2.5" Screws

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?

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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.

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fantastic to hear 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.

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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.

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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.

image

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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 can always use a screw, a standoff and a coupler screw (headless screw) to get the extensions you want.

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You could also turn custom screws up to 24" long from High-Strength shafts! :wink: Just take a picture showing the students doing the turning so you can pass inspection.

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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.

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welp time to custom turn out all my screws

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I think this rule change raises the question of why the screw length limit actually exists

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good question.

I presumed that the 2" limit existed because vex only sold screws up to 2" long, but now that it’s 2.5" that reason no longer holds.

you could say it’s due to costs, but really screws are cheap and a team is never going to need very many screws longer than 2.5" on their robot.

And using a lathe to turn your own screws from shafts is more expensive than buying them, but that’s perfectly legal.

So yeah I can’t see any great reason for a screw length limit. But it exists and it’s probably not going anywhere this year.

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We will be selling up to 2.5" screws. I’m sure there will be a new products post when they are available.

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