At Nasty's request, I moved this here for the benefit of all...
Ferrous' stacked leather handle process...
I have done such a handle on a swedish laminated steel blade and two hunting knives. It is quite easy, and if cured properly with beeswax (or beeswax-paraffin mix) it will feel warm, and grippy always.
First, remove the existing handle pieces. We'll be able to reuse the buttcap if we cut the leather accordingly. Cut the tang longer to be nearer the cho, as you mention.
Get some "cow butt" leather, at least 1/8th to 1/4 inch thick. (the thicker you use the less cutting you have to do). Compress the leather by hammering the sheet of it for a bit, or wet it first then hammer to compress.
Now on most leather handles, there is no really big diff in the leather washer diameter, but on the khuk you might want the butt to flare. These thinngs should be considered when you're planning this. Also consider diffs in tang shape and thickness, and how the holes in the leather washers must be made to fit according to their placement on the tang.
Now use pen/pencil to mark the oval outlines of the leather washers on the leather sheet. Plan for bigger washers, oversized, because we will remove excess leather during the shaping process. I don't even draw and cut ovals, because the leather is easier to cut into rectancles or octagons (rectangle with the corners cut off)
After the outlines are cut, cut or drill the tang holes in the center of the washers. cut smaller than you need to, as you want a tight fit. If you have some variance in the sizes of the leather washers on purpose (you will, especially where the tang changes thickness), then number the washers so you can recall the correct assembly order.
After all parts of the leather are rough cut, you are almost ready for assembly. Here I will recommend that you make two brass/copper/etc (metal) washers, one for the bolster, and one for the buttcap (if you will resue the old buttcap, then you just need to make the bolster one). These washers hold the leather washers in place and help to maintain/equalize compression.
Assembly is best done with the blade clamped point-downward in a vise.
To assemble, drop on the bolster washer, followed by the first leather washer. use pliers whose jaws fit around the tang, and hammer the pliers down to seat the washer snugly. repeat until all of the washers are tightly seated. leave at least a 1/4 inch of tang visible for peening.
Now, add the buttcap, and using a ball-peen hammer (the peening=rounded end) strike glancing blows from the center of the tang pin to the outside of the pin. You should get the feel of the metal 'mushing' out and down, and should see some mushrooming as you work from center to outside and down all the way arond the tang. When the assembly all feels tight, give the peened tang-end a whap with the flat head of the hammer. (NOTE: Although we are using roughly shaped leather disks, you may need to make one that is close to finished shape to fit properly under the pen knife cap)
Now for the final parts...
Now, you'll have this rough stack of compressed leather for a handle. To shape it, I use a sharp knife and roughly 'whittle' the desired shape. You can also use sandpaper, files, rasps, belt sanders, grinders, etc for shaping.
After shaping, there is one final step that needs to be done--a process caller Cuir Bolli--which involves brushing beeswax on the leather (or immersing the leather handle in beeswax). This will make the handle weatherproof and chem resistant, and will tighten the handle up. What happens is the heated wax opens the pores in the leather, and it rushes in to fill these spaces. This causes the leather to expand slightly, which adds to to tightness fo the assembly.
I use standard beeswax (a readily available by-product from the honey industry--check your local beekeeper), but have a buddy who adds 1 part paraffin to 2 parts beeswax, for extra stiffness.
Heat the wax (keep away from open flame!) so that it is all melted, but doin't boil it. then, either immerse the whole handle in the wax or brush it onto the handle. Once the handle seems totally saturated (will have a coat of wax visible on the leather), put your oven on its lowest setting and then put the piece in the oven on a cookie sheet or tin foil. This additional and even heat will open the leather pores a bit more, then will suck in the extra beeswax. when you see more runoff of wax then absorbtion, use a paper towel to remove the excess wax. when it dries and hardens, it can be poished up a bit if desired.
The key to this precedure is Compression! Tightness of the assembly is a must in every stage.
Keith