I buy kangaroo from Simon Martin (
www.whipmaker.com.au). I know Simon is selling kangaroo to a few whipmakers now, so I hope he doesn't mind me mentioning him here.
I buy cowhide from Siegel of California (
www.siegelofca.com). I buy both cowhide and deerhide from a leather dealer in Minnesota called The Leather Guy (1-507-932-3795). Since The Leather Guy is a smaller operation, he can probably get you better prices, though he doesn't have a website or a catalog.
With cowhide, most of the leather tanned that is suitable for whips that I use is tanned for use in making heavy-duty shoes and boots. As such, it can be hard to buy the exact same tannage of cowhide all the time as the tanneries change their runs to suit what the shoe companies want. Leather dealers usually don't buy as many hides as the shoe companies, so they're left dealing whatever hides they can get from the factories after the factories have filled the shoe company's order.
I've bought what Siegel calls 'Diamond Tan' over the course of two years, and I've gotten four or five different tannages of cowhide. All of it was about the same thickness (about 5 oz), and was strong, but the finish and temper of the hides varied a fair bit. I've also gotten two different versions of their 'tan workchap' sides.
If you buy veg-tanned cowhide, which is typically used for leather tooling, the production is more regular, so you'll be able to buy the same thing from year to year. I myself have found veg-tanned cowhide to be weaker when cut across the grain, which you have to do when making long whips, than oiled 'boot' leather such as Siegel's Diamond Tan.
Bernardo del Carpio uses a veg-tanned leather tanned in Peru. It makes a nice looking whip. I've tried some of it and I find, however, that there's still the problem of the strands being weaker once you cut across the grain, ie. cutting from the back towards the belly. Note: with cowhide, the strongest strands are cut straight along the back.
Latigo has also been popular for whips, but mainly for 4-plait stockwhips and heavy bullwhips. The advantage is that it's really strong, the disadvantages being it's limitation to use in heavier or coarser whips and it only comes in one color.
Depending on how much money you want to spend, it's usually best if you can pick out cowhides in person. This way you can check the temper, strength, and shape of the hide. When buying online you have to trust that the leather dealer can direct you something that will work.
Deerhides are even trickier to buy, and if I have to make one deerhide whip I try to buy several hides just to make sure I have one or two that will work for the whip.
One last thing, falls are usually cut from latigo or whitehide which is usually thicker than what the whip is braided from. I know Simon Martin uses kangaroo for falls on his kangaroo whips, but if you're going to make any cowhide whips you'll want to get some heavier leather for the falls. Right now I'm cutting my cowhide falls from 9-11 oz. latigo.
-Adam
www.winrichwhips.com
When it was made the roller wasn't center of it's axle and it would leave your leather with humps and bumps all the way along the strand. Not a pretty site! 