Travis @ Buggy Depot wrote: ↑
Sun Apr 08, 2018 1:32 pm
I agree with offering the 4x156 adapter separate.
Here are the manufacturing obstacles and limitations as I see it right now:
1. We'll need to use 7.5" rotors instead of the normal 5"
Plasma can't do small holes. The 6mm holes for the normal rotors are just too small, especially for 1/4" steel thickness. I decided to use a larger 4-bolt pattern common for scooter rotors. They look pretty cool, and will provide much more bite when the brakes are applied. With the trend that's starting of 25+ inch tires and higher HP engines, more stopping power is good.
This means I'll also need to provide caliper relocation mount to accommodate the increased rotor diameter. This isn't a problem, but will add cost.
2. We can't (easily) tap holes cut by Plasma.
Plasma cutting carburizes edges, adding (a lot of) extra carbon to the steel and make the affected area very hard. Especially with holes. I chipped and broke several regular HSS drills figuring this out. You really need a cobalt M42 bit to cut through the hardened material.
The most obvious solution would be to plan to cut the holes undersized during the plasma operation, then add a second operation to drill each of them out with M42 bits. Unfortunately, all of the extra handling and labor will make the hubs very expensive and I don't consider it a very practical option.
I think the answer may be to weld jam nuts to the back sides of each stud hole. Not the most elegant solution, but it'll get the job done without significantly raising costs.
3. Cutting the bearing slots will be time consuming
My lathes are completely manual. We'd have to figure out a way to either automate cutting the bearing slots, or make some type of fixture that adds easily repeatable hard stops to the lathe's XZ table travel. Developing either will be a big investment of time like the A-Arm tools.
The last thing I want is for my guys to have to remember and maintain consistency on another manual process. The more we can distill the intelligence directly into the tooling, the more reliable we'll be in producing the part. And the higher quality it will be.
I don't have a solution for this at the moment, and I think it will take a lot of hours to develop something that works well. But it does lead into the next point...
Most important: I'm the bottleneck
I've got to get my team to the point of being able to handle these projects without my involvement at the micro level. I just wrote a new shop update getting into it.
April 2018 shop update: Breaking the bottleneck... Will Yerf Dog support grow, or continue to die out?