Battery Buggy B

[hippo9]

I wouldn't be screwing into ABS. I would be screwing into cooled hot glue.

Screwing into hot glue is definitely not advised. Not only would everything melt, but anything placed into that hole would have very little support.

So I can't mount my micro switch like that?

I mean you could, but it would probably fall out after a while, but I guess you could try it.

[shrewdPanther46]

That makes no sense, why would u screw something into hot glue that literally makes no sense...
ur better off just supergluing or something... u need to design the mount so it has threaded holes

[MadCow2357]

That makes no sense, why would u screw something into hot glue that literally makes no sense...
ur better off just supergluing or something... u need to design the mount so it has threaded holes

How do I do that? Do I use the metric thread generator in Tinkercad?

[hippo9]

I don't know anything about Tinkercad, but if you used Autodesk Inventor it would be really simple.

[MadCow2357]

Ok, I have embarked on my quest for the perfect F1 Battery Buggy ! I 3d printed this file I designed in Tinkercad:
https://www.tinkercad.com/things/gvUEjg ... WOcrcBWqc=
My 8 mm square CF rod fits almost perfectly in the top square hole of the test print, but it is able to wiggle a little bit in the two bottom square holes. Is this normal?

The dimensions of each square hole are all the same: 8 mm side by 8 mm side by 1 cm depth. The hole in the middle is for the ball bearings.

Also, my test print came out a little bit warped. Not sure if that may be a problem.

Sorry for double posting, I am on a time crunch so I want to make sure people see my questions.

[MadCow2357]

Something is starting to bother me as well. Let me explain why. In the last post I mentioned that the rods could wiggle a little bit. windu used 3 CF rods on the bottom of his 2016 EV. And in a previous post windu described some sort of chassis torsion.

This is NOT a good reason to go with this design lol
The correct reasons are as follows:
Benefits: Elimination of chassis torsion and it allows for implementation of passive adjustable steering (as seen on EV 2016)
Cons: Difficult to implement correctly - fit between CF and 3D printed parts MUST be an interference fit or you WILL run into problems (you cant just glue/epoxy the rods in - the fit needs to be so tight that you have to lube the rods and hammer them in.
These pros/cons are not self-evident and i didnt realize them until I struggled with chassis torsion on my 2017 EV which required a complicated solution to solve.

Is 2 mm of ABS enough to keep the CF from breaking free of the 3D printed connector (see Tinkercad file)? And do the 2 rods on the bottom provide sufficient strength to hold my Battery Buggy together? Maybe I should put 3 on the bottom like windu did. The torsion thing is making me very nervous...
Again sorry for double posting, reasoning explained in previous post.

[shrewdPanther46]

If its making you that nervous, why are you doing it? You really should just chill on the mechanical design and work on accuracy. Speed isn't nearly as important.

Don't mean to sound harsh, just my personal suggestion.

[MadCow2357]

If its making you that nervous, why are you doing it? You really should just chill on the mechanical design and work on accuracy. Speed isn't nearly as important.

Don't mean to sound harsh, just my personal suggestion.

It's all good , will take that advice. Btw, a hooray that my partner's dad has a nice Dremel rotary cutter! To do good at Science Olympiad building events, it seems that you need a really handy dad, and I don't. Luckily my friend has a handy dad

[windu34]

Do you recall which print settings and filament company you used?

Makerbot Replicator 2 and Makerbot clear filament.

Is 2 mm of ABS enough to keep the CF from breaking free of the 3D printed connector (see Tinkercad file)? And do the 2 rods on the bottom provide sufficient strength to hold my Battery Buggy together? Maybe I should put 3 on the bottom like windu did. The torsion thing is making me very nervous...

2mm is actually the bare minimum. I would recommend 3mm if possible. I used the 5-rod trapezoid because I initially had a 3-rod triangle (https://www.youtube.com/watch?v=bGJrex059BY) (like yours) and found it to have too much flex, but it wasnt super significant. I would recommend the 5-rod trapezoid if you have the extra carbon, but if not, your current setup should be sufficient. the 3-rod configuration will be more adaptable to chassis torsion (counteract it more), but it wont be as stiff so it might end up being too flexible. I do not remember enough about my 3-rod config to be able to comment precisely on it.

My 8 mm square CF rod fits almost perfectly in the top square hole of the test print, but it is able to wiggle a little bit in the two bottom square holes. Is this normal?

The dimensions of each square hole are all the same: 8 mm side by 8 mm side by 1 cm depth. The hole in the middle is for the ball bearings.

Also, my test print came out a little bit warped. Not sure if that may be a problem.

There should be no wiggle so no, that is not good enough. 1cm of depth is not enough. Make it at least 3 or 4.

I wouldn't be screwing into ABS. I would be screwing into cooled hot glue.

Do NOT screw into either hot glue or plastic - it wont last in the long term, itll warp the material, and it is not aesthetically pleasing lol. I think the best thing to do is to epoxy the switch to the plastic and then add a second coat of epoxy once its dry. You could also have thru-holes and use a nut and bolt to fasten the switch to the chassis. Screw threads gripping into the material do not work though.

[MadCow2357]

Is 2 mm of ABS enough to keep the CF from breaking free of the 3D printed connector (see Tinkercad file)? And do the 2 rods on the bottom provide sufficient strength to hold my Battery Buggy together? Maybe I should put 3 on the bottom like windu did. The torsion thing is making me very nervous...

2mm is actually the bare minimum. I would recommend 3mm if possible. I used the 5-rod trapezoid because I initially had a 3-rod triangle (https://www.youtube.com/watch?v=bGJrex059BY) (like yours) and found it to have too much flex, but it wasnt super significant. I would recommend the 5-rod trapezoid if you have the extra carbon, but if not, your current setup should be sufficient. the 3-rod configuration will be more adaptable to chassis torsion (counteract it more), but it wont be as stiff so it might end up being too flexible. I do not remember enough about my 3-rod config to be able to comment precisely on it.

My 8 mm square CF rod fits almost perfectly in the top square hole of the test print, but it is able to wiggle a little bit in the two bottom square holes. Is this normal?

The dimensions of each square hole are all the same: 8 mm side by 8 mm side by 1 cm depth. The hole in the middle is for the ball bearings.

Also, my test print came out a little bit warped. Not sure if that may be a problem.

There should be no wiggle so no, that is not good enough. 1cm of depth is not enough. Make it at least 3 or 4.

I wouldn't be screwing into ABS. I would be screwing into cooled hot glue.

Do NOT screw into either hot glue or plastic - it wont last in the long term, itll warp the material, and it is not aesthetically pleasing lol. I think the best thing to do is to epoxy the switch to the plastic and then add a second coat of epoxy once its dry. You could also have thru-holes and use a nut and bolt to fasten the switch to the chassis. Screw threads gripping into the material do not work though.

I have decided that I will have a 5 CF rod bed in the middle, but I have yet to see if I have enough CF for an extra 11.5 cm CF rod(I may switch to 11 though). I bought 1 meter sticks (4).

I will see if I can make the holes 3 cm deep. Do I need there to be some material behind the rod so it does not portrude outward? You will probably understand my question if you look at my CAD file.

Windu what do you mean when you say that screw threads gripping into the material won't be enough? So should I make threaded holes?