New build project scrub psycho. 05B chain and sprockets focbox unity twin sk8 6374 192kv 4400w

ESK8 Builds
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After watching tons of videos and researching the crap outta this forum I’ve decided to start my eskate mountain board build. The aim is to custom make as much of the parts as possible. I’ll upload photos and updates as I go. IMG_20190215_163751 IMG_20190216_075743 what my build will include (as of now, but changes daily) Twin sk8 192kv motors - hobbyking (purchased) Gearing 8mm chain and sprockets (57T and 11T) purchased Psycho 2 kite /Beach board(purchased) Unity vesc (purchased) Lipos two 6s(16000 or 20000 Mah) Various little things off ebay like lipo voltage alarms from China

So far I’ve machined two sprocket carriers to fit to the wheels. Bored the sprockets to fit and made a set of bash guards for each wheel sprocket as they’re 155mm diameter and my wheels are 200 so I wanted some protection so I don’t bottom out my sprockets on kerbs and riding offroad. Next I plan on fitting all this together then start designing my motor mounts on master cam to cnc Mill them out of aluminium. Also Mill two slots in my trucks to locate the motor mount to. I’m a precision engineer so I have full workshop access to the latest hurco Mills and a variety of cnc lathes and a router room to use as needed. We work with metal and plastics so I’m lucky enough to source all my material from offcut bins. Am considering machining a board aswell but will see if that comes about.

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Where did you get the sprockets from? I’m trying to get 06B for a dual drive build

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Beltingonline.com delivery was really quick. I decided to go 05 because although 04 is fine I decided bigger is always better. Just bear in mind the sprocket dimensions as the bigger sprockets with 06B may be larger or very close to your wheel diameter. Also an important note is the drive sprockets 8mm bore sizes (if you have an 8mm shaft on your motor) is a sloppy fit. 8.15 so Im going to drill and tap 4 locating holes in my sprockets so I can run them perfectly concentric.

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I was using sprocketsandchain.co.uk or something and they had 8T 06B bore sprockets with 8mm bore otherwise I would have 08B chain (the biggest I can fit)

Would it be better to get something with 6mm bore and rebore it myself?

It costs the same to ship to here as the cost of all the hardware itself…!?

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Yes for sure if you can get 6mm bore and open it up to 8mm youl get the perfect fit. I didn’t know the fitting was going to be so poor until I received the sprockets. Maybe you could message the supplier though and ask them to measure the bores before they send them out, as they seem to be hit and miss… I ordered 4 small sprockets in total. One was 8.02 perfect fit. And the others were crap on bore size. Just make sure you order the sprockets with the journal rather than flat plate wheels so you have something to hold on to if machining yourself :). I was going to use sprockets and chains but they wouldn’t accept card payments and didn’t reply to email so found another company.

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be careful with the sk8s. make sure you use the copper (or brass or whatever it is) sleeve over the shaft like so. it keeps the can from falling off b4f6cbf375a23b8d80463e12cee1a27532b2d3de_1_472x500

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Instead of adding 4 screws, would it not be easier to bore out the sprocket a bit more and then create an adaptor, something like 8mm to 10mm to fit the sprocket. I’m just assuming you have a lathe due to the large bit of (abs?) or Pom stock

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Thanks matt yes I read a few comments on that. Thanks for the heads up. Pat Yes thanks for the suggestion. that’s something I thought about too. Boring the sprocket larger then turning another bit of steel to fit, then grub screwing that into the sprocket then boring that to 8mm but I would still have to add a locating screw to lock the sprocket to the motor shaft I figured that’s quite a tedious process too. Either way it’s a pain in the ass :joy: this is all trial and error though but I agree your way would be the best way to ensure no slippage! Im hoping the key slot combined with the four screws should make it a solid fit though :crossed_fingers:

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IMG_20190425_113155 wheels bash guards and sprockets machined and painted and assembled. Build is going slower than I had hoped as never enough free time but moving forward. Hopefully motor mounts will be machined and painted this week then onto the assembly of the drive chain and then designing the focbox unity housing

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IMG_20190502_174046 last part of the 3 piece motor mount cadded up. Now to run these ones off the mill then send them for anodising, batteries had to be bought this week as the prices have more than doubled on the batteries I initially wanted. Overlander 20000 Mah 6s were £130 have gone to over £300 each!, so bought the turnigy 20000mah 6s batteries while they had stocks as no eta once sold out. (could be 4 or 5 months wait)

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I’ve had to buy a battery charger as the batteries come from hobbyking discharged to 30% require charging to storage charge as soon as possible so as soon as they arrived I was forced to quickly find and buy a charger. This cost another £220 :sob:. I wasn’t planning on buying one until my build was complete. I also working on the focbox unity casing, most of my motor mount parts have been made and annodised. I’m waiting on the last bits to me machined though. I’ve also started the battery box design, this will be aluminium plate 10mm thick! This will make my battery box fireproof which will take that worry out of my mind. IMG_20190515_121936 IMG_20190513_123934

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IMG_20190606_145954 making progress now motor mounts are finshed

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IMG_20190607_175112 heatsink for the unity cost me £1.50 from. China and fits a treat. I’m. Not 100% happy with the unity enclosure as I made it using hand fitting when everything else has been precision machined so it let’s down the perfection side of things but it’s still fit for purpose and will do for now until I CAD and machine a solid one out of a billet.

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IMG_20190607_123558 batteries just being eyed up, I’ve bought some monsters, I wanted max range and performance, I didn’t want to be charging up batteries all the time so should get a good few rides between charges at least. The battery box though is going to be BIG.

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IMG_20190610_095429 one more strip down and add a kicker plate so I don’t catch the vesc enclosure with my foot. Then onto the wiring,… I’ve never soldered before and have bought the maytech waterproof remote so will be soldering a battery readout to the 2.4ghz antenna/unit

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I strapped the batteries on last night to try and get the board running, using the unity ui app failed. I had errors come up saying firmware failed but it let me continue, I had constant problems with motors running in random directions every time I touched the throttle and the motors just juddering hard. I will try the bldc pc tool later but right now I’m struggling to find a walk through on how to set up this way

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you aware that your lipos will puff and degretate fast if you hold them too long at a voltage over 3.9V?

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i dont have experience with the unity set up, but if your motors juddering and run in different directions, definitly the unity didn´t got a valid motor detection for either on or both motors.

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IMG_20190627_175925 I’ve neatened up my unity enclosure. Update on the motors juddering issue… . Carl at unity set my board up via remote desktop. Top bloke. Everything was being detected as it should with no errors. unfortunately when I put the board on the ground the motor juddering continued. I have Found a fix though, as soon as I unplugged the hall sensors the motors ran as they should so I may just run sensorless if I don’t find a solution but that doesn’t bother me too much atm. Loopkey thanks for the posts. how long can I leave above 3.9v? My plan is to full charge then use throughout the week for about half hour a day then discharge to storage if not using the board for a while. Is there a voltage range I should aim to keep in for short rides and storage? Thanks

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IMG_20190927_212040
IMG_20190927_2120403648×2736 2.96 MB
this is where I’m up to now. Aluminium fire proof battery box, test ride at weekend saw me crash in the 30’s mph range, broke my wrist in 4 place’s :frowning: battery box will be annodised next)

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