Because sprockets are widely used in industry, it is usually easy to obtain the CAD drawings for whatever chain type you want.
for example :
And their shape and flatness are good matches for laser or waterjet cutting, which is quite affordable and easy to get done locally. Typically much cheaper than CNC
That is clear. I was talking about 219 chain and needed dimensions. Did You already tested 219 chain?
Iam little afraid to covering chain. If You would like to use it, You must be clear that You will check extension of chain. So You will change chain befor will be break and block gears in cover.
Just remark. Custom sprocket for cart chain 219 type if fckn expensive:( I made drawings and received few offers. Price was include motor mount on gear drive level 
Would you mind sharing those drawings here? Iām really surprised to hear they were so expensive to manufacture. I wonder if the likes of @SabreDynamics, @moon or @Savage1 could advise on whether youāre being ripped off or if your design could be optimised for manufacturing cost.
Sure, design can be tuned to be cheaper, like remove of chamfer on pinion etc. I have price from local suppliers. I already asked on Alibaba some asian companies but Iwas not able find somebody with good reputation willing do so small series. Effort which i must invest to this activity is not equal to situation , that You can buy 06B or other most used chain sprocket common avalible on market.
Bellow pictures from 3D printed prototypes. In case that I will be an owner of cnc machine , maybe it will make a sense:)
I bet the expensive part here is in the motor pinion, not in the sprocket. Sprockets can be laser or water jet cut out of the right thickness material and then you have to sand the edges a bit on an angle to make the teeth more chain friendly. Thatās a 5mn job. Iād expect the sprocket to be around $10-30 each in small batches.
Pinion is more complex to produce, and Iād expect that to be quite expensive indeed, but it should be available already as is from AliExpress or similar. Or is that a crazily exotic chain type that no one in the world uses? Or do you have exotic requirements in terms of bore that make the available ones not compatible at all?
Appropos of nothing I have had this link in my list forever.
I have to admit Iām kind of turned on by the idea of a dual-chain sprocket 
I CNCād my sprockets out of Delrin, they work great.
Originally I started with a steel drive sprocket and wore it out way too quickly. Once I switched to Delrin, a couple of years on - Iām almost due for a new set. If I had dual Delrin I bet it would go forever.
Is it really necessary though? I feel like thatād only add extra drivetrain resistance and weight since the strength of the chain isnāt really a limiting factor. Even the thin #25H (04C in ISO) chain has a tensile strength of over 1200lb, which seems overkill even for a single drive.
H25 is definitly not enought for 3,5kW motor. Check pictures on Top of this article. The same result You will have if You will do calculation. Statis and dinamic strength are two different factors. Also people who are using H25 can let You know.
You are right. 219chain is used mainly in go cart also I saw it on some electric bikes. Main issues is pinion. Sure the shape can be more simple then on my picture. But finally : if You use the same diameter for B06 sprocket and 219 sprocket + the same center distance of both , as Iam remember correctly on my old calculation You will save around 8% of weight for 8 or 10 time higher price.If Iam wrong and You will save 20% of weight, it is still not affordable. Believe me, my target was to sell some parts and I really invest huge amount of hours to check it.
I mean Iāve been using #25H for over a year now, no problems even with 3.5kW motors. The charts above donāt have the H version, which uses thicker links and are nearly twice as strong as regular #25. You get to use way higher gear ratios with the smaller chain, Iāve seen single reductions as high as 1:7.
That is a point that You Used thicker version. With high gear ration. Also Your weight and riding style is very important. I know person which ride 06B and must replace it after 6 months.
Anyone come across any #25 sprockets available for kegel wheels?
You were quoting the stronger chain with the H designation, so Iām not sure what youāre getting at when youāre talking about a thicker version than that.
Sorry my mistake. I was thinking that is something additional. H25 is equal to 05B and H35 is equal to 06B. I was thinking that You are talking about some thicker H25 with strength same as 06B. Iam not familiar with USA standards:( Use chain according Your needs and setup. I need robust design transition system for Mountainboard , and Iam heavy so for me it is clear. When I made calculations for 3,5kW motor 25H was slighli bellow safety line.Mean not enought. So Yes, for somebody it can work perfect. Anyway on university in this case, we chose from safety reasons each time mere robust solution. So definitely it is not overkill for most riders of Mountainboard with 3,5kW motors ore more
I think Iāve seen ANSI #25 cross referenced as ISO 04C, it seems like the link distance is the same and the sprockets are interchangeable.
That is new for me. Thanks.
Not even vaguely (at least not with my relatively under-powered board)
