Hi Mark,

The main quality of a convex grind is its ability to keep a really sharp working edge on either unilateral or bilateral edges.

Should your broadheads be in the HRC 52 to 55, the convex edge will allow for added steel supporting the said edge giving it limited use ( but that’s basically all we need anyhow, right!?) however due to the lack of hardness, your edge will most certainly dull very quickly.

Now depending on the type of steel that same broadhead is made of you can give it a HRC by modifying its temper, then your in the drivers seat. Let’s say we increase the steel hardness from HRC 52 – 55 to HRC 58 – 59, watch out boys and girls, we now have a broadhead that will be able to support a higher form of pressure and will then retain its edge that much longer.

With todays and the past heat treating processes, we now know that certain types of steel can retain a memory. By that I mean once the edge is compressed by either hitting bone or hide, we can make it so that steel come back to its original edge, WOW !!!! And yes the edge will not curl and you will not see any evidence of intergranular fracturing due to stress.

So as not to get to into details, should you add a convex grind on a broadhead that been heat treated and tempered for its intended use, then, you will most certainly have a very effective edge.

I will most certainly make it a point to make such an edge for you and provide its actual anatomy on digital pics.

I would like to start by telling you that if any of you didn’t get the opportunity to read the Feb-Mar 2003 Special Adventure Seection Traditional Bowhunter Magazine, Mr. Gene Wensel wrote an incredible article on his observations on the traditional broadheads. He also explains why we need to use the right tools to get our broadheads sharp.

Some of the pictures that I will be posting will support his article and hopefully shed a little light on the anatomy of a true edge.

The first two pictures show you the actual broadhead that you receive when you either buy them in the store or online, the Ribtek and the Zwickey Eskino 4 blade.

The next two pictures are those of the same broadheads but with a closer look at the actual edge. Again these have not been sharpened and are new broadheads.

A last look at these two edges.

Here is a little food for thought, broadheads using stainless steel come with smoother manufactured edges and many of them come pre sharpened. The reason they are so darn sharp is they come with a bi level edge meaning a working edge 20 – 25 degrees over a main edge that is between 18 and 20 degrees.

Lets take the Thunderhead blades for example, these are made of stainless steel and come pretty darn sharp, well in the two following pictures, you’ll see why, they come with a two edge system.

Now here is the interesting picture, note the two edges on the blade.

Your right, J.Wesbrock, another reason why TBM is so dedicated to traditional bowhunting and their readers. Mr. Wensel I have to admit talks to talk but also walks to walk.

What I did in the next series of pictures was to give the Zwickey its first shot at the 6″ bastard file. One of two things happened; i got the burr that I wanted to show but at the same time, I added a edge that was too thin and noticed a splinter in the steel’s edge.

A splinter or hairline fracture generally occurs when you remove too much steel by givnig it sharp angle ( the edge is too thin ) so when you apply pressure on your following pass with the file, the edge splinters…..OUPSSSSS !! This generally happens with broadheads that are a little softer in the Rockwell hardness ( HRC ). Broadheads that are heat treated a bit harder than these, generally stainless steel, will chip instead. There is a way to prevent this but this is a whole new ball game in itself and they cost more.

Here is the first picture of the Zwickey when I finished the first pass witht he 6″ bastard file.

This is a closer look and its here that you can see the burr that the file work created.

Now, here is the hairline fracture, splinter that was left behind by removing too much steel.

These little steel splinters are not good !!!! However if you take your time and not add too much pressure to your file, theres a good chance they will not occur but they do on occasion, I’m kind of glad they did on this instance.

J.Wesbrock, yes that exactly where the hairline fracture is, plus you are absolutely right when you mentioned that I pushed the file into the edge. I might add that should you use less pressure and keep a slightly wider angle, these would not happen but we have to adapt the sharpening process with the type of steel we are using. Great points I might add. I’ll add a closer picture in a little while so people can see it better.

Snuffy, the anser to your post is yes we sill touch on the subjects you mentioned, stainless steel, bilateral and unilateral edges.

Thank you for adding your comments:lol:

You know folks, with very little effort and a bit of patience, you can get both the Zwickey and Ribtek shaving sharp with a file and medium croc stick.

Both broadheads easily cut through paper and shaved the hair off my arm.

Here is the picture of the Ribtek edge, very sweet.

What a great edge, no burr and razor sharp !!!!

Now, its time for stainless steel broadheads.

By making broadheads out of stainless you can also by heat treating them give the heads a HRC of up to 59 – 60. That means you can put a wider edge on them 25 – 35 degrees and still have them razor sharp.

Not too long ago, we seen a new revolutionnary broadhead come on board called the Silverflames. They too were made of stainless steel but the main edge instead of being flat ground were now hollow ground. I should add that the combination of heat treat, cryo quenched and appropriate tempering made them simply super sharp. Basically, they adapted the methods used in knifemaking to the broadhead.

The sharpening tool that I am now using is the KME broadhead sharpener and on occasion, the KME knife sharpener. These get the job done and more.

The two stainless steel broadheads I will use are the Silverflame 210 grain and the Alaska Bowhunting Supply Nanook 290 grain broadhead. Both of these heads have very particuliar traits. I will take the time, further down this tread, to explain how these traits make these heads so effecient but for now here are the two pictures of them.

An interesting point to mention is that both of these blade come with a precised machined edge that is slightly hollow ground and they both support a secondary working edge which is flat ground. They are very similar to the thunderhead blade I posted earlier.

Here is the picture of the Silverflame 210gr.

Here is the picture of the Nanook 290 gr.

Now the easiest and fail proof way to add a Extremely Scary sparp edge on these babies is to use the KME Knife sharpener with the diamond hones Ron sells.

4 strokes with the medium ( medium pressure on the hone )

6 strokes with the fine ( fine pressure )

This is the part of the tread that is taking time, I’m working on building diagrams and digitals pertaining to the advantages of a double edge system.

In this part, I will also explain the secrets to how to keep a knife blade and broadhead edge extremely sharp. It’s actually relatively simple once you know the ABC’s of why we do certain things but once you get the hang of it, watch out !!!! Another thing, knowing how your steel reacts to certain angles is your key to success.

Thanking all of you for being patient with me, we will be getting into the meat and potatoes of things in a bit.

Again, please feel free to provide your thoughts and experience in sharpening because in the end, we are all gaining from it 🙂

StandingBear

Trying to get the diagrams in but am having a bit of difficulty, lets see how I can do this 🙂

Finally, had to take a digital of the computer screen and VOILA !!! Who says you can’t do things.

Here is the diagram I built earlier today showing you in detail how we make this incredible bilateral edge. Its extremely strong and will get you to think twice at how you used to build your edges using a single angle. Keeping in mind this is mostly used for stainless steel broadheads.

This evening, I took one of my Silverflames that needed sharpening and decided to use it as an example of how to add a secondary edge on a stainless steel broadhead.

I enjoy using my trusty KME knife sharpener for this, and just to let you know, that is the first thing that goes in my hunting pack before a hunt !!!!!

So here, I clamped my Silverflame in the jaw and added 23 degrees on the sharpening angle scale.

A little clarification for you on the qualities of Stainless Steel as broadhead material:

– They can be heat treated and Cryo ( sub zero) quenched and tempered to a HRC of 58 – 62 depending on the types of stainless.

– They have the ability to retain a very strong secondary working edge ( which will impress you ). These edges last longer and are better apt to take pressure sustained when hitting bone.

– They adapted todays knife technology to broadheads which is why they cost alot more.

Here is how the set up looks when the nedium diamond hone is laying flat on the blade.

After following the sharpening method I mentioned earlier in this tread, I did:

– 4 strokes on both sides of the broadhead with the diamond Medium hone ( using medium pressure because you want to create a burr ).

*******IMPORTANT*******

When you finish sharpening one side of the blade – do not sharpen the same edge twice – because your edges will not be balanced. When you finish sharpening one side, turn the broadhead over and do the other side.

– 6 strokes on both sides of the broadhead with the diamond Fine hone ( using light pressure ) you still want to get rid of that burr which is why your doing it at least 6 times.

Once you are done this is what you will get :

And then the final test : ( yes that’s my arm ) 🙂 Now this is the time to take a few seconds and think about what I am going to mention, your in the bush, you need to add an edge on your broadhead, how long do you think it will take to add another secondary working edge…….about 2 minutes if that.

Question: Can you add a secondary working edge on softer steel broadheads?

Answer: Absolutely !!!!!!!

Here is a little story that happened to me and a couple of hunting friends last year. My friend and his son ( 14 years old ) came over to the house and to my surprise they had just got a moose. the son took a few minutes to tell me how he could not even split the hide off one leg because his knife came dull. Well, this knife was a K-Mart special, 19 dollars. I looked at his dad and then at him and I told him I could probably do something about that. I took his knife and the steel was really soft, I guessed the Rockwell to be about 52, if that. So I got my KME out and built him a main edge of 18 degrees, then I added a secondary edge of 20 degrees and showed him how it shaved hair off my arm.

To make a story short, my friend had gone hunting on the river with another hunter from the community and they got a moose. Guess what knife he had on him, yeap, you guessed it right, he only had his son’s knife on him. To his surprise, he and his friend both skinned, quartered and deboned the moose with their knives. He aske me what I had done to his son’s knife and I told him I simply added a working edge on the knife and he smiled and shook his head.

The next diagram and picture I will be posting will deal with unilateral edges ( single bevel edges ) and their uses.

Here is a little recap on the Broadhead Edge Terminology.

I think this is the time to have Sharpster join in and take a few minutes to explain the term “Double Bevel”. Ron is the product designer for KME Knife and broadhead sharpener and I wanted to take a few minutes to thank him for allowing me to use his knife sharpener in my tread.

I hope I was able through my explanations provide a bit of sense in what a edge looked like. I’ve been at this for a very long time but I always enjoy learning from our younger generation.

Single bevel broadheads:

– Is that edge strong enough?

– Can we add a secondary working edge on these broadhead?

– Why are people using them? ( I have my own theory )

– Have different cultures used this type of edge? And for what purpose?

– What can stainless steel do for that broadhead design?

– Have we re-invented the wheel with singel bevel edges?

These are some of the questions I will answer to the best of my ability and again, please feel free to join in and allow this great passion of bowhunting to grow.

I will be gone for a week to a traditional archery rendez vous in Alberta, wishing all of you the very best.

SB

I don’t see why you couldn’t use your Lansky Michael. Give it a whirl and let us know how it worked.

This is to let you know that I will be adding the single bevel portion very soon, been absolutely crazy here but I’ll get to it.

Thanking everyone for your patience 🙂

I haven’t forgotten all of you awesome people, will be back soon, need to take care of a few things and I will posting on the single bevel edge.

Meegwetch ! ( Thank you in my language )

Hi Danny, that’s a good question. Ron can really help you on this one, he’ll probably have a few things to say on how to get started using the appropriate angles and bevels. Give him a shout or better yet, perhaps he’ll join in and help you here.

Again, I think you asked the million dollar question, which is why Ron came up with his system.

Single bevel edges, hmmm, I think I’ve heard just about every opinion/comment about their use and effeciency. I must admit I can’t really add anything more to what Dr. Ashby has done in both his studies and experiences with that particular type of broadhead but what I can tell you is that the type of steel used in making them does make a huge difference.

Firstly, what is sharp and why are we adding a particular sharp edge on our broadheads. Is shaving hair on our forearms the determining factor on how a broadhead will work when going through an animal, well, I don’t think so. A 14 degree edge will shave hair on your arm but with certain type broadheads, the edge will not do what you intended them to do, instead, the broadhead edge will either curl, bend of break when encountering bone because the broadhead total hardness is too soft.

With either spring and or stainless steel broadheads made today, we have the ability to either add a 18 degree edge or a 30 degree edge on them and still have them razor sharp. The reason is broadhead manufacturers are now getting their steel heat treated, sub zero quenched and then tempered to a hardness that can rival any custom knife made out in the knifemaking industry.

A good rule of thumb is is you use a broadhead that has softer steel, then you should consider adding a finer angle to it. And again, if you have a braodhead that has harder steel ( some spring steel and stainless steel broadheads ) you can add a much wider angle to them increading their durability/ strength and still have them razor sharp.

Now since most stainless steel single bevel broadheads ( in the HRC 57 – 61 ) are being heat treated, sub zero quenched and tempered to a high quality broadhead, a much finer and thiner edge can now be considered as strong as any double beveled edge broadhead made out there today. Let’s face it, the single bevel edge is notorious at how devestating its cut is and then add to it a hardness that makes it extremely strong, well, you now have yourself a new generation of highly effecient broadheads that get the job done.

Should you see any type of bending and or curling on your broadheads, widen the edge a bit more so that you are giving the edge itself more steel support.

This a a gteneral guide that I use to add particular edges on my broadheads:

HRC 50 – 56 : 20 degrees ( primary edge 18 with 20 degree on top)
HRC 56 – 59 : 25 degrees ( primary edge 20 with 25 degrees on top – for North American Game)
HRC 56 – 59 : 30 degrees ( primary edge 25 with 30 degrees on top > for Dangerous Game ).

Please feel free to send any questions you have over regarding steel and its proprieties, I would be more than happy to send you the information you need to make the decision of what angles to add on your broadheads and why.

SB