TAC 15/15i Basic Unpublished Information

[Dorge]

As a personnel response to the information you've supplied, I only have one point that I'm not sure I agree with. While I understand that the Bitzenburger Fletching Vise may not be dead on accurate in its ability to index (rotate arrow shafts) at precisely 60 degree spacing or 120 degree spacing, it does rotate the exact amount of spacing each time on the same jig. That spacing might be 55 degrees or 125 degrees when going from one side of the shaft to the other, but it is the exact same spacing each time a user rotates the nock indexing knob.

That would indicate that each arrow produced on these jigs would have exactly the same spacing between each vane placed on each shaft with this jig. In order to achieve the same performance from arrow to arrow, its necessary to maintain the same exact alignment of the vanes, but it does not need to be exactly 60 degrees or exactly 120 degrees spacing. The 120 degree spacing is used to support maximum vane clearance from the cables and the 60 degrees is a spacing between each set of vanes on the two sides of the shaft, so I fail to understand why a deviation of 4 or 5 degrees would matter as long as every arrow produced had exactly the same 4 or 5 degree deviation?

You will very easily find out how. The 3 main point are below:
1) If pass experience is any indication, the chuck indexes are always off by 2 or more degrees each. With the 6 bitz I have which should all be 120 degree, it is actually ,120, 118, and 122 on all 6. It is not an IF, but what is out there.
2) it uses a nock receiver, which if you put the nock in, the nock has play and unless the nock receiver hold the nock perfectly and there is absolutely no movement at all. there is play, thus angles of absolute fletching can be off, not to mention as the angle of the shaft is always not going to be perfectly straight, the shaft is always going to be pointing down which as the nock rocks, the angle of the fletch on the vane will NEVER be even.
3) The play between the index chuck and the bitz main body itself. a 1 mm space gap will equivalent to about 5 degree base on the size of the arrow, assuming it is 0.204"

With the Aerovane Jig I designed, that is exactly what I have addressed.
1) The chuck is made of 6061T6 with Titanium Nitrate coating on a CNC machine with a zirconium nitrate ABEC#5 ball so the index is +/-0.005 mm or 1/72 of a degree
2) I use a 303 stainless 0.05 roughness slide chuck so by eliminate the nock, the inside of the arrow shaft should be the most accurate one can deal with. Not to mention by using a ball hearing hook holder base on specific shaft size, the leveling of the shaft will be just about PERFECT.
3) By using 2 ABEC#5 ball bearing with Thermo fitting process, the index will be +/- 0.0002" of play on all 3 axis.

That about sum up of why and how I take care of the fletching on jig accuracy issue.

Dorge

 

[jon.henry755]

Hi Dorge,
Once again, thank you for the input and the explanation on the lack of accuracy on the Bitzenburger Fletching Jig and the accuracy of the ones that you produce and sell.

Just to summarize for our readers that may be a bit less technical, please correct me if I'm wrong. What you are pointing out is the fact that what I had originally stated about the Bitzenburger Jig was incorrect because there is a sizeable degree of rotational error inherent within the jig and also within its nock receiver. This deviation can occur each time a new arrow is placed in one of these jigs, so the deviation from arrow to arrow can be anywhere from +2 to -2 degrees from the desired setting. This would mean that each arrow produced is not in the exact same alignment as previously thought.

Does that summaries it correctly?

Can you by any chance estimate how much flight deviation this margin might account for at longer distances such as 80 to 100 yards, in inches on the face of a target? Could we be talking about 1" of possible deviation or could we be talking about 3" - 5" inches?

This factor gives our readers an idea of how critical it might be to have precise arrow fletching equipment.

Thanks again for your technical input.

P.S. I just received a package of your TAC15 Firenocks and will be using them to replace the PSE TAC15 Standard Nocks that I had to remove during Spine Indexing and Spine Deflection Testing of a couple dozen arrows. I'm impressed with the design and fit of the new nocks.

Regards,

Jon

 

[Dorge]

Just to summarize for our readers that may be a bit less technical, please correct me if I'm wrong. What you are pointing out is the fact that what I had originally stated about the Bitzenburger Jig was incorrect because there is a sizeable degree of rotational error inherent within the jig and also within its nock receiver. This deviation can occur each time a new arrow is placed in one of these jigs, so the deviation from arrow to arrow can be anywhere from +2 to -2 degrees from the desired setting. This would mean that each arrow produced is not in the exact same alignment as previously thought.

Does that summaries it correctly?

That does not summaries it. The degree of each vane even on the same jig is already off due to the manufacturing process inaccuracy. Then the error/play of each part of the jig is where the error will compound to the accuracy of each vane, even on the same arrow, and it also can compound form arrow to arrow.

For simplicity I shall assume we use 3 vanes index which is most common, the four vane index had not been tested by me so I cannot be sure what the variation is.
1) 2 vanes are off or 2 degree together due to the inaccuracy of the index (4 degrees total), assume vane one is at zero.
2) the play (tolerance) of the jig to the body would be as high as 5-7 degree base on shaft size (assuming we are talking 0.300 ID shaft)
3) the nock play/rock (tolerance) of the arrow on the receiver, base on angle that it is resting on as it turns, will add another 5-7 degree to the inaccuracy.

Now you know why even with the same jig without some careful and know how to use the jig and chuck one can easily add 2+5+5 or 12 of maximum of 4 +7+7 degree off "EACH" vane. Not to mention the variation of each arrow to arrow, every segment of the error and happen to each arrow.

In most cases, the softer the vane, the less of an issue of vane accuracy due to what most common vanes do. Fluttering, delta vortex, 2nd and 3rd back end vortex issues. Not to mention sound/directional energy lost. Those are all contribution factors to how an archery projectile can impact the target accurately. When one use vane like Aerovane (which is airfoil base vanes) that little error becomes a very big deal as all errors are now amplified. At high speed, aerodynamic is KING which is also the reason why archery projectile if design right can be one of the few that can handle side wind! One only need to understand Giro and air drill concept to understand how those projectile can cheat wind and gravity via flying (circular lift). To learn more about Aerovane and why a perfect accurate vane setting is essential for Aerovane, you can visit Firenock: Home Page aerovane section and Aerovane FAQ for more answers.

I hope this help you to understand more about how and why most archery projectile are not to shot into long range and how come it is so difficult until now to be able to repeat the long range shooting with confidence.

 

[jon.henry755]

Hi Dorge,
Now that you've outlined how much deviation can occur in the fletching process with vane placement, can you give us a few words about what you've done with the design of the Firenocks to help improve the accuracy and consistency of the nocks over the standard PSE TAC15 nocks?

What is the biggest deficiency of the standard nocks?


Regards,

Jon Henry

 

[Dorge]

What is the biggest deficiency of the standard nocks?

Long range archery is about consistency. In one word, the more consistant one can make the nock to nock, the better it will be. At Firenock we only use Bayer makelon polycarbonate whcih besides the best modling consistant flow, light transmission, IZOD factor are about the best there is. and we have the lightest nock for the tac (firenock D is about 1/3 weight of the Tac). To have the absolute consistency, I only use single cavity mould so EVERY nock comes out of the same mould, thus if temperature if maintained, they can be +/- 0.000002 mm variance.

Like all true nocks, the nock throat consistency is the abosolute on release accuracy as the pressure off the nock and on the nock must be the SAME EVERYTIME.

PSE Standard nock is from a 35 year old mould. The tolerance is all over the place. The plastic it uses is about as average as it gets. The IZOD factor of that specific plastic is a lot less to be desire. Do not take my word for it. Press it through the string a few times and the nock throat opening will no longer be the same.

With Firenock D nock, you got a lighted nock if you so desire. To learn more about the different computer system you can get with Firenock, you can visit Firenock.com. At this time, we offer 18 variation of Lighted nock for the Tac arrow:
1) 1 nock color (red)
2) 6 LED colors
3) 3 circuit functions
4) 2 different batteries (Shelf life, temperature tolerance)

This would be what I would start as how we are different. Better? That would depends on what you desire and want.

 

[Konrad]

Coming from a molding background, I must say that I am impressed!

1: Bayer is indeed a leader in polymer engineering and quality control.
2: Making production runs of a part as small as an arrow nock from a single cavity mold is an extreme quality control measure and expensive to say the least. Regular replacement of the mold would be dictated due to wear from the molding process to maintain the strict standards you have set for yourself.

I congratulate you on your efforts.

What molding machine are you using?

 

[jon.henry755]

Hi Dorge and Konrad,
So let's break it down for the readers.

One way or another all TAC15 owners are going to need extra nocks. It doesn't matter what you do, you're going to occasionally break a nock or two by either shooting some up or through the fletching process or possibly during hunting season some shooters will want to try out the lighted nocks.

If purchasing extra nocks from the manufacture they will cost you $25.99 per pack of 12.

The Firenocks are sold at $9.95 per 7, so that's $19.90 for 14 nocks.

Not a bad deal when you consider that the Firenocks are a superior nock in every way. Better fit, better quality, better material construction, much more precise in size and weight and if desired the nocks can be converted to full battery operated lighted nocks, so they are technically a superior product that sells for less money.

I like it when we have have superior products at a lower price point.

Great work Dorge. Keep the good stuff coming, I'm sure our readers will visit your website for a first hand look at all your products.

Regards,

Jon Henry

 

[OkieBowie]

One way or another all TAC15 owners are going to need extra nocks.

I would revise that to say: One way or another all TAC15 owners are going to need Firenocks.

At least for me, the OEM knocks are to "grabby" and inconsistent.

With that said, I have not tried to measure if there is any FPS difference between OEM & Firenocks (bare / non-lighting type).

 

[Konrad]

All right guys, let's see some photos of those long range targets after performing all of the adjustments!

Konrad

 

[OkieBowie]

All right guys, let's see some photos of those long range targets after performing all of the adjustments!

Sure, as soon as I get a Super-Telephoto lens that can image those targets from so so far away.

 

[jon.henry755]

Hi OkieBowie,
Recently, I've been spending a good deal of my time and testing equipment looking into Dorge's information. I often appreciate new information, but also do a great deal of research to verify and validate information before I'll pass it along to others.

The good news is that I've found Dorge to be far more technical than any of us ever dreamed possible. Aside from a double engineering degree, Dorge has had extensive direct experience in a number of technically related fields. Needless to say, he researches everything to an exhaustive degree. As such, his information is his attempt to actually simplify a small part of what he has learned or already knows.

While it's true that his nocks are far superior to those produced by anybody else, there's a lot more to his products than just the simple things we've already discussed. One in particular is the margin of error within the Bitzenburger Fletching Jigs.

I've used a pair of Bitzenburger Jigs for the past twenty years and have always been very partial to these jigs. My uses have been exclusively 3 vane or feather fletching of either competition or hunting shafts ranging from every grade of aluminum to carbon / aluminum shafts from Easton.

I had never paid a great deal of attention to how much deviation or movement these jigs had and always assumed them to be fairly accurate with the selected indexing. Boy was I wrong!!!!

Recently, while producing the 60 x 120 degree four fletches for the TAC arrow shafts, I began measuring and comparing these finished arrows and I was also checking to see if the 60 degree spacing was really 60 degrees, as well as verifying if the 120 degree separation was in fact 120 degrees.

That's right, you guessed it, these measurements were way off and they were also different from arrow to arrow, even though they were coming off the same fletching jigs. Needless to say, I was very upset. I just spent hours and hours "Spine Testing", Sorting and Matching a couple dozen arrows. I spent extra hours matching shaft weights to the 100th of a grain (+ or - 3/100ths) and now I would need to remove all my vanes, clean down the shafts and re-do the fletching with a better quality jig.

I just learned an important lesson the hard way. I wasted the money of another couple packs of 50 Duravanes, and probably almost a dozen hours of my time before all is said and done and I wouldn't have ended up with the matched set of arrows that I was seeking to begin with.

The other big thing that I learned was in the bonding process of the Duravanes. Today, almost all manufactures are using Fletching jigs that are angled upward, but the glues that are being used are liquid cyanoacrylate ester based glues. These glues run like water, so an angled Jig is very difficult to use effectively without it running all over the arrow shaft and making a mess of a brand new arrow shaft.

The more important factor is that in order to achieve a vane to shaft bond that is capable of withstanding a few thousand pounds of force can only be achieved with 40 or more foot pounds of evenly disbursed downward clamp pressure.

The Bitzenburger Jig does not apply even downward pressure along the length of its clamp and 40 lbs. is way beyond the capability of its magnets. It's not level. so getting good even distribution of the glue is also not possible, so the problem with the vanes coming off on target impact is not just a problem of the glues that are being used, it's equally a problem of how the vanes are being applied to the shafts both at the factory and during home repair.

I hate to say this, but I'm going to be the one to stick my neck out and open the can of worms on this problem. Unless TAC owners are willing to invest in the right Fletching jigs to properly apply vanes to their arrow shafts, they'll be replacing vanes regularly forever. Eventually, it's going to cost them as much in vanes, glue and time as if they had just purchased a good fletching jig to begin with.

It might also be worth noting that there are only three commercial manufactures of the type of glue that I mention above, so it doesn't really matter which ones you try because in most cases you are using one of these manufactures products that are packaged and labeled for a particular seller or distributor.

The strongest bond between arrow shaft and vane is obtained with the thinnest coating of glue and the greatest amount of pressure applied evenly over the length of the vane. These bonds are so strong that the vane will rip or tear along their length long before the bond ever lets go.

The net, net of this whole thing is that while Dorges Jigs are a bit pricy, they're actually cheap when you understand what you are getting and exactly how many problems you are overcoming.

After seeing the difference these jigs have made and the type of bonding now attainable, my recommendation is that if a TAC owner is willing to spend between $1500 and $2200 on his xbow and buy arrows that are $90. per half dozen, then do yourself a favor and save your money long enough to purchase one of Dorge's Fletching Jigs, because it's the only thing that's going to solve a number of the problems with the accuracy and durability of the ammo used in these crossbows.

Dorge probably thinks I should work for him, but a good product is worth recognizing when it comes along, so for this one he gets a thumbs up.

Jon

 

[Super 91]

Jon, I could not have said it better myself. Dorge makes one fine jig. And addresses and overcomes all the problems of the conventional jigs. It would be interesting to know how much better many people would be able to shoot if they were able to have their arrows fletched with one of his jigs. Not many people "get it" and tell you to go ahead and spend your money on his "expensive" jig. But if you lay it out like you have, it really makes good sense.

 

[OkieBowie]

... my recommendation is that if a TAC owner is willing to spend between $1500 and $2200 on his xbow and buy arrows that are $90. per half dozen, then do yourself a favor and save your money long enough to purchase one of Dorge's Fletching Jigs, ...

Hi Jon:

You are to late! Sometime back I bought Dorge's Fletching Jig. I just can't comment on using it, because I have not had a chance due to serious illness in the family. There also is the legitimate excuse, I have to build or buy a Spine Tester, otherwise putting vanes on accurately, without regard to strong vs. weak sides of the shaft, is a wasted pursuit.

Still - thanks!

 

[Super 91]

Okie, you are definitely on the right track. Read the unpublished info thread here on the forum and you will see a ton of great info Jon and others have put together regarding just what you are speaking of in the post above. Sounds like you are right there with the others here on the forum as far as tweaking not only the TAC but the components to get the absolute best performance out of an already awesome shooting machine.