I've got the Handle and a layer of bolster on my seventh bullwhip. The handle is 3/8 inch steel pipe. The Bolster, core, and inner layer are actually going through the handle and are tied at the base. It was a tight fit, so I had to tie string around the boslter and whip and use that to pull it through the handle. I also added a little extra layer where the whip meets the handle. The pipe is threaded and I didn't want the threaded part rubbing directly against a layer of the whip.

I just calulcated the width of my next layer. It's going to be an 8 layer. So I found the follow formula in Morgan's fine leather braiding book:

4 times the diameter of the whip divided by the number of strands.

So I had a diameter of 3/8 inch and I mutiplied that by 4 and divided it by 8 (number of strands) and that gave me a strand of .1875 inches. But I wanted that in metric because it's more precise at smaller numbers so I plugged .1875 inches into this website http://www.sciencemadesimple.net/length.php and it game me .48cm for each strands width.

Now all I've got to do is cut out those puppies!

Also I'm debating on doing a wrist strap for this whip...don't know, but will have to make up my mind soon!