Extending a cantilevered drive shaft.

[Madison]

Here's a sticky situation that may or may not have an elegant solution.

I'm working to development a prototype drivetrain that my team will be building over the next two months with the hope that we will run into and solve any problems that crop up long before the short 2006 season starts. Among the requirements I imposed on myself, it must be easy to manufacture, cheap, easy to assemble and disassemble, and robust.

As such, I've elected to use a turn-key transmission. This iteration is based on the AM Gearbox from AndyMark. As things turn out, the output shaft is a bit shorter, I think, than that of the kit-provided transmissions.



As you can see, I have a sprocket hanging in space right now that probably won't stay put -- no matter how hard we all concentrate. I need to somehow extend the shaft to support that sprocket without making a new shaft.

What I anticipate is creating a cluster of two sprockets by bolting through each of them and a spacer so as to achieve and maintain the 2" separation I require. The end of the gearbox output sprocket appears to have a threaded hole, though Andy's drawings don't call it out specifically. I was considering then bolting through an extension and into that threaded hole, effectively extending the shaft length by 5/8" or so.




Is this a 'really bad idea'? I'm hoping that bolting both sprockets together will help to minimize the shear the currently unsupported sprocket exerts onto the extension it would sit upon.

Any ideas?

I know this is a really bizarre, obtuse question. I just wanted to see if I could get some additional opinions about best practices in cases like these so I am not later forced to abandon all of the neat design features this chassis has because of something as inconsequential as shear