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Tomba - All in One barrel sealing

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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T

tromic

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Aug 13, 2007
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This is my solution of sealing the barrel on my Mares Cyrano pneumatic gun. It is easy to make and versatile in using. It is also tolerance forgiving (because of using a small piece of sling rubber tubing over the O-ring and adjacent plastic rings. I use it with 6,5 mm shaft instead of original 7 mm.
The gun needs some kind of adapter on the muzzle to make the hole deeper for fitting the Tomba (15 mm x 11,4 mm in addition to 4 mm in the muzzle). I made it in inox. There are other solutions too. Sealing the holes in the muzzle is done with rubber tubing which is pulled over the muzzle. Tomba could be used like Tovarich as on the picture. But also like slider as in Kara-yo, Karamba or Mamba or even a classic gun if you pull off the rubber tubing from the muzzle.
tombamuzzlepicff8.jpg

Assembling Tomba on the shaft
tomba1dijeloving6.jpg


Tomba assembly ready for use
tomba1qg0.jpg


Tomba sealing test
tomba1testbrtvljenjazb2.jpg


Tomba stays in place after shooting if the friction between tomba and the muzzle is sufficient for firm connection (like plug in the bottle), and between the tomba and the shaft as low as possible, but sufficient for good sealing. This is accomplished choosing the right diameter for plastic part that fits in the muzzle and for the rings adjacent to O-ring. O-ring is 6x2 mm what makes the diameter about 10,5 mm on the shaft. Plastic rings diameter is 11,8 mm (depends on the used rubber over the rings) Inner diameter of the plastic rings are 6,6 mm. The biggest plastic part could have the inner diameter 7,2 mm (so it could be used with 7 mm shaft also). I measured the friction between tomba and the shaft. It was about 0,2 kg (2 N). But I would secure the tomba at the muzzle, for any case, with piece of spectra.

 
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foxfish

foxfish

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It seems you Croatian guys are a very resourceful bunch :)
You have some other interesting pics on that site too.
 
settingsteel

settingsteel

SettingSteel
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It seems you Croatian guys are a very resourceful bunch

Indeed, and welcome to DB:friday

You have some other interesting pics on that site too.

What site Fox???

Tromic is the "system" easy to install? how about a step by step pictorial...this system seems quite fresh.
 
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tromic

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There are same additional explanation at the first post.
 
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foxfish

foxfish

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I have had a closer look at your device, so the tomba says on the spear during the shot, how do you attach the line to the spear?
I like the idea because it is a simple mod that should add plenty of power, I am a little concerned that the tomba might come off when the spear passes through a fish?
 
settingsteel

settingsteel

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Indeed, I'm a little lost as to how the system works:head
 
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tromic

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This version of tomba, as at pictures, stays in the muzzle after shooting and the line is attached to the spear like in tovarich system: viewtopic.php?f=8&t=2577&p=37627&hilit=tovarich+karamba#p37627,
or see this:
http://www.webalice.it/svl555/Sub/fucileenglish.html
under: Level Two (complex mod).

If you use the shaft with the butt and a metal ring, then tomba stays on the spear. Then you have to make some modification to the tomba, adding something to tie the line to the tomba like at "scorrisagola".
 
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foxfish

foxfish

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Thanks - I would much prefer that the tomba stayed fixed in the muzzle, great stuff mate thanks.
Are you going to be selling this system?
 
T

tromic

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No I am not going to sell tomba. I think everybody could make it himself.
There is a new picture at the beginning to make it clearer. I would like some feedback if anybody make it.
 
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settingsteel

settingsteel

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Thx for reposting the pix Trombic:fridayBut man I don't understand it is everything that is on the shaft the "tomba" system?
 
foxfish

foxfish

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Tone, I think what tromic has done is to make a sealing system that can be simply fitted to a standard air gun without any internal mods or other tricky work.
You need to seal any water release holes in the muzzle & fit the device in the muzzle end.
You could also remove the spear end that pushes the piston so that the tomba stays in place when the spear is fired.

Tromic I had a weld put on my spear to hold back a line slider, it is about 150mm back from the tip...just one solution. http://forums.deeperblue.com/attach...d1208540403-sources-mamba-kit-p1030556-1-.jpg
 
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tromic

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... fit the device in the muzzle end.

After the adapter is glued to the muzzle.

You could also remove the spear end that pushes the piston so that the tomba stays in place when the spear is fired.

Tromic I had a weld put on my spear to hold back a line slider, it is about 150mm back from the tip...just one solution. http://forums.deeperblue.com/attach...d1208540403-sources-mamba-kit-p1030556-1-.jpg

Foxfish, thanks for help explaining how tomba works and thanks for pictures.

Yes, tomba system is what you see an the shaft, plus adapter to the muzzle, and the green rubber hose over the holes in the muzzle (last picture)
 
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settingsteel

settingsteel

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ok, I think I got it, so basically everything on the shaft goes flying out with the shaft? Where is the line retainer on the shaft?:confused:...now you know why I've not a Mamba on my gun:head
 
T

tromic

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Just the shaft is flying, and the line which is tied to the shaft near the spear tip. Tomba stays in the muzzle.
 
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settingsteel

settingsteel

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Thx trombic, but know I'm more confused...lets see,

The cyrannos has a adapter than goes into the barrel on one end this same adapter holds the ring the prevents the plastic line holder from sliding off the gun, I don't see that on your set up, if the system goes into the barrel and stays how do you take it out?...hmm perhaps some pix would help...sorry just both confused & intrigued about your system.
 
popgun pete

popgun pete

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Jul 30, 2008
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That is a good idea "tromic", especially as you do not have to cut any screw threads with your neat system of using rubber tubing to seal off and hold all the various parts together. That sealing rubber tube over the muzzle relief ports is a good idea as it can work like a sleeve valve if any water does happen to flood the inner barrel for some reason. Then any water trying to exit the barrel can lift up the edge of the rubber sleeve thus allowing some water to still escape via the relief ports, although the shaft will be slowed, but not by as much as if the ports were fully blocked off. During muzzle loading the rubber sleeve gets sucked tight against the ports as a vacuum forms in the barrel, thereby stopping any additional water entering via the relief ports. One improvement may be to clamp the muzzle mounted rubber sleeve at one end using a plastic cable tie making it harder for it to slide out of position on the muzzle, the cable tie being either forward or rearward of the muzzle relief ports ring so that the rubber sleeve can still act like a valve at the other end.

Those who have the capacity to have metallic parts machined can remove the extreme front end of the standard muzzle and replace it with a longer section that serves the same function as the aqua blue adaptor on your diagram, then they can "Mamba-ise" a standard muzzle.

By adjusting the "sleeve valved" muzzle relief port system it should be possible to add a small element of hydrobraking to assist piston deceleration at the end of barrel travel in addition to that provided by the standard rubber shock absorber that sits under the shock absorber anvil or "top hat". When you load a Mamba gun there is a certain amount of water inside the barrel by virtue of inserting the shaft in the muzzle when under the water. Only when this water forms a cylindrical (annular) plug inside the barrel does it slow the shaft, otherwise it is just being pushed along the bottom of the barrel by the advancing piston. If the volume of water present only forms this solid annular plug at or near the very end of the barrel travel then it can create a "splash down landing" for the piston and eliminate some of the piston impact noise. This combined hydro and rubber muzzle shock absorber system is not a new idea, but not many pneumatic spearguns have used it.
 
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settingsteel

settingsteel

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Well, well look who chimed in, I was beginning to wonder were the Mr.PopPete wasrofl...like always great insight, although I will add pictures speak 1000 words...the camera is your friend:friday
 
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tromic

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There is a Youtube video at the beginning. Popgun-pete, that is how it works and how it could be more improved. Thanks helping me explaining tomba.
 
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foxfish

foxfish

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Pete, are you suggesting that I could reduce any recoil by loading my mamba guns under water? I would normally load my gun before I enter the water & very often I can stand up in the shallow weed beds where we hunt.
 
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