Single Bevels, Broadhead Sharpness and the Clotting Cascade  - Dr. Ed Ashby

Being able to achive a thinner, smoother, sharp cutting edge is one major advantage of the single-bevel broadheads, but few bowhunters understand what the advantage is.

Dr. Ashby comments in his Michigan and other presentations on the subject of broadhead sharpness and the clotting cascade.

the Clotting Cascade

The clotting cascade is the physiologic process the body uses to seal off a bleeding blood vessel. When a blood vessel is cut the damaged cells lining the inner wall of the blood vessel release a protein called prothrombin. Prothrombin reacts with the blood plasma to form thrombin. Thrombin acts as a catalyst to convert fibrinogen into fibrin. The fibrin attaches to the ragged tissue tags at the cut edge of the blood vessel to form a clot, sealing off the vessel.


What's important to recognize is that the type of edge finish on your broadhead has an effect on the clotting cascade. When you use the thinnest, smoothest, sharpest edge fewer of the cells lining the blood vessel's inner wall are damaged. This means less porthrombin is released. At the other end of the cascade this means less fibrin is produced; but there's more. That thinnest, smoothest, sharpest edge also results in fewer tissue tags at the cut end of the blood vessel. That means there are now fewer tissue tags for the reduced amount of fibrin to attach to.


The net result is that a properly sharpened single bevel broadhead of any brand can achieve a thinner, smoother and sharper edge than any double bevel edge. That sharper edge will produce a cut that bleeds both more freely and for a longer period of time, and that's exactly what we want.




Watch a short video on how to properly sharpen a single bevel broadhead using a bench sharpener

Field sharpening using the BevelSharp


Watch Dr. Ashby's 2012 Kalamazoo Michigan Presentation on The Ultimate Hunting Arrow.


An interesting mention of clotting, fibrin and very long ago trad archery in this story about the demise of Otzi, the ice age mummy found at the melting of a glacier in Europe.

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