Hi, currently working on making a custom swerve in collaboration for another team. Out of convenience and price, we’ve noted that the 60T Bevel Gear found on SDS Mk3s and versions prior is one of most suitable for a potential design, however it seems to have disappeared off the internet, as it has been discontinued by SDS. Do any teams that have upgraded from those modules to Mk4/4i still have these gears left over and are open to sell or trade them? Looking for a set with both the 60T and the matching 15T.
Not really convenient, but I believe those were made by KHK gear. You could buy them from there, but they will have hubs that you’ll probably have to machine to suit your needs.
Thank you! I couldn’t find the vendor as the page on SDS was deleted
I’m pretty sure this was it. Looks like Misumi sells it, which might be easier or cheaper for ordering. Although, I’ve ordered direct from KHK and it wasn’t bad. https://us.misumi-ec.com/vona2/detail/221004937266/?HissuCode=SB1.5-6015
Thanks! This pretty much is exactly what I had in mind
There are several vendors on Aliexpress That sell these gears. With shipping it runs about 30$ per set with 3-4 week lead time. We have used these for about 4 year. Induction hardened teeth. Could use them for multiply years if it wasn’t for stupid First cots rules. The KHK gears are a little higher precision. And you pay allot for that. Be sure you have access to machining to cut them down. My guess is you design needs 4 to 1. If you go down to 3to1 there are more option. Our design only uses 2 stages of reduction and we need 4 to 1.
What are you modifying to make the non-COTS?
Either requesting mods or putting holes in them, probably.
This is what we buy.Bevel Gear
So you can see that there is some machining to make them look like the discontinued SDS gears. For some reason First wants to punish us for making these gears instead of purchasing SDS gears. First is supporting the “do it for me” mindset instead of teaching students how to “make”. I want to turn our students in to makers.
The 2023 Game Manual Section 9 rules are kind of confusing here. Seems like even if you machine it yourself it falls into Example 2, but I could also see some readings of Example 3 and my highlighted sentence that would make it legal.
You came to the right conclusion but cited the wrong rule.
That is the rule that defines COTS and just states that discontinued COTS parts that are not functionally modified are still COTS. However, the rule about parts made before the season allows for functionally equivalent parts:
Bonus rule info:
Those exceptions are referenced in the rule about what you can do during an event, and even though the blue box says you can’t 3D print parts overnight you actually can 3D print functional equivalents to COTS parts overnight.
I might experiment with this one as it’s currently the most cost efficient option, however I can’t seem to find a CAD file anywhere? Is there one on the vendor’s site?
It’s not a part of the MK3 CAD assembly?
I mean I don’t know the exact gear/vendor that SDS purchased from, and idt the dimensions would be the same.
If it’s the same tooth count and pitch, it should be the same (or very close) or someone did something very wrong. Where you’re looking for differences is the thickness and the bore.
Hmm… @PatrickW ?
I swear there was vendor or sponsor of some events I attended that were making 3D printed parts for any team at the event that needed them even if it was an overnight print.
I believe SDS originally used KHK gears. They have cad down loads if you register if I remember. The gear I noted is dimensional a little different. What we end up with is very close to SDS after machining. We remove more on the back side and the center is a little more hogged out. c to c distances are the same. On a good cnc mill this is an easy cut. All the work is in fixturing.