GNG, 1000W 48V BB-drive, $400

[gestalt]

I print the pulleys with a handle so I can dip them into acetone for 5-10 seconds which soaks into the tiny holes in the print and melts the plastic, strengthening the inter-layer adhesion, and smoothing the ridges off the outer surface of the part. After removing from the acetone shake off excess acetone, and blow on the pulley to evaporate any excess acetone quickly stop the melting (don't want to warp the print surface!) after a few minutes the pulley surface should be hard and dry enough to put it down. I've found that it can take a few days for the acetone to evaporate completely and for the part to completely harden all the way through.

I found this nifty way of using the acetone to improve the finish of the prints. might even make it stronger, regardless it would make the mold come out a whole lot easier when replicating the printed cogs with casting.

Their solution involves simply placing an ABS-based printed part in a mason jar with a few ounces of acetone on a hot plate. When heated to 90 degrees Celsius the acetone evaporates, but creates a cloud that is heavier than air. The cloud surrounds the model and melts the surface; after a couple of hours for cooling and solidifying the item has a mirror finish.

[youtube]Xj53P2YzYGM[/youtube]

 

[bee]

yeah I saw that method and have been meaning to try it. I'm interested in whatever method causes the acetone to soak into the print the most to improve inter-layer adhesion, rather than what provides the smoothest surface finish.

 

[LightningRods]

That's a cool solution for the build ridges on 3D printed objects. If it creates better layer adhesion it's a win/win. For making pulleys that may actually turn out to be exactly what we want. It seems that a rubber belt would last a long time running on a nice smooth ABS pulley.

Can it be that we're actually close to an inexpensive fix for the horrible drive pulley on the GNG??

 

[speedmd]

WOW Nice reforming of the surface. Wonder if you can get some hard metal or even non metal hard powder/ slurry on the surface to stick to them while in vapor. It would possibly make what I would call "STAR DUST ARMOR" type hard coat on the surface. May be possibly to roll them in a flour mix of suitable ingredients after they have been in vapor for a short time just to get the surface sticky enough to hold a good coatings thickness worth of it in place to fuse.

I print the pulleys with a handle so I can dip them into acetone for 5-10 seconds which soaks into the tiny holes in the print and melts the plastic, strengthening the inter-layer adhesion, and smoothing the ridges off the outer surface of the part. After removing from the acetone shake off excess acetone, and blow on the pulley to evaporate any excess acetone quickly stop the melting (don't want to warp the print surface!) after a few minutes the pulley surface should be hard and dry enough to put it down. I've found that it can take a few days for the acetone to evaporate completely and for the part to completely harden all the way through.

I found this nifty way of using the acetone to improve the finish of the prints. might even make it stronger, regardless it would make the mold come out a whole lot easier when replicating the printed cogs with casting.

 

[gestalt]

I'm interested in whatever method causes the acetone to soak into the print the most to improve inter-layer adhesion, rather than what provides the smoothest surface finish.

I would imagine that the penetration of the acetone vapor would be better than that of a liquid. But maybe soaking it first, then hitting it with the vapor would be the way to go.

 

[gestalt]

so I talked to charlie from reynolds advanced materials today, explained what we were trying to do and what they had that would work for our aplication. he said that their TASK performance casting resins were the way to go. there are a wide variety of them but he said TASK 13&14 were the way to go. you can check them all out here http://www.reynoldsam.com/index.php?cPath=1157. the price is at about $30 a pint for the resin, and I don't know yet what the cost would be for the materials. but for the driven cog it couldn't be that much since it's so small and a pint of resin could pour quite a few out of one pint. if you cast ten of them it would be at $3 a cog in material costs. you might actually want to make a mold for three cogs as it takes a day for these to cure, pumping out just one a day would be pretty slow.

I can do this.

whew!

and that was the abridged version, you can see the well done tutorial here http://www.reynoldsam.com/gallery.php?galleryid=455 to understand the whole process better but it looks like this would be a fantastic way to make not only slip on drive cogs from the printed original, but slip on driven pulley adapters. in theory, you could use a set of these cast pulley/cog combos and a set of lightningrod's adjustable plates and you should have a complete solution for anyone trying to use these kits at the stock levels. and hopefully beyond.

 

[flyinmonkie]

Check this out. Looks like a GNG motor with a driveline and differential. All for $54.40 plus shipping.

http://www.mistertao.com/taobao-products/taobao-item-18587052530.html

Kinda makes you wonder what's inside of that black case, doesn't it?

If you do some research you'll find that the gng motor is actually used for trikes and has quite a long output shaft with a helical gear cut in it. The shaft extends beyond the gear for what I assume is a support bearing in the differential. It mates up with the diff and the axle comes out either side for a trike. You can also find them without the differential attached for a good price on mistertao and aliexpress I think.

If you get your plates all sorted, you could order motors and have the shaft turned down and sell the motors and plates. Let the customer decide on controller, throttle, and batteries.

Clay

 

[LightningRods]

Absolutely! You guys are 100% on the right track with the pulleys. Flexibility, cost, performance. This process ticks all of the boxes.

When I came out with my new BB sheets a couple of weeks ago a bunch of you PMed me wanting to know if there would be a 73mm version of the lower sheets. I have the 73mm version designed and it's ready to go into production. Here's how it looks.

It turned out slick. Despite the fact that I designed the 68mm sheets first the 73s are simpler. Having the slide outside of the motor bracket not only makes the sheets line up perfectly with both bottom bracket and motor case, it does it with no spacers. There is just one fly in the 73mm GNG ointment.

The left side bearing cup is 5mm short to provide full support of the BB tube and engagement of the cup threads into the BB shell. I'm going to do some shopping around and see what I can find. Someone said they had gotten deeper BB cups at Sick Bike Parts. Once we have that last piece the GNG will be a bolt on for MBs with the 73mm BB.

All of you Endless-Spherians who PMed me previously about wanting this BB bracket, check back in and I'll get it into production for you this week.

 

[justlooking]

Check this out. Looks like a GNG motor with a driveline and differential. All for $54.40 plus shipping.

http://www.mistertao.com/taobao-products/taobao-item-18587052530.html

Kinda makes you wonder what's inside of that black case, doesn't it?

im thinkin of getting one or 2 of these, but wondering how reliable the company is ,,

do you lot think they are legit ?

 

[bee]

Oh hey, this acetone vapor polishing works great on the surface of the gears

After fudging with the parameters a bit, I got a 14 to 18t sleeve to print without any gap in the wall. This one will probably need a bit of filing to fit since I had to lie about the thickness of the print head a bit to get the g-code generator to squeeze plastic into the tight areas.

I'll send a few of these out to anyone that wants to try them. You will need the 95t or larger sprocket to use these sleeves, they are useless on their own since they change the gear reduction too much.

 

[gestalt]

Wrap it up bee! I want to take one in to the guy at Reynolds, he said he wouldn't be sure what resin would work best untill he saw the part himself.

 

[bee]

PM me your address.
You will need to file the pulley a bit so that it's snug fit, and not press fit, if you're casting.

PLA can also be cast in metal using lost wax casting methods if you guys know anyone with a backyard foundry:
http://3dtopo.com/lostPLA/

I don't like printing in PLA though, so you'll have to ask one of the other folks for a PLA pulley

 

[heathyoung]

Wow - shiny!

It will be interesting to see how the resin ones go.

 

[spinningmagnets]

I have been very keen to see how the 3D printed pulley-sleeves will turn out. bee, I am very impressed and very appreciative of your posts. For those who want the sleeve, but are concerned about how much it changes the primary ratio, I still believe this kit could prove to be very useful at 36V. Just a thought...

 

[LightningRods]

Check this out. Looks like a GNG motor with a driveline and differential. All for $54.40 plus shipping.

im thinkin of getting one or 2 of these, but wondering how reliable the company is ,,

do you lot think they are legit ?

I bought my GNG kit through MisterTao and saved $80 on it. It takes longer because the seller has to ship domestically to MrTao and then they ship it internationally. I got no sense that they were running a scam of any sort. As with any international commerce the main scam is the shipping. That cost me as much as my kit and will cost you probably 3x what they are asking for this setup. Still a steal of deal though.

 

[LightningRods]

Oh hey, this acetone vapor polishing works great on the surface of the gears

I'll send a few of these out to anyone that wants to try them. You will need the 95t or larger sprocket to use these sleeves, they are useless on their own since they change the gear reduction too much.

Awesome work, Bee! This is the fix for that pesky drive pulley for sure.

Any chance I can get an 18T and a 19T in 23mm width?

I'm going to replace the center freewheel on my 120T pulley with a flanged hub. I'll align bore it in a lathe after assembly to eliminate all of the runout. That pulley is 23mm wide so it would be great to have a matching drive pulley so I can run a 20mm wide belt.

Thanks!

 

[justlooking]

would this be a good idea to the solution of the weak bb shaft ??
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=48220&p=709617#p709617

I have never tried these, but they may be an option to keep in mind during your research.

Thanks to wildharemtbkr for the link. http://durgendesigns.com/ddfwadapters.htm

durgendesigns.com has a $35 adapter that makes a non-freewheeling crankarm accept a FW, intended for bolting onto beefy crank arms. I do not know the central hole ID, I assume its for a well-known beefy BB-shaft.

 

[justlooking]

Check this out. Looks like a GNG motor with a driveline and differential. All for $54.40 plus shipping.

im thinkin of getting one or 2 of these, but wondering how reliable the company is ,,

do you lot think they are legit ?

I bought my GNG kit through MisterTao and saved $80 on it. It takes longer because the seller has to ship domestically to MrTao and then they ship it internationally. I got no sense that they were running a scam of any sort. As with any international commerce the main scam is the shipping. That cost me as much as my kit and will cost you probably 3x what they are asking for this setup. Still a steal of deal though.

at $94.83 including postage with in a week i dont think the price is bad at all.

i would like to have a look inside one to see what would be involved to fix a sprocket on each side so that you have 2 chains going to the rear wheel.

or even just one chain, thus removing the belt etc from the system,

if it can not be done, then one chain would do.

if it dont work i can always keep it till later in the year and make a trike

 

[bzhwindtalker]

Have placed an order for the 800w mot or, will let you guys know.

 

[skyungjae]

would this be a good idea to the solution of the weak bb shaft ??
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=48220&p=709617#p709617

I have never tried these, but they may be an option to keep in mind during your research.

Thanks to wildharemtbkr for the link. http://durgendesigns.com/ddfwadapters.htm

durgendesigns.com has a $35 adapter that makes a non-freewheeling crankarm accept a FW, intended for bolting onto beefy crank arms. I do not know the central hole ID, I assume its for a well-known beefy BB-shaft.

Good find! I'd love to see what these look like installed on a ISIS crank arm.

 

[justlooking]

i think these are the arms to go with that freewheel adaptor
http://www.ebay.co.uk/itm/GUSSET-FIX-T-BMX-CRANKARMS-CRANK-ARMS-170MM-/271149338689

 

[Chalo]

They are not for ISIS cranks. They are for three-piece BMX cranks-- probably those with 22mm spindles, from what I can tell by looking at the photo. Here is one example of BMX 3-piece cranks with a 22mm spindle:

ISIS cranks won't work, because there is no standard diameter for the adapter to set up on, nor do ISIS bottom brackets even have enough spindle sticking out to allow enough room for the adapter.

I like Primo Powerbite cranks (the ones in the picture) because it is relatively easy to reverse-engineer a spindle of a different length for them. The interface is non-tapered square flats (19mm across if i remember correctly), and the generous spindle diameter means there is no need to use an especially strong material to get the job done. I have made special spindles for these cranks out of 304 stainless steel, 12L14 leaded steel, and even 7075 aluminum.

Someone with good machining capability could also make a spindle for Primo cranks that had the freewheel adapter integral to the spindle.

Chalo

 

[spinningmagnets]

Would anyone mind if the last three posts were moved to the:

"Strong freewheeling crankset"
http://endless-sphere.com/forums/viewtopic.php?f=28&t=47618&start=50

If no, I contacted Staton-inc, and they were willing to sell individual shaft-to-freewheel adapters (they carry 5 bore sizes), that were only pilot bored (1/4-inch central hole?), but that part would not have a keyway (obviously), or the two threaded set-screw holes. this leaves the buyer to bore it to 22mm (0.866-inch), and also finding a way to secure it to the shaft (welding?)

A second option is to buy their 1.0-inch bore FW adapter, and making a sleeve from 22mm to 1.0 inch.

1.000-inch
0.866-inch___22mm
0.134-inch = tube with 0.067-inch wall thickness.

Now that I know there are square-shank BB-shafts with no taper, it "looks like" the $134 AFT BB-shaft is that type, and has the required extra length on the right side.

 

[LightningRods]

They're 19mm spindles. Here is the Gusset store link:

http://www.gussetbikes.com/products-bmx-list.php?c=D

Here are the 19mm spindles in various lengths in chrome moly steel:

http://www.profileracing.com/estore/product.php?productId=343

I'm working on a sprag bearing adaptor for these axles.

 

[Chalo]

Now that I know there are square-shank BB-shafts with no taper, it "looks like" the $134 AFT BB-shaft is that type, and has the required extra length on the right side.

Do you have a link to that item?