Can anyone explain this "Rockwell" rating? I have been posting and interacting here on TG lately about broadheads. As I study different heads I note various descriptions including Rockwell this and that. . . I am not sure how to compare apples to apples.
For example- the STOS is an interesting design with the ferule going the length of the head plus it is more than one thickness at the tip. Now- the Tusker does not "look" as strong, however- maybe the Rockwell rating is stronger? How would you know?
Dan in KS
Dan,
The Rockwell scale is a means of measuring the hardness of an object that has been heat treated. To test a broadhead or any other object you will need a tester with a diamond point or go to a good machine shop and ask if they have a Rockwell tester that will check using the C scale. For us DIY types you can use a file and guesstamate the hardness by how much pressure it takes to scratch the surface or get shavings off the broadhead.
Regards,
Grouse
Thanks Grouse. I think what I a asking is how to compare the many different "Rockwell" listings on various broadheads. How do I compare apples to apples?
For example: Tusker = 50-52 Rockwell
Magnus Snuffer = 44c Zwicky Eskimo = heat treated (?)
What is the difference??
Put it on an arrow and stick an animal see what happens, if it's steel it will probably go through flesh.
Simple in my mind,
Unless you are going after some very large Dangerous animals it really wont matter, don't over think it.
Rockwell is (I think) an arbitrary series of numbers derived from pressing or scratching a piece of metal. The amount of effort it takes to scratch it gives a number. The more effort, the higher the number.
From what I see here and elsewhere, the number 50 is a good round number to look for, maybe a tad higher, for broadheads. You want them hard enough to take and hold a good edge, but not so hard that they are difficult to sharpen or will snap on impact.
Older Bear heads were softer steel (lower Rockwell) and although easy to get nice and sharp, were dulled more easily and bent a bit easier.
Some heads I have seen are much harder, are harder to sharpen, don't bend as easily and hold an edge better.
I am certain those that really know this stuff will chime in with actual numbers for more accurate information.
ChuckC
As a general rule, a higher Rockwell listing is normally more durable than a lower one. The higher one may also be harder to sharpen. After re-reading Ashbey's studies, single bevels needs a higher "R" rating due to the twisting forces caused by a single bevel. This can cause the edge to roll. Like already stated, most good double bevel broadheads are hard enough to do the job.
44 rockwell is softer than 50
I will chime in with what little I have found with rockwell differences in different heads. An original woodsman has a rockwell hardness of 44. Zwickeys are around 50, and so are VPA's. The only one I have really bent to the point of it being unusable is the original woodsman. My consensus is that broadhead design plays as much if not a more important part of a broadheads strength.
When you get up around 50 rockwell, knives and broadheads get difficult to sharpen with a file. It will skip off and not bite in. The harder the steel the more prone to breakage on hard impacts. The softer is more prone to bending.
Usually a happy medium works best.
do not be put off by what was said about the Bear Razorhead they have claimed MANY world records.
as Charlie said Rockwell is only a measure of hardness.There are other factors to consider such as brittleness. proper heat treating is an art. Broad heads have to be fairly thin. A thin edge with a high Rockwell # would stay sharp longer but might shatter on impact with bone, where a softer head would drive through. I used to see this a lot with stainless steel replaceable blade heads. high Rockwell #, very hard steel, but they would chip and shatter on anything.
A good steel can be VERY hard and not be brittle. A good knife blade will be up in the RC 58 to RC 62 range and still not be brittle. Problem is, such a knife will cost you $50 to $500. How many people would be willing to pay for good tool steel, properly heat treated in a broadhead they might lose? And how many would be willing to spend the time necessary to sharpen it? Like Charlie said, you could forget about sharpening them with a file.
Another point to remember is that a knife is expected to cut, and cut, and then cut some more. A broadhead only needs to cut once - in one side and out the other.
Way I UNderstand, A Knife Is A Different Critter. You Can Differentially Harden A Knife, To Have A Very Hard Edge And Softer Back To Make It "Best Of Both Worlds". Either Way, Make It Too Hard And It Is More Difficult To Sharpen.
chuckc
Great input guys. Thanks. . I have been at this for 40 years of hunting, 30 with trad. Blessed to have hunted a number of species and taken a number of mature/PY whitetails. . . I shoot 55#, 190fps, 31" draw, 550-600 gr arrows. But, I have had a couple of mishaps like 2" penetration last year on a 5 yd. shot at a 140"+ whitetail. I see a Tusker vid with the guy blowing though water buffalo shoulders. . . Ashby talks about blowing through bone. And no need for commentary on placement, sharp head, yada. . . I know. But I hunt a real world where shots and things do not always work out. I just want the marginal shot to do the job. Thus- my inquiry. . . Thanks again.
If you can cut it or sharpen it with a file it is something less than 50 RC. As was mentioned harder does not mean stronger.
Alright... KSdan you opened up a can, now you got to elaborate on the 2" of penetration, first off how do you know it was only 2"s did you recover the deer? where did the shot go, etc. etc.
come on now tell the story.
Broadheads are not knives. A Rockwell of 44 to 48 is great for broadheads as they are easy to sharpen. Durability of the edge is not so critical as it only has to cut 12" to 20" of meat to do its work.
I hunt with Stos - great heads. I have a sample of the Davies and Tusker heads and would use them as well. They seem rugged and well designed.
If you look at the Stos the design incorporates a VERY smooth ferrule transition. That was the key feature. Long and narrow with a smooth ferrule for penetration and to split ribs. This they do - I have taken deer with a rib hit on either side and the head still was outside the far side of the deer. :thumbsup:
One I am still carrying in my quiver went through a deer and buried itself flush in a root. The deer shapped it off with its hind leg when it spun and ran off. Had to saw the root apart to get the head back. A few passes with a file (and a new arrow behind it) and we're back in business.
Oh my. . . hate to relive it!
Waited for this textbook scenario to unfold in this exact spot. . .
6 does came through,. . . 20 minutes later this 3 yr old 140+ comes running. Should I take him? Stops 5-6 yards below my cedar tree on up hill side-making it a mere 8' below me. Quartering away just off the fringe edge of cedar twigs. Wind in my favor. Seconds to decide. . ?? Ok. Shoot now or wait until he walks out and up the hill making it eye level, 12 yard "fish in barrel?" "One in the hand" mind racing. . "Can't miss, just center it in his chest." Take 5 yd shot. The Magnus 4 blade is released, arrow hits and does not penetrate. Deer bounds up the hill 25 yards and stops for a minute or so. Entire arrow is hanging out. As he runs off the shaft breaks off on a tree. I wait for a short time just disgusted. I go up to where he was standing at 25y. The arrow is laying with the broadhead thread broke off at the insert. A couple of drops of blood on ground and a just a smudge on the insert itself. I go ahead and track with nothing but foot prints. Find a couple drops out to 80 yds from shot. Obviously broadhead in the shoulder blade. My one chance at near mature deer for the year.
This is the 3rd such incident in the past 17 years. I know for a fact 2 of those 3 lived-seeing them in following weeks/years. I hit one other deer in this manner/same head 13 years ago- the head made it just through the blade severing the spine- 173" buck down on the spot. 5 yd shot. (was a 700gr set up)
Stay away from blade I know. . . but things happen occasionally.
So- I have other success with same broadheads, but revisiting here with help of TG, etc.
Dan in KS
Sounds like the insert pretty much broke upon impact, that's gotta suck.
The insert broke off as the shaft struck a tree when the deer bounded away after it stood there for a minute. Every scenario on this type of mishap has been close encounters. Close happens often to me. I still would like to think that at 5 yds an arrow would penetrate the shoulder blade though. Just re-read my bow set up. Pretty good for trad.
With the power your setup has, you might want to read or reread the Ashby studies. Don't know if you can RELIABLY get through the shoulder with any setup, but you can maximize your penetration.
Will a hot melt type glue affect the heat treatment of a broadhead? I've heard of a lot of people using epoxy to avoid messing with the heat treatment, but I like being able to remove my broadheads and put them on fresh shafts every now and then.
I prefer the higher Rockwell steel, those heads carry their razor sharpness all the way through the animal, no dulled blades pushing vs cutting tho there are many factors affecting blade sharpness.
The unsupported edge of single bevels NEED to be a high rockwell.
KSDan if I myself had the same things happen to me I would be looking at my arrow set up to find out where the weak link is. I think your broadhead choice is fine unless you are shooting for the shoulder blade on purpose and even then there is no gurantee that a well built single bevel will make it through 100% of the time but it would be a better option if that is the shot you are taking. What I seem to get from reading your post though is that you might be using aluminum inserts and adapters, this would be your weak link in your setup and could be bending or breaking on impact with bone.
QuoteOriginally posted by grouseshooter002:
Dan,
The Rockwell scale is a means of measuring the hardness of an object that has been heat treated. To test a broadhead or any other object you will need a tester with a diamond point or go to a good machine shop and ask if they have a Rockwell tester that will check using the C scale. For us DIY types you can use a file and guesstamate the hardness by how much pressure it takes to scratch the surface or get shavings off the broadhead.
Rick hit it right on the head. Rockwell is a measure of hardness. As far as a blade being tough or resistant to breaking; well that depends on the steel it is made from, and how it is heat treated.
Regards,
Grouse
James- not trying for blade but like mentioned, 3 mishaps in last 17 yrs. I have had a few others within an 1" of it. I won on those!
All these are very close encounters with deer under 10 yds. The shoulder blade covers a lot at that angle from a tree stand.
May not be much I can do- as I have wheelie friends who have had the same result. But even after 30 yrs at this, an aging guy has things to learn.
I will say James- I did switch this year from brass to alum insert (some tuning issues I was trying to resolve). And as I think of it- the other failures were alum too. The alum on the arrow retrieval was distorted- though it could have been just the stress from the tree and broadhead breaking off.
BTW too- I really do not want to get into a debate (I know the arguments pro and con) but there was a day 20 years ago that higher poundage with longer limbs was part of the serious discussion. As many of us in this first wave of a return to trad have aged, and more entered this trad hunting the discussion has changed to lighter wts. with shorter limbs. I may just re-visit the higher # along with heavy shafts again.
Thanks again TGers
Very helpful
Dan in KS
As has already been said. The Rockwell scale is used to determine hardness and depth of hardness. The depth of hardness depends on the tip used in a Rockwell tester as well as the weight used used during testing.
Here is a simple explanation.(maybe overly simplified)
The Rockwell scale is differentiated by letters. Those letters tell you how the steel was tested. Each letter scale also has a numbered system. The numbers tell you where the steel is in hardness within that letter scale.
Rockwell A scale is for tungsten carbide and other extremely hard materials.
Rockwell B scale is used for medium hardness materials (Like a carbon steel) in an ANNEALED condition.
Rockwell C scale is for those same types of materials in a hardened condition.
It goes on from there but thats as far as we need to go when dealing with broadheads.
Broadheads are tested on a Rockwell C scale.
I have a Rockwell tester. If anyone is interested in seeing it I can take a picture of it but Tracy is at work today and I dont know how to post pictures. If someone wants to see it I will ask here to help me this evening.
So whats the best hardness for broadheads?
Like everything in our type of archery there is no all encompassing correct answer to that question! It depends on the style of broadhead. The shape of it and just as or more important is the type of steel used!Here is what i mean by the shape. A 3 blade could be softer than a two blade and still hold up to use because of its pyramid shape compared to the flatter shape of a 2 blade. (This is just an example)So you may be able to have a 3 blade that is say 45 Rockwell C and it hold up just about as well as a 2 blade that is 48 Rockwell C. One number different in the hardness of the scale is much more than it sounds. There is a huge difference between 45 and 48 Rockwell C.
As if shape is not enough of a variable what about the steel used? You can get just about any imaginable combination of steel. What makes it even harder to figure out is although its suppose to be the same. Steel can also vary from place to place. These are just a few things that you have to consider when trying to decide which hardness is best for broadheads. All of this and we have not even considered blade thickness yet. See what I mean about there being no strait forward "this is correct" answer.
Here is what I have decided is best for the Grizzly line of broadheads. Other manufacturers have made different decisions and I have nothing but respect for them. However this is the route we will continue on.
I like harder broadheads. I do not like a broadhead that the tip will bend badly. Nothing will stop penetration faster than a broadhead that the majority of the front of the head is bent at a 90 degree angle from coming into contact with heavy bone. I would rather it brake that tip off and keep penetrating than allow it to bend very far. Obviously we are not looking for a broadhead that is so brittle that it breaks often.
The perimeters on our heat treat for the Grizzly and Kodiak heads is 52-54 Rockwell C. Why? Because it works well for us. The carbon steel we use is tough enough and thick enough to take a 52-54 without being brittle. They can take not only use but abuse at that hardness. It would save me a lot of money in grinding if they were not so hard but I dont believe they would be as good of a broadhead if they were softer.
Another big plus a harder (but balanced with the type of steel used) head will have is edge retention. I think this is one of many variables that will cause a poor blood trail. Especially on pigs. A pig of any size is almost always muddy. IF your head does not have good enough steel or hard enough steel. It WILL be dull before it ever gets to the pig to do its job.
Not only the single bevel Grizzly's but also the 3 blade and double bevel versions will continue to be harder than most heads.
If you can not file sharpen a broadhead that is over 50 Rockwell C. Then you need a better file.
I know not everyone is going to agree with me. That's ok! That's why we have such a variety of great broadheads available today.
This was awesome input guys. TG has been incredible for this. Worth a yearly subscription fee.
I get it now on the broadheads.
As stated too- a good sharp head in the right place is really the main issue.
BTW Bill of Zipper- THANK YOU. Hate to say it though, the sharpening issue is my nemesis. I can not for the life of me get a grizzly/kodiak/abowyer sharp even after too much time trying. Believe me, I have tried-even with coaching. I like that I can take a Magnus, swipe it on a accusharp a few strokes, hit it on a ceramic stick, strop it on cardboard- and I have hair shaving in 2-3 minutes.
As I also stated- maybe the easier variable to control is bow # and arrow wt. Hmmm
I have plenty to consider now I guess.
Dan in KS
QuoteOriginally posted by basket-rack'89:
Will a hot melt type glue affect the heat treatment of a broadhead? I've heard of a lot of people using epoxy to avoid messing with the heat treatment, but I like being able to remove my broadheads and put them on fresh shafts every now and then.
No. Hot melt glue softens at 230°F. Way short of effecting the steel temper.
I use an electric hot-air paint stripper gun held in a vice, put the glue on the wood shaft first, tuck it inside the (alcohol cleaned) head taper and then warm the head just enough that the glue melts again. Not even so hot the paint bubbles on the broadheads this way.
Even More Than That Dan. The Flight Of Your Arrow Matters, Especially At Real Close Shots. An Arrow Hitting Less Than Sraight Can Negate The Broadhead Integrity And Can Help Cause A Failure Like You Described. In Addition, It Is My Opinion That If You Hit A Deer In The Shoulder On A Quartering Away Shot, You Likely Would Have Not Hit Heart Or Lungs Anyway If It Had Penetrated.
On Top Of That, A Wide Broadhead, Say Like The Silverflame Xl And Xxl (And Others) Can Catch An Edge On Steep Angled Shots And Rip A Gash But Not Penetrate, Almost At All.
A Lot Can Cause Or Affect The Things You Described Beside The Bradhead Itself.
chuckc
Agree Chuck on the many variables. Also too on the possibility of arrow deflection, bad release, etc. Again, why I want to account for all things as far as it goes with best equip I can muster. I know for a fact that there is human error and I do not always get the best shot off after sitting for hours in the cold, a big bucks shows, one shot quick, etc etc.
You are correct on severe quarter- but I should have said basically broadside with slight quarter. However, when a deer is really close and straight down broadside, the shoulder blade sure seems to be in the way on the barrel shaped chest. It is at least 1/3 the way down on a live deer. Also- contrary to another one of those interesting "myths" that seem to get passed around in all the media- when the leg moves BACK the blade lifts UP. When the leg moves FORWARD the blade moves DOWN. This means that on a true horizontal broadside- you are better to shoot when the leg comes BACK as the lung area enlarges with the blade out of the way. In reflection- the deer I have mentioned here had his leg forward, which dropped his shoulder blade down even more. That arrow sticking out truly looked 1/3- 1/2 down the deer.
Thanks
Dan
I really like the sound of the new BH's from Zipper Bows. As a knife maker, I hate soft steel. I don't mind putting some work into establishing the initial edge, but then I want to be able to just "touch it up" whenever its rubbed on something. It doesn't need to be "resharpened" if its good steel heat treated properly. You can shave with any of our kitchen knives and all they get is a few strokes on a fine ceramic stick to keep them that way.
The grizzly is about as tough of a head as they come thanks to what Bill is doing and if paired with a steel adapter or brass glue in glue on adapter I doubt you would have any more failures or your broadhead end of your arrow. The grizzlies have always been known for being some of the best broadheads available when bone is encountered and Bill's are the best yet! All that said I still think the key factor in your failures was the aluminum adapters.
Im a tool and die maker of 37 yrs. and have worked with a lot of steel as you can imagine. The Rockwell test is a penetration test on the better testing machines. Rockwell C scale is for tool steel hardness tests.That is what all these numbers such as 44-47Rc or 52-55Rc denote.
The real question to be asked is Whats the alloy content over the Rc number? With a poor alloy content an Rc number means little other than hardness as an abstract trait. What you want in your dreams is 80 or higher Rc and be able to keep it from shattering like glass on impact. Were not there yet, hence there are no carbide broadheads. Too brittle. The steel we are getting for broadheads is low-medium carbon steel with cheaper alloys for toughness. Its fine for what we do in most cases.
Now, I have always wanted to share this as its in stone... no exceptions ,....ever. You need 20 points of Rc hardness difference MINIMIUM to sharpen anything effectively. If you broadhead is 57 Rc and your file is 65Rc (which is very common for files) then you will ruin the file and possibly the edge of the broadhead. A broadhead at 45Rc and a file at 65Rc is therefore bare minimium for sharpening. You will need diamond encrusted files to do a much better job. These are over 90 Rc on the diamond. To sharpen a hard broadhead you need a diamond file and a stone/ceramic stick for the final shaving edge.
I think there is a lot more to the heat treatment than simple hardness. An overlooked part is how springy it is, in my opinion they should be rigid. I think that flexing can be negated by running the ferrule closer to the tip as a STOS or Eclipse does. My dad made some broadheads out of the same steel he uses for his knives and heat treated them as such and they out performed any commercial broadhead I had ever seen or used, except for knife quality broadheads like Silver Flames.
Thanks Charlie, haven't had problems with Zwickeys in the past, but didn't want to ruin my new Grizzlies.
Wallydog- that is great input right there. So- do files have a rating like that? Tells how ignorant I am and may explain A LOT of my years of frustration.
Also- I actually had some Silver Flames (a gift). They were truly the sharpest and hardest heads I had ever seen. I loved them, but 2 major problems: 1 )ridiculous expense and therefore possible loss , 2) They were impossible to sharpen- as I even sent one to KME and they could not get it back to the original sharpness.
I will continue on in my inquiry and quest here. . .
Thanks AGAIN TGers. Awesome input.
Dan in KS