Trad Gang
Main Boards => Hunting Knives and Crafters => Topic started by: tippit on November 15, 2009, 04:02:00 PM
-
I finally have a blade that fits most of my requirements. The last component was learning how to get a convex edge. It's a subtle difference from just grinding/sharpening a flat edge after forming the blade...but it sure makes a difference in the way it cuts and re-sharpens.
Once again I bow to the west to thank my mentor Doug Campbell. Doug showed me his procedure to convex the edge on my St Judes Elk Hunt with him & Claudia. We may not have harvested any elk...but my bladesmithing sure took a jump :thumbsup:
Little seven inch 5160 skinner that preformed real well at Bear Camp with a flat edge...but now it's flat out scary with the convex edge! Looks like I have a bunch of blades to fix up. Guess that's OK since I still need to get a forge built...Doc
(http://img.photobucket.com/albums/v110/tippit/Knives/SkinnerwithConvexedge002.jpg)
-
i like that alot, always love the forged finger choils. nice!
-
I really like this one Tippit! Curious, do you put a hollow grind on the blade and then convex the edge after heat treating?
-
Very nice Jeff. :thumbsup:
Jack
-
Mighty nice looking Jeff! :thumbsup:
-
Sweet, that looks very nice
dana
-
Very nice Doc! I like the way you get a wide flair at the finger guard, I can't seem to make mine that wide.
Let us know which style forge you go with! I chose a two burner atmospheric,(Chile forge)and I love it!
Steve
--------
ABS Apprentice
Potomac Forge
--------
IN GOD WE TRUST
-
Nice! Can you explain the basic procedure for the convex edge?
I was recently shown sharpening a blade using a slack belt (but adjusted pretty tight), with edge trailing. Very simple, but puts a nice edge on the blade, after buffing off the wire edge.
Dan
-
Dan, I guess there a lot of ways to do it...maybe Doug should come on to explain his set up. If not, I'll get some pictures of how I copied his :) Doc
-
Steve,
There are a couple of secrets to that Keeslar Brut de Forge flare. The afternoon I spent with Joe forging one out showed me all the things I was doing wrong. The main ingredient is his little French hammer...which I was able to twist his arm into letting me take one home :) Actually his arms are too strong to twist as he hammers his blades with a 10# hammer :eek: Doc
(http://img.photobucket.com/albums/v110/tippit/Great%20Smokey%20Mt%20Bladesmithing%20Symposium%2009/GreatNorthernGhostjackknife001.jpg)
(http://img.photobucket.com/albums/v110/tippit/Great%20Smokey%20Mt%20Bladesmithing%20Symposium%2009/GreatNorthernGhostjackknife004.jpg)
-
By the way, that knife Joe is holding is in the process of getting a silver/curly maple inlay handle by Joe. You can bet it will be on display and NOT touched except with silk gloves :goldtooth: Doc
-
It truly IS a long road Doc, and the road never ends!
That's what makes this all so much fun.
Joe had a few hammer heads in his truck in Ohio a few months back and I got one off of him as well.
He's a heck of a good teacher.
Doug is a great maker and I consider him a friend as well.
There's just soooooooooo much to learn, it helps when there are others to help show the way.
Have fun on your trip down that road, Doc.
-
another quick way to do that finger choil if you have a power hammer is this-
Take a piece of 3/4" round bar, better to draw it down a bit on the handle end, put a wood handle on it to absorb some of the possible shock if your holding it wrong.
Obviosly get the area you want the finger choil hot enough to move easy, leave the spine area a bit "dull" red.
Holding the blade with your tongs, spine down, slide your blade under the hammer (with your upper die in the "up" position if possible). Hit 2 or 3 good licks and you have a finger choil.
All this (besides heating the proper section) takes about 30 seconds, maybe quicker.
IFyou want it flared out even more, then switch to the hand hammer, ball peen works good too. A key is not getting the are a behind the choil too hot. if you can keep that area dull so that it wont move easy, the actual working area you want to flare will do so quickly.
man... i hope some of that makes sense!
-
Hey Doc,
What's the approx. weight of those hammers. I have a couple repousse (sp?) hammers almost the same shape but they're way light,less than #1 ea.
Thanks,
Larry
-
On Thursday evening I was able to visit with Joe and watch him forge one of his tradmark "brute de forge" blades. One thing that he said concerning the upset finger guard is to use a hammer that has the right shape to move the steel out to the sides more than down the blade. Yes, the guard will move down the blade too in effect, lengthening the handle, but notice the shape of the face on the top hammer in the above photo. The radiused face also has a curve the other direction. This (the curve)is what moves the steel outward.
I also noticed that he choke it up in the vise quite close to the guard when striking the guard, thus not allowing the upset to travel down much.
Just thought I'd put 2 cents in while it was fresh on my mind. It was nice to visit with him. I've got to make some tongs like those too. I was studying them while he wasn't lookin. Lin
-
Lin, You are correct in that the hammer head is not only rounded but angles backwards too. Keeping it close in the vise helps plus knowing that your handle is going to be elongated as you push metal forward. I've also found that you have to watch the ricasso area as it will bend/distort away from center if your blows are not equal from side to side. If you have it too close in the vise, the finger guard has a tendency to slip down leaving a mark from the vise. Sometimes using copper shields in your vise will hold the hot steel better.
(http://img.photobucket.com/albums/v110/tippit/Great%20Smokey%20Mt%20Bladesmithing%20Symposium%2009/GreatNorthernGhostjackknife003-2.jpg)
You will also notice on some of Joe's finger guards they are flared on the sides too. I really like that as it makes the knife feel comfortable in either right or left hand. Plus I think it looks a little sexier :)
As to the long road, I'm not complaining...just happy to be traveling and not sitting on the road side. Thanks to ya'll...Doc
-
Larry, The hammers aren't that heavy. I'll take a picture of mine for you.
-
A pleasant road to travel, indeed.
I dont make many in this style, but really watch it just in case I decide to. That could be anytime. It has an appeal to it. I guess what I am most interested in is the methods it takes to pull it off. I wonder if rounding the top of the jaws would help keep from scarring the front of the guard area? Lin
-
thanks for the pic tippit! posts like this one make me want to go make another. I may try it completely with hand hammers next time. I think working it completely with hand hammers gives a bit wider finger guard.
When I use the power hammer method, hard to get them that wide.
-
Lin,
Not sure how this got from convex edge to Keeslar finger flare...But there seems to be some interest in this Road too :)
That picture of the flare being hammered on the vise was the one Joe did for me in his demonstration. Once the straight flare is hammered in, then you need to raise it above the vise to hammer in the side flares. That is the time you need to pay attention to distorting the ricasso area because the vise isn't supporting it anymore. I'm not sure how Joe does that part but it has to be elevated to angle the flare forward. Here is a picture of one of my side flares. Hope this makes sense...Jeff
(http://img.photobucket.com/albums/v110/tippit/Great%20Smokey%20Mt%20Bladesmithing%20Symposium%2009/KeeslarStyleblade005.jpg)
(http://img.photobucket.com/albums/v110/tippit/Great%20Smokey%20Mt%20Bladesmithing%20Symposium%2009/KeeslarStyleblade003.jpg)
-
Larry, Here are a couple pictures of my Keeslar hammer. A most prised possession, I do keep it in the safe ;) Doc
(http://img.photobucket.com/albums/v110/tippit/Great%20Smokey%20Mt%20Bladesmithing%20Symposium%2009/KeeslarHammer002.jpg)
(http://img.photobucket.com/albums/v110/tippit/Great%20Smokey%20Mt%20Bladesmithing%20Symposium%2009/KeeslarHammer001.jpg)
(http://img.photobucket.com/albums/v110/tippit/Great%20Smokey%20Mt%20Bladesmithing%20Symposium%2009/KeeslarHammer003.jpg)
-
Thanks Doc!! I really appreciate the pictures!
Larry
-
Those are some great shots of the hammer. Sorry for getting so far off subject.
I guess I have taken the convex edge for granted by now. I have seen it hold up under some awesome abuse. Lin
-
Lin, Can you explain how you put a convex edge on your blades? Jeff
-
Sure. Let's say you have the blade heat treated and ready to finish grind. Depending on the type of knife, the edge should be somewhere in the range of .030-.050 thick. I use the description of a dime's thickness. If it's a hunting knife, I lean toward the thinner edge (thin dime) and for a large knife that will see some chopping, I will make it a little thicker, but not any thicker than a dime's thickness plus a hair.A nickle thickness might be too thick in my opinion. A properly heat treated blade will stand up to a lot of heavy use when this thin.
Note: If you have done your heat treating and the blade is too thick to fit the above description, using fresh belts or a sharp file, bring it on in till your happy with it.
That's where the convex edge comes in. Start by forming a bevel, I would say about a 10-12 degree up from the blade flat. I do this on a fresh 220 or 320 belt so as not to build heat in the blade. Even so, dip it in water as you feel the heat with your bare hands.
Nother note: Remember that by the time it's too hot to hold in your bare hands, the edge has probably gotten so hot that it's tempering has been messed up.
Go till you almost have a cutting edge. Now increase the angle slightly and make a pass on each side, never getting above you final desired sharpening angle. Now you are blending several angles forming a convex cross section of the first 3/16 or so of the edge. All of this should meet at the edge in the form of a sharp edge.
This also called an apple seed grind. Think about the shape of an apple seed and that will be a good guide. No extremes though. There has to be a balance. If it's too blunt, you can drive nails with it, but it wont cut worth shucks. If it's too thin, it will might cut good on very easy tasks.
What you want the blade to do (before you put the handle on it) is to chop wood and not chip or roll the edge, still shave hair, then cut a free hanging piece of rope.
The wood will test the heat treat. If it's not right correct it now at this stage of the game. This will require that you have a good idea of the geometry it will take to perform the test accuratly. Thin Apple seed grind. The reason I say "thin" appleseed grind is, I would like to "know" if it's going to chip or roll and at what level of abuse. Test to failure. Yes, Test to failure! Your not testing the overall knife to failure, just the edge geometry. This will let you know when it's a little too thin in geometry. If it is, you roll it on in some more, shortening the apple seed grind using the above methods. Not much, just a little and re test.
If the blade will chop and hold up, then you are good to go to the rest of the testing and tweak the geometry to suit the intended purpose of the given knife.
The convex edge requires a balance of three or four elements that should be in the makers control. The purpose of the blade, the heat treat, and the edge geometry. They all meet up at the cutting edge.
I have tried to explain my views, but will be glad to clarify anything that I have not made clear. Lin
-
For those who have trouble visualizing what's going on with a convex edge, check out this:
**I removed the link to the commercial site**
(http://img.photobucket.com/albums/v212/fliksr/Knives%203/convex3.gif)
The first on is a full convex grind. The next two are convex bevels - common on saber and flat ground blades. The last two are convex micro-bevels, where only the last 1/32" to 1/8" is convex. The last method is by far the most common I've seen. The first has the best cutting properties imo, but is the most difficult to pull off.
(http://img.photobucket.com/albums/v212/fliksr/Knives%203/convex2.gif)
The above pics were from Koster knives
-
Lin, What are you grinding on...flat platen, very slight slack area as in rotary platen, or what Doug showed me was a very minimal slack area on my flat platen by gluing on a thin piece of felt and grinding in that slack area above the felt. This gives me just enough slack to taper those multiple grinds into the convex shape...Jeff
-
Oops I hit enter twice...got too excited about my lesson from Lin :)
-
I use the slack belt.
-
Lin,
Once again you have been a tremendous help and asset to this site. Thanks for takin' the time...Jeff
-
Doc, as far as getting off the subject, I guess I'm responsable!
"Very nice Doc! I like the way you get a wide flair at the finger guard, I can't seem to make mine that wide."
But thanks to all for all that great info , that awnsers many of my questions!
I have tried different techniques as how to position the blade in the vise and tried using my tong handle striking it to shape the flair with little success.
Steve
---------
ABS Apprentice
Potomac Forge
---------
IN GOD WE TRUST
-
Steve,
I love these types of discussions. It's cool to see all the different knives that are made here...but passing on ideas is really fun!!
Doc