Wood gun stock, column design

[bobdonny]

I've got a lot of spare wood left over from the boat refit and I'm toying with the idea about building a wooden gun.
I'm seeing what I have and looking at some designs, I'm thinking a 95-105 gun, and I was thinking about a basic laminated stock, but then I saw a nice 28mm dowl that I thought could work so I looked for examples of wooden column stocks and couldn't find any? Anyone got any examples?

Surely a column as a structural object is more resistant to axial forces... and at this stage I am wondering why a wooden gun does not use a column's as a stock? and why they are usually made in some form of a rectangular shape, either as a singular block or laminated.

In structural engineering its well known that columns carry weight better and are more resistive to bending than square, rectangular or other angular structures, although you could have a mix with hexagonal structures and the like.

It seems further odd as well that most modern guns aluminium and carbon guns use this principle of a central column as a stock, but wooden guns do not?

Am I missing a glaringly obvious reason?

 

[foxfish]

Bob, do you mean a round profile?
One of the benifits of building a wooden gun is the mass you gain over a round profile ally or carbon Euro design.
The issue with standard Euro design is they kick hard when fired & are difficult to hold steady durring the firing process.
High mass neutrally buoyant woody's are great to handle under water, they are accurate & low recoil but, they also look so much better than a 28mm tube!!
Look at post 4 I built a 28mm round profile roller gun http://forums.deeperblue.com/spearguns-accessories/65342-spear-slider.html

 

[bobdonny]

ya thats the kind of thing, so i take it its mostly an asthetic reason they are not used?

yours looks super any more info on it? i'll have a look later, am on mobile now. doubt my first will be a roller tho'

 

[foxfish]

Not just aesthetics but, mass - high mass & weight = less movement when you pull the trigger.
I sold the roller gun but there are a few pics here http://forums.deeperblue.com/diy-homemade/85329-my-guns.html

 

[Tin Man]

Depending on the skill level of the builder, keeping a wood gun square also makes the setups to cut the track, trigger mech, handle, muzzle, etc much easier.

It can all be done on a rounded stock, of course, or the cuts can be made and the stock rounded later. But the square stock is certainly easier to work with. Especially if it's your first gun, or if you are the type to have a change of heart and "adjust" the design part way through!

 

[foxfish]

Bob, I always thought this was a great thread to follow if you want to build a nice woody... http://forums.deeperblue.com/homemade-spearguns/63452-teak-80-part-one-stock.html

 

[TomH]

Definetely agree with foxfish there, pretty much copied that design for the gun I made!

 

[Mark Lamont]

Hi Bob,
One of the drawbacks to a round wood shape that is not laminated is the ability of the wood to bend across the grain. Round is not the problem as long as it is laminated against the grain. Cut the wood and then flip the exterior sides to be interior or cross grain.
I agree that modifying the gun barrel for a mechanism or v slotted shaft guide is much easier in a laminated gun.
Being a structural engineer, you must see that the rubber loading is causing a cantilever effect on the barrel which manifests in a bent barrel unless a roller style gun is built. While designing the Scubapro Panther, the top of the barrel was narrow for a less compressive strength requirement while the bottom of the barrel was wide for improved tensile strength to combat these forces and allow for easier cocking and sighting. If the pressure of the rubber bands was directly in line with the column then I would say you are exactly right, that a column is the best shape.
Since aluminum tubing is so strong it is an obvious choice for most manufactured guns. In the case of the wood guns that I have made both for personal and prototype testing, I did not have a warping problem with a laminated gun barrel.

 

[bobdonny]

Hi Bob,
One of the drawbacks to a round wood shape that is not laminated is the ability of the wood to bend across the grain. Round is not the problem as long as it is laminated against the grain. Cut the wood and then flip the exterior sides to be interior or cross grain.
I agree that modifying the gun barrel for a mechanism or v slotted shaft guide is much easier in a laminated gun.
Being a structural engineer, you must see that the rubber loading is causing a cantilever effect on the barrel which manifests in a bent barrel unless a roller style gun is built. While designing the Scubapro Panther, the top of the barrel was narrow for a less compressive strength requirement while the bottom of the barrel was wide for improved tensile strength to combat these forces and allow for easier cocking and sighting. If the pressure of the rubber bands was directly in line with the column then I would say you are exactly right, that a column is the best shape.
Since aluminum tubing is so strong it is an obvious choice for most manufactured guns. In the case of the wood guns that I have made both for personal and prototype testing, I did not have a warping problem with a laminated gun barrel.

Super post Mark, thanks, that was the info I was trying to clarify... well put .
The angle of the rubber bands was my only concern, naively I thought the variation would be negligible or at least for short times the gun would be cocked.
I guess my premise for asking was because I have the wood, but if I have to do some more work, like cutting and laminating like you suggest I will consider another design...hmmmm I'll have to think on it a bit more.

Thanks for the designs foxfish and to the other guys for comments!

 

[foxfish]

One thing is for sure Bob - we love gun building on db & you will get plenty of help if you take the plunge

 

[Mark Lamont]

Definately for the person that likes to work with his hands and gets the gratification and satisfaction of both.