Tang sizing?

[Bob Opsitos]

I'm making a Raffan style spear point scraper from some A2 in the shop, 1/4" thick, 7" long blade.

What size (length, width, taper) should the tang be?

Currently I am planning to size it at 3" long, with 1/2" at the top and tapering so approx 3/8" at the bottom.

Does that sound workable?

let me know your thoughts
bob

[Paul Engle]

Bob,
That sounds good , rule of thumb would be no less than half the blade length and no thinner than half the thickness x width. it needs enuf bearing surface to spread the stress out over to the wood handle to keep it from cracking/splitting under load. ie if 6 " blade x 1 in wide and 3/8 thick = 1 3/8 = 1 6/16ths = 22/16th dvd by 2 = 11/16 or 5/8 approx wide . you could taper it down to the thickness ( say it's 3/8 thick) tang would be 3 in by 5/8 taper to 3/8 but margin of saftey could by 4 in long by etc.
Remembering that the placement of fulcrum/s can either increase stress or spread it out on a given section of the handle making it harder for you to control the shorter it is. LOOONNNNNgggg handles are easier to handle force wise than shorter ones especally the bigger the bite , the bigger the part you are working on..4 in bowl vs 14 in bowl , rim speed is waaayyy out there on the 14 :eek: , not so much on the 4 ". Hope this helps!:D