English trained bookbinders often use a modified spokeshave for long shallow bevels on the turn-ins, reducing the thickness in the spine area of a full leather binding, preparing a new piece of leather for rebacking, and for beveling binder’s board.
I’ve improved the modified Stanley 151 spokeshave that I make and sell by adding a shaving collector. I first saw this on a spokeshave  James Brockman was using in 1990. I can’t quite explain why it has taken me so long to get around to making one for myself — I’ve been busy??? He kindly shared details of the design with me, and mentioned he first saw this while working at Roger Powell‘s shop in the late 1960’s or early 1970’s.
The shaving collector really speeds up work with the spokeshave, since you don’t have to stop and clean off stray shavings every couple of minutes, and they don’t get trapped under your leather, which can cause tearing or holes. Additionaly, it is easy to dump the full collector into the trash.   More information about spokeshaves for leather.
Other modifications to the spokeshave include: reducing the effective cutting angle by grinding the base, truing the adjustment knobs, rounding and lessening the surface area of the sole, opening the mouth, flattening the blade bed by filing and filling with epoxy, flattening the blade cap, and replacing the thin chrome vanadium original blade with a Lee Valley PM-V11 one. This blade is reground to a lower angle, sharpened, and the corners slightly rounded to prevent ridges formed in the leather. All of these modifications make the spokeshave a much more precise instrument and reduce chatter
Even if you rough out the leather with Scharffix or Brockman leather paring machine, this spokeshave can quickly help reduce the ridges and unevenness the results from overlapping cuts and blade changes if you are working on large pieces. It is also essential for gradual bevels wider than the width of a double edge razor blade. And it is a lot of fun to use.
MODIFIED 151 SPOKESHAVE: $275.00 Â Â Â How to purchase
Peachey Conservation 
Indeed Chris Clarkson has one with a collector very similar to the one you deviced
Interesting, more confirmation that this idea came from Roger Powell, since Chris worked there as well. Powell really was a genius with tools, since he also designed the lifting knife shape that I slightly altered by rounding the corners. But the three-bevel idea was his.
Brilliant!!