Mousetrap Vehicle C

[rafaelnadal]

has anyone found a 1/8" wingnut? it seems to not exist.

also i just noticed the 1/8" ball bearings i ordered are 30 grams each??!?!?!?! how is that even possible??

I'm reordering lighter bearings but good waste of money right there ^ ....

also its been like 10 days and most of my parts haven't arrived...

yeah mousetrap isn't going so well for me right now haha

EDIT: also how do i attach mousetraps to CF tubes??

also, it's been more than 10 days and i still havent gotten my carbon fiber/bearings, should i be getting worried? im considering getting balsa, but i dont want to waste $$ on it if my CF will come like the next day...

[retired1]

You need miniature ball bearings--I just weighed a package of 4 with a total weight of 8 grams.
Flanged bearings eliminate one nut/collar at each wheel. A weight savings and probably simplified building.
1/8" wing nuts are available at most hardware stores including many of the big box stores.
For weight saving, consider cutting off the one wing that you do not use. Bolt cutters work best, but a hack saw will work. If you use an abrasive cutoff wheel, be sure to clean out the threads. A tiny amount of grit can show up at the wrong time.
The simplest way to attach the mousetraps to CF tubes is to super glue or epoxy pop sickle sticks to the tubing. Common wood glue will work, but it will take a couple of coats and it is slow drying.

[rafaelnadal]

You need miniature ball bearings--I just weighed a package of 4 with a total weight of 8 grams.
Flanged bearings eliminate one nut/collar at each wheel. A weight savings and probably simplified building.
1/8" wing nuts are available at most hardware stores including many of the big box stores.
For weight saving, consider cutting off the one wing that you do not use. Bolt cutters work best, but a hack saw will work. If you use an abrasive cutoff wheel, be sure to clean out the threads. A tiny amount of grit can show up at the wrong time.
The simplest way to attach the mousetraps to CF tubes is to super glue or epoxy pop sickle sticks to the tubing. Common wood glue will work, but it will take a couple of coats and it is slow drying.

I did get miniature ball bearings - Ob74 open miniature ball bearings that weigh 1.1 oz each....sounds wayyyy too heavy

If i superglue the mousetraps to the cf tubes, can i replace them??

Thanks

[Private Wang Fire]

You need miniature ball bearings--I just weighed a package of 4 with a total weight of 8 grams.
Flanged bearings eliminate one nut/collar at each wheel. A weight savings and probably simplified building.
1/8" wing nuts are available at most hardware stores including many of the big box stores.
For weight saving, consider cutting off the one wing that you do not use. Bolt cutters work best, but a hack saw will work. If you use an abrasive cutoff wheel, be sure to clean out the threads. A tiny amount of grit can show up at the wrong time.
The simplest way to attach the mousetraps to CF tubes is to super glue or epoxy pop sickle sticks to the tubing. Common wood glue will work, but it will take a couple of coats and it is slow drying.

I did get miniature ball bearings - Ob74 open miniature ball bearings that weigh 1.1 oz each....sounds wayyyy too heavy

If i superglue the mousetraps to the cf tubes, can i replace them??

Thanks

You could always use acetone to dissolve the superglue, but personally I'd try to design some other way of attaching the mousetraps, like a plastic platform or something.

[retired1]

That is why I suggested using pop sickle sticks which will make an effective light weight platform.

For less weight in bearings, look for thinner ones with the smallest OD that you can find.

[MangoTTT]

Did anyone encounter problems about the vehicle not being able to push the cup? Is it just the surface that I test the car on or is there not enough force?

[antoine_ego]

Did anyone encounter problems about the vehicle not being able to push the cup? Is it just the surface that I test the car on or is there not enough force?

Almost definitely you just don't have enough force. The issue often results from having too long a lever arm or high friction along the axle.

[PM2017]

If I'm using a 3mm axle, and 4 in wheels, what size lever arm should I use?
Also, should I utilize some sort of pulley system so as to virtually increase axle size?

[retired1]

The length will be determined by trial and error. Start long and progressively shorten until you find an optimum. At this point, you can cut off what you do not need.
You might want to taper a small cork and put pins in it so you can start out with a bit more torque while starting and pushing the cup
Unless you have quite a bit of experience, I would not do this. If you only want to increase the diameter of the axle a tiny bit, You could glue on a close fitting brass tube. Personally, I would look for appropriate sized plastic tubing.

[PM2017]

I think I just had a nearly trivial, albeit clever idea for the dowel: using a very thin blade, cut along the length of a plastic straw (bigger than 1/4 inch in diameter), and just fold it in to fit into whatever slot you're using for the dowel. It is adjustable but also doesn't move on its own, due to the friction created by the elasticity of the straw.

It doesn't change a whole lot but makes life just a tad bit easier.