"Butter" Measurement for Sleeving 2" SCH-40

[markfh11q]

I have done some testing over the past few days on the "butter" measurement for cutting the inside segment of a 2" SCh-40 sleeved golfball barrel. I have looked and looked and the only definite, (not vague), answer I could find was on Aturner's site, "...maybe an extra 1/16"...". I decided to do some tests.

All of these ideas were done making a short 3" barrel segment.

The first was a 7/8" strip cut out the inner pipe. This worked, but was freaking DIFFICULT to start sleeving and the fit was loose on the golfball.

The next one was a 1" strip cut out, thinking since Aturner just estimated how much more he cut out, I'd just cut the 1" strip out. This one sleeved VERY easily, yet the golfball couldn't fit. You had to shove and hammer it to get it into the barrel.

Finally, I tried 15/16". This one was moderately difficult to sleeve, but once started it was only a matter of hammering the inner pipe in with a pipe wrench, (which subsequently fell apart and flung the adjustable head at me). This was almost a perfect fit for golfballs! I could probably make a *PERFECT* barrel if I had more time and if I felt it was worth it. This would involve measuring with with an accurate ruler, (1/32" incriments), and cutting with a table saw.

The conclusion? If you cut a 15/16" strip out the inner pipe with perfectly square and parallel edges, while accounting for the width blade of the saw, (mind you), you will get a fine barrel for golfball spudding.

<center><img src="http://i10.photobucket.com/albums/a123/markfh11q/2inchGB.jpg"></center>

As with all barrel pictures, the supposed "gap" is a composed of a lot of shadow. The fit can be comparable to 1-1/2" SDR-26.




And last, I still agree that the best barrel you could get for golfball launching is a sleeved 1-1/2" SDR-21/26 barrel. Hell, there are a lot of places you can find the stuff. Irrigation places are a good way to start off. They usually use the stuff. As for the SCH-80 to sleeve it in, you can sleeve it in 2" SCH-40 with spacers, but with that idea, if the barrel cracks your screwed and have to start over. With SCH-80, the barrel is held a lot better and won't crack.

Good luck, and happy spudding.

[Velocity]

nice... good idea to test this kinda thing...

Do any test fires with this barrel?

[markfh11q]

It's not a barrel. It's a sleeved 3" segment produced by the 15/16" test.

I used to have a 1.5" SDR-26 barrel sleeved in 2" SCH-40, but the small little combustion launcher I shot it with is now scrapped. I have to work a way to get it to 2" male threads.

This barrel, if a little easier to make, (sleeving is WAY more difficult than it appears... and I'm only making 3" segments), would make a nice choice, but I'd still stick with an SDR barrel anyday.

Problem is, some people can find any SDR-21/26.

[aturner]

Mark, that is a very nice sleeve job. If you manage to pull that off with a full length barrel, then you are the man. I was never able to get such a narrow gap on mine, b/c it would "bind" near the beginning of the sleeving process, and became nearly impossible to continue. That's why I had to trim a bit more when sleeving.

As for your short test segments. I also tried some short test segments prior to sleeving an entire barrel, and found it difficult. By comparison, it was easier to sleeve a whole barrel, at least by this method of ripping 2". The reason seemed to be that a full length provides a built-in "handle" on each side, which can be used for leverage. With a short section, I didn't have much leverage to work with.

When sleeving a full barrel, the first three or four inches are the most difficult, and after that I found it was just a matter of pounding away. So you have done the hardest part!

And yes, you are right on about the benefits and drawbacks of this type of sleeve. The ability to get 2" sch40 at almost any store that carries pipe is the major benefit. The drawbacks are, you need a tablesaw, and you end up with a seam. So if you can find a supplier of the SDR series, I think that's the way to go.

Edit: what do you mean by "Butter" measurement?

[KlugeBoy]

Just a note; I spent a lot of time at plumbing supply places looking for SDR pipe but never found it. Finally one guy at a plumbing store suggested I try a Well and Pump supply place. Most towns of any size will have one. My local Well and Pump supply had every flavor of SDR pipe I'd ever heard of. They also had 2.5" pipe for a tennis ball barrel and the 2" x 2.5" adapter I needed.

[BC Pneumatics]

Did you try leaveing the outer barrel in the sun for a while? Tends to help me whenever I sleeve barrels.

[markfh11q]

Nah, I didn't leave it in the sun. That might've helped a little.

And by butter measurement, I mean the sort of, "best, easy" measurement. All butter... that sort of thing.

And most every town has <I>someplace</I> to find SDR-21. Irrigation places are a good place to start. I got my SDR-26 out of a fly-rod holder.

[BewareOfDog]

Perhaps, what some of us fail to realize, is that the trick would be to make your cut at the correct <b>angle</b>...

Marking 15/16" is easy enough. But when you make your first cut, if it is at 90 degrees (to your working surface), then your second is made by rotating the pipe and cutting another cut at 90 degrees (to your working surface)... Then you'll have a cut that is slightly too small, because these angles will not align with one another once the pipe is compressed.

Although far from exact, maybe this will describe what I'm talking about:

<img src="http://img.villagephotos.com/p/2003-9/398596/sleevingangle.GIF" width=800 height=600>

<center><b>( Left = correct</b> / <b> Right = incorrect ).

[markfh11q]

I see what you're saying. I think I might have actually done that on "accident", because of the seam I've got. It lined up pretty darn near perfect when I hammered it in there...

[aturner]

DR, that is a good idea. Can you offer suggestions as to how one might go about cutting the more precise angles you recommend? The best approcah I can think of, would be to keep the blade of the table saw centered on the pipe, but to "lean" the blade to the correct angle.