Posts by Wood Guy

OK, now you can start to see why I made the blank so wide. Rollerguns tend to be high because they have bands on both top and bottom, so my goal was to make the gun as streamlined as possible by grooving the top and insetting the cocking lever up into the gun as much as possible. Problem is that when you do that, a lot of the wood is removed. In this case, the track goes in 1/2" from the top and the cocking lever goes up about 5/8" in from the bottom, so most of the strength of the blank comes from the wood on the sides- everything's a compromise. I'll have to hunt with it to see if the width is a problem, but it shoots a 1" group at 14' in the test tank, so I like it so far.

The lever is set up to give a 2:1 mechanical advantage when cocking from the bottom. When the band is cocked on top, it's about a 190% elongation. On the bottom, it finishes the load at anywhere from 300 to 400% elongation, depending on band length. That's where the lever comes in. There's no way I could handle 350% elongation, but with the lever it's half of that. 175% I can handle.

It's late- more pics tomorrow.

I used a Neptonics reef mech, and went with the side slot for the release lever since it was at the height on the gun that would match the muzzle. I had to make a longer lever since the gun was too wide for the lever supplied with the mech. I wanted it to auto reset so I made and installed the Tin Man auto resetting torque spring "thingy".

Then it was on to the muzzle. I drilled the hole for the "axle", which was a 1/4" diam. threaded insert, then milled the slots for the delrin rollers that I had made earlier. I made a combination shooting line anchor and muzzle reinforcer from 3/16" thick aluminum. It fits in a slot milled into the underside of the gun and extends 6" back from the end of the gun. Two pins hold it into the gun, and since the axle passes through it, it transfers load from the axle back into the gun and takes load off the end pieces of wood, which really just hold the axle in place.

Next post I'll get into the lever installation.

Quite awhile back my teak supplier told me he had a handrail from a yacht, and that it would make a great speargun. Since the deal sounded "too good to be true" I ended up the proud owner of a yacht...handrail. He was right about the wood. It was really a beautiful piece, and it was when I looked at the shape of the handrail that I decided I would need to break some of the conventional rules of building spearguns. So I decided I would start with what would be almost the final shape, and go from there. Good thing I got a deal on the wood. The piece looked like an inverted "U", and the legs were kind of beat up, so I planed them off and ended up with a piece like this.

Then, I cut a piece out of the middle to give me the 2 halves I wanted. I ripped 2 lams from the piece I cut out and glued them to the bottom, giving me my blank, which now looked like this.

I installed one of my delrin enclosed tracks without any problem since I'm using a milling machine and the bottom and sides of the blank are flat. This would have been a real challenge with a router. I decided to use a Tin Man handle and trigger/ pushrod, and that went in the same way you would install it with a conventional gun. But, since I was going to be using brushed aluminum for some other stuff on the gun, I didn't want the black handle frame. Tin man to the rescue- turns out he had a couple of prototypes from when he was developing the handle, so they were bare aluminum- just what I wanted. More in the next post.

I'm not sure it would be very easy to find a moderately priced production gun made of teak these days. Guys that have made comparisons recently might have better numbers, but Mahogany is typically $8-10/ board foot, teak more like $25-30/ board foot, so the cost difference for a typical production gun might be around $20- $30, depending on the deal for the wood and the amount used for the gun. That doesn't sound like much, but production builders are trying to save any cost they can in a very competitive market, so they have gone to mahogany and other woods.

Lots of guns have been made out of wood other than teak, and with epoxy coatings, other woods work very well. I would want to know what the wood is, but would look equally at other features such as craftsmanship and the quality of the components, and I wouldn't let a mahogany stock dissuade me from buying the gun if the other stuff looked like quality.

The bottom of the mech needs to clear the top of the handle frame when the mech fires, so you need enough space for any springs or anything that hangs down below the mech. Other than that, the top of the handle frame can be as close to the bottom of the mech as you want. You might have to shape the blank behind the handle for clearance for your forearm, but with a rear handle that's easy enough.

Quote from sheff

The trigger is too long for my set-up. anyone see a problem with me shortening it with an angle grinder? I don't know much about stainless metals.

With the gun as wide and high as you are making, make the handle as close to the mech pocket as practical, say 3/16" or so for a handle over mech gun. That will minimize muzzle jump as much as the mass of the gun will. Grinding the trigger with a bench or side grinder is done all the time- just go easy and cool the trigger from time to time as you go to keep from discoloring

Very Nice! I really like the oval shape with the natural teak. :thumbsup2:

If you're starting with a 57" spear including flopper, you're probably going to end up with a gun around 55- 60", depending on where you put the trigger mech and how much overhang you prefer. You could use a Neptonics reef mech if you're only using 2- 5/8 bands, but I would suggest using the tuna mech and building the gun for 3 bands. You could use 2 most of the time, but could add the 3rd if you had an opportunity to hunt something that required shooting longer distances. There is no single gun for all situations, but if you're building a gun that long you might as well build in the capability for 3 bands. Something to think about. I would also consider making your second shaft a 5/16". If you power up to 3 bands you might like it better.

Sure do. PM sent

If you're trying your hand at making a rollergun, you might have found that it's not easy getting exactly the roller you want. Sailboat rollers work, but often aren't available in the right size. Custom rollers often go for $20 or more apiece. I've had several requests lately, so I've started making some for other than my own guns. I will make a custom set of 2 delrin rollers to your specs, 2" or less in diameter, for $25 plus $8 flat rate shipping anywhere in the US. No additional shipping charge for more than one set as long as they fit in the flat rate box.

Shown below are sets of 1" and 1-1/4" rollers.

Bill

Awesome looking gun overall, and the handle in particular is really impressive. How did you fasten the handle to the blank? Screws from the top of the gun? Any pics of the handle before it was installed?

They really turned out nice. It will be hard to top these on your next builds. :good:

Here's the link. Pick the one where the small end is as big or bigger than the gun butt cross section. They are thicker than you'll need so each stopper makes 2-3 loading pads. I've had good success using Permatex # 81158 black silicone adhesive sealant for gluing the pads on. Being black, it blends in well with the butt pad, and it's waterproof and flexible.

http://www.mcmaster.com/#tapered-rubber-plugs/=gxt827

I've been using the rubber for over a year and no problems so far. I like it because it's a little firmer than the old sandal sole and seems to hold up really well. And when you can get 2 or 3 for $6 I just don't think you can go wrong.

By the way, the smaller ones with the holes in them also make great tip guards- you can get a pack of 40 for about $6.

I cut the G-10 tracks that I make at about 1200 rpm with a fairly slow travel speed. I also take as much of the material to be removed as I can out with a straight end mill the size of the neck of the ball cutter. Mine are 3/16" but I'm not sure what Josh's cutters neck size is. Go slow with the straight cutter and make several passes- I broke a 3/16" end mill the other day trying to take too much out in a pass. With the ball mill, I go down and back, then turn the mill off, re-position the blank with the ball cutter still in, and re-start the mill. I go back a few inches further than the start of the cut so I can start the travel, then start the mill. This will give you a smoother transition between the cuts, and cutting both ways will give you a smoother track.

Quote from Don Paul

I'm not a typing critique, but 25% elongation won't fly around my house.:laughing:
Who says '' specimen length'' shouldn't count for something...... OK I suck at nerd humor.;)

I like to stretch my rubber Specimen L X 3:thumbsup2:

Cheers, Don

Picky, picky, picky! It's more of a challenge with only 25% elongation- you have to get the fish to swim directly at you really fast! :laughing3:

Quote from capt offshore

I have been working on a gun now for a couple months and almost have it completed. I chose to go with muzzle ferrules and split bands for this one instead of the traditional method. How should I calculate the correct length needed to cut the rubber when I make the bands . . . . use the 3.5/1 ratio and subtract the amount of rubber there would be in the stock . . . . or is there another mothod? Any helpful advice would be great from some of you guys who've made guns with this type of muzzle.

Thank you much! :thumbsup2:

Here's how I would do it. Take the distance from the ferrule to the sharkfin, then subtract the distance for the wishbone at the sharkfin (including the part of the wishbone in the rubber). Then subtract the line from the ferrule to the band (including the line in the band). This is the stretched length of the bands. Divide this length by 3.5 and you have the unstretched length. Add back the length of band at each end for covering the line and wishbone, and you have the length to make the band for a 3.5 ratio (25% elongation).

The grain does look like pine but the density is way off (25-27 lb/cu ft for pine vs 47.5-48.5 for your piece of wood).

Based on the dimensions you gave, the volume is .99 cu. ft, so at 47-48 lb. the density is 47 or 48/ .99 = 47.5-48.5 Lb. / cu. ft. Teak is 45, mahogany is 35, cyprus is 35, white pine 27, red oak 45, white oak is 47, hickory is 40-55, pecan is 47. So, it's a hardwood, and if your numbers are correct, pretty dense- a lot denser than cypress, or mahogany. It could be teak, based on the density, but the grain just doesn't look all that much like teak. The density would match oak, and it would have been used as a building material. It's hard to tell from the pics, but a local lumber yard or building contractor could tell right away if it's oak. :confused2:

Now you need to "tune" the flopper. The flopper should open almost all of the way by itself, but only go the rest of the way when you push it gently, or spin the shaft - then it should stay open. You do this by tightening up the pin by gently tapping the pin - but only enough to get the desired results. Go easy- it won't take much. The idea is that the flopper will open completely when a fish tries to get away, but will stay open if the fish gets back up the shaft during the struggle.

The gun turned out really nice- and apparrently shoots straight as well!::excited1: