1. Designing The Frame in Solidworks
In this part I will cover the basics of how I construct the steel base and test how much force it could handle. So let’s start with the bottom part of our model. I firstly extrude a rectangle and drill 4x 6 mm holes on both sides. A 0.5 mm fillet is applied on the corners and the bottom part is complete. Now let’s make the sides. I drew a 60 x 30 rectangle and extrude it for 20 cm with thin feature. Then I make two cuts on both sides, the first one is 60° and the second is 30%. After that I cut a hole through entire body that will serve as our shaft for the bike. A few fillets and the sides are complete. Last two parts we need to make are two steel pipes each of them extruded exactly to a specific length. So now when we have our parts we can make an assembly and this is where the fun begins. I tried to use as less mates as possible and another tip here for positioning the pipe exactly in the middle of the base is to use an advance mate called width. Lets save the first one and quickly make the second with the shorter pipe. So after finishing making the assemblies we can now test how much of a stress could handle our assembly.
2. Stress test | How much force it could handle
I already applied the material to be steel, add a fixed geometry at the bottom and apply the force of 1000N which is around 100kg (220 lbs) in the downwards position through the pipe. After that create a mesh as fine as your computer could handle and click run. The model that we can see now is the deformed result and we can see with the red color where the maximum stress is. We could add a fillet on the corners to make the model even stronger but the maximum stress is way lower that the actual stress needed to break the construction. Lets find out how much force could handle the model before it broke. 5000 N is still acceptable force but what if we apply 2 tons of force (20000 N). Now the situation is a bit different. We can see the maximum stress the material could handle is in the red zone so the construction is gonna pretty much collapse. So now just for fun I mount our bases to the actual bike and a pair of skies to see how it is going to look like when I finish it.
3. Making the Steel Base Frame
For the frame we are going to need a 60 x 5 mm bar, 12 mm iron pipe and a 60 x 30 mm rectangular profile. I start with cutting the bar to a 26 cm and at first I though I could easily cut it in horizontal position, but I needed to flip it vertically to speed up the process. Next, I cut the pipe and rectangular profile to a needed length and I had to flip the bar a few times to cut it completely because my angle grinder wheel wasn't large enough. Now, make a 60° cut on one side of each profile. I clamp it down to the table to prevent it from moving and I was able to make pretty decent cuts, but It was very time consuming and with 30° angle it would get even worse, so I clamp it in a bench wise and cut it by hand. Yes I know, the cuts wont be perfect but with some grinding later on we could make it pretty damn good. I tried to grind every piece as perfectly as I could and it went pretty well, so lets get outside and weld them together. After welding I tried to smooth and hide every weld as much as I could so they won't be visible after painting. Now, lets drill a 12 mm hole for the pipe. Also don't forget to apply a few drops of oil before drilling to extend the life of any HSS drill. The hole was still a bit too small so with the round file I make it slightly bigger and now we can weld it to a frame.
4. Remaking the Skis
OK the most important part SKIS. So I decided to buy an old pair of 80 cm in length skis that I think will be just right for our skibike. I firstly remove all the screws that were holding the ski bindings in place. After that I file off the holes that were a bit raised up compared to the flat middle area. Now I just drilled 2 holes on each side so the M6 screws could go through easily and I repeated the same process on skis as well. On the other side I countersink all holes with 12 mm drill bit so the head of a screw could hide all the way in. Everything fits together as it should so before appying any paint lets grind, smooth and sand down every surface and clean it with the rubbing alcohol to remove any leftover oil. I firstly paint it with the grey metal primer so the surface coat will last longer and will be more durable on impacts. For the second coat I decided to be a glossy yellow which is gonna match well with my logo on the bike frame. After painting I left them like that over the night and the last thing to do was to secure the skis strongly to the frame with M6 lock nuts and bolts.
5. Remaking the bike frame
In this part I will disassemble the bike, paint it with new color and finally finish it up so we can test it on the snow. So, to start with, we firstly gonna need to remove the wheels, pedals, brakes, chain, practically almost everything so we can later scrap off an old paint and apply the new one. I have used a paint remover which actually melts an old paint so we can easily scrap it of with a chisel or a sharp knife. After I removed the paint I cleaned the surface and applied the metal primer with an air compressor. I wait a few hours for the primer to dry and then apply a new coat of medium gloss black paint. Of course I had to put my logo on it so I have cut a negative out of vinyl on my laser cutter and paint it with the yellow so as the rear suspension spring. On bottom bracket nuts I have welded a pedals that will ensure a strong and non slippery surface to stand on. Last thing we need to cut are 2 pieces of a M10 fully threaded rod that will serve as our rear and front axis. After that I assebled everything back together, apply a few drops of oil and the skibike is almost finished. I have also designed a handle grips and printed them out in a black PLA. On the inside I have used a regular nuts but on the outside I have used the ones that have plastic on one side which prevents the nuts from selfunscrewing because of vibrations. Last thing I have done is that I sharpen the edges and fill the screw holes on the bottom and the skibike is finished.