What category of board is this thing, anyway?

[MysticalDork]

So, a year or so ago, I built my first esk8. It was a hackjob start to finish; oversized motors and battery, janky wiring, ugly DIY fiberglass enclosure, all on a cheap crappy Amazon longboard deck. The 6374 motors meant I had to go dual diagonal, and thus came all the issues with that. Despite all that, I greatly enjoyed the build (when I wasn’t tearing my hair out over it ) and I had a lot of fun riding it.

Then it was stolen. I never got it back.

Fast forward 8 months or so, and I just had to get back on the horse, which leads to this build log. I tried to address all the issues I had with the first build, and I think I did pretty well overall.

Feature list:

6" pneumatic wheels, because the roads around here are crap. Caliber 50 degree 184mm trucks with custom axle extensions to fit the big wheels Custom CNC’d and welded motor mounts Dual sealed sensored 6355 motors from @JLabs 10s4p INR18650-25R battery pack with 80A BMS Custom LED headlight, soon to be taillight as well A cheap drop-through bamboo/ply combo deck, nice and rigid, with good wheel clearance (Still had to remove some extra to get decent clearance) Initially I had dual DIYES Vesc-alikes v4.12, but I ended up blowing the DRV8302s on the maiden ride. I then managed to shoehorn in dual VESC6s, which are gorgeous by the way.

Some photos showing parts as they arrived:

Motors, lens for the headlight, bullet connectors and a big sheet of Kydex:

The LEDs. The long skinny ones are for the tail llight (and possible underglow, we shall see) and the hexagon ones are the high power white for the headlight:

Voltmeter, LED drivers, A RC relay (remote light switch using GT2B 3rd channel), a button (installed but currently unused, planned to be used to enable/disable underglow), and lots of screws and nuts:

Deck!

Thread inserts:

The wheels took some machining to get something that wasn’t monstrously too wide and unwieldy, as well as some custom adapters to allow the standard 8mm(5/16") truck axles fit the 1/2" bearings.

Two-piece hubs as they arrived, with spare batteries to for scale:

After machining:

Front hanger with wheels:

Here you can see the axle extensions I came up with:

Custom LED headlight: Single Cree XHP50 running at 12v and 700mA, with elliptical beam pattern lens. Pro tip: Blue Permatex threadlocker causes polycarbonate to crack:

Designed to mount under the front truck:

I decided to mount the motors behind the trucks because I was a little tight on space underneath:

Many batteries, much danger:

Add one BMS:

Much careful soldering later:

Quick mock-up to see what size cover I’d need:

Thermoformed Kydex enclosure, very nearly too tight to fit everything:

Grip tape:

Near-final assembly (I have since routed a channel for the LED wires and embedded them with hot glue):

It’s not DONE done, but it’s rideable. I still need to figure out some kind of handle, it’s heavy to lug around at around 22 pounds (10 kilos), as well as finishing the tail lights and possible underglow.

Any questions, comments, suggestions or recommendations are welcome!

[Smorto]

Awesome! How did you make that enclosure? Sick build dude!

[Decdog]

I think he used kydex.

@MysticalDork

Thermoformed Kydex enclosure, very nearly too tight to fit everything:

[1Q-Ford]

Great looking build dude👍🏾

[anorak234]

WOW!! This is one hellofa build! You should consider selling your machines wheels as I’m sure they would gain plenty of attention!

[ACIN]

Cleeaan! Two questions: Since you went for the big grippy rubberwheels - what is the torque like? Do you think you found the right balance between torque and speed within your motors, gearing and wheels?

[jga]

Amazing! I also have a couple of questions: . what is the size of the Kydex sheet you used? And how did you manage to heat it up (it does not look it would fit in a conventional oven…)?

• I am interested by the axle extension on your trucks. Can you develop a bit how you did that? Thanks

[MysticalDork]

@Smorto I made a positive mold out of MDF in the shape of the electronics, and a negative mold out of Harbor Freight foam floor mat to push the Kydex into shape around the MDF. I made a frame to hold the Kydex, then stuck it in the oven for a few minutes until it was soft. I then sandwiched the Kydex between the molds and stood on it for about 20 minutes while it cooled. Once cool enough to hold its shape, I used a paint stick and a heat gun to fine-tune the shape and get better definition where I needed it.

@ACIN I’ve been riding it very gingerly, but so far I think it has torque to spare. The gearing results in a top speed around 25mph.

@jga The Kydex was 12"x24" and was just barely large enough. I decided to make a frame for it to keep it from contracting as I molded it, otherwise I think I would’ve run short. It was just big enough to fit in our oven with about 1/2" to spare. The axle extensions are basically just tubes, with a 5/8" inside and a 1/2" outside, The inside has threads at one end to match the skateboard axle, and the outside has threads on the same end to take a 1/2" nut. The opposite end has a little flange to let the bearings sit up against them. Here’s a rough cad model, the final design is a bit different.

[Smorto]

Awesome, do you have pictures of those? Looks like a great way to make a kydex enclosure.

[MysticalDork]

I don’t, sorry. I made a huge mess in the garage during the build and I already threw them away during the cleanup. The foam is only really good for one use anyway, the heat causes it to compress and not spring back. Later I can come up with a drawing or something to clarify, but I’m at work right now.

[wmj259]

What did you machine off the wheel as it looks the same in the not assembled and assembled picture after that, unless that is the final product?

[MysticalDork]

Admittedly not the best angle to see. Basically the hub was a lot wider where the bearings go, so I removed about half an inch of material on each half and then re-bored the bearing seats so they were closer together. I’ll add a better photo and a sketch later.

[MysticalDork]

Here’s a PDF with drawings of the unmodified wheel hubs, as you can see the hub extends quite a ways out past each of the tire flanges. This results in a very stable and strong wheel because the bearings are widely spaced, which distributes forces and minimizes leverage, but means you’d need crazy-wide trucks or extensions. I took off about 1/4" on the inside (towards the truck) and 1/2" on the outside. This gives about 1.45" between the outside bearing face and the inside bearing face, and I made the axle extensions to fit.

@Smorto Here’s where I got my idea: http://www.electric-skateboard.builders/t/thermoforming-a-kydex-battery-enclosure/8642 I did it a little differently, I cut out a hole in the foam that matched the shape of the wood mold, to allow it to take the shape better, and would reduce the force required to compress the foam, since I didn’t build a press and instead simply relied on my own weight.

[MysticalDork]

UPDATE: I took it out for an evening ride to see how the headlight works (It works pretty good!) and as I was coming up the hill to my house, I noticed that it felt distinctly sluggish compared to last time. When I got off, I did a general inspection and found this:

@JLabs you want to weigh in on this? This motor has only seen maybe 10km and no crashes or similar trauma. Any idea where I can get a replacement shaft?

On a brighter note, it appears this board can climb my hill respectably even with one motor disengaged from the wheel, with 40A battery current and 60A motor current (each)

[markyoe]

Where did you find such a big sheet of Kydex?

[JLabs]

I have to say, I haven’t seen that before… I’ll work on gettinf you another shaft and some more set screws. I have a shipment coming soon.

[MysticalDork]

I got it from a seller on Amazon.

@JLabs thanks man! I really appreciate it!

[JLabs]

Yeah no problem, I’ll take care if it or replace the motor.

Please PM me so we can communicate further.

[stealth71]

If you’re in the US knifekits.com carries a bunch.

@MysticalDork Nice build.

[MysticalDork]

Update the wheels I’m using have started to show signs of stress cracking around the bearing seats. I’m planning to replace them with either Psychotiller’s awesome 6x2 SixShooter wheels, or maybe the 7" Evolve wheels.