unnamed drum spinner

[Max]

here is the video (not the best video i've watched but does the job)

[jonny]

nice!

[Max]

They're some hefty bearings!! With the cast iron housings they weigh almost half a kilo each do they not? Suppose it's fine if weight's not a problem, but if your robot's too heavy they'll be a prime candidate for weight reduction.

Overall it's looking rather fine though. Always nice to see another drum

They are only 0.4 kg actually!

[Max]

Did a bit more work on the robot today, all the hdpe is now screwed together and all the motors/electronics are inside. Just got to screw on base plate and put in an led then it will be ready for testing! No idea where I will test it as it has do little ground clearance (about 1mm by the look of it!) so I make have to screw/glue on some thin rubber. Also had problems with space for the wheels, basically there wasn't enough of it so had to do some modiffying. Only other problem is that only one battery fits in the robot so I don't know what I'll do about that.

[typhoon_driver]

They are only 0.4 kg actually!

Lol my bearings weigh only a few grams a piece. I would advise that next time, have a solid stationary shaft and then have some needle roller bearings inside the drum. Makes for a stronger structure overall and means you don't have to use those large bearing blocks.

Not looking too bad at all though.

[PJ-27]

I take it Needle Bearings are up to the impacts and RPM then?

[typhoon_driver]

For a drum yes as the impact energy is actually very low. Boner only has around 700J in it when it's going full speed and that's with a 3.8kg drum.

The danger from a drum isn't from a single large impact like a disc but rather a series of smaller hits that keep coming again and again.

[PJ-27]

Yeh I've heard before that Boner is only 700J but it must us them very effectively!

Ok that's interesting to know. What sort of RPM does Boner spin at?

[typhoon_driver]

around the 4000 rpm mark. The reason for the low KE is the relatively small diameter of the drum. If I took the same 4kg and increased the diameter then I could in theory store more energy in the disc than typhoon 2 however the resultant disc would fail on impact from lack of structure.

[Max]

Did a bit more work today, I wired and fixed in my led and put in some 25 amp fuses from tecnobots to protect my esc. Tried to screw it onto the base plate but my countersink sucks so the screw heads scape along the floor so need to get a new decent countersink tomorrow hopefully! I can't weigh it to see how it's doing because last time I tried I broke my mums bathroom scales so I no longer have any, what type do most people use to weigh featherweights?