Design Feedback?

[SerpentEagle]

Originally Posted by Jared

My biggest concern would be the bearing in the .125" thick plate with a cantilevered spool at the end. If you're moving that six stack up and down quickly, there's going to be a lot of forces trying to bend the plate or make the hole into an oval.

Art Dutra brought up a valid concern with putting too many bearings on the same shaft and 'overlocating' it, but I think you could get away with a third bearing on the plate closest to the output side if you used a previously cut plate as a fixture for the next plate so they would be lined up. You're also using hex shafts and hex bearings, which tend to have sloppy fits anyway.

Yeah that's true. I'll go ahaid and experiment with 1/8" thick sheet metal and bearings at our next meeting, and make a little prototype with just the shaft and bearings so that I can apply a load and see how it holds up. Thanks!

[philso]

Originally Posted by artdutra04

I would avoid making gearbox plates on a manual mill, unless you have either a highly-experienced machinist or a moderately-experienced machinist and DROs. Otherwise, it's way too easy to put the bearing holes a few thousandths off which could cause excessive binding of the gears.

What about clamping and bolting the pairs of the plates together then using the mill to drill the holes for the standoffs and bearings?

Start by clamping the pair of plates together then using the mill to drill the holes for the standoffs. Bolt the pair of plates together using the standoff holes. Machine the holes for the bearings so that the holes in the two plates match. You may have to make a block to support the work piece that has recesses for the bolts used to hold the pairs of plates together.

[cadandcookies]

Originally Posted by philso

What about clamping and bolting the pairs of the plates together then using the mill to drill the holes for the standoffs and bearings?

Start by clamping the pair of plates together then using the mill to drill the holes for the standoffs. Bolt the pair of plates together using the standoff holes. Machine the holes for the bearings so that the holes in the two plates match. You may have to make a block to support the work piece that has recesses for the bolts used to hold the pairs of plates together.

Would you try to do the gear spacing this way? Seems to me that would still be difficult to do manually, though I have limited machining experience.

[asid61]

Originally Posted by cadandcookies

Would you try to do the gear spacing this way? Seems to me that would still be difficult to do manually, though I have limited machining experience.

I usually clamp all my plates together and mill them at once; it's far easier to do all the plates at once than one at a time. If the plates are all the same, I just clamp them all together with some kant-twists.
From the design I'm seeing here, you could try and make all the plates identical and do it on a manual mill. However, lightening patterns on a mill are rather tricky to pull off, and that may be a deal breaker for you if you're dead set on making this thing light (in which case I'm wondering how you plan on lightening that gear).
Putting bearings a few thousandths off on a mill is really hard if you're using a DRO, and still pretty hard if you're not. The mill takes the guesswork and eyeballing out of it in my experience, as the dials are all graduated and easy to read. If you're using a bad mill, that's one thing, but it's hard to screw up on a Bridgeport.
Flanges are magic. We supported the entire superstructure and our intake last year with a 1/16" thick sheet metal gearbox which also powered our intake. It held up until a head-on collision with our intake bent it up.

If this is your first year doing this, you're really good. Keep it up!

EDIT: You may want to opt for a 2-plate design if only 2 plates will have bearings anyway. JMO.

[SerpentEagle]

Originally Posted by asid61

I usually clamp all my plates together and mill them at once; it's far easier to do all the plates at once than one at a time. If the plates are all the same, I just clamp them all together with some kant-twists.
From the design I'm seeing here, you could try and make all the plates identical and do it on a manual mill. However, lightening patterns on a mill are rather tricky to pull off, and that may be a deal breaker for you if you're dead set on making this thing light (in which case I'm wondering how you plan on lightening that gear).
Putting bearings a few thousandths off on a mill is really hard if you're using a DRO, and still pretty hard if you're not. The mill takes the guesswork and eyeballing out of it in my experience, as the dials are all graduated and easy to read. If you're using a bad mill, that's one thing, but it's hard to screw up on a Bridgeport.
Flanges are magic. We supported the entire superstructure and our intake last year with a 1/16" thick sheet metal gearbox which also powered our intake. It held up until a head-on collision with our intake bent it up.

If this is your first year doing this, you're really good. Keep it up!

EDIT: You may want to opt for a 2-plate design if only 2 plates will have bearings anyway. JMO.

If were gonna use 1/8" then its gonna be up to our sponsor to laser cut it for us. I think that 1/8" is sufficient if there are frequent standoffs for support. Anyways, each gearbox (2 in total) will be lifting a max of ~30 pounds (6 stack weight / 2). Illl go ahaid and experiment with flanges too. Thanks!