This season there’s been a change in <R12> that allows for screws up to 2.5" long to be used, compared to the previous 2" limit.
<R12> Certain non-VEX screws, nuts, and washers are allowed. Robots may use any commercially
available #4, #6, #8, M3, M3.5, or M4 screw up to 2.5” (63.5mm) long (nominal), and any commercially
available nut, washer, and / or non-threaded spacer (up to 2.5” (63.5mm) long) to fit these screws.
I think this is great, it allows for more freedom when building with screws that doesn’t require creating custom screws from shafts.
I currently use the colored robosource torx screws, and after experiencing how much better torx screws are than hex I never want to go back. However, I have not been able to find 2.5" long torx screws with the right thread size anywhere. The closest thing were these hex screws from McMaster-Carr. These would work, but like I said, I’d prefer to not have to use hex for anything.
So my question is, has anyone else been able to find 2.5" T15 8-32 Screws anywhere?
and if not, is it a safe bet that robosource will be selling some in the near future, or should I just suck it up and buy the hex screws?
Kevin (from Robosource) talked a little on VTOW and said he is working to stock the new screw lengths, so our team will most likely be waiting on that.
I’m curious where robosource would get stock for these screws if places like McMaster-Carr don’t even have any, but it seems like somebody out there must be manufacturing these kind of screws.
I expect robosource.net is having screws custom made by a screw manufacturer. That’s how it gets the colored screw-heads done, and the various shoulder screws that fit vex metal perfectly. McMaster Carr is just a reseller/distributor.
I only see hex on McMaster. If you want to build or prototype early season, I’d just use hex but if youre waiting, then Robosource will probably have them eventually.
My reading is that they don’t need to be T15, so these T20 pan head 60mm (2.36in, almost max length) would be legal.
It’s another driver to carry and keep track of, but it’s probably worth it. I’ve ordered some and will comment on their quality when they arrive.
There are longer screws of the security type with a peg in the centre of the star socket. Perhaps that could be ground out, but of course they’re designed to resist. Utility might justify that effort, but until I need those extra mm, I’m unlikely to get to trying. If the screw must be of a legal length before any modifications, then it’s 60mm until someone finds a 2.5" source.
You could also turn custom screws up to 24" long from High-Strength shafts! Just take a picture showing the students doing the turning so you can pass inspection.
You win today’s internets. (I learned a thing - deleting a post puts it in that withdrawn state. Will endeavour to avoid wasting quite so much space in the scroll in the future.)
Respectfully disagree. With a screw joint used in a dr4b for instance (but really any weight bearing screw joint), it’s a common build practice to use c-channel couplers and extra pillow blocks for more support. Doing so max’s out a 2” screw, leaving no room for spacing adjustability in the joint. And no, a standoff and coupler extension won’t fit. This has been an annoying build constraint in past years, so thank you Vex for finally eliminating this unintentional challenge.
@Sidoti, and Kevin from Robosource (I don’t know if he has an @ on the forum), is there any progress on this? 2.5" Screws would be very helpful…
And @u89djt, how did those screws work out? Did you order them?
I ended up needing quite a few 2.5" screws for my robot (they work perfectly for a screw joint on a 6 hole wide drive side.) so I went ahead and ordered the hex screws from McMaster that I linked in the original post.
They suck because they’re hex head, but they work. Just be careful not to strip them because I speak from experience when I say removing a nylock off a 2.5" stripped hex screw is about as terrible as you can imagine it is.
I did but they haven’t seen action further than checking geometry and a couple of experimental assemblies, so I can’t comment on material quality. Robosource are probably having enough trouble with their existing portfolio with container shipping as it is these days.
Just take a picture showing the students doing the turning so you can pass inspection.
