How much of a PITA would it be to drill out one of Mike's pinions? What do machine shops usually charge to have a shaft turned down?

The SDPI gears are made from 12L14 - can be case hardened (at home even with some kasinite and a torch). It wouldn't be worth trying to ream/bore one of my pinions - they are through hardened and are too hard - it would require a stiff, beefy lathe, an expensive tool and coolant to even make a go at it.

Wowsers, Big diesel bastards they are ! Sweet.

Take both peices(pinion/motor shaft) in and see what they say which would be easier/cheaper. Keep us posted if you decide to do this !

I'm thinking it would be easiest to have the shaft turned down. It can be done at home if you're careful but I'm worried about getting the shaft too hot, gotta stop to let it cool often.

Drill press,emory cloth,lotsa beer for patience,Repeated oil dips.
Shouldn't take to long for a 1 mm ?

Whoa, just read that, 6mm shaft?

Now I couldn't use it even if I did have it....which I don't. No word on mine yet.

Drill press might be a bit difficult, I was thinking of rigging up something to get the motor spinning at partial throttle and then using either some really good sand paper or maybe carefully use my Dremel to take off little bits at a time.

Just checked my credit card online and I was charged for my order today, so its is on the way, just didn't get an email....

There is a prob though - they charged me full price for the 1717 even though I ordered on 11/30. Guess I'll have to get that straightened out tomorrow on the phone.

Then it gets to sit while I fugure out what to do about finding 6mm pinions...

Hmm, thats a bugger. I have a feeling CC will be getting a piece of my mind if the 1717 shows up with a 6mm shaft. How hard is it to proof read your website? Seems like we do it fairly frequently (check this thread for examples...). I will have to contact CC about sending me a modded shaft to replace the 6mm unit... Of they can send me about 50 mod 1 6mm bore pinion gears to replace my stock...

I had a kb45 turned down once, but it was not ground for a flat area yet. I had to make up a pvc collar as the machinist did not want to magnitize his lathe with the rotor magnet. A real PITA, spent about 1 hr at lowes getting the correct sizes of pvc rounded up. Then he had to turn it to fit the rotor to clamp it properly. A grinding stone and partial throttle should work, but I really do not want to do that to a 200 dollar motor.

I'm curious why they would put a 6mm shaft on it, they are basically building it for US and other future RC-M nut jobs and we all run 5mm shafts. If it has something to do with a helicopter needing a 6mm shaft or something, put that shaft on the Heli version with the ground down fins and give us the 5mm shaft! I'm not going to pitch a huge fit over it because I bought the motor before there was anything really known about it (said 5mm shaft on the chart, but it wasn't the only error) because I had faith in CC that they wouldn't do something so stupid as to give us the shaft like this.

No worries guys, It's not hobbysh1tty were dealing with. Maybe a misprint warranty that still covers a grinded shaft and/or a easy rotor swap out?

How about 8mm mod 1 pinions? + with Mikes 8mm-6mm adpt.?
http://i300.photobucket.com/albums/n...i/PC100004.jpg

Thats just beautiful...

+1 on Unsullied_Spy

45k rpm max is kind of a let down

common bondo! we can do better than that!
i'd go with removing the rotor and finding some way to tail-stop it then machine with a carbide tip in the lathe.

If yall are looking for 6mm bore pinions ......look here http://www.kershawdesigns.com/,,,scroll to the bottom of the page select "pinions" and again scroll down select "mod 1 pinions"and the 6mm mod 1 are at the bottom.
.

My main issue is that I have a ton of 5mm bore pinions, and I only buy 5mm bore pinions cause I only buy motors with 5mm shafts...

I guess this 1717 motor can go in the 1/7 scale on road project I have, I was going to use a kb45 xl motor, and had mike enlarge the center of his 2 speed adapter to 6mm to fit that shaft. This has to have a custom made motor mount anyways... Sucks that I cannot use it with the lst (although I could if I use the 2speed adapter with the losi tin gears...)

Just a bit miffed that the info was wrong... Not much I can do about it now, my CC was charged yesterday and I am sure I will see the motor next week.

I was curious what the RPM limit on these would be, I was expecting it would be 60,000 like the 15** motors since even their 2220 (or 2225, I don't remember) has a 45,000 limit. I don't plan to push it past 35,000 but it's always nice to know you have the headroom for safety or to push it faster if you so desired.

Got mine today. Thing is massive!

http://i736.photobucket.com/albums/x...r/DSC_0150.jpg

Century Heli has 6mm mod 1 pinions in 9-11 teeth. Apparently pretty common for heli applications?

Must be a heli thing, probably 600 sized. How good are those pinions? If they aren't properly hardened we'll wear those things out in no time.

Sorry guys -- we just realized that the car versions of the 1717 were incorrectly listed as having a 5mm shaft.

About the 45000 RPM limit -- at 45000 RPM the magnets have a centripetal force of over 1500lbs/sq in on them (about 30,000 Gs -- seriously...) -- that's about the physical limit of the kevlar reinforced magnet structure. To go any higher, we would need to get a stronger material than Neo/iron/boron magnets. :(

We just don't know (yet) how to hold the structure together at above 30,000 Gs.

Maybe you guys should contact NASA. They test that stuff out! :lol:

Very thin carbon fiber tube will do the trick. It's been used in very high RPM motors.

So we have to grind down our shafts, drill our pinions, or find new pinions?

These are listed as hardened, but they are not. Not bad pinions, nothing compared to rcm pinions though.

Okay here goes a KB45 grind on my brand new 1717 motor................

If we were to harden them at home (heat until cherry red then quench in used oil) would they be any better or would that make them worse? I ran an RC-M pinion for about 8 months before changing it out and there's a slight bit of wear on it (just from tons of use), I need something that's going to last as well as or close to an RC-M pinion.

Mike: Any chances of getting us some 6mm bore Mod 1 pinions?

Yes, we tried that. Kevlar actually worked better in our testing, up to about a limit of 30K gs. We've also tried stainless steel sleeving, and titanium sleeving -- they worked well but increased eddy current losses to the point where it wasn't worth using the sleeving.

You really don't want to go above about 45KRPM anyway, hysteresis losses become really big really fast at those commutation frequencies.

9-11 tooth are most likely to small for us and this kv and stay below 30k Gs.

The 11T would be perfect for my application (would put me at 40-45 MPH) but may not fit because of the width of the motor.

What kind of wattage are these motors rated to?

dry ice on the motor shaft and a torch on the pinion!:yipi:

was that just supposed to be funny? or are you saying, "no way am I grinding my new motor" ?

because in the time used to make that video if you had actually touched the dremel to the shaft you would now have a 5mm shaft. And nothing would have been harmed.

it's a fricken steel rod you guys aren't going to hurt it.

So as it looks atm, 6 mm shaft? And how do you guys think it will fit Muggy w/RCM motor mount?

it wont without modification,the rcm muggy mount is ment for 3mm screws and this motor uses 4mm screws

Para:yeah that was lame but really that's all I ended up doing but it took me about two hours. I just didn't want to fubar it up. The flat spot was stripping The sand off the sand paper strips, my files just smoothed over and buffed the shaft, So I whipped out the Dr with the cutoff wheel for most of it.

I think a flat piece of grinding stone would have been the ticket, and some way to hold it parallel to the motor shaft. Maybe have a pivot so that you could "feed" it towards the motor shaft as the shaft is spinning.

ok, so just make the hole slots in the mount 1mm larger then?

A custom front motor cover would be a better idea - it would be easy enough to make the front cover attach via the m4 motor holes and leave a pair of m3 tapped holes to attach to the motor mount.

Have you thought about offering the RCM Pinion Gears with a 6mm bore?

Looks like the demand for these will be on the increase. :yes: