Custom Gearboxes

Hi All

Been designing the gearboxes for my second feather weight for some time now, and it has to be said, I have made some pretty catostrophic errors in the design stage (i.e. brushless drive). I have since started my 4th or 5th attempt at this design, and really struggling with some of the basics. For example: How do I attach gears to shafts?
How do I hold a bearing?
How do I attach the shaft to the bearing?

Another thing that I am having problems with is... will it actualy work! (i.e. will it be strong enough etc)

Any help on this will be greatly appreciated!

Thanks :)

No to dampen your spirits but I wouldn't go there. Don't design your own gearboxes. We can tell you what you need to know but even the top teams buy in parts like gearboxes unless they have very high end manufacturing facilities.
If you really want to do it I suggest buying a few old gearboxes for feathers like Banebots or Gimsons and seeing how they are assembled and built but you will waste a lot of time and money by going down this route and it will give you no advantage at all. Sorry, but its true.

I get your point, but... robots like Satanix, Tiny Toon, Bonx, 540 and even Tiny Hurtz run off home made gearboxes.
Heavy weights too, all most every heavy weight I know uses custom gearboxes.
So... People must have a way a making them, don't they?

It all depends on what sort of ratio you need and space as to if its worth buying or making gearboxes. I tend to build all mine (access to a mill is ideal). Speed 900's all tend to use custom gearboxes as the ratios are only small - and therefore can get away with a single stage gearing. These can be really simple and easy to build like the ones in Satanix and beauty. It gets tricky when you need to go more towards a 2 or 3 strange gearbox and you need better equipment, alignment and the gears generally aren't cheap. It can save you a huge amount of weight though and get you motor positions mucho better.

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Originally Posted by SamO

Hi All
Been designing the gearboxes for my second feather weight for some time now, and it has to be said, I have made some pretty catostrophic errors in the design stage (i.e. brushless drive).

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If you don't know everything of the motor, , nor have tested it, it's already difficult to make a gearbox for it.

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I have since started my 4th or 5th attempt at this design, and really struggling with some of the basics.

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I got the basics 25 years ago, in school.

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For example: How do I attach gears to shafts?

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Any means is good. from welding to grubscrews, from key and keyway to spline. Even glue will do, if used well.

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How do I hold a bearing?

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Simple methode. Buy bearing with their own bolt on housing. Like this one.
Less simple methode is very very accurate holes in plates (we're talking of 0.001mm jobs), or glue (for the small mistakes)

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How do I attach the shaft to the bearing?

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The shaft should fit snuggly in the bearing. If that ain't the case, there are bearings with longer inner races with grub screws. Otherwise it's glue-time again.

btw, for robot applications I prefer bushings. Way bigger tollerances, making it easier to work with.

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Another thing that I am having problems with is... will it actualy work! (i.e. will it be strong enough etc)

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That can't be predicted. But 1 thing is a fact. Keep It Simple.

540 uses the dewalt gearboxes from robot market place

Didn't it use to run off S900's with custom gearboxes though?

originally ran on dewalts then dave tried a speed 900 setup but when I bought it I went back to the dewalts and ran them on low speed rather than high speed. Even on low speed the dewalts were red hot when it came out the arena after three minutes

Is that with the magnet?

Are they Dewalt's from Robot market place or did you strip them out of drills?

Dave got them from robot marketplace originally and they were red hot without a magnet on board. It takes a lot of power to move and steer a 6wd machine and push other machines around the arena.

There's pictures of various custom made gearboxes that I've built in the past (including 540's) in my build diary.

Thanks, thats the sort of thing I'm aiming for :)