Author Topic: Getting higher FOC on a primitive head  (Read 1306 times)

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Offline Kenneth

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Getting higher FOC on a primitive head
« on: March 02, 2022, 09:56:31 am »
Something I like to play with is bone heads, usually I make my broadheads out of heavy spoons which end up weighing 190-200 grains. These get decent FOC like balancing at 18-19" on my 30 inch shoot arrows. Same with my field tip arrows I make out of Surewood shafts with 190 grain points, usually they balance at 19". The issue was my bone head arrows which fly well in practice but did not normally balance or weigh at all the same as the aforementioned arrows. That's because the bone heads weigh 125 grains at best, most come in at 100 grains if you're lucky. I'm using deer bones by the way. Also, I was using shoot shafts which spined lesser so they could better accommodate the lighter head. So overall I had arrows that were weighing at times less that 600 grains and balancing at 16.5". Compare that to my average 650-750 grain with balance at 18-19 inch arrows.

The method I came up to solve the issue was this, first I disassembled all the arrows that were too far out of the group and just used the parts for other arrows with heavier heads etc. Next I made new shafts but left the last four inches toward the tip fatter, around 1/2" instead of 11/32". Total length was 30.5 before adding bone head. Next I added bone head and fletchings. I got an FOC balance of just over 19 inches and total arrow weight of 760 grains. I dialed it back some by reducing the fat front end slightly by scraping with a knife blade and sanding down, bringing the weight to 736 grains and balance point to about 18.5". This is very comparable to my regular broadhead and field point arrows.

I don't care to have to use a grain weigher since this is all about being primitive and using whats in nature etc so I made a sizing tool with a hole that I can put the fat end in as I'm making the arrow to reduce the end to fit through the hole. When its all done I will just check the balance point and adjust till its around 18-19 inches which should put the arrow weight in range. Here's a photo of one of the finished arrows. Getting excited about this. They fly good too. Plus its nice to have the extra wood where the arrow gets slotted since all my shoot shafts have an inner hollow or pith.

Offline Kenneth

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Re: Getting higher FOC on a primitive head
« Reply #1 on: April 19, 2022, 10:11:09 am »
After watching Ryan Gill's recent youtube video discussing this topic I looked at my arrows and realized the fat bump of wood just behind where the head inserts into the slot is going to be a real issue in penetration, especially with a dull bone head. I had thought of this before but I thought I had to get that FOC up there!! Gill doesn't factor FOC into his rig really. I get it. So my bone heads are going to fly just a little differently than the steel and that's ok and to be expected. I may tune up a bow to match the bone heads flight. So I started this morning by taking the head back off an arrow, slimming down the end of the shaft behind the head and re-attaching.

Offline BowEd

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Re: Getting higher FOC on a primitive head
« Reply #2 on: April 19, 2022, 12:05:43 pm »
The front end of your tapered shaft needs to be blended into the back of the arrowhead no matter what you use for an arrowhead.No problems with it obstructing penetration then.My dogwoods mostly are 9/32" at the nock and 23/64" at the tip.That's over 1/16" diameter or 5/64" lessening of the taper full length.
I've used a sizing shaft tool myself.It's from a moose horn.The holes remain the same after many arrows made.

BowEd
You got to stand for something or you'll fall for anything.
Ed

Offline gutpile

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Re: Getting higher FOC on a primitive head
« Reply #3 on: April 25, 2022, 01:42:36 pm »
it is main reason I foreshaft my cane.. well worth the extra efforts.. yes a smooth transition from point to shaft is critical.. found out the hard way when I literally bounced a shaft off a doe... that has never happened since though.. lesson learned.. gut
to take from nature the materials needed to take from nature the meat needed...they all die from natural causes osage, rivercane, stone points,...

Offline Pat B

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Re: Getting higher FOC on a primitive head
« Reply #4 on: April 25, 2022, 02:03:18 pm »
I sometimes make a long taper(2" or so)of the head end of the shoot shaft to help ease the transition which will help with the penetration. The natural taper of the shoot shafts gives better FOC to the arrows.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline Kenneth

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Re: Getting higher FOC on a primitive head
« Reply #5 on: April 25, 2022, 05:13:27 pm »
Ok I will take advantage of the natural taper and stop making them so even front to back. Looking at BowEdís photo, I was thinking about my sizes and I canít really go down much below 11/32 on the nock end cause of the wild rose having a pretty thick inner pith and I like to leave the walls a little thick to add strength. Overall I think my main issue now will be that most of my arrows will be somewhat overspined since I dropped my average bow weight to 45 pounds. Its going to be a bigger issue with the bone headed arrows since the tips are so light. I make my steel broadheads at around 190-200 grains which is helping to add flex to the shaft. I really shoot well with the lower bow weight and it seems like itís easier to finish the bow with less set, probably cause im working with a lower weight
« Last Edit: April 25, 2022, 05:16:36 pm by Kenneth »

Offline BowEd

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Re: Getting higher FOC on a primitive head
« Reply #6 on: April 25, 2022, 07:00:31 pm »
Yes my multi flora rose shafts are not as much tapered as the dogwoods.The pith in multi flora rose leaves the nock end a scooch under 11/32" inch also.Leaving the point end at 23/64".A person can put a wood or horn insert in them if they want.More work though.
They are great candidates for fore shafts too.
Good heavy arrows though as is.580 to 620 grain range with 125 grain tips.Not quite as much FOC % as my dogwoods.
My black raspberry canes here are just too big in diameter with a larger pith in them yet than multi flora rose.I don't use them.
BowEd
You got to stand for something or you'll fall for anything.
Ed