Scrambler C

[joeyjoejoe]

And the beautifully simple formula for this is:

S = Pi*DLT
where
S=distance traveled
D=diameter of wheels on break axle
L=length of break nut travel
T= turns per unit length of break axle

I usually do all the math in inches since the threaded rods around here are all given in turns per inch.

So for CD wheels (app 4.75"), 1/4" threaded rod (usually 20TPI), in order to travel the 11.7 meters (app 460") you would need at least
460/(pi*4.75*20)=1.54" of break-nut travel.

[dodgers31296]

Quick question i'm using a threaded axle and I have my wheels fixed on with nuts and washers. How do I stop my axle from sliding back and forth without stopping it from spinning?

[iwonder]

You could put washers on the axle and snug the up to the frame very loosely, that'd stop it for the most part.

What we do is just wrap tape around the axles along side the frame (it acts like a washer) but that's because the other teams vehicle doesn't use all threaded rod and it's already slightly thrown together

[joeyjoejoe]

How are you fixing your bearings to your car? Pillow blocks? If the bearings are fixed to the car so that they can't move left and right, then putting a double nut on the axle on both sides of the bearings will work (could use nylon nuts to limit weight). You could just put the double nuts on either the inside of the bearings or the outside to reduce weight.
If you tighten each pairs of nuts towards each other until you can't turn them any more, then they will not move on the threaded rod. Doing this on both sides of the bearings (leave a mm or so) will effectively prevent the axle from sliding left or right.

I've even seen a car that had its bearings super glued to the axle although I would never want to get that stuff anywhere near my bearings!

In the future, if you can find bearings with an extended inner race, you can take a single nut on both sides and tighten them all the way up to the race.

[dodgers31296]

Thanks for the replies. I think i'm gonna go with the tape also my teacher suggested straws do you think that would have less friction?

[iwonder]

Straws would work if you don't have any kind of bearing. (so if your axle right now is just stuck into a hole in the wood) They won't stop the shaft from sliding back and forth, but they'll make it turn easier.

[dodgers31296]

So adding straws as bearings and tape on the outsides will fix my problem?

[_HenryHscioly_]

I use nuts and get them close to bearing, with about .5mm of space.

What do you think is "rigid"?
I used two 1/4" thick balsa pieces to make my backstop. (much lighter than some piece of lumber)
However, I'm afraid it is too soft?.. I broke two eggs, and now there is a very very slight indent on the backstop. I spread some super glue over that spot, but still...
I know this is not official, just wondering if anyone had any ideas/experience regarding this matter.

[iwonder]

I would call that rigid. Personally I think anything that's able to stay flat with a dowel and it's own weight would be rigid.

[A Person]

I use nuts and get them close to bearing, with about .5mm of space.

What do you think is "rigid"?
I used two 1/4" thick balsa pieces to make my backstop. (much lighter than some piece of lumber)
However, I'm afraid it is too soft?.. I broke two eggs, and now there is a very very slight indent on the backstop. I spread some super glue over that spot, but still...
I know this is not official, just wondering if anyone had any ideas/experience regarding this matter.

Using super glue was probably a good idea. I think that what iWonder said would make sense, you shouldn't have any problems.