Hollow Grinding! Your favorite techniques, jigs, tips...pay your skills forward

S

samdaknifeman

Joined
Jun 14, 2011
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Hi from the less experienced knife makers! :)

We all know how daunting hollow grinding is to a novice knife maker. Here is your chance to pay your skills, tips & techniques forward to the new generation of knife makers.

We have all seen a lot and read a lot about hollow grinding, but we have always wondered the 'silly noob' questions like these:

How do you get the line straight and perfectly curving towards the tip?
How much meat do you leave on the edge if finishing with a double bevel edge?
Does a jig really help that much?
How do you know what size wheels to use?
What speed is best to run the grinder at?
What is the best way to finish off a clip-point tip where the cutting edge meets the swage?

Obviously it takes an enormous amount of practice and repetition to get it right, but any initial advice and help is absolutely invaluable to not wasting that beautiful blade steel!

So go for it Masters of Knife Making! Please help us out... :thumbup:
 
It's tough, I can't do it.



You may like to watch this video

The Fine Art of Hollow Grinding with Johnny Stout
89 minutes

Watch as legendary Texas Knifemaker Johnny Stout walks you through the finer points of hollow grinding. Get an over the shoulder view of Johnny teaching you his techniques and secrets on one of the most important aspects of knifemaking.

Enjoy multiple camera angles, split scenes, and extreme close-ups as Johnny grinds both fixed blades and folders in this spectacular video. This video is a "must have" for both the beginner and the professional knifemaker!
http://www.centercross.com/shadowbox.php?p=video&V=11
http://smartflix.com/store/video/275/The-Fine-Art-of-Hollow-Grinding

http://thepiratebay.org/torrent/579...nife_Hollow_Grinding-Johnny_Stout-KnifemakerC
 
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I started out hollow grinding and have tried flat grinding and find it much harder...........I made a simple jig out of two pieces of angle iron to start my hollow grind and free hand it after that................I have tried flat grinding a few times and always go back to hollow grinding............Just me......All my knives are hollow ground for this reason.................To old to learn a new system, i guess............carl.
 
I don't use any jigs at all...yep, there was a nice learning curve involved, but I find I can make a better blade that way. Everything is made by "eyes and hands" so to speak. I was taught by my mentor to use a jig, but became discouraged by the absolute certainty of a screw up if I didn't hold the blade "just so" with no deviation each time it passed across the grinder, not to mention from one side to the next....it became a process of trying not to screw up, rather than just grinding a dang blade if you catch my drift.

I finally said screw it, I can do this with only my hands laying on the rest and after a while, things worked out. It helped me to learn to lock my elbows rigid against my love handles and use the same motion each time. Muscle memory will eventually kick in and you will have your grinds down pat. Another thing I noticed when grinding by hand is that it is much easier to fix up your mistakes and/or uneven grinds...that was my biggest plus when I got the hand grinding worked out for myself. A little higher on this side? Or perhaps the angle of the grind does not match?....no problem, you can fix it to make things symmetrical.

Another thing I did back then (and do now on new, more complicated grinds) is to practice on something else other than $$$$$ blade steel. Go to the paint store and get you some paint stirrer sticks...I'm not kidding. Cut out your profile of your knife and go to grinding and catch your mistakes on the wood stick and correct it before you start grinding on a $10 chunk of steel. The paint stirrer sticks are about the same thickness as blade steel too. Just don't let anyone catch you grinding on the sticks...they will think you are crazy or something!

Best of luck. Don't think that anyone's way of grinding though is the best way for you....each of us has had to develop what works best for us, usually taking a little bit of info from this guy, and another guy, and adapting it to our way of getting things done. Find what works for you and go for it.

Take care.
 
I had a hard time with the hollow grind at first, repetition is key.

Touch the grinder lightly but deliberately with the knife. Keep your elbows in tight and locked... belt tension high.

Oh yeah, repetition...
 
I am a novice and not a "master knifemaker". Anything can be done freehand and without the use of jigs. However, no free hand can match the tolerances of a well made jig. With the proper jig, you can grind to tighter tolerances than "the masters" each time, every time.
 
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I like to establish the main groove or trough with a jig pre-heat treat. I grind with a pretty fast belt speed pre-heat treat. After heat treat I grind freehand and go slowly. Grinding after heat treat I am in a constant state of correction, a little there, a little here, till I sneak up on where I want the bevel and spine to be.

Charlie
 
BMK said:
I am a novice and not a "master knifemaker". Anything can be done freehand and without the use of jigs. However, no free hand can match the tolerances of a well made jig. With the proper jig, you can grind to tighter tolerances than "the masters" each time, every time.
Click to expand...

I thought the same at first; I did my first four with a jig. The major problem is that if you move anything when you do your post HT clean-up it will not grind the same. After the first four I gave up and (now only free hand) have never looked back. My excuse was that I am only a part timer and I will not get enough practice to be proficient (Bull).

Next month I am a year in; have about 30 knives under my belt and have been complimented by some of the greats, so I encourage you to practice (O1 is cheap).

To answer some of your questions:

Practice; as mentioned good body form/muscle memory is a must.

I go to approx .020" before HT, I have never had issue with warpage. I also grind one side at a time complete so I have a target.

Not in my experience.

Grind height calculator http://bimjo.com/free/widget.html I use mainly a 10" because I like tall blades (would like to have a 14"); I also have a 1.5, 3, and 6" wheel for other things.

I encourage a slow grinding speed (don't pay attention to the cool shower of sparks seen in videos) you can recover from small/slow speed mistakes better than big/high speed mistakes.

I just finished a test "Chute" grind I had success with grinding the top and then when the primary bevel is ground it will sweep the grind line up to the tip.

Of course all of the above is IMHO.

David Sharp
Sharpwerks
 
David66 said:
I thought the same at first; I did my first four with a jig. The major problem is that if you move anything when you do your post HT clean-up it will not grind the same. After the first four I gave up and (now only free hand) have never looked back. My excuse was that I am only a part timer and I will not get enough practice to be proficient (Bull).

Next month I am a year in; have about 30 knives under my belt and have been complimented by some of the greats, so I encourage you to practice (O1 is cheap).

To answer some of your questions:

Practice; as mentioned good body form/muscle memory is a must.

I go to approx .020" before HT, I have never had issue with warpage. I also grind one side at a time complete so I have a target.

Not in my experience.

Grind height calculator http://bimjo.com/free/widget.html I use mainly a 10" because I like tall blades (would like to have a 14"); I also have a 1.5, 3, and 6" wheel for other things.

I encourage a slow grinding speed (don't pay attention to the cool shower of sparks seen in videos) you can recover from small/slow speed mistakes better than big/high speed mistakes.

I just finished a test "Chute" grind I had success with grinding the top and then when the primary bevel is ground it will sweep the grind line up to the tip.

Of course all of the above is IMHO.

David Sharp
Sharpwerks
Click to expand...

A good jig is one that has repeatability. Again, a good jig will maintain closer tolerances than any freehand operation each and every time.
 
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I actually flatgrind before heattreat, and go to my TORMEK wetgrinder after heat-treat to finnish up the hollow-grind.
I have one with a 10" wheel for my small knives, and 14" for my large blades, and I really love it.
It has a jig that adjusts all over the scale, after your needs and wants. I`ll deffinitely recommend it, if you can get something like it where you live..
 
I have a small box of knives with this grind that didn't make the cut, I finally got one right today! It isn't a hollow grind but to me it was a tough one. Keep trying, the satisfaction is worth it!

[youtube]kIdIQugkHyw[/youtube]
 
I was taught to hollow grind when I first started. For me it was a practice thing. You will develop your own style. The best way to learn is to find a maker that hollow grinds and go hang out with him one day. You'll learn more in a day than you can teach yourself in a year.
 
Most of theb questions you asked have very different answers from one grinder to another. The answer is YOU must learn to do it with a way that works for you. As the man said, "Get out there and do it until you've got it." If I was to tell you how I do it would you follow that way until it worked for you? Only if it was what you thought would work. So do it your way and it will. Frank
 
Wow! Your responses have been amazing! The number of years of experience contained in this thread is huge! A massive help to us who are just starting out. Thank you all.

One question (also in the 1st post) is this:
What is the best way to finish off a clip-point tip where the cutting edge meets the swage?

After a few tried and failed attempts in practicing (on cheap steel fortunately) has left me with this question. Finding the balanced curve or line where the swage flat-ground bevel meets the hollow ground plunge cut is so difficult!
 
samdaknifeman said:
Wow! Your responses have been amazing! The number of years of experience contained in this thread is huge! A massive help to us who are just starting out. Thank you all.

One question (also in the 1st post) is this:
What is the best way to finish off a clip-point tip where the cutting edge meets the swage?

Taper the swedge toward the tip&cutting edge.
Ken.
Click to expand...
 
Daniel Fairly Knives said:
I have a small box of knives with this grind that didn't make the cut, I finally got one right today! It isn't a hollow grind but to me it was a tough one. Keep trying, the satisfaction is worth it!

[youtube]kIdIQugkHyw[/youtube]
Click to expand...

Hey that's a pretty cool little chisel grind. So shiny to! Well done. Almost looks like a thick throwing spike. ;)
 
kc custom said:
samdaknifeman said:
Wow! Your responses have been amazing! The number of years of experience contained in this thread is huge! A massive help to us who are just starting out. Thank you all.

One question (also in the 1st post) is this:
What is the best way to finish off a clip-point tip where the cutting edge meets the swage?

Taper the swedge toward the tip&cutting edge.
Ken.
Click to expand...

So obviously shaping the cutting edge and plunge cut first? And then shaping the swedge into it? Is that correct?

Getting the line straight or a nice curve to the tip is quite difficult! Maybe its just me...
Click to expand...
 
My mentor is kind of ornery.He insisted i free hand hollow grind.Im glad he did now.Just takes practice and a few screwups like anything else.For me ,once i realized i was forcing things and settled down to let the machine and belt do the work,it was easy(easier)
 
I would like to introduce makers to a jig system for grindind hollow, flat, not convex, recurves, Persians, and more. It will happen I hope early in the new year when I get a shop again. I just moved. This is not something I sell but give to those who have visited me. I never did pictures and have never posted pictures to a forum unless someone has been kind enough to help me. It is so simple people won't try it when I describe it. pictures are needed and then the simplicity can be believed in. I don't sell parts . Like you I try to sell my knives. Basically what you need is a tilting table and two blocks of micarta say 3" X 3/4" x 7". This will happen . I will get this to you, yet. Don't beluieve the hype about using jigs to be ignorant. The way a knife is made no long means made by hand. It means how good it is in the end. I may not be great but I am good enough to show my jig system works!!!! It will for you to when I get it out there. There are a few pictures on another forum you might find. Frank
 
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