Kagama Hinge pin suggestions

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Oil quench on the 4140 did not help much. They bent....less, but still pretty mangled after 2 packs. Mind you I am driving aggressive, but so far I'm not at all impressed with 4140. I'll research quenching and see if I can get something that works better. All things considered, the Amazon 4mm HSS rod isn't that bad. It snaps, but at least you know its broke. Otherwise you are driving around on a bent hinge pin and you don't know why the car's handling is off...

I'm considering just going to 5mm and hogging everything out to accommodate. The negative here is that I'll likely start tearing arms off.
 
danl said:
Oil quench on the 4140 did not help much. They bent....less, but still pretty mangled after 2 packs. Mind you I am driving aggressive, but so far I'm not at all impressed with 4140. I'll research quenching and see if I can get something that works better. All things considered, the Amazon 4mm HSS rod isn't that bad. It snaps, but at least you know its broke. Otherwise you are driving around on a bent hinge pin and you don't know why the car's handling is off...

I'm considering just going to 5mm and hogging everything out to accommodate. The negative here is that I'll likely start tearing arms off.
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Or you could drive your cars within their limits.
 
SirCrashALot said:
Or you could drive your cars within their limits.
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That’s just silly!😜
I’ve pulled apart many rigs for repair and discovered bent hinge pins that I never realized were bent.. the Arrma 8s are notorious for this. Though I have realized that when the suspension becomes unusually stiff, I know I have either bent hinge pins or pillow balls.. the 8s rigs do bend pillow ball studs quite easily I feel.
 
KnowAir said:
That’s just silly!😜
I’ve pulled apart many rigs for repair and discovered bent hinge pins that I never realized were bent.. the Arrma 8s are notorious for this. Though I have realized that when the suspension becomes unusually stiff, I know I have either bent hinge pins or pillow balls.. the 8s rigs do bend pillow ball studs quite easily I feel.
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Makes replacing the pivot balls less painful to the wallet:

https://www.aliexpress.us/item/3256801899579216.html

I've been using them on my Asuga, compared to Corally balls the standoff is 0.9mm longer the thread is 2mm shorter and the ball is about 0.07mm larger (13.89mm instead of 13.82mm diameter) so close enough to not make a difference and way less expensive. I bought 10 packs of them all at once.

Also watch out for the thread when buying off brand balls sometimes it differs from the stock thread, these match the coarse Arrma and Corally thread but I've seen balls that have a fine thread instead.

Also these are stainless steel while the Corally balls are not but I haven't noticed that the Corally balls are any less prone to bending.
 
Atomic Skull said:
Makes replacing the pivot balls less painful to the wallet:

https://www.aliexpress.us/item/3256801899579216.html

I've been using them on my Asuga, compared to Corally balls the standoff is 0.9mm longer the thread is 2mm shorter and the ball is about 0.07mm larger (13.89mm instead of 13.82mm diameter) so close enough to not make a difference and way less expensive. I bought 10 packs of them all at once.

Also watch out for the thread when buying off brand balls sometimes it differs from the stock thread, these match the coarse Arrma and Corally thread but I've seen balls that have a fine thread instead.

Also these are stainless steel while the Corally balls are not but I haven't noticed that the Corally balls are any less prone to bending.
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Thanks👍
I haven’t really had too many issues with Arrma or TC 6s pivot balls, the 8s do bend rather easily though. I feel like Arrma didn’t scale them up proportionally from the 6s version. Sure the ball itself is much larger but the taper between the ball and stud seems to be the weak point.
 
KnowAir said:
Thanks👍
I haven’t really had too many issues with Arrma or TC 6s pivot balls, the 8s do bend rather easily though. I feel like Arrma didn’t scale them up proportionally from the 6s version. Sure the ball itself is much larger but the taper between the ball and stud seems to be the weak point.
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A thicker ball standoff reduces your maximum steering angle, my solution would be to use a stainless steel or PTFE ball with a nickle plated 12.9 threaded stud that screws into it.
 
Atomic Skull said:
A thicker ball standoff reduces your maximum steering angle, my solution would be to use a stainless steel or PTFE ball with a nickle plated 12.9 threaded stud that screws into it.
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Currently it’s the cvds that limit steering angles on most all the rigs I own with pivot ball front ends. I typically set the end points to just before the cvd’s start binding. No fix for that as far as I know of. On the 8s Arrma’s it’s quite limiting for the steering. Is what it is.
 
KnowAir said:
Currently it’s the cvds that limit steering angles on most all the rigs I own with pivot ball front ends. I typically set the end points to just before the cvd’s start binding. No fix for that as far as I know of. On the 8s Arrma’s it’s quite limiting for the steering. Is what it is.
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On my Asuga the limitation is the aperture for the pivot ball neck in the steering block. This only happens at full suspension droop. The maximum CVD angle is larger than what the steering block allows and the ball will bind on the edges of the aperture before the CVD binds.
 
Atomic Skull said:
On my Asuga the limitation is the aperture for the pivot ball neck in the steering block. This only happens at full suspension droop. The maximum CVD angle is larger than what the steering block allows and the ball will bind on the edges of the aperture before the CVD binds.
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I’d say that’s a good thing so long as you’re satisfied with the turning radius. Prevents premature cvd wear. The Arrma’s are the opposite in my experience, too much steer angles causes the cvd to bind and the wheel starts hanging up and jumping up and down.
 
I screw the stock pivot balls into a 6mm threaded coupler nut. I then clamp that into my vice. While unthreading the pivot ball with an Allen wrench, it’s easy to identify where it needs persuaded with my brass persuading hammer. A couple precise sacks and it’s good as new.

The stock corally pivot balls and hinge pins are very strong. So far I’ve yet to find something better.

I’m working on a way to get the hinge pins to last longer, but it’s going to take a couple weeks to make the parts and a couple more to test it.
 
danl said:
I screw the stock pivot balls into a 6mm threaded coupler nut. I then clamp that into my vice. While unthreading the pivot ball with an Allen wrench, it’s easy to identify where it needs persuaded with my brass persuading hammer. A couple precise sacks and it’s good as new.

The stock corally pivot balls and hinge pins are very strong. So far I’ve yet to find something better.

I’m working on a way to get the hinge pins to last longer, but it’s going to take a couple weeks to make the parts and a couple more to test it.
Click to expand...
You can bend them back but they will never be perfectly true and my OCD can't handle that. I've found a cheap $2 solution to the occasional bent ball though and they also don't rust unlike the Corally balls.

If the Corally balls are stronger than the stainless steel ones I haven't noticed they seem just as prone to bend, it's not common but sometimes you hit the wheel just right and it happens.
 
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