Straightarrow

Black Frog, you got me thinking. I could probably mount rollers on a piece of wood that hangs from underneath. Wood is real easy to adjust to an exact weight. I don't have much in the way of metal working tools , but I do have planers, sanders and an electronic scale to get the weight real close on a piece of wood.

This is what my arrows rest on now. I bet they'd work for hanging the weight and they only cost about 59 cents. I don't like the bolt for a weight because it has to be placed exactly the same way each time or the reading will vary a bit.

Black Frog

SA, Sure that would work! You could easily shape something out of wood to hang the weight on. If you got a hunk of lead for the weight, you can carve that down to what you need. Or if you're a fisherman you may have a lead pot to melt sinkers. Steel is tougher to work with, and aluminum was too light. I had a chunk of stainless steel that I used and just kept shaving off the bottom until the weight was correct. The "official" weight amount is 880grams. I think that is 1.94lbs. I'm lucky I have access to VERY accurate and calibrated scales here at work, but you could always take it to the Post Office and check the weight on their scales if yours doesn't go that high. My scale at home didn't.[:@]

I checked a Mitutoyo 1" dial indicator which is different than the one I used on my jig. The Mitutoyo also approached 100 grams of spring force near the 1" of travel! Just by pressing it with my finger I would not have guessed it to be that much....

Exactly why I went with the hanging weight by bearings method. Very repeatable and smooth on the rotation of the arrow. Those .59$ cabinet rollers may not be fancy-schmancy bearings , but I bet they would still be smoother than having the bolt head directly on the arrow shaft. It would be a cheap experiment for you to try out! Couple of hours of tinker time with some cold beer.....

Sagittarius

Todd,

Beautiful workmanship !
Doesn't surprise me at all, since you're the guy who built it.


Sag.

Straightarrow

I've been thinking about the suspended weight and got to wondering if spreading the weight out over an inch or two would affect the way the arrow bends. It seems to me that pressing at two points would result in a different reading than pressing at one point. I'm wondering if it wouldn't be better to suspend the weight from an eye-screw that the arrow passes through. This would concentrate the pressure at one point, and yet the weight should hang the same way each time, since the roundness of the eye-screw should act much like a couple rollers. The plunger on the dial caliper would have to sit a fraction to the side, but I can't imagine that would affect the reading to a noticable degree.

Thanks for the lead idea. I no longer have my sinker-making gear, but I could easily drill a hole down the center of a piece of hardwood and then fill it with lead to the appropriate level. Then I'd put a lid on with the eye-screw attached to the lid and maybe it would work. . .

And I'll have those cold beers after I finish making the weight.

JeffB

Todd,

VERY nice spine tester..very nice. Wish I had your skill at crafting things.

It's really an eye opener when ya start testing all these carbon arrows. Some of the stuff manufacturers sell us is just complete crap..even higher dollar arrows.

If I ever get the time and inclination to get back to shooting, I'll be shooting Carbon Tech, or good 'ol A/C/Cs. They spine magnificently.

Black Frog

Sure does make a difference. I tried to keep as close to my plunger as possible, leaving only .300" for the plunger in between my bearings. The farther you get away from center, the more the end supports are taking some of the load.You'll be fine!

Jeff, I just threw some of my navigators on there and I was impressed with the consistency of the few I measured. I could detect no stiff or weak side on three I tried. I am giving up on some carbons that I had been using for hunting arrows the last few years and using ACC's this year. ACC's are a damn good arrow.

pdq 5oh

BF, that tester is a work of art. I must say, the machining is great.

Nubbb

Black Frog

Fine work on your spine tester. It looks very well thought out and executed!

We weigh, spine test and then bare shaft all shafts out of a shooting machine (glorified Hooter Shooter on steroids) for consistency of performance. We can often rotate the nocks on a shaft and get it shooting to the same hole as the rest of the bunch once we are at a very tight spine variance.

We have found that the stiffer the spine relative to the bow weight, the less critical the spine match becomes.

That being said, ACCs are pretty hard to beat in my book for an all around shaft.

We don’t spend much time on carbons with the exception of some CTs once in a while.

What has your carbon testing revealed? In other words whose carbons have you found to be close to ACC consistency if any, and what has been your experience among the different brands?

If you don’t want to let it all hang out on the forum, a personal reply reply would be appreciated.

Jeff, your input is always highly regarded as well.

Black Frog, once again….very nice work.
Best….Nubbb

Black Frog

Nubbb,

I just got this tester assembled this past weekend, so my tinkerings with shafts are very preliminary. In fact I still need to finalize the indicator mount I'm milling that will place the indicator DIRECTLY above the centerline of the shaft, and perfectly verticle (at least within a thousandth of an inch or so...). Currently I just have an indicator holder rod assembly, and you can position that in just about any orientation.

But as we get toward the outdoor field season and hunting season, I'll be trying a new batch of Navigators for field and ACC's for hunting. I do some work for other people and will be checking their arrows as they come through so I can get some idea of what's marketing advertising and what is for real....

JeffB

Just make sure you are not wearing any new/clean drawers..chances are..they ain't gonna stay that way [&:]