pic: Off-Season Drive Project

[Ty Tremblay]

loading photo ...

It seems like with the octagonal frame, you have room for 2" wide - if not wider - wheels. With the 4" Colsons coming in a 2" wide variety, is there any reason you opted to choose the 1.5" wide wheels?

[Ty Tremblay]

Originally Posted by Andrew Lawrence

It seems like with the octagonal frame, you have room for 2" wide - if not wider - wheels. With the 4" Colsons coming in a 2" wide variety, is there any reason you opted to choose the 1.5" wide wheels?

Good catch. I had originally designed the drivetrain without the octagonal frame up top. Now that I've added it, I have room for the 2" wide wheels. The only qualm I have is that I won't be able to use an e-clip to hold the wheels on the shaft because the WCP hubs are 1.5" thick. I suppose a screw, a washer, and some loc-tite would suffice. Thoughts?

[Deke]

Originally Posted by Ty Tremblay

Good catch. I had originally designed the drivetrain without the octagonal frame up top. Now that I've added it, I have room for the 2" wide wheels. The only qualm I have is that I won't be able to use an e-clip to hold the wheels on the shaft because the WCP hubs are 1.5" thick. I suppose a screw, a washer, and some loc-tite would suffice. Thoughts?

We have used bolts and washers to hold wheels on the past few years with cantilevered axles, it works great and eliminates any 'slop' in the assembly.

Originally Posted by Ty Tremblay

Good catch. I had originally designed the drivetrain without the octagonal frame up top. Now that I've added it, I have room for the 2" wide wheels. The only qualm I have is that I won't be able to use an e-clip to hold the wheels on the shaft because the WCP hubs are 1.5" thick. I suppose a screw, a washer, and some loc-tite would suffice. Thoughts?

It will be a bit more tedious than normal, but using a 1/2" snap ring would definitely be possible since you can fit a snap ring tool inside the small amount of space the Colson bore opens up. Alternatively, as you mentioned, a tapped hole with a screw, washer, and loctite will also be an effective method.

Another question - is your bellypan just not lightened yet, or are you using a solid piece of aluminum? If you don't have the resources to waterjet a diamond-bellypan, I highly suggest using a solid piece of 6mm or 1/4" thick plywood as a bellypan. It's much lighter than a solid aluminum plate, and will serve well as an electronics pan as well as providing the torsional stiffness the diagonals that a diamond bellypan provide.

[EricDrost]

Originally Posted by Ty Tremblay

I suppose a screw, a washer, and some loc-tite would suffice. Thoughts?

This works well. I'd use a hex cap screw (which you can tighten with a wrench, not a screw driver/hex key) so you can get some extra torque on it.

Originally Posted by EricDrost

This works well. I'd use a cap screw (which you can tighten with a wrench, not a screw driver/hex key) so you can get some extra torque on it.

EDIT: I was unaware you were referring to a socket wrench, not a regular wrench

Spoiler for My original post:

In this particular scenario where there is a small, confined space for a tool to fit into, I'm not sure if you will be able to position a wrench in a way that allows you to get a significant torque advantage. A standard socket head should be sufficient to get the required torque, and the loctite will help in keeping things in.

[EricDrost]

Originally Posted by Andrew Lawrence

In this particular scenario where there is a small, confined space for a tool to fit into, I'm not sure if you will be able to position a wrench in a way that allows you to get a significant torque advantage. A standard socket head should be sufficient to get the required torque, and the loctite will help in keeping things in.

MORT ran 2" wide colsons with this retaining method this year. We had issues on our practice bot with socket head screws and loctite not being enough to retain the wheel. YMMV, but I would recommend a hex cap screw.

Spoiler for No longer relevant to topic:

Originally Posted by EricDrost

MORT ran 2" wide colsons with this retaining method this year. We had issues on our practice bot with socket head screws and loctite not being enough to retain the wheel. YMMV, but I would recommend a hex cap screw.

Maybe I'm misunderstanding you, but I'm not understanding how you could fit a wrench inside the 1 3/16" bore of the wheel and hold it perpendicularly to the axis of rotation so that you can get the mechanical advantage to gain the extra torque.

[Akash Rastogi]

Originally Posted by Andrew Lawrence

Maybe I'm misunderstanding you, but I'm not understanding how you could fit a wrench inside the 1 3/16" bore of the wheel and hold it perpendicularly to the axis of rotation so that you can get the mechanical advantage to gain the extra torque.

Socket...not adjustable...

[EricDrost]

Originally Posted by Andrew Lawrence

snip.

This is our drivetrain with incorrect screws retaining the wheels.

We used large washers for cosmetic reasons, we did some machining on the face of the wheel and wanted to keep it covered.

Edit: Or as Akash pointed out, socket wrenches work in the set up you have CADed.

Originally Posted by Akash Rastogi

Socket...not adjustable...

That makes more sense than a regular wrench - my apologies.

I revise my previous statement to say that, thanks to Eric's example, a hex cap screw works equally as well any method of retaining.

[Ty Tremblay]

Originally Posted by Andrew Lawrence

Another question - is your bellypan just not lightened yet, or are you using a solid piece of aluminum? If you don't have the resources to waterjet a diamond-bellypan, I highly suggest using a solid piece of 6mm or 1/4" thick plywood as a bellypan. It's much lighter than a solid aluminum plate, and will serve well as an electronics pan as well as providing the torsional stiffness the diagonals that a diamond bellypan provide.

The plan is to use either .0625" polycarbonate or garolite to allow us to leave it solid, maintain the weight advantage, and to easily mount and insulate electronics.

http://i.imgur.com/W7jAg3A.jpg

We're partnering with another team to help with the waterjetting.

[AustinSchuh]

Originally Posted by Ty Tremblay

The plan is to use either .0625" polycarbonate or garolite to allow us to leave it solid, maintain the weight advantage, and to easily mount and insulate electronics.

I'd seriously question that decision... Polycarbonate will be very floppy.

[sanddrag]

Originally Posted by EricDrost

This is our drivetrain with incorrect screws retaining the wheels.

That is a thing of beauty. I can't believe I haven't seen it before. What's the part number on those wheels, and do you have a link to any more pictures?