Breaking the spine

Mark Behnke

Well-Known Member
Not sure what this means.

When the grind goes to the spine without any space between the two?

Is this bad? If so why?

Seems I've seen alot of knives ground this way.
 
From what I understand you're referring to grinding all the way up to the spine? I think that's what you mean. Far as I can tell it isn't so much a performance issue as it is a cosmetic thing. Leaving a space from the top of the spine to the top of the grind line is showing your attention to detail, especially when you get both sides matched up perfectly. One way you can fix it if you do break the spine is by taking some 50 to 80 grit paper with a sanding block and sand the spine, where you want to show a space between the spine and the top of the grind line. You want to sand it flat, not with the angle of the blade grind. Did I explain that well enough? Getting perfect grinds also shows the ability and talent of the knife maker, it takes a lot of work, practicing, and a lot of grinding to be able to do it well each time.

There are ways to get better faster, I think Fred Rowe's Bubble Jig is a great tool, but I don't use it to do all my grinds, I use it to help me with learning how to judge my angles. It's a great tool to be able to do a a beautiful grind, but using a jig like that takes practice as well, and for me it has been more of a learning tool than a crutch as some folks like to call jigs. Being blind in one eye I guess I need a crutch, because my depth perception is extremely bad!
Either way, you still have to practice, you still have to learn and it will take time, the best tool you can have to be a knife maker is perseverance! The never quit attitude is the key to becoming a great knife maker!! Just my 2cents, hope I helped, Rex
 
A full grind goes ALL the way to the spine... with a tiny space or curve between the bevel and the corner of the spine. Full grinds make the most of the thickness of the stock for strength, allow for a very accute overall bevel that cuts really well, and highlight the maker's skill. I think they're the bee's knees. Much like a nicely tapered tang and blade, it shows off attention to detail that results in a high-performance blade.

Breaking, rolling-over or running into the spine is when you do a full-flat or full-convex grind, and the plunge or bevel goes into the spine. This leaves a noticeable ding in the spine when you look at it top-down. Where the ricasso is the thickness you want, but there's a divot where the blade starts. It looks terrible.

It comes from digging into the plunge a little too much as you grind the bevels... really easy to do. Just have to work slowly and gently in that area, I guess. Setting the plunge with a chainsaw-file before doing the bevels definitely helps. Sometimes it happens because I'm leaning back and sort of rounding over as I get close to the spine. A jig like Fred Rowe's would likely help prevent that.

I do it way too often and it's really driving me crazy... the only thing keeping my fragile grip on sanity is Harvey Dean's flat-grinding video, where he admits that he still does it sometimes and shows how to fix it.

I have come to the conclusion that the plunge-line is the most-important, most-looked-at and easiest-to-goof-up part of a high-quality hand-made knife. If the plunge is sweet, there's a very good chance the maker has the experience and craftsmanship needed to give you confidence in the rest of the knife. The Big Dogs make it look easy, pups like me have nightmares about it :eek:
 
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Rex, James

Your explanations have answered my questions. Very clear.

Trying to get a good sweeping plunge, it was going great in the coarser grits then rolled over on one side trying to "clean up" with 400

Had a nick in the spine but cleaned it up with your tips.

Thanks
Mark
 
Rex, James

Your explanations have answered my questions. Very clear.

Trying to get a good sweeping plunge, it was going great in the coarser grits then rolled over on one side trying to "clean up" with 400

Had a nick in the spine but cleaned it up with your tips.

Thanks
Mark

Mark,
If you have any questions feel free to ask, I'll go ahead and speak for all the Dawgs here as well as myself, helping folks like yourself is part of keeping the art alive, and not lost, like it almost was at one point. If I know the answer to your question I'll gladly try to explain it, if I don't know, I'll keep quiet, or share what I do know. I take the time to do this because it's the same thing other guys did for me when I was starting, I still consider myself a newbie, but I've made a few nice blades, AND I am continually reading, studying everything I can to learn more and to see different ways of doing things. The best thing about knife making is that it never gets boring, there is always something different to learn to expand my skill level. Once I get my fixed blades in a place that I'm satisfied, I think I'm either going to learn how to do engraving, or go to folders, maybe both! Then there are all the different steels that can be used, it's a never ending cycle of learning, and I LOVE to learn, that's part of what the greats were good at, and like I said before, NEVER GIVE UP! I would also include that it's best to keep it fun, make the type of knives that you like, don't get caught up in trying to make money at it, if you get your skill level up to snuff, the money will come once you show buyers that you have everything figured out. Re
x
 
rex well said . Ive learned alot about hollow grinding in the past 4 weeks and have a high tec jig but prefer to grind free hand. I am very close to having exactly the same depth of grind and to leave a small space is the proper way for a knife. razor blades typically grind all the way to the top and have about 16 different depths of grinds . From a wedge 1 to extra full hollow grind XIV . Most of the hollow grounf razors typically have 2 grinds with one grind over the other to get a slightly thinner blade thus resulting a sharper but more flexible blade. kellyw
 
Thanks Rex
Good advice, I'm using one steel, 1084, and it's tempting to sell but think you're 100% right on that one.
 
Thanks Rex
Good advice, I'm using one steel, 1084, and it's tempting to sell but think you're 100% right on that one.

Speaking of 1084, where did you get it? A piece of advice I got from someone when I started was to pick 1 steel and master it, know everything about it that there is to know. The great thing about 1084 is that it is similar to other steels like W-2 and 1095, with a few differences like temps, and some folks like to do a soak 1095 for (usually) 5 minutes. And for future reference, if you didn't get your 1084(fg) from Aldo Bruno, he is the ONLY guy to get your steel from! I've used other 1084 and it did OK, but his 1084FG, the FG is for Fine Grain, it sharpens wonderfully, heat treats easily, and is fairly inexpensive, he has it in 1 1 /2 X 1/4, sells it in 4 foot sticks, and is a great guy. He's a pleasure to do business with. He's expanded his business from doing knife makers steel on the side, to doing knife makers steel full time and he has about every steel you can ask for. Give him a shout if and when you need steel, his email address is njsteelbaron@gmail.com, tell him Rex from Alabama told you about him, he'll get a kick out of that and probably make jokes abut me being a redneck or such, (for the recored, I'M NOT!)
Anytime I can help, just let me know, Rex
 
Now Rex, I believe your neck was a little red when I saw you at Batson's at Tannehill. ;) Just kiddin Rex. You were like the rest of us there. Wait a minute, maybe we were all red necks!!:D
 
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