Hi Everyone, we’re trying to convince our instructor to purchase either torx screws or phillips screws to replace our hex screws. In my experience, I find the hex screws to strip quite easily as their shape is already similar to that of a circle. In addition to this, the screwdrivers that we purchase from vex are made of steel and, generally speaking, are fairly low quality (they strip also).
In other words, I’m conducting a survey of the vex forum to see who uses what kind of screws and why to assist me in my proposal to our instructor.
Personally I prefer and continue to use hex screws as they can be tightened at an angle with ball-end allen keys, which is quite useful when it comes to mantainence. But torx and phillips are certainly useful when it comes to components which require significnant amounts of tightening which may strip a hex screw.
When stardrive screws were first introduced in starstruck, I kinda rolled my eyes at them too.
But that’s not a fair assessment- they’re incredibly helpful. First off, torx screws absolutely do not strip. I’ve maybe stripped 2 per season, as opposed to over 10 per week with hex heads, and the shape of the screw allows them to be made from slightly lower grade steel which makes them lighter (at least compared to the old hex heads). You can also tighten them much more without worrying about stripping, which means your standoffs and keps nuts will never fall off. And because the screw drivers don’t strip either, you can be a lot less careful when you’re tightening. Just crank as hard as you can and you’re good.
If you’re worried about the lack of ball end screw drivers, they actually do exist. This is a really good one I’ve used in the past, the biggest issue being price -
I’ve also been really happy with these screw drivers for normal applications, the biggest advantage being that they’re slightly magnetic so you can balance a screw on the tip and you don’t need to get your fingers into tight spaces.
And because the ball end screw drivers are a little thicker (and produced in Europe, not China : ) you don’t need to worry about the ball breaking off.
So yeah, it’s more expensive than it should be, but it’s totally worth it.
Torx drive (“star drive” is best, by far, for screw stripping, with the exception of socket head cap screws (which you’d have to buy from McMaster or elsewhere). For either hex or torx, good tools are a must. Be sure to check out www.robosource.net for tools. They have a kit of star-drive tools to help make the conversion for a team from hex to torx easier, too.
Nylon screws are great, just not a replacement for steel screws. Nylon screws are a great way to cut down on weight but should only be used on very low stress areas like bearings. Also, i would buy the torx (star) screws as they hardly ever strip and can actually hold weight unlike nylons.
Nylon screws are amazing to use with pillow bearings, standoffs, bearings, and lexan. They take Phillips head and flat head, so there isn’t a need to buy a separate screwdriver. Just be careful to not overtighten them, I’ve had the heads of them break into standoffs when people who haven’t used nylon screws as extensively put them in. You can take them out with pliers, but in some cases it ruins the standoff.
I’d also recommend getting Aluminium screws for weight reduction. They are really only supposed to be used for structural stuff, so, using them as a joint is a really bad idea. I had a member use that for a DR4B joint and it was definitely not fun to replace…
Hex screws are normally fine, even for tightening a lot. Buying nicer screwdrivers is a good idea (ace has some good ones). Last year, our whole robot used about 2.5 pounds of screws and nuts, which was about 12% of the total weight. If we switched to nylon wherever possible, we could’ve saved about a pound or a little more, but i don’t think it’s worth it to lose the structure and stability even in low stress applications.
I used hex only. I had tons of high stress situations … I never stripped a hex, you need a driver than isn’t stripped, and you need to always be pressing into the screw, the more torque you need to use the harder you need to press in. I know I know screwdrivers 101 but you’d be shocked how often you can strip if you aren’t careful. Honestly Id say go buy nice grade screws identical to what VEX sells. Live with the hex and enjoy the convenience of a ball hex. Also as long as you tighten enough you should never have to double nylock a bolt (I should know I’ve done plenty of stupid crap in my days). IF for some forsaken reason you need a high torque gear box of 343 to 1 to release some rubber band tension, bluntly you’re wrong,
My thoughts are nuanced based on users more than anything else.
For myself, I’ve never had a problem with hex head screws, and I’ve been using them for several decades. I also appreciate the ball ended hex-tipped drivers. I have many at home, though the school doesn’t have any. I still have torx drivers at home because enough things (such as my washer) require them. Working on VEX robotics, I’ve never had an issue with hex-head screws I’ve tightened.
For my students, I have to regularly teach them about screws and their proper use. Their idea of a tight screw is commonly enough what I consider hand-tight. They don’t know how to fit the drivers into the screws well, whether that’s finding the orientation blindly to begin with, holding it in securely while turning, or keeping them aligned well while turning. As a result, the hex tools have gotten stripped a lot (not really the screws). For comparison, I can still tighten/loose with a fairly stripped hex tool better than my students can with a fairly new tool. That’s OK. It’s something I teach them, and I’m their teacher. But it does mean that I don’t like the hex-head screws as much as the torx screws for my students, because they seem to be able to work with the torx drivers better than the hex drivers.
I’ve gone from working nearly exclusively in hex with cheap tools, to exclusively using torx with nicer tools (still most of them only cost around $10).
It’s absolutely worth it.
Seriously, not ever having to worry about stripping your tools or your screws alleviates such a big headache. It especially helps when undoing screws with thread lock or nylocks and also allows for worry-free use of electric screwdrivers and t-handles.
We switched to Torx the year they were introduced, and since then we have never stripped a screw. We’ve been using the same screws for years and never had a problem with it. I would definitely recommend these over those hex, because for us those caused so much misery. We have had to spend entire 2 hour meetings just taking off our flywheel because all of the screws on it stripped immediately.