically, eliminate or minimize any and all possible human contact points - even if they don't appear to be possible contact points.

I am not a designer but I have my share of sledding accidents with the resulting pain and damages prompting my inputs.

Good luck, we'll be anxious to see future designs.

makjosher (author)theojt2017-03-27

Thanks for the suggestions. I agree 100% on trying think about potential safety hazards during the build. I know there are still some hazards on this sled and I'm sure I will be addressing them in my future designs.

relbatto (author)2017-03-26

great sugestions offered in a warm and freindly manner, this has great potential and is definitely going somewhere. cant wait for the inevitable sequel of open sourcery three point .2

makjosher (author)relbatto2017-03-27

Haha. Of course there will be a sequel. I'm already thinking it through :-)

JoeS94 (author)2017-03-26

This is the absolute coolest design ever. When i was a kid, we would ride our sleds down a one lane gravel road above my house. Because it was gravel and somewhat steep, the runners of the normal sled became bent and the sled broken. This design is sheer genius. I so want to build this now. Great job, shows a lot of work, design, and creativity. Love it!

makjosher (author)JoeS942017-03-27

Thanks man! I'm glad you're inspired. Go for it!

curiosity36 (author)2017-03-26

Congratulations on a great project. All done without the aid of high-tech tools too! Pass along a big high-five to your dad for being part of your dreams.

Might I suggest some sort of rod on each side that would prevent fore & aft movement of the skis. Somewhat like a Panhard rod or mechanism on an automobile. Might relieve a lot of stress on the suspension attach points - which currently take up much of those forces.

Great videos too. Wasn't that drop off on your left a bit scary on you maiden flight?

Wishing you continued success. Thanks for posting.

makjosher (author)curiosity362017-03-27

Thank you! I will keep your suggestions in mind for next time. I wasn't too concerned about the drop off - it really wasn't quite as steep as it appears :-)

TK Trooper (author)2017-03-26

One word .... "Kickstarter"!

makjosher (author)TK Trooper2017-03-27

Haha. Thanks man! I'll keep it in mind if I feel I get it tuned properly.

TK Trooper (author)makjosher2017-03-27

I sincerely hope you do, great design and something us bikers can enjoy in the winter when the motorcycle is hibernating.

betwys1 (author)2017-03-26

Detailed Design Fixes.

The angle screws are a design weakness, arranged to catch on YOU if you slide
off. So it's better to arrange the bracket underneath, and fold it from
sheet aluminum UNDER the steering bar: stronger and safer. Loved the use
of stepped screws. Better to have a wood slat over the center spine - it's warmer!

makjosher (author)betwys12017-03-27

Points taken. I have addressed some of the issues with the location of the tie rod mounts. I didn't notice getting cold from the center rail - perhaps I had a bit too much adrenaline in my veins at the time :-)

Toga_Dan (author)2017-03-26

I'd like to see the steering mech kept below the deck. Sooner or later, the sled will stop while rider continues on.

makjosher (author)Toga_Dan2017-03-27

Yea, I knew it was a risk from the outset. I've since changed it (note last picture) as I didn't think there was any benefit from that arrangement.

4DIYers (author)2017-03-25

Awesome work and idea!

makjosher (author)4DIYers2017-03-27

Thanks!

mtairymd (author)2017-03-25

Nice job with the design and documentation. The filming with the drone was awesome. I was wondering about the snow in PA since it was a no show about 200 miles south of you in Maryland :).

makjosher (author)mtairymd2017-03-27

Thanks! We didn't get a lot up here until around 2 weeks ago. Still, it wasn't a terrible winter - I feel your pain.

MACCUBBIN1962. (author)2017-03-27

The tie rod assembly connections on the skies in the front could really do some damage to the driver, very dangerous!

fschill1 (author)2017-03-26

I think this sled is awesome. I was wondering if you used 4 skis, where the rear skis would bear the load of the sled and the rider and the front skis would do the steering. If they were mounted to a cross bar via a rod passing vertically through them, that would allow the front skis to actually turn instead of flexing. Just a thought.

makjosher (author)fschill12017-03-27

You could do this. I wanted to solve the issue of with two skis as I find it much more elegant. Companies like hammerhead sleds use 4 skis and have very good results. Thanks for the kind words!

cdavenport (author)2017-03-26

Would lengthening the design add to its stability (to keep it from trying to throw you off) without compromising its maneuverability? I've got a grandchild coming; this would be a great ride when she is 25 or so! LOL!

makjosher (author)cdavenport2017-03-27

I would think that would increase the stability, but it would probably come at the cost of some maneuverability. I'm going to put up a video in the next few days showing how I fixed the issue of it trying to throw me off. Go for it - these things take years to perfect!

ee_eng (author)2017-03-26

Great project & really good video's!

Rarely is a design perfect first time. I really liked your videos that showed your early tests followed by iterative improvements. I did notice that as Toga_Dan commented, your videos showed that you had already moved the steering links to a below deck approach - a good safety improvement. You might want to consider using heavier (aka: thicker walled) channels as this would give you greater strength, increased design margins, and the ability to handle larger payloads (bigger people).

Again, excellent videos and graphics.

Take care and keep up the good work.

makjosher (author)ee_eng2017-03-27

I'm sure you noticed that I did end up breaking quite a few pieces due to insufficient metal strength. I've replaced some of those pieces with much stronger pieces, but you are right that they are probably still a few weak points. I'll keep this in mind. Thanks.

trimbandit (author)2017-03-24

What an awesome project! I have so many great memories of bombing down our rural road as a kid on my flexible flyer. How would you say the control and stability compares to a traditional runner sled?

makjosher (author)trimbandit2017-03-24

Thanks. I'm glad you like it. I would stay stability-wise this thing is rock solid. With it being over 24" wide it really seems impossible to flip it. Steering (control) I would put at about the same level as a flexible flyer - although it still isn't quite where I want it. I'm able to shoot into switch-back like corners at around 20 mph and come out the other side, but I'd really be more comfortable if that number was closer to 30 mph. The major advantages on the runner sled are the flotation in powdery snow and obviously the suspension.

RichL34 (author)makjosher2017-03-26

Have you tried or even thought of machining or somehow applying some small "V" shaped ridges, possibly one or two, length-wise down each ski ? That should add some stability to aid the sled in maintaining a straight path instead of a totally flat plate contact plane as you have now.

makjosher (author)RichL342017-03-27

The way I have it set right now, the ski is in a negative camber position when running in a straight line. This allows the metal edge of the ski to grip the snow - essentially doing what a "v" shaped ridge would do. Thanks for the idea though!

trimbandit (author)makjosher2017-03-24

Thank you!

skrubol (author)2017-03-26

You mentioned an angle grinder and aluminum. Grinders with abrasive wheels (other than specialty aluminum specific wheels,) should NOT be used on aluminum. Aluminum will clog up the wheel and ruin it, or worse can make the wheel shatter. This goes for angle grinders, bench grinders and abrasive chop saws.

You can get away using a table saw, miter saw or other circular saw normally used for wood on aluminum with the right blade. They typically run a bit too fast for aluminum though, so the blades won't last too long if you can't reduce their speed.

Milling machine and a carbide chop saw would be the best tools for doing the cuts you did. But if your options are an angle grinder and a hack saw, the hack saw is by far the better tool for the job.

makjosher (author)skrubol2017-03-27

Agreed. For aluminum I prefer a hacksaw in general as I find it much more accurate. Plus it makes less of a mess.

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Bio: As long as I can remember I've been building stuff. I think it's high time I shared these projects.
More by makjosher:A Better Rocket BoatMetal Gift BoxHow to Solder Copper Pipe
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