Can you please post some pics, or may be a "walk through" for the spine reduction bit.
I also have this "heavy" problem
and was wondering what will happen if I reduced / slimmed the spine a bit.
I have a bad habit of not taking picture when I work, though taking pix is my second hobby. Let me just put down a quick guide for you here:
1. PLANNING:
Firstly measure the current handle. I often measure the width and thickness in 02 places, in here I called the "first rivet" and "second rivet" as those places are crucial to me. They form the curve/ergonomic for the whole handle. Then work out how much the tang you should shave off. I think every one of us need to know by heart their handle size, it's similar to the size of our shoes, or pants or shirt. A good source of reference is other HI handle. Choose the one you are most comfortable with to get the dimensions. Then I use an a marker pen to draw the area I need to shave off, both in thickness and width. Do ensure the ergo for the best grip.
2. SHAVING
It's best to go with a belt sander but I cant find it here. Shipping from US to VN is mad. I thought of a kind of contraption of using the small belt sander used for wood with 36" belt but haven't tried. It looks weird. I just use a machine I called the hand grinder with a 4" 120 grit sanding disc. You can have a look at this tool in page 1 of this thread.
Shaving top & bottom line:
I keep the sanding disc 90 degree to the metal tang, then I drag bit along the curve, from pommel towards bolster. But always bear in mind of never shave the tang near the bolster in bottom line. It must be kept the same. The tang here need to be about 2mm more prominent than the bolster. Shave few strokes, take a short rest, shave few strokes, take a short rest,
repeat until you get to the desired depth.
Please always bear in mind when shaving top line and bottom line, this means you are shaving an "in-consistent material", consisting of wood and metal. One part is hard, one part is softer. There is a high risk that with the same pressure, the sanding disc eats deeper into the wood scales than in the metal tang. Then always keep the disc square 90 degrees to the tang. I did a few test with my hand grinder to check if the shave is even. Thanks to high speed, it cuts the wood slab and the metal tang at the same depth, then I confidently proceed to shave further. Do it bit by bit, little by little. Haste makes waste. You are working on a finished product. One step wrong you will ruin the whole thing. Take a deep breath, take a sip of tea, pet your dog, sms your girl friend,
then continue to shave. If you shave too hard, the metal tang might get hot. The part of slab next to the tang would be burnt into coal & look ugly. You dont want it to be ugly, do you?
Shaving slabs:
First of all, I would like to thank OldSchool for his experience he shared while re-handling his CAK. Learning from him that I know big diameter Alu rivet stock can hardly be found. I often steal some alu clothes hanger from my wife for the rivets. Her clothes hanger hook keeps becoming shorter but she doesn't know why.
. But for the case of this M43, the diameter of alu clothes hanger is way too small, then I don't bother her this time. Then I need to play some trick here. I just shave down the wood part. I did not shave the area near the rivet, later, I used a file to file off the wood part around the rivet to the desired depth. You can see the rivet is about 2.5mm prominent in the pix in page 1.
You need to use a piece of 180 grit sand paper to make the slab even, esp. the part around the rivet before peening. Peening an uneven slab is really hard to fix later on, even my dad cant!
3. PEENING RIVETS
I just used a very small hammer, you can see in the pix. It was lying somewhere on the floor, next to the horn handle of the HI Friendship knife (another project I was working on, too). I used such small hammer just to better control the force. Firstly, hammer the outer ring first. I dont hammer in the center of the rivet. Then I could bring the rivet to kind of cornical shaped. The anvil is a piece of steel. Do it slowly and keep the hammer force even. When the force are even, the rivet would be mushroomed in a round shape. If you hammer in the center too soon, while the outer ring is not even, it might make the rivet become odd shaped.
After peening, shave the excess part of the rivet down until you have about a hair line left from the surface of wood slab. At this stage, never use rough tools. You are arriving at finishing stage.
4. FINISHING:
I used a fine file to file off all the excess part of spine, wood and rivet, then use a piece of 250 grit sand paper to do the finetunings. Until here, you already have a villager-finished handle.
Look again, right at this stage, the rivet is not round for sure. Its in a shape that is close to a circle, not a real circle. Then we need a trick here. I used the karda to cut the odd part in the outer ring of the rivet to bring it into a circle. This part is really thin and small and wont affect the holding ability of the rivet. Make sure 4 circles are equal. Would be ugly with one big two small, the other in between.
. Then fill up the tiny gaps around the rivets with super glue.
Then sand off the whole handle with 400 grit sand paper. The metal spine can arrive at a satin finish with 400 grit sand paper, too. Increase to 800 grit, 1000 grit, the wood shines itself.
Good luck guys!
The work you did on that handle is amazing. The Hmong Knife is stunningly beautiful, in fact I haven't seen any of your work that I wasn't impressed with yet. I hope I can do as well with the tools as you do without them. God Bless you Hung! You are an inspiration!
