Fabricating A 90° Gearbox

[twocik]

Looking to make simple 90 degree gearbox with very little to no backlash. The box isn't going to be ran at high or even low rpms, simple turning back and forth to focus a camera lens. I'm curious on what gears would be best to use for something like this. I've looked into miter, but someone mention a worm setup might be better. Any links, sites, tips, tricks, etc that could help me figure this out would be great !


Currently using the Rino miter 90° gearbox, but the backlash is pretty bad 0.2" out. Not to mention they run close to $45 each...





Rino Mechanical: Plastic Gearboxes


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[packrat]

The PDF for your gear box gives a backlash spec. of 2 degrees so thats what you got. can you take the box apart? If so you can shim the between the gear hubs and bearing housings to move the gears closer together, reducing backlash.

cary

[will gilmore]

for an application with very low force and slow speeds you could probably just spring load the output shaft to reduce backlash

[twocik]

No taking that box apart I don't think is going to happen without a mess. Looks to be some sort of plastic injected operation. Yes the 2 degrees is way too much for the application I'm using it for.

I really like the spring loaded idea, but I guess I'd need to look at gears, shafts, etc.. first.

As soon as I find the parts I'm going to run a box thru my CNC mill. This is my first time making something like this and any tips on that would be great too.


Any sites you can recommend for gears, shafts ?

[will gilmore]

Precision Gears Timing Belts Timing Belt Pulleys Precision Bearings Brakes Clutches Precision Couplings Sprockets Chains and Maufacturing from SDP/SI

[rowbare]

It doesn't sound like your force requirements are all that high. Have you considered using a friction drive? It is simple enough to mock up and test.

bob

[packrat]

Originally Posted by twocik No taking that box apart I don't think is going to happen without a mess. Looks to be some sort of plastic injected operation. Yes the 2 degrees is way too much for the application I'm using it for. As soon as I find the parts I'm going to run a box thru my CNC mill. This is my first time making something like this and any tips on that would be great too.

Instead of buying new gears, why not break or saw this one apart and reuse the gears from it?

[twocik]

Thanks for the link.




"Have you considered using a friction drive?"


Not familiar with friction drive ?






"Instead of buying new gears, why not break or saw this one apart and reuse the gears from it?"



I would, but I was planning on making these to sell.

[rowbare]

Here is a link to a patent for a friction drive. This particular one isn't an angle drive but it demonstrates the concept:
LONG WEARING FRICTION DRIVE MECHANISM - Google Patent Search

While looking for friction drives I came upon this patent using a spring as an angle drive:

Right angle dental hand piece with ... - Google Patent Search

bob