Finally got to do some preliminary testing on my extreme FOC cedars. Fly great, and seem to hold up quite well.
Here's the scoop. Started with 11/32 cedar shafts, 9-inch tapered to a 5/16 Bohning classic plastic nock. About 28 7/8 inches to back of point, spined 70-75#. Fletched and untapered, they weigh about 425 grains. Four control arrows weighed 580-584 grains with a 160 grain field point, yielding an FOC of 14.5%
To get to extreme FOC, I tapped another set of 4 almost identical arrows with a 3/16 inch drill, using a jig to hold the shaft perpendicular under a drill press drill bit. I drilled the shaft 2 1/2 inches and epoxied in a three-inch section of 3/16 inch steel rod, then cut the rod and sanded it flush with the end of the arrow and finally tapered the arrow. A 125 grain field point, yielded arrows of about 674 grains and 18.5% plus FOC. With 160 grain field points, the shafts came out at 708 grains and 20% FOC plus/minus a few tenths.
Shot them out of a 62# Howard Hill at a 3D course today. They flew well. To test their durability, I shot each arrow into a 1-inch plywood back stop. In each instance, the arrows bounced back from the plywood undamaged. Unfooted arrows usually break when I try this. I also shot one shaft into a live oak tree (intentionally). It stuck with no damage to the arrow. I did manage to break one shaft by glancing it off of another large oak tree trunk (unintentionally). The internal footing stayed intact inside the point, but the shaft split nearly it's entire length.
Obviously, more testing needs to be done, but my initial impression is that these arrows shoot very well and they're about as rugged/durable as one can get out of cedar. The steel internal footing seems to strengthen the shaft behind the head, preventing breaking there. The steel internal footing also yields more FOC than external wood footings. Wenge footings, on the same spine, diameter, weight and length shafts yield 15%-16% FOC with 160 grain broadheads.
A couple of notes re construction. Despite using a jig, made out of wood, I was not able to get the holes perfectly straight in the shafts. I have since devised a steel jig that could be used with a hand drill that will yield perfectly centered holes, but I will need a machinist to make it.
In epoxying the steel rods into the hole in the shafts, I applied too much epoxy to the sides of the hole, which was forced to the bottom of the hole as the steel rod was inserted. In three out of the four cases, when I pushed the rod home the last 1/4 inch, the epoxy broke through the shaft wall. (A 3/16 hole in an 11/32 shaft leaves only 5/64 of shaft surrounding the steel footing, if the hole is perfectly centered, somewhat less if it's not.) Regardless, I expect the cured epoxy rendered the area sound and strong. However, less epoxy, or perhaps none at all, or perhaps drilling a 1/64 hole perpendicular to the shaft at the base of the hole to let excess epoxy escape, might be better approaches.
This isn't a new idea, of course. Others have talked about increasing an arrow's shafts weight and strength by drilling out the end and inserting a nail of one size or another. The 3/16 steel rod, available at hardware stores, is just a tad larger than a 16 penny nail and weighs about 48 grams per inch. My 2 1/2 inch internal steel foots weighd an average of 122 ounces. Many hole diameter and length options are possible, and likewise, other materials such as brass, threaded rods, etc.
Kind of fun for those who want to mess with it. I think it yields a pretty good arrow to boot. Looks like we woody shooters won't have to switch to carbon to get extreme FOC. Have at it.
Topic: EXTREME FOC CEDARS (Read 657 times)
