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terence.tan wrote:is it just me or is everyone having issues reaching the 8 meters?

Mine actually went over 8 meters. Originally, I had some trouble getting over 8 meters but then I just extended my drive arm.

terence.tan wrote:is it just me or is everyone having issues reaching the 8 meters?

Same. We just got it today in fact by putting our mousetraps back further.

So I just built my first prototype but am experiencing some issues particularly with the axles. I'm using 1/4" threaded rods as recommended, but the issue is that as they spin they will actually rotate like a screw in the axle holes, so then the car will become misaligned and the wheels will hit the side of the car. How do I prevent this?

Also, I'm currently using fishing line for the drive string, is that the best option? My fishing line stretches a little so I'm not sure if that's bad or not.

sciencecat42 wrote:So I just built my first prototype but am experiencing some issues particularly with the axles. I'm using 1/4" threaded rods as recommended, but the issue is that as they spin they will actually rotate like a screw in the axle holes, so then the car will become misaligned and the wheels will hit the side of the car. How do I prevent this?

Also, I'm currently using fishing line for the drive string, is that the best option? My fishing line stretches a little so I'm not sure if that's bad or not.

Are you using bearings in your axel holes? They will reduce the amount of screwage. Also, I would recommend securing your wheels to your axel on both sides with nuts (ny-lock nuts if you want to get really fancy). That way, when some side to side slipping of the axel inevitably does happen, it will be only those nuts that come into contact with the bearings rather than the entire wheel, which will cause very little friction.

Fishing line should work fine/I've seen a bunch of teams use it. I was also experiencing some issues with mild stretching last year so I eventually switched over to some thinish string that I had lying around and that seems to have solved the problem. Experiment. See what works.

Wabbit wrote:

sciencecat42 wrote:So I just built my first prototype but am experiencing some issues particularly with the axles. I'm using 1/4" threaded rods as recommended, but the issue is that as they spin they will actually rotate like a screw in the axle holes, so then the car will become misaligned and the wheels will hit the side of the car. How do I prevent this?

Also, I'm currently using fishing line for the drive string, is that the best option? My fishing line stretches a little so I'm not sure if that's bad or not.

Are you using bearings in your axel holes? They will reduce the amount of screwage. Also, I would recommend securing your wheels to your axel on both sides with nuts (ny-lock nuts if you want to get really fancy). That way, when some side to side slipping of the axel inevitably does happen, it will be only those nuts that come into contact with the bearings rather than the entire wheel, which will cause very little friction.

Fishing line should work fine/I've seen a bunch of teams use it. I was also experiencing some issues with mild stretching last year so I eventually switched over to some thinish string that I had lying around and that seems to have solved the problem. Experiment. See what works.

I use braided Kevlar fishing line, and it doesn't stretch for me. My rod bends, though... As for the screwage, do you have any tubing the proper size to snuggly fit over your threaded rod? That's what I've done.

Things2do wrote:

Wabbit wrote:

sciencecat42 wrote:So I just built my first prototype but am experiencing some issues particularly with the axles. I'm using 1/4" threaded rods as recommended, but the issue is that as they spin they will actually rotate like a screw in the axle holes, so then the car will become misaligned and the wheels will hit the side of the car. How do I prevent this?

Also, I'm currently using fishing line for the drive string, is that the best option? My fishing line stretches a little so I'm not sure if that's bad or not.

Are you using bearings in your axel holes? They will reduce the amount of screwage. Also, I would recommend securing your wheels to your axel on both sides with nuts (ny-lock nuts if you want to get really fancy). That way, when some side to side slipping of the axel inevitably does happen, it will be only those nuts that come into contact with the bearings rather than the entire wheel, which will cause very little friction.

Fishing line should work fine/I've seen a bunch of teams use it. I was also experiencing some issues with mild stretching last year so I eventually switched over to some thinish string that I had lying around and that seems to have solved the problem. Experiment. See what works.

I use braided Kevlar fishing line, and it doesn't stretch for me. My rod bends, though... As for the screwage, do you have any tubing the proper size to snuggly fit over your threaded rod? That's what I've done.

I also use braided kevlar fishing line since this strong and never stretches. As for the wheel and axle problem use something to hold it in place like the nut lovks as suggested above.

Is there a certain brand people are going with for mousetraps? Or does it not really matter as long as they provide enough force?

cheese wrote:Is there a certain brand people are going with for mousetraps? Or does it not really matter as long as they provide enough force?

I go by force, not brand. I found a basket full of unopened 4 packs for a dollar each, and they've worked fine. They're good, and they were cheap. The 2 qualities of a good material.

DarthBuilder wrote:

Things2do wrote:

Wabbit wrote:
Are you using bearings in your axel holes? They will reduce the amount of screwage. Also, I would recommend securing your wheels to your axel on both sides with nuts (ny-lock nuts if you want to get really fancy). That way, when some side to side slipping of the axel inevitably does happen, it will be only those nuts that come into contact with the bearings rather than the entire wheel, which will cause very little friction.

Fishing line should work fine/I've seen a bunch of teams use it. I was also experiencing some issues with mild stretching last year so I eventually switched over to some thinish string that I had lying around and that seems to have solved the problem. Experiment. See what works.

I use braided Kevlar fishing line, and it doesn't stretch for me. My rod bends, though... As for the screwage, do you have any tubing the proper size to snuggly fit over your threaded rod? That's what I've done.

I also use braided kevlar fishing line since this strong and never stretches. As for the wheel and axle problem use something to hold it in place like the nut lovks as suggested above.

Already using metal nuts on each side of the wheel to hold it in place. The screwing of the axle and the winding of the string move it out of place though.

As for the bearings, should I go with ball bearings specifically or just bearings with some graphite lube?

sciencecat42 wrote:

DarthBuilder wrote:

Things2do wrote: I use braided Kevlar fishing line, and it doesn't stretch for me. My rod bends, though... As for the screwage, do you have any tubing the proper size to snuggly fit over your threaded rod? That's what I've done.

I also use braided kevlar fishing line since this strong and never stretches. As for the wheel and axle problem use something to hold it in place like the nut lovks as suggested above.

Already using metal nuts on each side of the wheel to hold it in place. The screwing of the axle and the winding of the string move it out of place though.

As for the bearings, should I go with ball bearings specifically or just bearings with some graphite lube?

Right now I’m using regular ball bearings then I soaked them in WD40 for a few mins then applied graphene I think? But eventually I’d want to get ceramic bearings.