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The hardness tester that I use is called a "micro hardness" tester. It uses a controlled force to push the point of a very small diamond tipped probe into the steel, and determines hardness by how deep the probe goes. We're talking thousandths of an inch. You can barely even see the little spot where the probe was. Most platings are a few thousandths of an inch thick. I noticed that the hardness of the shaft was considerably higher in an area where the coating was intact, and considerably softer where I had belt-sanded the shaft surface flat. It didn't get hot in this area, so I don't think that I softened the steel.

The only other explanation that I can think of is that the sanding may have left the shaft surface rougher when viewed with a magnifying glass, which could possibly have affected the hardness readings.

When I did hardness testing on the shaft that I welded for Dan, I found the coating to be harder than the underlying steel. I don't know what the plated coating is, but it ain't galvanized. Galvanizing is mostly zinc, which is very soft.

I usually order mine from www.mcmaster.com. These are older prices from my catalog, but should still give a comparison.

Black Delrin 1" diameter round bar is $4.04 per foot (8576K21). Square bar is available, but about triple the price. I would just buy a slightly larger round and cut it down if I wanted square.

UHMW is available in round bars, hollow round bars, and square/rectangular bar. 1-1/4" diameter round (white) is $2.40 per foot. 1-3/8 OD by 5/8" ID is $5.60 per foot.

Not saying that those are the right sizes, just a comparison.

I know absoultely ZERO about pneumatics, so I would certainly defer to those that do. But I do have a little experience making things from plastic.

PVC is strong, but a little the brittle side, especially if it is exposed to lots of sunlight. CPVC (gray color) is a little better on both counts.

Delrin is stronger, as well as tougher, and the black color helps resists deterioration in sunlight.

Or, use UHMW. UHMW is not as strong as Delrin or PVC, so a slightly larger diameter piece should be used. But it has extreme impact resistance and toughness, meaning it will bend but not break. And different from PVC and Delrin, UHMW floats, which seems like it might be handy for a freediver.

My gun wasn't quite that large. I think it was about 1-11/16" wide by 1-7/8" tall before shaping. He doesn't do the poured epoxy tracks, but he can do a regular wooden enclosed track. He can also include a short dovetail delrin section about 6" long at the muzzle end to protect the wood track from breaking out if the gun falls over or something strikes the shaft. I should also clarify that the prices I mentioned are just for the stock, with a 1-1/2" wide by 2" tall stock going for around $150. Tracks, trigger pockets, tapering, and other cutting/machining are all possible, but cost extra.

He is not really out to build guns. We just noticed that laminating the stock and then aging and staightenning were the parts that most people would prefer to avoid, and are MUCH easier with the right tools. His stocks are all hung vertically, aged, and guaranteed straight to within 0.015" on top and sides, and usually they are closer to 0.010". This way, when you get your stock, it's time to start the fun part!

I'll start a thread in a bit, but here are a few pics of my stock. He makes laminated stocks to whatever size you want, with laminations usually about 3/8" thick. Most stocks range from $130 to $180 depending on the size. All Burmese teak, and laminated under pressure with West Systems epoxy.

Will do.

Dad can also provide dovetailed Delrin enclosed tracks. Very tough material, but cuts and finishes much nicer than UHMW. It's a little heavier, though.

If you look carefully, you will notice that the right side of the sectional drawing shows a screw inserted, while the left side shows an empty hole for reference. :poke:

I saw the thread. That's what got me thinking about it!

I was thinking about this recently as well, Dan. Here is the drawing I made. No significant differences, really. I drew it with the intent that the attachment screws would bite into the section of the muzzle which is inside the barrel. I also designed this sketch with very little "wrap" around the barrel, so that it could easily be installed off to one side to provide clearance for the shooting line on the other side. That might affect balance, though, depending on how heavy the spike was.

No problem there. I have modified my mold so that the weights now fit all of the standard belts, at least as far as I know. Rob Allen works, as does the softer Omer, and anything else in between of the same approximate dimensions.

Yes, USPS. They have a flat rate shipping box. Anything that will fit inthe box, to anywhere in the U.S. for $9.95. It is the best deal going for heavy stuff that is not too big.

Quote from SporaScrub

THought shipping was $10?

Yep, $10 will cover 40-45 lbs worth, depending on whether they are 2-lb or 1.25 lbs sizes.

Dan - I seem to remember that you investigated a couple of different "grippy" coatings for the handle. What did you settle on?

Also, could you show a shot of how the handle fits your hand? I have no doubt that you tuned it exhaustively to suit you , but at first glance the shape looks unconventional.

I designed it from scratch, did the calculations, drew all the plans, and did all the welding. I did incorporate different features from other cats that I saw. By comparison, none of the dimensions on this style of catamaran are nearly as critical as on the high speed version.

It rides very well at just about any speed you want to run in seas up to 3' or so. We don't intentionally go out if the seas are over 4', but I have been caught in 6' seas in thunderstorms. At those heights, the period of the waves becomes an issue. It is still only a 22' hull, so you have to be carful not to go so fast down one wave that you stuff the bow into the back of the next wave. One nice thing is that it doesn't really have a "planing speed" where it suddenly pops up out of the water. So if the waves are breaking, I just throttle back to about 16-18 knots to match the seas, which is hard to do in most mono-hulls without bogging down.

The two widely spaced motors are great when circling a small wreck, or any other time that you want great maneuverability. I can reverse one engine, forward one engine, and turn in my own radius like a tug boat.

Got the old man to take a few more pics while he had it on the trailer.

Quote from FREEK

That's good to hear!!:thumbsup2: Have you been out to check out damage?

Nope. Quite a mess to clean up in the yard, but no damage.:thumbsup2:

Got it back late Saturday Night! :hooray:

I'm very happy, considering the power company had previously estimted up to two weeks!