drum carder / wool carding machine question

Hello all,

I came across a length of "carding cloth" a few years ago. After looking at some drum carders online I eyeballed/guesstimated up some sizes and kludged together a couple of wooden drums in a frame.  ...and there it sat.

Now I'm trying to declutter and get rid of some old projects.  I bought some 6mm urethane belt material (this stuff, fyi) with the idea of making some pulleys to drive the drums.

This brings me to my question:
If you own a drum carder, what is the pulley size ratio between the large and small drum supposed to be?
In your answer, could you also please include how long your hand crank is? (because that would change the speed as well)

Better yet, if you've got a link to some vintage plans, all the better! Though given the nature of this project, I'm not picky enough to hold out for that. LOL! ;)

The big book of handspining by amos might have the ratios and math needed.

My drum carder's two pulleys have an exterior diameter of 45mm and 135mm. They have a triangular groove in them for the wedge-profiled belt that runs the drive mechanism.

Hope that helps! Good luck building your drum carder.

The ratio of drum to pully is good to have too.  

If you look at Ashford's best selling drum carder, the pully ratios (between the two pullies) are usually 1:4 or 1:6 (download the manual here: https://www.ashford.co.nz/drum-carders )

But there is a lot of freedom in how you make it.  So long as the system can be adjusted.

The cloth will also determine the ratios.  Do you have a photo of it or know the specifications?  

Wow! I like that Drum Carder! Didn't know those existed, but they look amazing! Not sure if I have the carpentry skills to build those. This swinging one, or picker, looks easier to build. It appears to have a large bolt, or rod, at the top to create the swing.