Testing Chinese Tubes
Posted 29 December 2011 - 09:53 PM
say guy's can you give me some info on what you use to aquire you weight of ammo, and your weight in draw. I've been ask to do some of these and can't, also maybe I can also bother you in how to put in photos .... I've got some real uglys to show ya
This is what I use for draw weight.
Check here for something to weigh your ammo.
Edited by pgandy, 29 December 2011 - 09:53 PM.
Posted 30 December 2011 - 01:37 AM
In 29C temp,3/8 steel with a loop then single to give a 2:1 taper,10.5inch long,55-60inch draw: 10 shots averaged 306.3fps,maximum 314.4fps.
This setup seems absolutely perfect for 3/8 steel,more so than 1745.
The 1745 is just as fast but is much harder on my elbow.Thus my choice for such light ammo would be a no brainer. I expect tube life will be shorter than with1745 but I'm hoping it should still be superior to flats.
The 1745 is probably ideally suited to 3/8 lead and slightly heavier.
A trial with a 5.5 inches of 2050 joined to 5.5 inches of 1842 was a let down.
Edited by timdix, 30 December 2011 - 01:49 AM.
Posted 30 December 2011 - 04:03 AM
My favourite catty, Yellowhammer, is a stubby tree-fork with eye-bolts and is the sweetest shooting catty I've come across. Which is why I only have one other as a spare. I like office bands for the simplicity but the best ones are hard to find here. Going to get a big pile of 1842 now.
- Larry Bourgeois likes this
Posted 30 December 2011 - 07:43 AM
Thanks again for all this good info.
Posted 30 December 2011 - 07:57 AM
I made a brief side trip into the raw power side of tapered 1842. I wanted to see if I could get 200+ fps with .495 lead balls. I got 222 fps (67.7 ms), 19.96 lbs/ft (26.69 joules). I have no doubt there is more power there, but I'm not strong enough to pull past 32 inches without shaking enough to endanger my Chrony. I'll have my son take a crack at it later. This is Mr. Stubby with the double tapered set.
Glad you didn't use my pouch with this setup. I doubt it is strong enough to use safely, as it is not intended to be. It is great to see the exporation you are doing with the tubes however.
JIm, there is no better pouch on the market for its intended use.They last just about forever, and are the perfect size for 3/8 ammo. I love them, but I noticed when I got into the 300 fps range that they tended to wear faster, so I went with some thicker shoe leather for the power bands.
I'll take this opportunity to caution everyone about powerful slingshots. Everything has to be up to the task. Make sure the fork is strong enough and comfortable to hold. Make sure you can hold onto it when you release. Inspect everything often, and especially, wear good eye protection. Also, if you are experiencing frequent fork hits, fix that problem before you explore high power.
Posted 30 December 2011 - 08:11 AM
Well 330fps with 3/8 lead! Does that out- joule my 338fps with 9mm? Bloody close id say lol, great research mate.., Ben
The 3/8 balls I'm using now are 9.2 mm and weigh 71 grains, so if you're using steel, I have the edge. If yours are lead, it's very close.
Posted 30 December 2011 - 08:26 AM
Henry, I got to tell ya "Mr. Stubby" is just plain coooooool looking - I think at some point I read here how you installed those eye-bolts if ya wouldn't mind going through it again it would be appreciated.......thanks
had I knew how efficient those 1842 bands were I would have ordered those too, thanks for your info
I used steel eye bolts 3 inches long. I drilled a hole in each fork 2 inches deep, the length of the . The hole is sized so that the bolts screw in with very little force. Then I forced as much 2 part epoxy as i could down the holes and coated the threads on the eye bolts with it. I screwed the bolts in and gave it 24 hours to cure. It is very important not to make the holes too small as that would put radial force from the inside on the forks and the last thing you want is a steel eye bolt hitting you in the face. I tested the eyes by applying 50 pounds of pull with a rope and my fish scale.
Posted 30 December 2011 - 01:59 PM
Posted 30 December 2011 - 04:15 PM
I'm also building a cousin to "Mr. Stubby" to keep a shot count on a short loop version. I would appreciate it if the rest of you who are using 1842s would let us know what kind of life you get out of them.
Posted 30 December 2011 - 04:58 PM
The tutorial is now up on my website. Here is a direct link so you don't have to look at the commercial stuff.
Henry, Marvelous job on the tutorial!!
I have been following this thread and I appreciate the time, experimentation and sharing you have done.
These tutorials are so good for the newbies to have posted as a "sticky". When I first came to this site there was not the dedicated places to find tutorials like this. This is the best stuff...even for us that have been around.
Note: Edited by Henry to change link.
Edited by Henry in Panama, 14 September 2012 - 09:32 AM.
- Larry Bourgeois likes this
Posted 30 December 2011 - 10:32 PM
Posted 31 December 2011 - 08:34 AM
Edited by pgandy, 31 December 2011 - 10:13 AM.
Posted 31 December 2011 - 08:56 AM
Henry...With a possible problem at the loop connection could it be that the constrictor knot is creating an unusual amount of stress at this point...Would it help to use a bit of contact cement here ( at the connection ), allow it to dry then attach the connection ( with pressure ) ...Over this adding a short section of 1745 tubing...?
I have my doubts that this is a solvable problem, but the contact glue is worth a try. A common characteristic of approaching the upper limits of performance is short band life. Please elaborate on the short section of 1745 addition.
Posted 31 December 2011 - 08:59 AM
Thanks again Henry. I appreciate your efforts and time in this project and I am sure it will be helpful go many. Approximately how much force are you applying when stretching the bands during fabrication?
I stretch them to near maximum, about 5 times relaxed length. The next time I make a set I will measure the force.
Posted 31 December 2011 - 10:38 AM
Posted 31 December 2011 - 11:17 AM
Henry...What I meant about adding the short piece of 1745, was to actually fit ( with narrow pliers ) a 1/4 inch ( or slightly shorter ) section over the area where the loop connects...Neil was doing this type of surgery in the construction of his fixed tubes on his Trophy slingshot...With the contact cemented area under this extra layer of tube, this should make a good connection with less severe stress on the connection point...If it were really necessary you could fix a constrictor knot over this 1/4 inch section of 1745, but I personally would try to avoid to much stress at this point...When I learn how to use this #@%"# computer I`ll try to be more articulate in my explanations ( I might even take a few shots with my #@%"# digital camera if I can learn how to get it on the forum display )...
OK, I got it. That is the method I use to tie my Theraband tubes and I tried it on the tapered #107s. I'll have to try to figure out a way to expand the reinforcing tube. Maybe the tips ends of my Circlip pliers will work.
Posted 31 December 2011 - 12:30 PM
Posted 02 January 2012 - 09:31 AM