I finally made it! Thanks everyone for inspiration, especially Mike81 for making this possible!
I put a caliper and the ball diff in my pocket and went to a local hobby store measuring some 1/10 scale dogbones. I was surprised that nearly every 1/10 dogbone they sell had the right ball/pin size, so i got the cheapest made from metal.
https://www.conrad.de/de/reely-10465-ersatzteil-zentrale-kardanwelle-1365357.html
So here is what i did:
Tools needed:
- Installed 3 Racing Ball Diff for Mini Inferno or equivalent like Mike81 did.
- Dremel with cutting disc (or a metal saw and a rasp)
- 5mm dia. shrink tube (or other centering helper depending on shaft dia.)
- Epoxy glue
- 1 Dogbone (ball dia. 6mm, pin dia. 2mm, shaft dia. <=4mm)
- Some 4x5x0.5mm shims
- Caliper for exact length adjustment during gluing may help
1. Switch the outer telescopic axle part from diff-side to hub-side like Mike81 did.
2. Cut the dogbone in half. Mine had 74mm length (pin2pin) which made 2 exact fitting bones.
3. Flatten out the center part of the shaft between the shrink tube on opposite sides like in the picture. Dont flatten where the centering shrink tube parts rest.
4. Slide 2 small rings of shrink tube over the shaft like in the picture. This is for a 3.3mm shaft. It may vary for your dogbone. Target dia. is about 4mm since this gives a snug fit in the telescopic part of the axle. This makes centering and adjusting length easy.
5. Epoxy the dogbone into the outer telescopic part of the original diffs outdrive. Pay attention that there is no air left so the whole axle is filled with expoy.
Target length of the assembly should be 42mm measured like in the next picture. Be sure to measure your ideal length before you glue it in since my bone got a flat head so you probably need a bit more or less length.
6. Install the axle and put some 4x5mm shims between the outer hub bearing and the little wheel pin to remove the in/out play. This is important for maintaining the right ball position in the diffs outdrive.
DONE - F.Yeah!
Btw: i put Losi Mini 8ight Wheels on, which fit perfectly. They are nicely soft, a little bigger, provide excellent traction and look damn cool. Now my Roost looks and feels like a real Buggy. It feels rock solid and very responsive. Soon i will change the front diff too but first i will beat the hell out of it now. Hmm.. lets have a look for a nice brushless system...
I put a caliper and the ball diff in my pocket and went to a local hobby store measuring some 1/10 scale dogbones. I was surprised that nearly every 1/10 dogbone they sell had the right ball/pin size, so i got the cheapest made from metal.
https://www.conrad.de/de/reely-10465-ersatzteil-zentrale-kardanwelle-1365357.html
So here is what i did:
Tools needed:
- Installed 3 Racing Ball Diff for Mini Inferno or equivalent like Mike81 did.
- Dremel with cutting disc (or a metal saw and a rasp)
- 5mm dia. shrink tube (or other centering helper depending on shaft dia.)
- Epoxy glue
- 1 Dogbone (ball dia. 6mm, pin dia. 2mm, shaft dia. <=4mm)
- Some 4x5x0.5mm shims
- Caliper for exact length adjustment during gluing may help
1. Switch the outer telescopic axle part from diff-side to hub-side like Mike81 did.
2. Cut the dogbone in half. Mine had 74mm length (pin2pin) which made 2 exact fitting bones.
3. Flatten out the center part of the shaft between the shrink tube on opposite sides like in the picture. Dont flatten where the centering shrink tube parts rest.
4. Slide 2 small rings of shrink tube over the shaft like in the picture. This is for a 3.3mm shaft. It may vary for your dogbone. Target dia. is about 4mm since this gives a snug fit in the telescopic part of the axle. This makes centering and adjusting length easy.
5. Epoxy the dogbone into the outer telescopic part of the original diffs outdrive. Pay attention that there is no air left so the whole axle is filled with expoy.
Target length of the assembly should be 42mm measured like in the next picture. Be sure to measure your ideal length before you glue it in since my bone got a flat head so you probably need a bit more or less length.
6. Install the axle and put some 4x5mm shims between the outer hub bearing and the little wheel pin to remove the in/out play. This is important for maintaining the right ball position in the diffs outdrive.
DONE - F.Yeah!
Btw: i put Losi Mini 8ight Wheels on, which fit perfectly. They are nicely soft, a little bigger, provide excellent traction and look damn cool. Now my Roost looks and feels like a real Buggy. It feels rock solid and very responsive. Soon i will change the front diff too but first i will beat the hell out of it now. Hmm.. lets have a look for a nice brushless system...
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