Rebuilding the 6 gear transmission.

[FordPSD]

I am now determined to rebuild his thing and make it spin at least 16 seconds! I already took it apart and started working on it. I'm ordering ABEC 7 ceramic bearings for it. What I have now are ABEC 1s. ABEC meaning how well the bearings turn. When my kids were little they wanted to update their roller blades from ABEC 1 to ABEC 7 bearings. They almost killed theselves with the 7s!

I used my Dremel and 400 grit/800 grit sandpaper to clean up the gears shown and polished them. They feel nice and smooth.

Dremel has a green stone that is almost a perfect fit for the outdrive area of the case. It takes that raised area down flush nice and smooth with the rest of the case interior. The holes where the outdrives fit through were also enlarged nice and neatly so there won't be any chance of the outdrives hitting the case anywhere.

I need to order new black idler gears.

I ordered some spare parts dirt cheap. Old parts can be found if you look and search the web hard enough.

Any other thing I need to know?

[soniccj5]

You should also purchase two 3/8 x 5/8 bearings for the outdrives.

Explained in more detail:

http://www.rc10talk.com/viewtopic.php?f=7&t=8834

ED

[FordPSD]

Ed thanks for the link. I've been studying it and haven't quite figured out what he's talking about for the outdrives although I have an idea. The pages were hard to read even when enlarging them. I have all bearings including the outdrives. I'm replacing all of them with better bearings.

[jwscab]

without the extra bearing in the outdrive, the outdrive can flop in and out. by placing the brass spacer on the outdrive gear, it prevents the gear from walking out. it hits the gear on one side, and the outdrive bearing on the other, providing the same effect the inner bearing did. that's why they open the case up, so the case doesn't rub on the brass spacer. you need to put that little screw on the one side so the bearing doesn't push out.

good luck with that 16 seconds. I have a feeling you will gain the most with the filing of the center shaft of the spine to allow a looser gear mesh.

[FordPSD]

File down the shaft of the center spline or file down the hole that the shaft goes in? It would seem filing the shaft would lead to slop plus the bearing would be lose and possible start spining on the post.

I just tried spinning the outdrive with one and two internal bearings. I saw no difference and felt no more resistance. In the article posted here the author/builder said it would be hard to line two bearings up inside the outdrive to make a smooth friction free rotation. That made sense to me. But then when working on the tranny I realized you're not lining them up in the outdrives. They're being aligned on the center spline shaft which makes a perfect alignment.

When I get the new bearings I'm curious if there will be any difference. I never used bushings so I don't know how much of a difference bearings made. But my biggest improvement was filing down the gears for a smooth mesh. I had even filed down the original white idler gears.

To get 15 seconds of rotation on that tranny I think it must be installed in the car and it being spun by the tire. I don't think there is enough weight/mass to make it spin that long on it's own.

Butch

[jwscab]

filing the hole open for the shaft. It's in that halsey article, to slightly change the distance between the outdrives and the idler gear.

aligning 3 bearings in that close a distance can add to some drag becuase even though they are 'precision', there are still imperfections. you probably won't feel it, but it could add a second or 2 onto your goal.

the gears are very much the most important part. I've even got a set of gears that I rounded the edges off, to look like a losi profiled gear. easier than trying to hand file the flashing off of each tooth.

when they say 16 seconds, they almost have to be referring to having the dogbones and rear tires in. there isn't enough mass without it, like you said......

[a01butal]

I built one of my 6 gear trans according to this article and used the Thorp 48p internals. I agonized over every little detail especially getting the brass sleeves exactly the right width. In the end it spun a lot easier than before but even with axles, wheels and tire mass never went 15 seconds. I just finally put it in the way it was and decided that's enough.

[FordPSD]

Thorp made internals? They musta been nice. Probably impossible to find today even on Ebay.

I still haven't figured out this brass tube yet. But trying to figure it out I came up with an idea which may not be new. Use a washer that is 5/16 in diameter along with a piece of 5/16 OD brass tube. Cut the tube to the size of the inner bearing MINUS the thickness of the washer. Then install those two pieces instead of the inner bearing. The tubing would be up against the outer edge of the outer bearing thus not interfering with the inner rings rotation of the bearing. The washer is there for the screw to go through holding the outdrives on. I don't know how much the side play from contact with the tube and outer bearing would slow it down. But one bearing would be eliminated. Anyone ever try this? Any thought on problems I would have?

Does someone have a pic of the brass tube I haven't figured out yet?

I'm thinking it's just a piece of tube for the outdrive exterior bearings to sit in. I can't make out some of the articles pics and what they are trying to say.

Butch

[jwscab]

ok.....I'll see if I can make this clearer. You know how the outdrive bearing goes on the outdrive, over the dogbone cup area? the brass spacer goes on before the bearing the same way, on the outside, so that the gear can't slide 'out' becuase the small inner bearing is gone. the brass ring hits the side of the gear and the inner race of the outdrive bearing.

so the assembly in the trans goes in this order, from outside to inside:

outdrive bearing>>brass ring>>outdrive>>outdrive inner flanged bearing>>snap ring.

no need for the existing retainer screw and washer, but you need the one screw on the non-motor mount side.

if it makes it easier for you, if you could find a small unflanged bearing that fits in there, you could drill it out to not touch the shaft, yet allow the screw and washer to contact it to keep it from sliding outwards.

yes, thorp made 48 pitch gears that go internally. I have a couple sets in transmissions, they were popular mods before the stealth arrived. they work well, still not as efficient as the 3 gear stealth.

[a01butal]

yes, thorp made 48 pitch gears that go internally. I have a couple sets in transmissions, they were popular mods before the stealth arrived. they work well, still not as efficient as the 3 gear stealth.

Gotta agree the Stealth is the nuts. The thorp stuff is still available on eBay and just saw some go off last week. I think some more parts are on there now but maybe not all the pieces.

[FordPSD]

I never did see what size tube they used. I couldn't read the writing. But I think what you're saying is that it fits in between the outdrive gear an the 5/8 outside bearing. It pretty much barely touches the two for lateral movement. I was thinking that the tubing was 21/32 OD which would mean the outside bearing would fit in the tubing and the tubing running to the gear.

I thought it was the outside 3/8x5/8 bearing pocket that was getting rounded out or torn up from the torque of the outdrives. That's why I was thinking the bearing went in the tube and not against it. I didn't see how the tube going between the bearing and outdrive gear would stop that area from getting torn up. That's why I though the tubing was larger and the bearing would go in the tube. I can see how that would stop the area from being torn up.

I went to the hobby shop today for some KS brass tubing and the place was no longer there!

I don't plan on racing this RC10. But I do plan on getting the tranny as smooth as I possibly can. It's the challenge and satisfaction of knowing it is tricked and smooth.

Butch

[a01butal]

Whatever size was in the article I think I went next size smaller, actually took the outdrives over to the hobby shop and fit it to the outdrive. It just has to seat up against the race of the big outside bearing and back against the out drive gear face. It took a couple few tries to get the width of the brass spacer correct as you had to assemble to see if it was not too tight or too loose.

[FordPSD]

The brass tube making contact with the bearing race or te outdrive gear didn't have any affect of slowing it down with the lateral movement? I'm wondering if tapering the tube at both ends would help. It would be less surface contact on the gear and bearing.

Now I just want the new bearings to arrive to put it back togther. But I still have to find a place to buy the brass tubing now. I have two cases so maybe I'll assemble two different trannys trying two different methods.

Thanks for your input!

Butch

[jwscab]

you can try some craft stores if you have any in the area, around here we don't have many hobby shops anymore, but some arts places still sell stuff for trains, they may have it. The article said to use 7/16" tubing, which, if it has OD of 7/16", and 1/32" wall(.031), then it should slide right over the outdrive.

you don't have to worry about the side play of the brass adding drag, just try and make that tube as close as possible without binding, and it won't provide too much side load on the bearings.

[FordPSD]

7/16 tubing. That is definetly smaller than the bearing which is 10/16. In fact the inside of that bearing is 6/16 so the tubing just fits the inner ring of the bearing. That would probably make my outdrive holes too large since I bored them out for clearance. I'll get 7/16, 5/8 and 21/32 tubing and play around with all 3. I wish I could still buy a 6 gear case. I thought of a used 6 gear on Ebay but even they go for $20 and on up. Im probably gonna get 4 pieces of tubing. I might try substituting a tube for that inner bearing to see what happens.

We have another hobby shop about 30 miles away that is still around plus a couple of craft stores.