Single bevel question

[LostArra]

Disclaimer: I've never used a single bevel bh but listened to Ashby on Meateater so I'm only about half way to being an expert.

Are left wing single bevels a bad idea? With the rotational force on impact are they likely to come unscrewed and negate the rotational advantage? Will adhesive (epoxy, JB Weld, superglue) hold them in place? It seems like adhesive should work since glue-on bh are available too.

I realize in today's climate using "left wing" anything is cause for concern but I've got two lifetimes of left wing feathers from 2" to 5" to uncut and this might be my excuse to not try new broadheads.

 

[Bmoore]

 

[Runningwater]

IMO, as an engineer, the rotational advantage of a single bevel broadhead is nearly (if not totally) immeasurable in the field. A bit gimmicky like the "non-stick coating" I've occasionally seen on some broadheads. That said, if you shoot them straight they should work great. Use the same glue you'd use for any other broadhead. Good luck!

 

[popapi]

aBoyer!

 

[LostArra]

Interesting. I just read something from Bishop Archery that stated the opposite and was the basis for them not making a left single bevel. see below:

>>
Yes, even with bow-wax, thread locker, to even resorting to superglue on the threads of left-bevel prototype variations of our patent pending heads, it is a big waste of time. Our single-bevel designs would have to be watered down significantly for them to not come unscrewed on impact in a left-bevel screw-in. We are still working on a glue-on left-bevel and right-bevel with disappointing results, but the screw-in/screw-on left-bevel has been given up on a couple of years ago, even before we started selling broadheads to the public. It is a total waste of time to try to make a left-bevel screw-in and literally more than 90% of the world's arrows are right-offset/right-wing anyways.

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[Beendare]

Delete

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[LostArra]

FWIW, Im a lefty that tried fletching LH for awhile many years ago and as I recall everything came unscrewed.



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Exactly. If field points on left wing fletched arrows come unscrewed (not completely but just loosened) in a 3D target then you would think a two or three blade broadhead would also but the single bevel should be no worse than any double bevel broadhead. I've had no problem with unscrewing if a small amount of glue is used on the threads of field points or broadheads.

 

[Samdemarais]

I have been shooting left helical for a few years and don’t really notice fpts coming loose more then anyone shooting right. I have been told that you shouldn’t left bevel with right helical or vice versa from the guys RMS gear.

 

[Mighty Mouse]

I think the left bevel unscrewing theory is valid, but I don't know if it's truly an issue in practice. I think the unscrewing theory would go something like this:

• As the head enters the target medium, rotation of the head slows down due to the increased resistance of the denser medium.
• Shaft rotation also slows down as the shaft enters the target medium, but it slows to a lesser degree because the shaft has a smaller diameter and experiences less resistance traveling through the channel cut by the head (instead of through virgin/uncut target).
• A left-fletched shaft spins counterclockwise (viewed from the nock end) as it flies. CCW rotation of the head tightens the head/insert connection, but CCW rotation of the shaft loosens the connection (the video linked above fails to mention the latter point). So if the shaft does indeed rotate faster than the head as it travels through the target, the head/insert connection will unscrew.

Unscrewing in this manner would only occur if the differential torque applied to the head vs. shaft exceeds the breakaway torque of the connection. If the heads are just screwed on finger tight, breakaway torque would be quite low and I could believe that initial entry of the head into the target could create enough differential torque to break the connection. I'd think Loctite on the threads (or maybe just using a wrench to get the heads more than finger tight) would increase the breakaway torque of the connection enough to eliminate the concern (sounds like Bishop Archery would disagree though). I bet if you called RMS Gear, they could give you an informed opinion on whether or not there's truly a need to worry about their left bevel Cutthroats unscrewing.

 

[Mighty Mouse]

On the general topic of single bevel heads, I do think they offer a potential penetration advantage (probably slight) as long as the steel is strong enough to prevent edge curling. I've been shooting 150 gr right bevel Cutthroats for a few years, and the heads do noticeably rotate as they sink into a target or travel through an animal. I've heard Bill Vanderheyden say a few times on various podcasts (e.g., Rokcast episode linked below at 2:40) that he was initially skeptical of single bevel heads but later concluded that there is an upside and began offering Iron Wills in single bevel. The Iron Will single bevel design is a little different than most with its bleeder blades and a slightly greater edge bevel angle.

Deep in Arrow Builds with Bill Vanderheyden

This week Bill Vanderheyden with Iron Will Broadheads joins us to take a deep dive into arrow builds. He talks about arrow spine, penetration, fletching, momentum and a number of other things he's been testing.

www.rokslide.com

 

[Titan_Bow]

I’ve shot a few deer with single bevel cutthroats out of my longbow, and the arrows zipped through the same as my old STOS and Magnus heads. While I like Cuthroats and RMSG is my local archery shop (so I like to support them) I really can’t think there would ever be a scenario where someone could legitimately say “Thank God I was shooting single bevel or I would have never found that animal”. I mean how much deader do you want them? It’s like the difference of pulling your arrow 8 inches out of the dirt after it passed through versus 8.3” out of the dirt LOL
I do match my bevel on my cutthroats to my helical, but it’s as much my OCD as it is a realization that it would actually make any noticeable difference in penetration.(which I doubt it would)


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[popapi]

Awesome information