yet another rollergun

[GilbertG.]

I thought I'd post a link to pictures of my 90cm rollergun proto since it seems to be a pretty cool topic lately. Its definitely not as sleek as Persiko's nor is it as compact as Defo's. I was curious to see what this roller gun thing was all about so I made a quick adaptation from one of my regular guns. It's set up with a 9/16 band and a 1/4 inch riffe shaft. On my recent trip back to Hawaii I lent it to a friend of Brad (w3ac) and he seemed to like the gun and adjusted to it very quickly. He was able to put some holes in some fish with it on its maiden dive. I tested it out in very shallow water a few days earlier to see how it shot and how it handled. Unfortunately I never got to fire this baby at any fish. Oh well... I'm better at making guns than using them anyway.

It's also my first experimentation with purple heart. Hope you like it.

http://www.spear-diver.com/rollergun/

Gil

 

[ajwaverider]

Not to bad . Did you notice any problems with the shooting line tangling with the bottom half of the bands?

 

[fuzz]

That's the first thing that struck me too! The prongs facing the back of the gun on the underside look like it'd catch on stuff.


Beautiful gun! I love purpleheart

 

[Amphibious]

oh my, that gun is rather sexy very very nice

 

[leighdu]

very nice

how do u do your handles? i like the join between the handle and barrel and how u done the thin stip of prurple heart.
Aslo what do you use to rout your enclosed tracks? i cant find and ball bits, i cant even find 8mm cove bits, im just using a 9.5mm bit. for my next gun im just going to try to make the rail out of resin.

Do you anymore links to your guns? ive seen another one of them before

 

[leighdu]

just found your agressor guns, there beautiful guns

and found out that you use CNC machines for your handles and enclosed track

 

[GilbertG.]

Snagging wasn't an issue when we tried it. The hooks are actually nicely shadowed in the corner between the main stock and the wings. I was actually more concerned about the shooting line snagging onto the rollers up front since they stick out a fair bit. Like I said, it was a quick morph into a rollergun so it can stand to use some improvement.

Hickory is slightly less dense then purple heart. Pretty heavy. But a whole lot stronger. Both woods are difficult to work with and dulls the crap out of your blades and bits.

Leighdu, nice work on your custom gun! My handles are joined to the stock with a mortise and tenon joint.

gil

 

[GilbertG.]

Oh, I get my bits from Bill Kitto. 50 bucks a pop.

 

[defofthecrown]

Looks good as always. I was considering using very small rollers like those or even a bar. I have no way to test it, but I was thinking the larger the arbor on the roller the faster it can accelerate (like a low gear in a car). Therefore the bigger the arbor and roller the faster the gun shoots, right? You always have good imput on these enginering queries- I'd like to know your thoughts as you put this thing together.

-Chris

 

[GilbertG.]

Good question Chris. I wanted to keep the rollers really small mainly to minimize the added bulk up front and didn't give the roller acceleration much thought until just now. So strictly on theory, a smaller roller/pulley/sheave would "spool up" faster than a larger one because it has less rotational inertia. Kind of like spinning a bicycle wheel with your hand versus spinning the big wheel on "the price is right". "One dollar Bob!!!!" But the difference in inertia between a 1 inch diameter roller versus a 1/2 inch roller is probably peanuts anyway so it wouldn't matter very much.

One thing I did notice was that the rubbers didn't pull back as smooth as I would have liked. It seemed "grabby", which would suggest a good amount of friction between the roller and the arbor, increasing as you pulled back farther. In this regard, the larger your roller diameter and the smaller the arbor diameter, the easier it is to overcome the friction. But I guess if you have rollers with ball bearings it would be a non-issue.

Seeyah,

gil

 

[ajwaverider]

Where do you get your wood from and what is diamondwood?

Albert

 

[gonetobaja]

Man thats a beautifull gun. This is the first time I checked out this section of the fourm. I like it!

GTB

 

[persiko]

truly a beautiful job.

 

[GilbertG.]

Albert,

Diamondwood is a resin impregnated wood composite that is laminated under very high pressure and heat. It is very very dense and is virtually waterproof. I go straight to the manufacturer for this stuff but you might find it in some woodworking catalogs.

Hickory I bought a bunch in bulk a while ago from a hardwood supplier in the midwest but you can find it at any decent hardwood store.

Like anything else, if you buy in bulk you'll get better wholesale prices.

gil