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Old 04-24-2005, 11:38 PM   #21
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I split this into it's own thread, hope you don't mind JIA.
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Old 04-25-2005, 12:04 AM   #22
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Quote:
Originally Posted by BENDER
Wow, very nice BultacoJim!! Is that your creation? Is it manually operated?
Yep, right now I have to manually pull the shift for in & out.
Failed at making an electric solenoid work.

Trying to fab up a Y-cable using music wire like the RC planes use so a servo will operate both axles at once.
No synchronizers though, have to come to a complete stop to shift. :?
Works like the Dana 18 transfer case in my CJ2A Willys.
I used the plastic/steel gears from a GD600 & put them into the aluminum case.
Used the GD600 18T pinion gear to get a ratio of 2.5 for the crawler box.
With the stock 13T pinion on the motor, I have ratios of 30:1 and 75:1
Case is a little heavy. Will probably make two more out of Delrin for the final version.
Trying to finish my aluminum axles tubes to go with my aluminum hubs.
Not enough hours in a day! :?

Last edited by BultacoJim; 04-25-2005 at 12:31 AM.
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Old 04-25-2005, 12:12 AM   #23
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Very cool!! I thought that looked like a plunger for shifting. Keep us updated for sure!!
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Old 04-25-2005, 04:49 PM   #24
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BultacoJim, that's pretty slick! (but you already knew that)

Don't worry about heavy. If you make two more just put the delrin case in the rear and the aluminum one up front. No better weight than dead weight on the axles. ;)
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Old 04-25-2005, 04:54 PM   #25
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Quote:
Originally Posted by BultacoJim
You mean one of these 2-speed transmissions?
Why the hell don't you ever come to any of our get togethers? I wanna see this crap!
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Old 04-25-2005, 06:01 PM   #26
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Quote:
Originally Posted by jason
Why the hell don't you ever come to any of our get togethers? I wanna see this crap!
Why? So he can make us all feel like 3rd graders in art class?
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Old 04-25-2005, 07:20 PM   #27
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Quote:
Originally Posted by jason
Why the hell don't you ever come to any of our get togethers? I wanna see this crap!
I was wondering the same thing, I'd like to see some of this stuff too.
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Old 04-25-2005, 10:27 PM   #28
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Quote:
Originally Posted by jason
Why the hell don't you ever come to any of our get togethers? I wanna see this crap!
I work weekends right now, but I値l be getting Saturday/Sundays off in about two months.

I知 a newbie with this RC Crawling stuff.
Joined this forum last October & probably read every post made.
I never had to ask any questions, because they were already answered.

I am trying to build/design a 4:1 crawler box for my 1:1 Willys, that is why I知 experimenting with a crawler box for the Clod. This present Clod design looks cool, but I知 having issues with the plastic gears I robbed from the GD600. I知 rethinking my design, so don稚 expect any earth shaking things from me real soon. It will go to the back burner while I steal Ace痴 idea of wider axles on the Clod. Gotta get these Aluminum axle tubes and hubs built.

I知 getting a kick out of building my own RC crawler lately.
I started with a stock Clod and it keeps 杜orphing.
This sucker will be all aluminum before I realize it.
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Old 04-30-2005, 05:56 PM   #29
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Kinda hard to follow up with Jim's posts, but here's the current status of my 2 speed:

Decided to start with a fresh piece of delrin late last night due to a slight design change. Used a compass to lay out the entire motor/tranny plate...just light scratches on the surface to use as a reference so I don't mess up at 1:30 in the morning. Notice the ultra-trick fixture made of a 3mm screw, conical washer, and nylock. In the following picture I've already cut the majority of material away where the diff cups will poke through as well as cut the walls around the bearing pocket.




Motor pocket and wall around it cut. Again, notice that ultra-complicated fixture.


Cut the gears down so everything fit just right.


Installed it all...


Still have a little left to do. Going to take a bit of material off the top where the "ears" are as well as clean up the area below the bearing pocket.

This was my first real project with the mill other than the lock rings on this thing.

Now to make the other tranny plate.
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Old 04-30-2005, 07:05 PM   #30
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Lookin' good there Delrin Boy. I am really diggin' that fixture you whipped up. Man, you must have spent hours in CAD laying that out and building it all :-). Bah, looks awesome and I have to keep reminding myself what these parts are being made with. Noooothing against Sherline equipment, you've certainly got a knack for machining up pretty trick stuff with it. Is cool to see your tranny plate coming to life now that it has some profiles to it. You can admit it.........you have a Delrin fetish now don't ya? If I could.......I'd make everything outta Delrin. So much fun to work with, just gotta keep your tools sharp. Plastic don't like to cut too pretty good with dull tooling. It likes to "crawl" and do weird things that at 1:30 in the morning makes for lots of dirty words

Last edited by RCALLOYS; 04-30-2005 at 08:10 PM.
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Old 04-30-2005, 07:57 PM   #31
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Nice work JIA!! Delrin is fun to work with.
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Old 05-01-2005, 08:16 AM   #32
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Jason,

Very nice work. With your hand-eye coordination, you don稚 need no stink地 CNC.
You discovered the secret. Fixtures

Question,

I found this site: http://www2.towerhobbies.com/cgi-bin...?&I=LXBM38&P=V

Your smallest pinion looks like: an 8T.
The largest looks to be 杜aybe 16T.

If you don稚 mind, what is the tooth count and the two different gear pitches of the gears in your transmission?

I知 trying to mix & match gears from available RC manufactures, to avoid making my own. I知 trying for the widest separation in gear ratio as possible between 1st and 2nd. I need to solve two simultaneous equations to get the correct gear mesh for a 2-speed in the confines of the Clod transmission.


Formula to calculate the separation of two gears for proper mesh.

Center distance = (D1+D2)/2 = (N1+N2)/Pd = {Pc(N1+N2)}/ (2*3.14)


D is: Pitch Diameter
N is: Number of teeth
Pd is : Diametral pitch
Pc is: Circular Pitch
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Last edited by BultacoJim; 05-01-2005 at 08:58 AM.
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Old 05-01-2005, 08:29 AM   #33
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Quote:
Originally Posted by BultacoJim
Jason,

Very nice work. With your hand-eye coordination, you don稚 need no stink地 CNC.
You discovered the secret. Fixtures

Question,

I found this site: http://www2.towerhobbies.com/cgi-bin...?&I=LXBM38&P=V

Your smallest pinion looks like: an 8T.
The largest looks to be 杜aybe 16T.

If you don稚 mind, what is the tooth count and the two different gear pitches of the gears in your transmission?

I知 trying to mix & match gears from available RC manufactures, to avoid making my own. I知 trying for the widest separation in gear ration as possible between 1st and 2nd. I need to solve two simultaneous equations to get the correct gear mesh in the confines of the Clod transmission.


Formula to calculate the separation of two gears for proper mesh.

Center distance = (D1+D2)/2 = (N1+N2)/Pd = {Pc(N1+N2)}/ (2*3.14)


D is: Pitch Diameter
N is: Number of teeth
Pd is : Diametral pitch
Pc is: Circular Pitch
That gear set is from the transfer case i used in my Jeep. I got the tranny on Ebay for $5 but never knew what it was from, I had to really modify it to make it work with electric. I had to take the higher gearout and lock the shaft to the gear for reverse to work. But it works awesome now.
Here are the pics of my work on my Jeep and the tranny.
http://www.imagestation.com/picture/...c/f4e5699c.jpg
http://www.imagestation.com/picture/...b/f4e56996.jpg
http://www.imagestation.com/picture/...b/f4e5698c.jpg
Installed
http://www.imagestation.com/picture/...2/f47e3707.jpg
http://www.imagestation.com/picture/...c/f47e370e.jpg
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Old 05-01-2005, 09:22 AM   #34
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Jim, Thanks!

The gears are all 1 module.

First gear is an eight tooth pinion (10mm dia) coupled to a 56 tooth spur (58mm dia) for a 7:1 ratio.

Second is a 12 tooth pinion (14mm dia) with a 52 tooth spur (54mm dia) for a 4.3:1 ratio.

Those numbers give me a distance of 34mm on center for both gearsets.

Works perfecto.

As for the tranny you're looking at:

Both the tranny I'm using and the one you linked have 1st gear on a one-way bearing. This is so 1st can free spool while 2nd is engaged.

Not sure if you knew or not.

Last edited by JasonInAugusta; 05-01-2005 at 09:29 AM.
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Old 05-01-2005, 11:22 AM   #35
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Looks good jason.. What is this going to be used for?
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Old 05-01-2005, 11:50 AM   #36
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Jason,

Nice ratios, that gives you about a 1.6 difference between 1st & 2nd.
I知 trying to achieve between 2.0 and 2.5 difference for a 田rawler gear.


Questions,
1. How do you shift it.
2. Does it have reverse with the 1-way clutch?
3. What are the two pitches? Are they 32P & 48P ?

I知 only interested in the gears. I will make custom hubs with 電og teeth for engagement. The hard part is finding two pairs (pinion & driven) of gear sets with a gear ratio difference between 2.0 and 2.5, yet have the same center difference.
Here痴 a drawing of mine if you're interested.
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Old 05-01-2005, 04:09 PM   #37
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Jim,

The tranny will shift with centrifugal force. A clutch shoe kicks out to engage 2nd. You can adjust the shift point by adjusting a setscrew. Take a look at the following manual for a similiar tranny:

http://ofna.com/pdf/95-2speed-40111.pdf

There's no reverse. If the electric motor goes to reverse 1st gear will free spool (and 2nd will as well since the clutch shoe inside the tranny will be disengaged). So..I'll be using a forward only controller with brake.

Pitch...these are 1 module (metric) gears. A chart can be found here that give more info on gear diameters, equivalent diametral pitch, etc.

http://mdmetric.com/tech/modulegeardata.pdf

1 module is easy to work with. Just measure the diameter of the gear in mm, subtract 2mm and you have the tooth count. ;)

Last edited by JasonInAugusta; 05-02-2005 at 08:07 AM.
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Old 05-02-2005, 06:21 AM   #38
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Jason,

Thanks for the info. I kinda thought that must be the way they worked.
Never had an opportunity to examine an RC cars transmission up close.
Great looking design you have there, can稚 wait for the finished product.

I know now why my homemade gears aren稚 meshing correctly.
The Clod gears are designed on the standard ISO metric rack.

http://www.sdp-si.com/D785/PDF/D785T007.PDF

I was wasting my time on pressure angles.
Thank you for setting me right.
Back to the drawing board.

-Jim
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Old 05-02-2005, 10:15 AM   #39
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rofl.

Amazing that I helped you. There's no way I'd be able to make gears right now. I'm just making what's available work.

Here's the finished, cut down mount. I moved the motor closer to the center so I could have a nice, round wall around the motor pocket. Also made the motor pocket smaller for asthetic reasons. Now all that's left to do is cut slots for access to setscrews, counterbore the holes for the motor screws, drill holes for some press-fit threaded inserts, and hit it with an abrasive to get a nice finish. Will have to wait on that, don't have the right size ball-nose endmill.



Now to make the other tranny plate with the brake cam and such. That should be fun.

Last edited by JasonInAugusta; 05-02-2005 at 10:17 AM.
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Old 05-02-2005, 07:08 PM   #40
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What is derlin, plastic? Where do i find it?
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