Primitive Archer
Main Discussion Area => At the Forge => Topic started by: Trapper Rob on November 10, 2018, 08:40:03 am
-
What angle do you grind your cutting edge when making a knife?
Do you use a jig to grind them? If you use a jig could you post some pics of your jig I'm thinking about making one.
-
I'm not a blade smith, but I think most working knives are ground to 20 - 25 degrees. I use 20 on mine. I think it depends a bit on the type of steel,too.
Hawkdancer
-
It depends on the intended use of the knife. On my kitchen knives I do 15° per side, for general utility 20° per side, a chopper gets 25° per side. My hunting knives are a happy medium around 18° per side.
-
Rob,
I use a platen for my flat grind...It's done by hand no jig...Don't know the degree of edge but it's 1/8 thick x 2" wide...You can do some pretty good work by hand being patient...I have used a drill press vise to clamp and set angle, then slide it back and forth on the belt...
Don
-
This is the model I have...You can clamp a blade by the handle and adjust your degree...Then place on platen and slide back and forth...I have made some big blades this way...
Don
-
Don where did you buy it at?
-
We're talking about the "primary bevel" and not the "edge bevel"?
For primary bevels I use these blocks of steel sitting on my tool rest. Each side it cut and ground to an angle, starting at 7° and ending at 3°. A precise angle doesn't really matter as this will change depending on if you're grinding 8th inch vs quarter inch thick steel and whether it is 1 inch wide or 2 inches wide. The important part is just having a step down in angles as you progress, starting with rhe steepest and working down till you get the the point you want. If I'm doing a flat grind I work my way down till the grind reaches the spine. If I'm doing a saber grind I'll stop stepping down when I reach the desired depth of grind. Below is a pic of two choppers .25 inches thick and 10 to 11 inch cutting length, the one on the left is saber ground with just the 7° block, the one on the right I worked down to the 4° block and then free handed it the rest if the way to the spine.
I can't really take a pic and work at the same time, but you rest the steel against the block and push both in to the grinding belt, and then pull the blade from plunge to tip. You want to roll the tip laterally in to the belt while maintaining the same angle up against the block. Hard to describe this part, you don't want to let the knife pivot toward where the edge will be, keep it flush against the block, but pull back on the handle away from the grinder so the tip makes more contact with the belt as the main part of the blade pulls away. Otherwise you end up with an obscenely thick tip.
(https://66.media.tumblr.com/b5408040b62d716efc00a20083ab5286/tumblr_pi1l57ADVn1ubi548_1280.jpg)
(https://66.media.tumblr.com/453fd26e8dd22bbdc8163331fd8dd49b/tumblr_pi1l5oppT51ubi548_1280.jpg)
-
Home Depot has them for around 40.00, can't give a direct link...
Don
-
Thanks guys.
-
Robbie I Mark where I want the bevels to stop and freehand it. I usually do flat grind with kind of a convex edge
-
Bubby I'll give that a try this weekend.
-
When I learned, there were not really any practical jigs available. So I learned to grind freehand. I'm not certain it is actually any better, but it is more versatile.
As to the question of what angle to use, that depends entirely on what the purpose of the knife is.
****Warning! I'm about to get all opinionated and slightly preachy! If you don't want to read that sort of thing from a guy who is pretty new to the boards here, please skip the rest of this message! You've been warned!
There are two things I believe any blade maker really must do if he is going to sell his work to the public.
1) Use his knives and compare them to others. Would you trust a pastry chef who never eats pastry to make the best pastries in town? How would he even know if his were any good? Yet, I see some really awful knives (often quite pretty and very well finished) sold by guys who know how to do the process, but don't actually use knives. How do I know they don't use knives? Because I use knives! All the time. I can look at a knife and I can't tell you for certain the maker is also a user, but I can tell you for certain if he isn't a knife user. I'm not qualified to make a fighting knife because I have never studied knife combatives. I am qualified to have an opinion on cooking knives and wood carving knives, though. Those are near-daily activities for me.
2) Test his blades regularly to the point of failure. I know exactly how much abuse my blades will take. I know just how far I can trust a knife I've made. I know because I destroy blades on purpose to learn what they can and can't handle. If every blade means so much to you that you can't imagine doing something that might damage it, you haven't done the work of making blades to kill them. And until then, you haven't really learned enough about your process and results to offer your blades to the public.
I know these opinions do get some people riled up and they don't directly address the questions. However, by using your knives, you learn what bevels work, how fine to grind a blade for your intended use, what sort of finish to leave on the steel, and all the other things that I think are really only learned by doing, trying, testing, destroying, and starting over.
I don't measure the angles and I'd be guessing if I gave you a number. What I do is use my knives. A lot.
-Patrick