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Old 03-30-2020, 02:43 PM   #61
popgun pete
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Re: Made a 145cm inverter, 10mm shaft

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Originally Posted by Satdiver View Post
Hi Majd, Thanks for your complement.
I will try to up load video's of target testing and the shaft lifting with my older model Alemannia Vela, now I have finally worked how to do this.
The new model Vela I have is balanced perfect. This gun will almost float a 10mm Hunt double offset flopper shaft with 8.4mts of 1.6mm cable.
The video's I have of my new Vela are back in Bali on a hard drive.
With the new Vela I was shooting quite high at 6 & 7 meters pool testing, I contacted Alemanni and asking why. Itio told me the gun was underpowered and to cut the bands. I'm still shooting a bit high, so maybe I need to cut more.
Alemanni does not have a track in his guns. I suspect one of the reasons is because of shaft lift and the gun flexing.

Once I get back to Bali, I can do testing with different diameter shafts & compare the Vela to my 145 gun, will be a interesting test. I will try and make a 11mm shaft to test as well. Also can tie rubber at a less percentage and try smaller O/D bands as Neven suggested as well.

I have the front rollers as low as I can get them, also the front rollers as far forward as I can on my 145 inverter.
The bands on my 145 invert weigh's 1.1kg which helps add mass to the gun and reduces recoil.

I have attached photo's of my Alemanni Vela showing shaft lifting.
Lens distortion tends to banana that image. The best way to judge what is going on is to see the whole gun and some constant reference horizon that does not move in the photo frame. In your earlier photos we had the tiles of the pool as a constant background.
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Old 03-30-2020, 04:31 PM   #62
popgun pete
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Re: Made a 145cm inverter, 10mm shaft

All spearguns create a couple trying to twist gun up around your hand.
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Old 03-30-2020, 07:26 PM   #63
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Re: Made a 145cm inverter, 10mm shaft

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Originally Posted by Satdiver View Post
Had a go at building a of 145cm inverter. Overall length 165cm. 10mm Hunt double offset flopper shaft.
My mate wanted one so built 2 guns.
20mm bands through the back rollers and the rest 19mm bands.
Carbon strips between the laminate to stop the gun flexing.
Two 19mm x 6mm ceramic's bearings in each Delrin rollers.
Titanium stopper tube to reduce weight to help ballast the 1.1kg shaft and 1.6mm coated cable.
Ermes double roller trigger.
Nicely built beast of guns!
Thanks for the video. I love my invert guns, their low recoil, and accuracy. Holy cow though on 10mm shafts.
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Old 03-31-2020, 02:20 AM   #64
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Re: Made a 145cm inverter, 10mm shaft

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Originally Posted by gspearguns View Post
New Ermes trigger works fine. Especially long version is very smooth, but long version is not suitable for eurostyle guns with high positioned handle because rear screw goes outside the handle.
So I ordered from Mario custom trigger rotated backward, and plan to shorten trigger housing.
Yes many people ask for small modifications to fit their needs. One nice trigger is actually a little longer without wings and pinned ... for pipe guns that seems to be something that people want (actually even some wood guns want that). I personally think that wings are crucial to getting perfect shaft to mech height as this allows you to optimize for different shafts and even use american shafts. If you asked for changes you should ask to put your logo on your trigger, it makes for a nicer more custom look!

One thing to note ... thinning out the backside to elevate the handle really weakens that area as there is much less wood. So I highly recommend that the back area and trigger pocket be reinforced with Carbon Fiber. This stiffens the weaker area and doesn't allow flexing. Flexing can cause shaft instability which is of course detrimental in many cases. You can of course put CF between the laminates, but I think that the entire back area should be reinforced including the trigger pocket. I have made a 3D printed shape that allows you to perfectly mold the space for the trigger and allow all moving parts to move fully ... even allows for .3mm CF layer ... this allows you to put CF inside the pocket and press this part in and have a perfect strong inner pocket which can then be mated with the outer CF body. It also has perfect shaft to trigger height alignment to make things easier and quicker. There is no question that a gun with stiffened back end shoots much more accurately than one that is not stiffened. I will see if I can put this 3D file out on Mario's website so anyone can 3D print it and use it. With this you can modify any gun trigger in minutes ... something that used to take me hours or even days.
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Old 03-31-2020, 07:50 AM   #65
Satdiver
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Re: Made a 145cm inverter, 10mm shaft

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Originally Posted by spearq8 View Post
Great job Paul ... really made huge improvements! Looks like that gun is very controllable and has lots of power. I think this gun needs to be compared to how an Alemmani Vela 135 shoots and from the video it certainly seems like you sorted out a lot of the problems there. Congrats!

Low shooting is really very hard to control with rollers, especially once you start ramping up the power on lighter shafts ... for some reason the tail lifts and causes low shots. I mentioned that way back a few years ago but got flamed and trolled endlessly for just trying to point out facts and hoping those problems could be worked on. In this case I think Paul really did a good job with tail lift and if you compare a side by side comparison with say an Alemmani Vela 135, you will see a huge improvement in that area. I am still not sure why tail lift is such a problem with rollers, but a lot of people are just getting used to the gun shooting lower and somehow adjust aim ... or reduce the power by 30% and accept that (that is what I do if I have to use a roller gun). Of course with tail lift ... low shooting is not the only problem ... it also means that the shaft is unstable and thus you will not get optimal performance as an unstable shaft sheds velocity a lot quicker and of course accuracy is not the same. However at hunting distances maybe the compromise of a little lower shot is worth it to gain less recoil for some.

I think the way to really improve things with rollers is to test with light shafts ... say a 7mm to 8mm shaft. A thick stiff shaft masks a lot of problems. That is what I did when I was trying to control shaft stability with classic guns. Tail lift is also a huge problem with classic guns and many guns also have problems with that. Initially in testing the max I was able to control at full power was a 145cm shaft @ 7mm .... anything longer and shaft whip was a problem. But 2 years later I was able to control even a 165cm @ 6.7mm shaft with full stability. With rollers a lot more stuff is happening ... but I think the handle is also an important factor ... however you also need to check roller height, wishbone stop location and also the location of where you attach your wishbone on the shaft seems to be an important factor. Progress usually comes in small increments where you look honestly at the test data and then adjust accordingly and test again.
Hi Majd, I have uploaded to YouTube target testing my older model Alemanni 135 Vela to 6 & 7 meters and side views showing shaft lifting.

https://youtu.be/quK3KmCIIwc

Last edited by Satdiver; 03-31-2020 at 01:01 PM.
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Old 03-31-2020, 08:09 AM   #66
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Re: Made a 145cm inverter, 10mm shaft

These shots look OK.
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Old 03-31-2020, 10:31 AM   #67
Mikel_24
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Re: Made a 145cm inverter, 10mm shaft

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Originally Posted by spearq8 View Post
... I have made a 3D printed shape that allows you to perfectly mold the space for the trigger and allow all moving parts to move fully ...
Holly crap! I have a few friends with 3D printers.... but if that piece is printed in metal, then you are playing in another league!!

I do have a basic shop where I wrench, make some wood guns, weld, etc... but that's a whole different thing!

Mikel
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Old 03-31-2020, 10:35 AM   #68
Satdiver
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Re: Made a 145cm inverter, 10mm shaft

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Originally Posted by popgun pete View Post
Lens distortion tends to banana that image. The best way to judge what is going on is to see the whole gun and some constant reference horizon that does not move in the photo frame. In your earlier photos we had the tiles of the pool as a constant background.
Hi Pete, I have uploaded to YouTube some side view shoots of my 145cm band stretch inverter Speargun. You can also see the shaft lifting & recoil.
Theses test was done with a blank 9.5mm test shaft with 2.2mm mono. The last test in the video was 1.6mm stainless cable on the test shaft.
The reason I start with a blank shaft is to see how accurate the gun shoots, then I then move onto 1.6mm stainless shooting cable, then to a 10mm double offset flopper shaft then to slip-tip shafts. Step by step.

https://youtu.be/eFGpL95v6R0

Last edited by Satdiver; 03-31-2020 at 10:56 AM.
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Old 03-31-2020, 10:40 AM   #69
Satdiver
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Re: Made a 145cm inverter, 10mm shaft

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Originally Posted by popgun pete View Post
These shots look OK.
Hi Pete, You can see the 10mm shaft flexing as it leaves the gun. But the shaft flight is quite flat.

Last edited by Satdiver; 03-31-2020 at 10:55 AM.
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Old 03-31-2020, 10:53 AM   #70
Satdiver
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Re: Made a 145cm inverter, 10mm shaft

Quote:
Originally Posted by spearq8 View Post
Yes many people ask for small modifications to fit their needs. One nice trigger is actually a little longer without wings and pinned ... for pipe guns that seems to be something that people want (actually even some wood guns want that). I personally think that wings are crucial to getting perfect shaft to mech height as this allows you to optimize for different shafts and even use american shafts. If you asked for changes you should ask to put your logo on your trigger, it makes for a nicer more custom look!

One thing to note ... thinning out the backside to elevate the handle really weakens that area as there is much less wood. So I highly recommend that the back area and trigger pocket be reinforced with Carbon Fiber. This stiffens the weaker area and doesn't allow flexing. Flexing can cause shaft instability which is of course detrimental in many cases. You can of course put CF between the laminates, but I think that the entire back area should be reinforced including the trigger pocket. I have made a 3D printed shape that allows you to perfectly mold the space for the trigger and allow all moving parts to move fully ... even allows for .3mm CF layer ... this allows you to put CF inside the pocket and press this part in and have a perfect strong inner pocket which can then be mated with the outer CF body. It also has perfect shaft to trigger height alignment to make things easier and quicker. There is no question that a gun with stiffened back end shoots much more accurately than one that is not stiffened. I will see if I can put this 3D file out on Mario's website so anyone can 3D print it and use it. With this you can modify any gun trigger in minutes ... something that used to take me hours or even days.
Hi Majd, I believe I have stopped this gun bending and flexing with the 1.6mm carbon strips that run the full length of the gun and plus the high position of the handle is why I believe is why this gun is very accurate.

The tigger template look great. That would save so much time in installing a trigger and could get the trigger housing perfect. Would be good to have one just for the trigger housing and another with the trigger housing and the track depth. Would you sell them?

Last edited by Satdiver; 03-31-2020 at 01:00 PM.
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Old 03-31-2020, 02:40 PM   #71
popgun pete
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Re: Made a 145cm inverter, 10mm shaft

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Originally Posted by Satdiver View Post
Hi Pete, I have uploaded to YouTube some side view shoots of my 145cm band stretch inverter Speargun. You can also see the shaft lifting & recoil.
Theses test was done with a blank 9.5mm test shaft with 2.2mm mono. The last test in the video was 1.6mm stainless cable on the test shaft.
The reason I start with a blank shaft is to see how accurate the gun shoots, then I then move onto 1.6mm stainless shooting cable, then to a 10mm double offset flopper shaft then to slip-tip shafts. Step by step.

https://youtu.be/eFGpL95v6R0
If you click through these photos look at your hand and the cuff of your glove to see what is going on with the recoil. The timing clock readout is a bit misleading, but look at the red line advancing. Also look at the dangling shackle and the muzzle.
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Old 03-31-2020, 02:45 PM   #72
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Re: Made a 145cm inverter, 10mm shaft

Quote:
Originally Posted by Satdiver View Post
Hi Majd, I believe I have stopped this gun bending and flexing with the 1.6mm carbon strips that run the full length of the gun and plus the high position of the handle is why I believe is why this gun is very accurate.

The tigger template look great. That would save so much time in installing a trigger and could get the trigger housing perfect. Would be good to have one just for the trigger housing and another with the trigger housing and the track depth. Would you sell them?
I'm interested too, but only if Mario promises that no changes in trigger housing will occur in next year or two.
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Old 03-31-2020, 03:14 PM   #73
popgun pete
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Re: Made a 145cm inverter, 10mm shaft

Here are the images combined with a white line through the shaft and a red line through the gun. A flick comparator is a handy way to look for movement, unlike this image, but it allows measurements of angular movement such as the muzzle lifting which rotates the whole gun around your hand. The spear being freed at the tail is not being revolved as the gun body is, hence its angle is not changed much from just before the release of the tail.

In the second image I drew a measuring gauge using the top of the frame and then advanced it up with the cursor arrow to the top of the upper frame, note the shaft alignment has barely changed. This analysis confirms that the shaft stays on course even if the gun rotates on your hand with recoil and still hits the target. However too much recoil with a light body gun then the gun rotates before the shaft clears the end of the gun which results in the spear tail being clipped upwards sending the shaft off course. In closed track guns the lifting muzzle will bust the end of the track unless the shaft can blast clear before any appreciable movement of the stock.

Huge ballasted multi-band guns, often referred to as tree trunks or logs, have so much inertia that they can spit a shaft out of a fully enclosed track because the shaft mass is eclipsed by the mass of the gun. Often these monsters just need an outboard motor fitted to make them self-propelled guns (Main Battle Tank, see below)!
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Old 04-01-2020, 01:54 AM   #74
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Re: Made a 145cm inverter, 10mm shaft

Pete, is the gun rotating around the Hand, or is the hand being pushed down?

Majd, nice tool.
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Old 04-01-2020, 02:34 AM   #75
Satdiver
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Re: Made a 145cm inverter, 10mm shaft

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Originally Posted by popgun pete View Post
Here are the images combined with a white line through the shaft and a red line through the gun. A flick comparator is a handy way to look for movement, unlike this image, but it allows measurements of angular movement such as the muzzle lifting which rotates the whole gun around your hand. The spear being freed at the tail is not being revolved as the gun body is, hence its angle is not changed much from just before the release of the tail.

In the second image I drew a measuring gauge using the top of the frame and then advanced it up with the cursor arrow to the top of the upper frame, note the shaft alignment has barely changed. This analysis confirms that the shaft stays on course even if the gun rotates on your hand with recoil and still hits the target. However too much recoil with a light body gun then the gun rotates before the shaft clears the end of the gun which results in the spear tail being clipped upwards sending the shaft off course. In closed track guns the lifting muzzle will bust the end of the track unless the shaft can blast clear before any appreciable movement of the stock.

Huge ballasted multi-band guns, often referred to as tree trunks or logs, have so much inertia that they can spit a shaft out of a fully enclosed track because the shaft mass is eclipsed by the mass of the gun. Often these monsters just need an outboard motor fitted to make them self-propelled guns (Main Battle Tank, see below)!
Hi Pete, Your findings of recoil is very interesting. You have highlighted these very well with your screen shots.
I use to think it was just the shafting lifting. But from your findings, I can now see with the recoil of the gun and the handle dropping is coursing the shaft gap between the rear of the shaft and the gun body as the shaft leaves the mechanism.
It begs the question, does a powerful gun need a track?
I remember Jon saying about handle dropping in a earlier post. Also Majd saying that a good & fitting high handle helps with accuracy. You have highlighted this with your findings.

I can also understand from your findings. The large diameter bands which weigh 1.1kg on this gun, plus the mass of the gun and a good fitting & high handle, reduces recoil and improve accuracy for inverter spearguns. Also need a very fast shaft speed, so the shaft has left the front of the gun before there to much muzzle lift.

You have answered the question about enclosed tracks with your findings, enclosed track would be quite a problem with the recoil and course quite a accuracy problem with all inverter, roller and classic guns.

You have now made me think how to make a better video for testing and to learn more about how the guns preform's. I'm thinking a better camera and a back ground with lines.

That is one monster gun, I'm sure there would be some crazy recoil.

Last edited by Satdiver; 04-01-2020 at 07:00 AM.
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