"Big knife" for luthiery?

[Mike Recchione]

I just saw a YouTube video of Pablo Requena carving the heel on a classical guitar neck, and at one point he used a knife that I'd never seen before. It had a long handle - long enough to use with two hands, and a fairly long blade, but the edge of the blade was relatively short. He could get into really tight places with it, and the long handle and non-cutting part of the blade gave really good control.

I tried to find it, and did find some references to a "big knife" used by Mexican luthiers. I got the sense that most people make their own.

Does anyone use a knife like this? How is it sharpened? (looked like a chisel grind, kind of like a drawknife.) Has anyone made one?

Saw some pointers to places that sell luthiery knives of various kinds, but none of them really looked like the one he was using. I tried to include a screenshot of him using the knife, but kept running into an error. The link to the YouTube video is here: http://youtu.be/5gzanQcRMGM

[Jim Creech]

It appears to be a Japanese woodcarving knife. Do a search on Japanese wood working tools and you will find assorted variations on that same blade.

[george wilson]

Old Spanish luthiers made themselves a long handles knife with a blade made from a ground down old razor. I made one for myself,back in the 60's, tempered the MUCH GROUND DOWN razor to a FULL BLUE color to make it softer and to have a spring temper. Instantly the razor broke off,just missing my head!! So,I took some 1080 steel from Dixie Gun Works,which is for making springs,and made another blade. It had less carbon than the razor,and would PROPERLY take a spring temper. Those Spanish makers must have heated their old razors hot enough to completely anneal them. I suppose the very high carbon content may have enabled the razor to still hold a decent edge when cutting the soft Spanish cedar guitar neck.

I still have it. It allows great force to be used while roughing out the heel of a guitar,laid fingerboard side down,clamped to the top of the work bench. The traditional wood for classical or flamenco guitars is Spanish cedar. The long handle knife easily cuts through the cross grain of that wood.

[Mike Recchione]

That's interesting. I knew a guy on another woodworking forum many years ago, who more or less left engineering to pursue bow-making full time (the violin kind, not the bow and arrow kind). He made a knife for bow carving out of an old razor. Completely different geometry from this one, but he said these knives made from old straight razors were the best for carving the pernambuco and other bow woods. Also many years ago, I made myself a Pacific Northwestern style crooked knife from an old razor, kind of a one-handed drawknife. I never liked how it worked - I think I got the angle on the handle wrong. Maybe it's time to re-purpose that blade...

I've also still got a couple of leaf springs that I've been saving for 10 or more years, waiting for the right knife project to come along - might be good to put one of them to work.

Thanks for the reply!

[Mike Recchione]

I did look at Japan Woodworker, Amazon and a few other places before I posted last night, and while some of those single-bevel knives look similar, they're a lot smaller than the one this guy was using. At least, that's how it looked to me...

[matt stott]

Tools for Working Wood (and others, I am certain) carry a very, very similar knife. I have one, and while the knife in the video appears slightly longer I cannot be sure of this (they may be the same knife). This knife is hollow ground flat on the back side, just like the one in the video.

https://www.toolsforworkingwood.com/...m/MS-JLANKN.XX

slightly different here: http://www.japanwoodworker.com/Produ...-Scabbard.aspx

fancy pants version: http://www.japanwoodworker.com/Produ...---Shozon.aspx


Matt (no affiliation to sellers)

[george wilson]

I watched the video. My knife is much different from his. He has some kind of Japanese knife. My knife has about an 18" handle and a 4" long blade. I clamp the neck fingerboard down on the bench. I can brace that long handle against my hip,and can out carve this luthier several times over. My knife is more authentic to the old time tool used by the Spanish lutheros.

I never found it necessary to use any templates like this luthier. I just used my eyeball gauge to carve the heel symmetrical on both sides. But,this does require a good eye,and more skill. Been doing this way since the 60's. In the 50's I had not yet heard about the long knife. But,it speeded up things very much once I had this tool. Mine is sort of a quick and dirty one,but it does the job very well.

I also never make those large grooves for the sides to be set into,and snugged up by wedges. I know that many luthiers use that method. I think it is sloppy. What I always have done is saw a cut with a regular thickness old Disston back saw. Then,I slip a scraper blade made from an old crosscut saw snugly into the first cut. I let the back saw saw another cut right up against the scraper. It actually did not seem to ever wear down the set in the saw. But,it left a groove exactly wide enough for a snug slip fit of the sides into the slot. A much neater and more workman like way to fit the sides into the neck.

[Mike Recchione]

Thanks, saw those last night. I think they're shorter. Might order one anyway (not the $205 one!!!)

[Mike Recchione]

I watched the video. My knife is much different from his. He has some kind of Japanese knife. My knife has about an 18" handle and a 4" long blade. I clamp the neck fingerboard down on the bench. I can brace that long handle against my hip,and can out carve this luthier several times over. My knife is more authentic to the old time tool used by the Spanish lutheros.

I never found it necessary to use any templates like this luthier. I just used my eyeball gauge to carve the heel symmetrical on both sides. But,this does require a good eye,and more skill. Been doing this way since the 60's. In the 50's I had not yet heard about the long knife. But,it speeded up things very much once I had this tool. Mine is sort of a quick and dirty one,but it does the job very well.

I also never make those large grooves for the sides to be set into,and snugged up by wedges. I know that many luthiers use that method. I think it is sloppy. What I always have done is saw a cut with a regular thickness old Disston back saw. Then,I slip a scraper blade made from an old crosscut saw snugly into the first cut. I let the back saw saw another cut right up against the scraper. It actually did not seem to ever wear down the set in the saw. But,it left a groove exactly wide enough for a snug slip fit of the sides into the slot. A much neater and more workman like way to fit the sides into the neck.

Thanks, George. Would you be willing to post a picture of your knife? It sounds really intriquing... I was impressed by this guy in the video, but I'm just looking at my first "real" acoustic guitar build.

[george wilson]

I don't know about a picture. The knife has been declared a secret weapon by the cia,nsa,fbi and the chnic.

[Mike Recchione]

I don't know about a picture. The knife has been declared a secret weapon by the cia,nsa,fbi and the chnic.

Oh no, not the chnic!

[george wilson]

I wonder where my wife has gotten my camera now? Her's broke down,in spite of being a Nikon.

[Chris Fournier]

I use a Frost knife to help carve the heels on my guitar necks, you can buy them at Lee Valley. Not large but sharpened well they get the job done quickly.

[george wilson]

If I find the camera,you will see a knife that gets the job done even faster.

[nima hadavi]

I believe the knife is called a "masuda" I own one without the handle or sheath, but do remember seeing handled ones.