Teaching someone how to grind

Geoff Flato

Geoff Flato

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May 23, 2017
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This may actually be a beginner question that hasn't came up here before.
I'm great at learning things, but admittedly not the best teacher.

My dad is getting close to retirement, and is wanting to try making some knives in addition to the woodworking and machining he already does. He's extremely experienced in the shop, with pretty well everything possible except bevel grinding. And that's where my question comes in. I've taken it on myself to teach him how to freehand flat and hollow grind. We started last night, and he's doing surprisingly well so far for a first attempt at grinding.
I thought I could explain what I've been doing and my thought process behind it, and see if anyone who has actually taught someone how to grind before would have any suggestions on making it easier.

Firstly I've been showing him how to grind the way I do, simply because I make a mess of it whenever I try something different. Its been 100% freehand, no jig or work rest, and I opted to start with hollow grinding.
My logic for starting with hollow grinding is that I'm a lot better at it than at flat grinding, I personally find it easier, and I always hollow grind a blade before flattening on the Platten anyways.
Just using mild steel practice pieces to avoid wasting 154cm, and 60 grit belts instead of my usual 36 just to slow the process down some. My grinder isn't that fast, but it is fixed speed so dialing it way down isn't an option.
Ended up trying a few different things. Firstly I started with the 12" wheel as it's what I usually grind with. That seemed rather hard for him to feel the hollow, so I switched to my 8" wheel after the first attempt. I've had him grind the left-handed side first on each one in an effort to take care of the most challenging part first.

The main issue has been following the track of the grind consistently. I tried a 120 grit belt which didn't help much, and just practicing finding an getting a feel for being in the hollow without really applying any pressure. That did seem to help some.

I'm just wondering if anyone has some suggestions on helping him develop the feel of following the hollow? Switch to the 5" wheel? Put a dull 400 grit on and get him to practicing an existing hollow I roughed in? Or just keep going as I have and cut a big pile of practice pieces?
 
I believe Kevin's idea is one that might help. Establish a full grind with the 12" wheel on a mild steel outline and let him get a "feel" for that without the grinder operating and then with it on.
Frank.
 
I'll give that a shot on the next session. I've alsogot some rough ground blades in my pile of things I'll never finish, might try getting him to try the finish grinding with something fine until he gets the feel of following a track, then revisit rough grinding. Following the groove with a worn out trizact will be cheaper than blasting through roughing belts too
 
The above sounds like good advice. But you said you started last night? How long did it take you to get where you are now? Have a little patience. Your dad is a smart and skilled man. It takes time to develop "feel". He will pick it up. But overnight might be asking a bit much. ;)
 
Well worth remembering. I took probably 10-20 before I had something usable, 100 before I could really make nice freehand grinds, and a couple hundred before I was able to grind any sort of blade I wanted to without worrying if I could do it.
I know he'll be able to get it, I'd just like to make it as easy as possible. He's already got his first couple knives profiled and heat treated (a pair of small 154cm kitchen knives) and wants to get to the point he can grind without screwing up on mild steel before progressing with his first knives.
 
He'll have years shaved off his learning curve because his teacher is his biggest fan. He's in good hands.
 
I've learned lots from him over the years, spent most of my childhood making shaker furniture before he got onto machine shop stuff. Taught me how to do hand cut dovetails when I was 9, and how to run a lathe and milling machine when I was about 12.
It's nice to finally be able to return the favor.
 
Geoff, I've got an opinion like everyone else. I think if you want to teach hollow grinding then some things to consider that might be helpful are: Use fairly thick steel to start..3/16 so you have room to save a grind going bad and also try to use an 8 Inch wheel to start because it will make a good hollow that s easy to follow with finer grits and start out with a new 80 grit belt that lets you grind a little slower and make corrections easier. These ideas are only MY opinion and you can judge my advice by looking at my knives and see if they are up to the level of professional work that you eventually want to see from your dad. I wish you the best and hope that your dad can feel the pride in a well made first try and then subsequent work . Larry P.S. use a small work rest to start. LL
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Geoff
give him some 1/4 paint sticks and a 120 belt to rough gring then go to 220 so he establishes the feel for going back into the groove.
 
I've taught a few people and what I find to work best is to profile 2 blanks that are exactly the same. Let your dad watch while you grind yours and explain exactly what you are doing and why. Also, remember the mistakes you made when learning and explain them to him so he wont make them too. Go slow and encourage him to ask about anything he doesn't understand. After that, let him start on his and guide him through the process.
It is important for you to remember and to explain to him that everybody grinds a bit different so you're just giving him the basics and the only way to really learn to grind is to make lotsa sparks and dust. Good luck and have fun.
 
LARRYZ10 said:
Geoff, I've got an opinion like everyone else. I think if you want to teach hollow grinding then some things to consider that might be helpful are: Use fairly thick steel to start..3/16 so you have room to save a grind going bad and also try to use an 8 Inch wheel to start because it will make a good hollow that s easy to follow with finer grits and start out with a new 80 grit belt that lets you grind a little slower and make corrections easier. These ideas are only MY opinion and you can judge my advice by looking at my knives and see if they are up to the level of professional work that you eventually want to see from your dad. I wish you the best and hope that your dad can feel the pride in a well made first try and then subsequent work . Larry P.S. use a small work rest to start. LL
vUcbKh2m.jpg

]
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I think we're going to try the first idea of getting a feel for being in the hollow first, and then probably do exactly what you've suggested. We've decided to stick with the 8" wheel until that is down, and the practice pieces will be 3/16" 1018 to avoid wasting a pile of blade steel. I've never used 80 grit belts myself, but I ordered a couple of 80 grits (two cubitron and two blaze) to give a shot. I'm not opposed to work rests, I just can't seem to grind anything on them without making a mess of it. I'll put the one I use for profiling on so he can see if it works for him though. I've also seen a piece of round stock for a tool rest recommended by some for hollows, might give that a try too.
The work rest at first might actually help with getting over the natural tendancy to try and keep your fingers away to prevent sanding them, and at least give full support rather than propping it up with your index finger.

Your grinds are exactly the sort I do, so I'd have no problem trying other approaches for getting there. The path doesn't matter as long as you end up at the same place.
I even take the approach I've seen loveless and Merritt do of grinding the blade in sections. I find it easier to do a consistently good job and correct issues that show up grinding a section at a time rather than ricasso to tip on every single pass. Makes it harder to grind the tip off too.
 
Darrin Sanders said:
I've taught a few people and what I find to work best is to profile 2 blanks that are exactly the same. Let your dad watch while you grind yours and explain exactly what you are doing and why. Also, remember the mistakes you made when learning and explain them to him so he wont make them too. Go slow and encourage him to ask about anything he doesn't understand. After that, let him start on his and guide him through the process.
It is important for you to remember and to explain to him that everybody grinds a bit different so you're just giving him the basics and the only way to really learn to grind is to make lotsa sparks and dust. Good luck and have fun.
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I've sort of done that. He's watched me at the grinder over the last couple months and asked questions about how I do things. I've had a blade on the go at the same time he's learning so I can show him how I do things, and use my blade to show how to correct issues he runs into. I think it's going quite well, and I expect he'll be making nice hollow grinds after a week or two worth of evenings and a good pile of practice pieces.
I've gave him a list of videos on grinding to watch and hopefully find anything either I missed out or would work better for him.
 
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