Modular ECaster Based Otherbord MP1 Caster

Now that my SBX supermod is almost done I was starting to think about making an entire efreebord from scratch without any summerboard parts at all.

Based on the Otherboard MP1 caster. I intend to make a motor mount and wheel adapter that should allow almost any motor size and a max wheel size of 80x40mm.

The Otherboard MP1 is supposed to be a super durable freebord orientated caster.
I already have the motor mount and idler figured out and 3d printed. even my 3d print is strong enough to stand on since most of the weight it distributed directly to the caster. Eventually I will seek out someone to make this part in aluminum. Still needs a lot of work tho.

I am currently figuring out the adapter.
My currant plan is to use the space for the bearing to house the adapter.
Almost all skateboard wheels have a lip the separates the two bearings on both sides.

I am going to cut out a section of this and then insert it into the wheel.

The final design will be based on a shaft coupler but it will have a keyway on the outside as well that locked into the the shaft and the wheel.

For this to work I need a find a suppler for a 8mm shaft with a 3x3mm keyway cut into it or make my own.

next big challenge is the slipring. I think I found the supplier summerboard uses for their SR360.

Hopefully I can get them to make me a custom slipring that I can attach to the Otherboard caster.


Awesome!! I would love to implement all those parts on my freeboard as soon as you figure everything out.


The Leif and the SBX slip rings have the same diameters for all the rings, so if you were going to make the same type of slip ring it would be helpful to keep those dimensions for your version. Unless you see a reason not to.

Lastly if you think DIYing the slip rings from scratch is difficult, on the leif the bushes regularly get pushed all the way down and you have to bend them back to their position. Thats like the same process as making from scratch with diy bent brushes and a pcb. If you wanted to make your design very modular the brushes could be on their own mini pcb then they are all held down by a bunch of screws into a printed base, burn a brush somehow you just swap it with 2 screws and and wire.


Any thoughts on hub motors?

I believe what causes the sbx slip ring to get compressed is the fact that you are standing on them. I want to mount them in a way where they aren’t supporting any weight. This manufacturer has a one piece slip ring that should be perfect for this.


If I can find a hub motor that is spherical shaped and ~80mm without having a shit wattage then I’d be happy but I don’t think such a thing exist. Electric Skateboard Hub Motors Kit - BOUNDMOTOR is the closest I could find and it is still 105mm far to large for my application.

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This is the bearing block mounting dimensions for SBX and Leif.

This comes into play in relation to the slip ring because on the SBX sr360 disk/plate the opening is just wide enough to let the entire caster be removed while the sr360 plate is held in place theoretically.

possibly helpful for service especially if you wanted your slip ring to be constrained separately from the castor.

Part of me bringing this up is I wanted to ask how important you feel the CAM/Caster self-centering is for an electric board with a slip ring? perhaps important enough for me to try making a sbx size/compatible bearing block and cam (including the ability to remove through sr360 center hole as just mentioned)

Which is what it sounds like the deal would be with your slip rings from
grand slip ring co

Slip ring would have a bearing feature standalone is my assumtion from looking at them.

Any thoughts on a 3 gear drive like this?

I forgot to mention I have the CAD model for the JMK Freeskates wheels, I also should mention reports of them failing and causing crashes at high speeds due to heat/core failures. Not sure if adding that printed part you showed and a lot of epoxy can help with that.

Update. Redesigned the whole caster bracket to be laser cut and bend into shape. same process as the original. Since everything is now once piece then it should be stronger and easier to assemble then before.

This design uses a wheel adapter that sits in the core of JMK wheel in place of the brearing. This adapter will get epoxied into place. The flanged bearings are mounted inside caster frame. The adapter will be keyd and this will allow the entire axle to spin freely. Spacers sit between the bearing and the wheel adapter.

Time to test sendcutsend!

Made the caster wider for more wheel options.


Lol I didn’t know about any issues with JMK. If the issues are with the core then I shouldn’t have that problem with overheating since I’m not putting the bearings in the wheel.

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no I don’t think they said the wheel core failure was due to bearings failing (although possible) I think they said the heat built up from the outside of the wheel traveled in and the core eventually snapped.

Worth opening a chat up with Marco Other although he does not like you posting pics like that last one.
The solution they use now is smaller longboard wheels that are lathed for rounded profiles.

When I heard of this I wondered if encasing the wheel core in epoxy + glass fiber would help or hurt.

Interesting. Well I did intend for the caster to be compatible with other wheels so I’ll check that in the future. Lol what you mean he doesn’t like the pic? Is he mad about a efreebord is that I am using his design to do it?

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I saw someone posting about them so I asked for a picture of the cam and I got this msg

btw my thoughts on your interesting choice of bending your castor frame are that its probably cheap compared to buying large alu C channel extrusion and needing multiple CNC operations. My only concern is how accurate the 2 bends will be because that would determine how the drive shaft lines up and if the motor/wheel pulleys are exactly aligned as well. Very interested to see how well your belt survives testing.


Are the flanged bearing temporary? They do lend themselves to a very economic solution as you showed.

I have pondered something like this CNC part

to be used like so on castors and many stuff like this. Anti-specialCNCparts and anti-flanged bearings aren’t I fun.


Damn forgot about this project lol. Yeah I plan to keep the flanged bearings in the final part tho.

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Did you get the part and to what cost/delivery time and would you recommend them? Thickness and material?

Took about 2 weeks. Cost was like $40 per caster but I only ordered one and their pricing decreases with the quantity you order. Don’t remember exactly but I believe I used 3mm stainless 306 or 603.


Finally got back to working on this ecaster.
the original plan was to use a custom made slipring from but after I realized the cost involved in custom making a slipring($150-200) I decided to use some of the old leiftech/sbx sliprings I had lying around. I do still plan to have a custom slipring made in the future once I have verified that all of the caster parts work.

I had a slipring with a broken housing with got me thinking. I could just print a custom housing for it. most of the issues with summeboards sliprings seems to come from when the brushes loose contact and ark/short against the rings. so If I could press the two half’s together in a more reliable way then it should eliminate some of the failures that come from the original design.

The design is inspired by the M1 Otherboard caster. Final version might even be interchangeable with only the fork being different.

I still got to make a wheel adapter and figure out how to lock the wheel/pulley/shaft together in a reliable way. Final design will have a pulley idler as well.

Second Design
This is a hub motor design using the boundmotor 105hub motor.
and this 3way 30A capsule slipring. Hopefully this thing can actually handle the current.

I hope the hub motor design works.

Both these designs were optimized for SendCutSend’s Sheetmetal & laser cutting services.


this appears to have a secondary bearing for sealing the SR360 disk plate, looks slick! totally makes sense why Aaron removed the pegs there, only the wires connect rotationally?

Any chance you want to share the sbx brush PCB CAD file?

I wonder if its worth putting some metal cover over the base/plastic slip ring part.


You should buy a lenght of 8mm axle rod, a xy-vise, good milling bits and a stationairy drill (if you don’t have one). If you want I can show you how to do it.

Btw. Love your autocad work! :muscle::sunglasses: