Advice on making a SAI

D

dnc101

Joined
Feb 11, 2002
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I am a martial artist who likes knives, and I've taken on a project with my 11 yr old son (also a martial artist) to build two pair of Sai. Since making knives is new to me, I thought I'd get some advice.

The style we're thinking of making resembles an '03 bayonette, except the guard (quillon) is a long, curved piece which looks like a set of horns curving forward. The butt (pommel) is a striking surface which also acts as a counterweight, similar to those on medievel swords- the ballance of the piece should be just forward of the guard. Blade and tang should be one piece for durability, but round or scale tang may be used (round is more common, wraped with linnen tape or chord, or wire). The blade length will be about the length of our forearms measured from the point of the elbow to the tip of the outstretched fingers, though I may make his a little larger so he can grow into them. The blade must be double edged and should have a fairly large ricasso because the fingers must wrap forward of the guard. I'll probably use a flat ground blade for strength, though I'm open to suggestions on that.

My biggest problem right now is in choosing the right steel. The blade must take and hold an edge under abusive conditions, and do all the things a bladed weapon normally does. In addition, its primary purpose is defense against most any type weapon immaginable. It must parry or block blows from staff, nunchaku, swords, spears, chain, or just about anything you can think of to launch at me. It is also used to trap weapons and attackers. So the steel must withstand heavy impact to both edge and side, and must endure severe torsional stresses in entrapment situations. I'm thinking I may have to use a mild steel and a heavy bevel on the sharpened edges as at this stage tempering hard edges on a more flexable blade is a little beyond my capabilities (I'm not a metalworker). Any suggestions or pointers would be appreciated.
 
Not an answer to your questions, but one of my own. Why do you need your sai to hold an edge ? Sai are impact weapons, not bladed. They are an iron truncheon, not a blade.
 
Well.... I don't completely agree with Gama. There are as many different styles of sai's as there are swords. The design you described sounds interesting. I'd use 5160. I wwould also (IMHO) opt for a very sharp almost diamond shaped grind for strength. It won't have the same cutting ability but should hold up to all kinds of abuse.:eek:
 
one of the steels that would work for this is 420j stainless, not the best in edge retention but the trade off is it can take the beating you describe. i feel the edge would be all you would need. unless you want to do the rolled mat slice type stuff. or for plain carbon steel you might look at 1050 or 1070.
 
most sais i see are either 1-piece cast/drop-forged or have the horns welded (spot-welded by the ends of the horns and then a thick build-up around them).

for japanese-style fighting, the orthodox sai is needed. if you want to be more liberal (and apply real knife-smithing), try the chinese version (sai really just denotes "dagger").

the chinese version is a long knife designed for trapping long swords. the handle is bulky and has a rectangular cross-section (better grip when trapping a big sword). the blade has an edge (usually double-edged). the trapping horns are similar to that of the sai but is built as a very sturdy hilt on the dagger, not welded or integral to the blade.
 
Thanks for the replies so far- very interesting. To answer some of the questions, we are starting with the more common truncheon style. But we want to go on to the knife style because it interests both of us. My sons' base is TKD, with Escrima as a sub system. My base is Kenpo, but I work out with some of the local escrimadores. The sai is such a versatile weapon that I think the bladed style could be effectively combined with all these styles into a very interesting art form. And making our own seems like a good learning experience for both of us.

As for construction details, I'm leaning to the full scale tang which would make the handle stronger and give it a more rectangular cross section. I will probably checker the scales also to help with grip. I was thinking of silver soldering the guard in place- would this be strong enough? I'm afraid that welding a knife would ruin the temper and weaken the sai at this critical juncture. Any other suggestions on how to join the guard to the blade? Tips on welding if that would work?
 
how about this: forge the horn into a massive, one-piece u-shaped stock. and then, use a machine press with a built-in microvibrator!

reading a 50s edition of popular mechanics, i saw an article with weird photos and readers were challenged to explain them. photos were:

1. a boy scout jackknife driven halfway though a large machine drill bit (securely too)

2. a small nail file driven halfway through a large wood rasp

3. a dining fork with the tines driven trough the side of a drinking glass.

answer: the small pieces were mounted on a press that vibrated several thousand times a second by only a few thousandts of an inch. then the impromptu "drill bits" were slowly pressed against the object they were to pierce. the vibration caused the hard objects to "flow" at room temperature. the process can also be reversed to withdraw the driven objects.

ask a nearby polytechnich school or machine shop if they have that kind of machine.

:D
 
Why don't you look at good old 304 stainless. It won;t hold an edge real well, in fact can't be heat treated, but it is tough and impact resistant, relatively easy to work, inexpensive, and polishes well.
 
I'd go with either 5160, as has been suggested, or, if I could find it, chrome moly. George's suggestion has merit, (as always), but welding stainless can be tough. Silver soldering would NOT be strong enough, in my experience with sai. I'd forge them out of three pieces of steel with a twisted handle. That would be the easiest, and you could make the blade a good tool steel and use a softer steel for the tines that way. You could also flatten the twisted handle into whatever shape you like, or leave it as is, like a fluted handle. I think this would make the best sai, and probably be one of the easier methods. If you go with the two piece construction, welding on the tines, don't worry about the temper, as heat treat would be done afterwards.
I know you said you're not a metal worker, but no matter how you attempt this, you'll need to be a bit of a metal worker to accomplish it.
Sounds like a really cool project. I may try a set when my hand heals.
 
Here's a thought for an integral sai, though it would require a fairly skilled bladesmith/blacksmith to make. Take some fairly wide and thick 5160 bar stock and hot cut two slits lengthwise down the bar
making the three pieces (one for the blade and the two side pieces for the guard/tines. Seems like this would, if carefully forged and properly heat treated would make a very strong sai (conversely, if improperly forged and poorly heat treated it would probably make one of the weakest). Interesting project though.
 
Again, thanks for the ideas. I've been researching some more, and this is going to take a little thought. It is definately getting interesting.
 
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