First Build - Featherweight Bar Spinner

[Ocracoke]

To answer your questions directly:

1. Ish. My axe motor does this on my middleweight I think but not by very much. I would prefer the pinion gear to be wholly on the axe motor itself since I don't really want to end up bending the shaft.

2. In my experience, no, not on a drive train but keyways do help lock in a gear or a wheel hub onto a shaft. The axe motor I have on my middleweight has a small keyway which I drilled a specific point to allow the grub screw to sit in. Depends on how much force is likely to go through it. In the lighter (i.e. Beetlweight) classes, I don't bother with this and simply screw the grub screw onto a flat on the motor shaft.

[Dr. Crane]

Hello - hope everyone enjoyed the holidays!

Thanks to the kind advice above, I have bought new Gimson motors as suggested. In order to accommodate these larger, heavier motors my design is now larger across all three dimensions.

This then presented a weight problem and so I have designed some cuts in the chassis to try and save weight - I'm estimating the chassis to weigh in around the 4.5kg mark (based on a 2.71g/cm^3 density).

The good news is I now have access to a makeshift and somewhat limited workshop but it does mean I can do some of the machining myself.

I have a few more questions and would, as always, be really grateful for any advice:

1.I currently have one 5S 4000mah 30-40C LiPo - is this going to be enough to power the drive and the weapon or am I going to need two?
2. From my attachment "Overview" v2 - I have never worked with aluminium and so I am wondering if parts of the chassis are likely to bend under force given I have now cut weight-saving holes?
3. From my attachment "Motor Bracket" - I am wondering how I can drill these horizontal holes into the bracket? I am also looking to thread them. It is 1/2 inch thick (note in my CAD the holes go all the way through just for ease but I'm only expecting to drill enough to bolt it to the bulkheads).

Thanks once again and a Happy New Year to everyone when it comes!

Cheers

[Dr. Crane]

Hello all,

I’ve made a few changes to the design - mainly reducing the thickness of the chassis from 1/2” to 3/8” or even 1/4” where I think it will allow.

The aluminium has arrived! I spent an hour making the attached cut The marked section is one of the bulkheads.

This is the only remaining 1/2” section though so that’s as hard as the blade will have to work. They aren’t super fancy blades so I imagine I might go through a few but will see how it goes.

Ive sent off a piece of 3/8” sheet to be cut by waterjet - this is for the V shaped arms at the front which are now much simplified. The shop is miles away and only open Mon-Fri so will be a while before I can pick them up! Lots to do before I need them anyway...

Plan is to get the bulkheads cut and then start drilling holes for attaching the drive motors. I have a cheapy pillar drill which I am hoping will prove to be good value!

As im at the startup phase - the biggest expense seems to be buying lots of little bits like drill bits, saw blades, files, lubricant etc. - all adds up!

I’ll get some more cutting done this week(end).

cheers,

P.S. does this thread need to be moved to Build Diaries? Can a mod do that or do I need to start a new thread?