How Thick is Your Shaft

[ihab]

For Enclosed Track Guns Only.

I’ve been reading that when Shaft diameters are reduced from their original intended use, shaft may warp & effect accuracy.

To make my self clearer.
If a gun comes balanced & rigged with a 7 mm shaft (for example) and you replace it with a 6 mm shaft…it is bound to warp and loose accuracy due to the shaft being overpowered.

If this was true…does the same principle apply for Enclosed Track Guns…I’m assuming NOT since the shaft travels through a tunnel thus eliminating the wrap factor.

Anyone with different opinion(s) is welcomed.

Cheers,
Ihab

 

[jimdoe2you]

What you have heard is correct. All features of the speargun such as shaft diameter, bands sizes, number of bands, band lengths, barrel stiffness, etc. need to be in balance with each other in order to maximize the guns performance.

There are four ways that divers can tune their guns incorrectly.
1. Over power the gun
2. Over power the shaft
3. Under power the gun
4. Under power the shaft

If you take a gun that has been tuned for a 7mm shaft and add a 6mm shaft instead without adjusting the bands, the 6mm shaft will be overpowered thus resulting in "shaft whip". The accuracy of the gun will be considerably decreased if the gun was originally finely tuned for the use of a 7mm shaft.

Enclosed track guns allow divers to efficiently over power the shaft without shaft whip, but care must be taken not to over power the gun itself.

 

[ihab]

So what's the difference between
1- Over powering the Shaft
2- Over powering the gun.

Please explain

Cheers,
Ihab

 

[Marwan]

Example of overpowering the shaft:
using 2x18mm bands on a 6.3mm shaft and a wooden gun (that is designed to shoot with twin 18mm bands with no recoil)
Example of overpowering the gun:
Using twin 20mm bands on a rob allen carbon (probably will be overpowering the shaft as well in this case)

 

[Marwan]

by the way the title of this thread is quite bad

 

[Newbie_spearo]

Bout an inch and a half?:troflroflrofl

 

[Marwan]

Bout an inch and a half?:troflroflrofl

rofl rofl rofl...sounding like a locker room in here..rofl

 

[petar_dj]

by the way the title of this thread is quite bad

at first, I wasnt sure what he was talking about either=)

 

[Mr. X]

A railed barrel reputedly also offers protection from shaft flutter, probably not as much protection as enclosed barrel.

How thick are my shafts?

6.6mm RA spear/railgun- originally used with single 16mm RA bulk rubber, now used with single 20mm RA bulk rubber (I would happily have stuck with the factory configuration of 16mm rubber if it were available, both work fine though.).

6.3mm Omer spear/unrailed XXV - single 18mm Omer rubbers.

 

[ihab]

by the way the title of this thread is quite bad

The title of this thread sounds as clean as the ear of the beholder:naughty:naughty:naughty...so let's think from the waist up.:t:t

And BTW...my question is still not answered...somehow I'm not getting the right answer to...CAN you over power a shaft that is used in an ENCLOSED TRACK....YES or NO
Please give reasons

Cheers,
Ihab

 

[Groupermadness]

I Know i shouldnt answer this question but sadly for myself i must.. yes the shaft will flutter when leaving a closed track.. why?.. because when you release the trigger the force from the bands transfers to the BACK of the shaft effectivly PUSHING the shaft along the tube, this can only and will only hold the natural bending of the shaft until it finds its freedom, it will be reduced significantly depending on the length and diamater of the restricted area the shaft is traveling in, and also on the shaft diamater,length/power release formula. basicly if over half the shaft has left the tube before the bands have released their power, it will have very little effect against the flutter effect and bend.

story
If you shoot an arrow with 4mm dia from a standard bow it will flutter all the way to the target. If you fire a broom handle at the same target 1. you need a bigger bow 2.you need bigger arms to hold all this power 3 the broom handle will fly as straight as an ARROW and still hit the same target.

Moral of this being, if you cant sneak up and get your prey within 2m thus reducing the need of a monster gun with multiple bands then take up archery...

Peter.

 

[Marwan]

And BTW...my question is still not answered...somehow I'm not getting the right answer to...CAN you over power a shaft that is used in an ENCLOSED TRACK....YES or NO
Please give reasons

Cheers,
Ihab

i think its better to be more specific, i dont think the difference between a 7mm and a 6.75 will be that significant versus say an 8mm and a 6.25

 

[ILDiver]

You can over power a gun causing the barel to flex. Also over powering can cause increased wear and possible damage to the trigger group. Yes you can over power an enclosed track too. Same thing, wear and tear on the track and gun. Take proper care of the equipment and it will last a lifetime.

If your trying to get more range out of the gun, then you need a longer gun designed for the task. If you are not penetrating fish, then your either using the wrong gun or it's not rigged in it's original configuration and under powered. One gun for every situationis a tall order.

 

[spearstudtx]

I just switched to a more powerful rubber and did some testing in my pool to determine if the increased band diameter would cause shaft whip. Initial setup was 16mm rubbers on a 6.5mm shaft and it worked fine but I wanted more range and stopping power (penetration).

1x18mm rubber to a 90cm Beuchat with 6.5mm spear. No problem with shaft whip, not enough recoil or reduced accuracy to make me think I should switch back to 16mm. If I had a thinner spear, or had added another 16mm rubber though, it would have been too much.

If your trying to get more range out of the gun, then you need a longer gun designed for the task. If you are not penetrating fish, then your either using the wrong gun or it's not rigged in it's original configuration and under powered. One gun for every situation is a tall order.

Thats what I keep telling myself so I can keep buying guns

spearstudtx

 

[Bill McIntyre]

I haven't done any high-speed photography, but I'm convinced that an enclosed track prevents shaft whip, even if only the rear half is enclosed. I use a 9/32" shaft in my Wong Magnum hybrid which has a track cut for a 5/16" shaft. With three 5/8" (16mm) bands, it is very accurate.

The way I see it, the whip (bending) is going to happen when the bands first accelerate the shaft. If a track prevents that, then the shaft comes out straight and true, with no other forces to make it oscillate.

 

[ihab]

Thank you Guys...this has been very helpful.

Another related question.
If we agree that overpowering a gun to a certain degree.... does not effect accuracy in an Enclosed Track gun......Then if we change the original shaft by a smaller diameter shaft...will recoil be reduced or increased.
Example:
If an enclosed Track gun is originally setup with a 7 mm spear and we switch to a 6.75 mm spear………for more range/power/speed…………would that increase Recoil or reduce Recoil.

Cheers,
Ihab

 

[spearstudtx]

Reduce, not very substantially though. If you know anything about firearms, it is the same concept recoil wise. A bigger bullet with the same amount of powder has a little more recoil as compared to a smaller bullet. The amount of recoil lessened will be directly dependent upon how much you reduce the diameter of the shaft.

Also, try it out. You need spare parts anyways so why not buy two different shaft sizes, try them and then use them for whatever style of hunting you are going to do that day. Undoubtedly they will perform differently, and that way you can tailor your equipment to the type of fish or hunting you prefer. It is important to note that each gun will perform differently with different bands, wishbones, rails, shafts, tips, etc. Buy slightly different stuff, try it out in a controlled environment (pool) and decide what you like better. Some of this stuff depends on your specific style of hunting and personal preference. The only way to know for sure is to try for yourself.

spearstudtx

edit: if a enclosed track gun is made for 7mm spear, a 6.75mm will not make much difference, but a 6 or a 5mm spear will still have a certain amount of "whip" however small it may be. point being that an enclosed track is made for a specific diameter of spear and it will work best with that diameter. also an enclosed track gun will not accept a bent shaft (important to know because you want extra shafts every trip you go out).

lastly a 6.75mm spear will not give you more range/power. less actually. it will give you more speed but because it will have less mass, it will carry the energy less efficiently than a 7mm spear therefore, less "stoning" range on a equal fish.

 

[Bill McIntyre]

A smaller shaft should decrease recoil- that's why I used one.

What is more murky is the effect on range and hitting force. It comes out of the gun faster, but then its lighter, so what is the effect on kinetic energy? And since its lighter, it will slow down faster, assuming that the heavier shaft was pushed by big enough bands to get it up to speed.

But even though a lot of guys in SoCal preach that we need heavier shafts, I like the reduced recoil and greater accuracy of the thinner shaft. Every white sea bass over 50 pounds that I have taken was with a 9/32" shaft, including a 62 pounder I took a few months ago. And week before last, I stoned two fish in a row, with that thin shaft driving right through their spines.

 

[ihab]

Nice catch Bill...I see a slip tip on one of them....I think this settles it...smaller diameter shafts reduce recoil and the opposite is true.

The info we get on DeeperBlue makes it really an enjoyable experience.

Cheers,
Ihab

 

[Bill McIntyre]

Nice catch Bill...I see a slip tip on one of them....I think this settles it...smaller diameter shafts reduce recoil and the opposite is true.

Yes, the slip tip didn't even get to function. It was left dangling on the far side of the fish because the shaft was wedged in the spine. As I pulled the fish up, the shaft didn't even pull back out.

On the other fish, the slip tip is just barely protruding from the fish. The shaft was wedged in the spine and that is as far as it got. I had a hell of a time getting it back out of the fish.