Washers on Sprockets

[Spirator]

Hello, I was just wondering whether this was a good idea. What could we use as an alternative?

Lets just say, our students were inspired last night.

http://filesmelt.com/dl/IMG_20110213_101820_resized.JPG

[alex334]

Why not manufacture some sort of spacer? This year, we made a spacer out of delrin to accomplish that function.

[ezygmont708]

FIRST Team 708 has traditionally made spacers from 1/2" and 1" delrin rod. They have proved extremely durable and are very easy to machine.

[Jeffy]

Spacers like this (http://www.andymark.com/ProductDetails.asp?ProductCode=am%2D0189) are a good option. They can be made very nicely with a few hole saws and a drill press.

I wish we used more spacers like that, but we have always used a standoff on each bolt. We bought 80+ this year from mcmaster.

[Spirator]

We're thinking of using metal spacers instead. What difference would it make?

[kevin.li.rit]

I'd use 2 extra nuts before I use a stack of washers like that...

[thefro526]

We're thinking of using metal spacers instead. What difference would it make?

If the washers tighten up and stay flat then you should be fine. We've stacked a washer or two as a spacer before and never had any problem.

Making a small metal, plastic or even wood spacer is the "right" way to do it, but they all function the same way.

[Spirator]

The only reason why I'm concerned is that last year our bolts sheared out of our wheels and snapped.

[CidTeach]

hey guys
we typically use various sizes of these types. they are so cheap, its almost not worth making your own.

http://www.mcmaster.com/#spacers-and-standoffs/=b0e7kk

sorry the link isnt perfect,but they're nylon and come in many lengths for almost any bolt size. item #94639A506

[MrForbes]

you can buy nylon spacers at places like Lowes, Home Depot, Ace hardware, etc.

[Gdeaver]

This page shows how we set up the plactraction wheels and sprockets.
http://wiki.team1640.com/index.php?title=DEWBOT_VI_Drive_Train

[pbawesome]

a spacer would be best. measure out some low profile nuts (or normal nuts if you need alot of spacing) and thread them onto the wheel then attach the sprocket. The washers are a really bad idea! the sprocket may go all over the place and knock the chain off!

so use either nuts or turn down some spacers out of PVC

[JesseK]

Spin the wheel without chain attached to it. If the sprocket doesn't wobble, you're fine. in other words, if the sprocket is perfectly parallel to the wheel, you're fine.

If it does wobble, then consider shaved off washers as shims, or use spacers as suggested above.

[MrForbes]

Looking at the pictures, it looks like they might be springs, not washers....