gearbox compatibility issues

[Ian Curtis]

Originally Posted by DonRotolo

Are you saying that the diameter of the shaft of (something) it too large to do what you want? If so, find someone with a lathe and have them make the too-large shaft smaller. Or, if possible, use a drill to make the hole into which the shaft needs to go larger.

Don (or anyone else),

Have you done this before (i.e. turned down the BB output shaft to the diameter of the CIM pinion bore, and then milled the keyway in)? I was discussing a BaneBots to Toughbox last night, and wasn't sure what teams have done before. I imagine turning down the hardened shaft would be a royal pain.

[IndySam]

I would wait on the 24" cylinder until we get an update on how many air tanks we are allowed for storage or if we can use a non-bimba cylinder. If we only get the one tank in the kit that cylinder will be almost unusable.

I would suggest two 1 1/16 or 1 1/2 cylinders put together Darth Maul style if we are limited.

[Weisemanjohn]

In the FIRST Choice, they gave the option to get another tank, that would make you think you would be allowed more than what was provided in the KoP

[JB987]

Originally Posted by IndySam

I would wait on the 24" cylinder until we get an update on how many air tanks we are allowed for storage or if we can use a non-bimba cylinder. If we only get the one tank in the kit that cylinder will be almost unusable.

I would suggest two 1 1/16 or 1 1/2 cylinders put together Darth Maul style if we are limited.

Wait is over...see Update #2. Good news for all!

[Teched3]

As far as I know, the banebots output shaft is not hardened, and you should have no trouble reducing the diameter. You would need to deepen the keyway on a vertical mill (2 mm) . The shaft diameter is 8mm on the CIM (.315) motor. To be certain the shaft is not hardened, file test it. If it files, it can be cut easily with HSS or carbide lathe bits.

[Weisemanjohn]

how can we widen the keyhole in the CIM gear to match the BB shaft?

[Ian Curtis]

Originally Posted by Weisemanjohn

how can we widen the keyhole in the CIM gear to match the BB shaft?

You won't need to. When you turn down the BaneBots output shaft from .5" diameter to .315" diameter, you'll turn off the keyway (i.e. the material the keyway is in will be taken off). You'll then need to mill a new keyway into the BaneBots output shaft that matches the CIM pinion keyway.

See this drawing.

BaneBots says the output shaft is hardened 4140. Is this not the case?

[Weisemanjohn]

how could i mill the keyhole on the bb shaft, either piece we lathe/drill we will need to remake the keyhole.

[Teched3]

You will need to broach the gear with a 2mm A broach using an arbor press, and use a vertical mill with a 2mm end mill to mill the keyway into the shaft. Alternately, you use a 3/32 A broach and 3/32 mill, but have spare parts made for insurance. I usually mill the keyway a little deeper than 2mm to account for the chordal distance across the shaft. In addition, when you order keyway stock, get unplated steel stock as plated stock is a little tight and will require some sanding or filing for a proper fit.

[DonRotolo]

Originally Posted by iCurtis

Have you done this before (i.e. turned down the BB output shaft to the diameter of the CIM pinion bore, and then milled the keyway in)?

No, we have not. I misunderstood the question apparently.
In a case where I had a motor with an xx size shaft and
A) Something that can be drilled out: Drill it out. (e.g., a gear that's not hardened)
B) Something else (Like a CIM gear that's hardened): Make a shaft adapter: One end drilled for the motor, the other end sized to fit the (something else).

It would be a royal pain to cut down the shaft of a motor while it is still part of the motor, and I would be reluctant to attempt it. If space for a shaft adapter was an issue, I'd seek a different gear.

Or did I misunderstand the question again?

[Ian Curtis]

Originally Posted by DonRotolo

No, we have not. I misunderstood the question apparently.
In a case where I had a motor with an xx size shaft and
A) Something that can be drilled out: Drill it out. (e.g., a gear that's not hardened)
B) Something else (Like a CIM gear that's hardened): Make a shaft adapter: One end drilled for the motor, the other end sized to fit the (something else).

It would be a royal pain to cut down the shaft of a motor while it is still part of the motor, and I would be reluctant to attempt it. If space for a shaft adapter was an issue, I'd seek a different gear.

Or did I misunderstand the question again?

I believe the original poster (and at any rate, I am) was talking about taking the output of a P60 BaneBots and powering an AndyMark Toughbox for a super reduction. The CIM pinion is too small to drill out to the BaneBots output shaft diameter (.5"). The only way I could think of was to turn down the BB planetary output shaft to the diameter of the CIM output (.313"), and then mill the 2mm keyway in.

I've seen this done before though (BB planetary to toughbox) and was wondering how other people successfully interfaced them.