Hello everyone,
I was designing the drivetrain in cad, but I’ve realized the total spacing is odd (1.942 in) and it doesn’t fit a c-channel at the end. Is the following order viable?
Flat Side C-Channel → Lock Nut → 48 Tooth HS Gear → 3.25 Wheel → .5 and .25 Spacer (OD .375) → Sunken Side C-Channel
Thanks in advance for your helps!
Hello,
I’m not a designing master and I’m sure there are other people out there who could give better advice, but I’ll help in any way I can.
Firstly, the screw joints themselves.
I would like to make start saying I’m still researching screw joints, so I definitely don’t know a ton about them, but I got some decent advice on the G2M forum (giving credit where credit is due, I got a lot of good information from Amanda on that forum). Here’s a link to the thread (if it’s not allowed to share links to 3rd party sources, my dearest apologies, mods): Drive Screw Jointing - #13 by VexTeamZ - general-discussion - The G2M Forum
I would consider adding another nylock nut to essentially “sandwich” your joint. This would help in preventing the screw from getting lose and basically slowly unscrewing as you drive it.
In general, I would just keep experimenting with spacers, washers, etc. until you get a conventional width that is applicable in Vex.
Here is a design that I developed for my team’s drive. Granted, this could be completely wrong and not a viable design (I mean I really am new to them), but I designed it using knowledge from others. (also sorry that the text is hard to see if you’re using dark mode like me–this was made for a lighter background)
(Please do your own designing, this is just an example)
Note that this is a 4 hole wide drive which is not necessarily the most advanced, but I frankly didn’t trust myself making a 3, lol.
I used …
Now, time to talk about the drive sandwich caps…
While I have nothing against using the C-channel, it can be rather bulky and hard to screw to the drive sandwich. Perhaps you should consider using standoffs and shaft collars instead (You will need a coupler to connect them when you build them).
Now other people may have their own (and probably better) bits of advice, but there was mine.
Hope this helps.
Hey, first of all thank you for your lengthy reply. I ran into another issue while cading. The shaft collar doesn’t really fit. I’ve read some other forum posts, they used rubber band and zipties. Is this a viable option or should I drop this design?
One key issue I notice is that the nut for your screw is in the wrong place, what you want to do instead is to put the nut directly on the opposite side of your screw on the other side of the c channel. this way it will free up some space and allow for that nice sweet five hole wide drivetrain.
ahh yes I have ran into the same issue before. you can buy the custom spacers on robosource that are thin enough to fit in between. you can just run these through out the axel.
the solution is quite simple. put the screw to where it is screwed from the other side and that other side is the outside of your drivetrain.
This makes it where u can put the lock nut inside the C-channel where it doesn’t stick out and gives u much more wiggle room for the wheel
Heres a picture from my teams cad this year
Hop[e this helps 
Any time! Our organization is a library–we like to write… 
