Swords suck

sharpeknives

sharpeknives

Joined
Jan 13, 2006
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Ok! I have been working on a pet project for about a year. Its a Katana. I have kept it a private project and not shown it to anyone. Till today a friend came by and suprised me in the shop. Anyway, I did the rough grinds with my grinder and 40 grit. The rest has depleted 4 files, 2 Dremel tools countless dremel sanding drums and a pick-up truck load of sand paper. The blade has a convex grind with a fuller. My problem is I cant get the worbles out of the groove or the spine. Any ideas ? Or info is welcome. Blade is 28.25" OAL is 38.5
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Cool! What steel is it and what's your plan for HT? Forgive my ignorance but what do you mean by worbles?
 
Steel is 5160 its tempered at 57RC. Gave it a nice springability. The groove is wavey. I have sanded and sanded and can't get it smooth.
 
What are you using to sand and how? I haven't made anything this large or even with a bo-hi but... I'm curious.
 
I used sandpaper with a rubber bacing glued on and smoothed the blade, it came out pretty good. I have been useing sandpaper and my finger on the groove. Maybe if I used a small piece of dowel rod wrapped in sandpaper I could smooth it out.
 
On Fogg's site there's a great tool used for forming the grooves. It's a carbide cutter bolted in some metal. Imagine a center scribe but with a carbide cutter instead... I also recommend a sen for working loonnnnggg blades. I've only worked on one katan type piece and a sen ate the steel up as opposed to using files.

Looks great though!
 
I'll check out Foggs site. Thanks. I think this may be my only Katana. I could have made 20 knives in the time I've got in this thing and its only at 150 grit finish. I haven't even started on the handle or fittings.
 
I'm suggesting your solid block for backing would do it. If you had a small sharpening stone and could shape it on a grinder or? that would work even better. Frank
 
Weld a peice of round bar alittle smaller than your fuller size to a peice of flat bar on the end, then weld a handlebar on that, make it atleast 5" or 6" long, that way it won't ride into the low and high spots but cut down the high spots.
 
sharpeknives said:
Swords Suck!
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yep they sure can;). They have the ability to try a smiths patience beyond the levels of any knife. Adding a second edge doesn’t make it any better either.

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Here is a picture of the tool Enomoto Sadahito uses for cutting hi. I got to work with it on a blade Sadahito San was working on at Rick Barret’s gathering this fall. I was nowhere near as productive with it as its owner. He made it look rather effortless to carve the groove in no time. Sen and these type of cutters work really well in very simple steel like tamahagane, or 1050, but modern steels with alloying and carbides can provide a real challenge to them.

We are often told that in other countries smiths are not as free with information as they are in the U.S., Enomoto Sadahito challenged that assertion for me. I have seldom seen a smith so willing to share and teach as he is. Despite different languages, the information sharing was fantastic, all it took was similar experiences with the materials and a bit of creative pantomime.:)

I do a lot of the narrow fuller on rapiers, to smooth them out you can use a 2" long section of round file and work it up and down the groove, then follow it with a tool I use that consists of a 1" long chunk of steel rod welded across a steel bar for the handle. Stretch a strip of abrasive across the rod held by your hands on either end of the handle and sand the groove smooth with 220x and then 400x.
 
One problem in keeping a first time project secret is that no one can head you off from a dead end or wrong turn.

The bo-hi , or fuller ( please don't call it a "blood groove"), is formed and smoothed before the HT ,usually. It is a lot easier to get it right then. After the HT the hi is smoothed with stones, and then sandpaper backed by dowels or metal rods. A small medium grit pocket whetstone can be shaped on the sides to fit the hi and worked up and down until all is smooth and even.Fitting this stone into a block of wood makes the task go easier and faster.

I suspect you used your Dremel tool to carve and smooth the hi, thus creating a lot of ripples. This is a tempting thing to do.....but I would advise you to not do it again. The only way to get the hi smooth is with long and even strokes, not a series of thousands of tiny dips like the dremel wheels will make.

Another good stone to use for smoothing the hi is a sickle or scythe blade stone. They are about 6-8" long and canoe shaped (sort of tapered both ways and rounded a bit). They can be re-shaped to the proper curvature and used effectively when forming the hi. Other stones/things that may work are pieces of round files ( grind the broken ends smooth), small slip stones, ceramic rod pieces, and EDM stones. Any of these are easier to use with a piece of wood placed over them to apply even pressure and make moving them up and down the groove easier on the fingers. Just put a slight groove in the block of wood to grip the stone/rod/file/etc.

A final tip is to shape the long edge of a 6X4X1/2" hardwood or micarta block to fit the groove ( taper the block to a wedge at the long edge, and round the edge to fit the groove). Sand the opposite edges to take the corners off a bit, so it is more hand friendly. Put a bit of grinding compound in the groove, and work the block back and forth. Add compound as needed. Mark the block with the grit used, and make a block for each grit.Store the blocks in plastic bags. Regular valve grinding compound can be used, but an even better compound can be made from the loose grit silicon carbide powders used by lapidaries for stone polishing and tumblers. These grit powders can be purchased in kits that have five or more grits ranging from coarse up to super fine polish. Check ebay for "Rock Tumbler grit ". A several years supply will cost about $20-30. These are mixed with a little oil ( anything from cutting oil to olive oil) to make a paste ( or with dish soap for easier cleanup). Put each grit in a shallow ,wide mouth jam jar and add some of the carrier. Label each jar. This system can grind out and mirror polish a bo-hi in very little time.

Stacy
 
Thank-you all. I now have tools to make and more stuff to buy. You guys are a bottomless pit of information. Thank you for letting me dive-in. This is really good stuff.Alot of which I can carry over to my knives.
 
Another tip I've read but never tried is to make a fitted sanding block using polymer clay. Form the clay to the shape you need then heat in the oven and voila! you have fitted sanding blocks in about 20 minutes.
 
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