angle for sharp broadheads ??????

[doug77]

what angle do you use for sharping a 2 or 4 blade broadhead. I seem to have trouble getting super sharp edges. any advice.

doug77

[robslifts]

single bevel or double?

[doug77]

double. I have tried the true angle system. KME system and now going to try the Smith systen. I can get the sharp but I know they can be sharper.

doug77

[Recurve50LBS]

I think that 25 degrees for single bevel and 12 1/2 for double bevel heads.

[Orion]

Tru angle works great.  What kind of heads are you trying to sharpen?  Triple laminated points like Zwickeys and Magnus need to be taken down with a file first.  Then, run the blades through the tru angle file system before progressing to coarse stone and then fine stone, and finally a leather strop if you wish.  Takes me about a half-hour per head from beginning to end of this process.  Shaving sharp.  Of course, they touch up in minutes.

[Tree man]

Recurve50, Doing 12.5 degree angles is possible but not with most sharpening aids-the ferrule gets in the way. Besides which......extremely thin edges can be fragile and some steels won't support such edges even for light use. A more realistic option for double bevels is probably about 18-22.5 degrees each side giving a total included angle of 36-45degrees. Common knife sharpening angles fall into that range.A fillet knife  is usually sharpened  to a very fine edge and will have an included angle of 25-30 degrees. Three blade broadheads sharpened by running 2 blades on  a flat sharpening surface wind up with 60 degrees included,which is a rather "blunt" angle but they can me made very sharp and the edge is very durable. Fine/thin/low angle edges do cut easiest and smoothest (which is why razor blades are sharpened that way) but aren't designed for or suitable for high stress and impacts. Sharpening an ax at 15 degrees included is futile-likewise a razor with 60 degrees included will give a lousy shave. Dr. Ashby advises a 25 degree single bevel....but that is based upon using one of the hardest steel broadheads on the market and he has cautioned that some good heads with softer Rockwell C ratings may not support such an edge.
BTW, most people can train themselves to "eyeball" a 22.5 degree sharpening angle rather easily. Draw a right angle-90 degrees (for those who forgot all of their geometry-one corner of a rectangle...er sorry you forgot geometry I mean a box corner.   :p  ) divide that angle in half= 45 degrees . Halve that one... =22.5.

[Sharpster]

Doug,
PM sent.

-Ron

[Dr. Ed Ashby]

Most BH steels are not sufficiently hard to hold their edge when the TOTAL angle is 25 degrees. The thin edge rolls to easily on soft steels.

The lower the angle, the thinner the edge. The thinner the edge, the sharper is can be made; all else being equal.

We're interested in only single-slice durability, but we don't need an edge so thin it rolls on bone impacts. Another factor to consider; a 'thinner' edge will slice with less effort, and more deeply, than an "equally-sharp" edge that is 'thicker'. You want to use the lowest sharpening angle that your BH's steel-quality permits.

It takes more effort to sharpen hard, quality steel, but it can be made sharper than softer steels (because the edge can be made thinner while still durable - long lasting - enough for our required single slice. It's also far easier to resharpen them to a 'truly sharp state' after use; because they 'dull less' during penetration.

If you're holding a precise angle, which should be no problem  with all the jigs you've tried, the reason you're not getting the desired results is probably related to either the quality of the steels/stones you're using or the pressure you're applying; and I'd speculate it's the pressure you're using.

Especially on the courser grits, using too much pressure will result in deep microscopic gouges in the edge. It takes a lot of fine-stone work to fully remove these (and ALL fine stone work should be at light pressure; it's purpose is only to polishe the edge you've established with the previous stone(s). You also need to pay careful attention to the removal of any microscopic wire-edge that may be resulting.

As far as angle, on most commonly used BH's the best overall double-bevel angle ends up being 20 to 25 degrees on each side of the bevel, for a total edge-angle of 40 to 50 degrees. A single bevel should, ideally, be at 25 degrees (and zero on the other side) but this REQUIRES hard steel to work well, around R52 minimum. The maximum hardness for single-bevels is about R62, or the steel becomes too brittle. Around R57-58 seems about ideal. Most commonly used BH's range from a hardness from the low to high 40's; too soft for an 'ideal' single bevel, or a low-angle double-bevel.

A long reply to your question, but BH sharpness is an important issue. I see many self-purported 'scarry-sharp' broadheads that are not truly sharp enough.

Cangratulations in being conserned enough about your BH's sharpness. Try using less pressure between the blade and the steels or stones. It takes longer, so be patient. Once the bevel is correct, and the BH sharpened properly, it's fast and easy to re-sharpen them. Look at initial sharpening as a one-time task; good for the life of the BH, unless there's a catastropic event.

My other recommendation is, if you still have problems after trying low pressure and patience, is to pick up the phone and call Ron at KME. He knows sharpening well.

Ed
TGMM Family of the Bow

[Dr. Ed Ashby]

Woops, I see Ron is already on the job. When it comes to sharpness, Ron's the man.

Ed
TGMM Family of the Bow

[doug77]

thanks to all for the advice I think i will take Mr. Ashby's advice maybe I am pushing to hard on the stones.

doug77

[killinstuff]

STOS are 25 degrees standard

[Lin Rhea]

Doug77,
       I hope I'm not intruding. Along with what Dr. Ashby has noted, I'd like to suggest that after you are satisfied with getting your bevel "set" on the coarse stones, that you increase the angle, slightly, to cause the actual cutting edge to engage the next (finer) stones. This in effect will give you a faceted edge geometry. The closer to a radiused edge being the strongest. We call it an "appleseed grind" after the shape of an apple seed.
     
      I say this from experience I got from knives. I also realize that broadheads slice into the target, whereas knives sometimes chop. Treeman gave a good illustration between an axe and a razor. Knives and broadheads fall somewhere in between those extremes. I still think that, perhaps, to a lesser degree, having a slight radius to the cutting edge, broadheads would cut better, hold up better, and be easier to sharpen in this manner.  
 
    Again, this is just another opinion, but it might help.
                          Lin

[BobW]

doug77:

I'm struggling with this too.  After talking this over with a few, my problem is getting the "starting edge", usually with a file.  Give your KME system a go, but start with sandpaper on a sheet of glass instead of the file.  You get the necessary angle, then finish it off the way you have been with the stones.  I'll bet you get it the way you want.

I too will be trying this as my solution later this week.

good luck,

BobW

[doug77]

thanks guy's I will work on them.