Post by snyper on Dec 15, 2005 9:20:22 GMT 8
Got this info from this thread:
acm.jconserv.net/viewtopic.php?p=32#32
Just the same I'd like paste it here:
How do you test for the spring power?
Installing a spring on an aeg and taking an actual chrono is a little time consuming. I estimate that it will take me at least 60 minutes to install a new spring, tests it, and reinstall the original spring. I must also make sure that the changes in velocity readings are attributed to the spring only. This means all other parts must be the same before and after the test such that I must reassemble the aeg really carefully and in the same manner. And Hell, I must set aside an aeg for the sole purpose of testing springs and I don't intend to do that. I already have too many aegs lying around the house.
The one time test by PowerEdge Hawaii is helpful. Although it shows that the various springs are pretty close to their rated or estimated capabilities I am not interested in testing all available springs side by side. It also makes no sense to reinvent the wheel as I won't be able to do the test any better. Acquiring all those springs alone are beyond my test budget.
What I am interested in is in making a device that I can use to test unknown springs once in a while and/or whenever a new spring pops up. I have actually created my own gadget more than a month ago have just finished making a stronger version capable of testing strong spring. The original unit cannot test springs stronger than the X120. The new flatbars are twice as thick and in fact broke and redefine the shape of several of the drill bits that came with the drill. I wanted to buy a titanium set but at P2,600 I opted to buy a taiwan made set at less than P1,000.
I replace the hollow tube from an umbrella with a solid stainless steel bar. Boy, was drilling into a 6mm solid stainless steel bar a challenge. Everybody, including th salesman, said it can't be done with a regular hand drill with non-titanium bits and that I must bring it to a machine shop but hey, we ACMers learned to make do with what we have and I manage to drill not only 1 hole but 2 holes - at both ends of the round bar and the 2nd hole being cleanly done. The new device also has a spring guide.
This is still not the device I want. What I really have in mind is cylinder and piston type of gadget where the hop up and nozzle are in a fixed position, maybe even glued, so that I can isolate the variables and confidently attribute the changes in velocity readings to the spring. This device will truly test the fps-velocity that the spring is capable of.
Anyway, as we ACMers make do with what we have I decided to use my spring compression testing (SCT) device to test the strength of the spring (not the fps it is capable of). This device may not be accurate as the markings in the ACM scale shows only readings by half pounds. I will also be the first to question the accuracy of the scale itself and the durability of the spring inside it. However, this SCT device is what I have now so let's MAKE DO and see how it fares. I tested the poundage it requires to compress the spring to 60mm length. The space inside the cylinder, without spacers, being 70mm when the piston is pulled back and ready to fire.
Stock Marui spring (7.5 lbs)
Stock WELL (7.5 lbs)
PDI-170%/M120 (17.5 lbs / PI 230%)
M130/PDI-210% (21 lbs / PI 270%)
PI-170% (EMV350) aka X120 (13 lbs / PI 170%)
PI-240% (EMV400) (18 lbs / PI240%)
The percentage figures in parenthesis with a PI prefix are my comparative ratings versus a stock TM spring. PI stand for Power Index. EMV stands for Estimated Muzzle Velocity based on the PI of other springs. the FPI170% value of the X120 means that it takes 170% more force to compress the X120 than required to compress a Marui spring. Although I haven't tested a M100 or M110 spring I suspect that the X120 is somewhere between a M100-M110 spring and therefore rated it as PI-170%(EMV350) . Many of you may have made that conclusion months back but I want to be a little more scientific.
BTW, a normal TM spring is about 160mm long, the PDI-170% is 150mm, the X120 is 165m, and the PI-240%(EMV400) is 180mm long but is capable of being compressed to 60mm to fit inside the cylinder. And yes, the PI-240%(EMV400) actually comes in many sizes which is a product of poor production techniques. I won't be surprised if the strength varies from batch to batch or maybe within batches. What I rated as PI-240%(EMV400) will be tested.
If my calculations are correct, the new PI-240%(EMV400) spring is every ounce comparable to a M120 and is 40% stronger than the X120 spring. At only P250 shipped (150 pick up) this spring is defintely a must for power-mongers who don't want to spend P900 on an equivalent high end spring.
Now I don't have to resort to high end springs to get the velocity I want for my outlaw series. The PI-240%(EMV400) packs more than enough punch.
acm.jconserv.net/viewtopic.php?p=32#32
Just the same I'd like paste it here:
How do you test for the spring power?
Installing a spring on an aeg and taking an actual chrono is a little time consuming. I estimate that it will take me at least 60 minutes to install a new spring, tests it, and reinstall the original spring. I must also make sure that the changes in velocity readings are attributed to the spring only. This means all other parts must be the same before and after the test such that I must reassemble the aeg really carefully and in the same manner. And Hell, I must set aside an aeg for the sole purpose of testing springs and I don't intend to do that. I already have too many aegs lying around the house.
The one time test by PowerEdge Hawaii is helpful. Although it shows that the various springs are pretty close to their rated or estimated capabilities I am not interested in testing all available springs side by side. It also makes no sense to reinvent the wheel as I won't be able to do the test any better. Acquiring all those springs alone are beyond my test budget.
What I am interested in is in making a device that I can use to test unknown springs once in a while and/or whenever a new spring pops up. I have actually created my own gadget more than a month ago have just finished making a stronger version capable of testing strong spring. The original unit cannot test springs stronger than the X120. The new flatbars are twice as thick and in fact broke and redefine the shape of several of the drill bits that came with the drill. I wanted to buy a titanium set but at P2,600 I opted to buy a taiwan made set at less than P1,000.
I replace the hollow tube from an umbrella with a solid stainless steel bar. Boy, was drilling into a 6mm solid stainless steel bar a challenge. Everybody, including th salesman, said it can't be done with a regular hand drill with non-titanium bits and that I must bring it to a machine shop but hey, we ACMers learned to make do with what we have and I manage to drill not only 1 hole but 2 holes - at both ends of the round bar and the 2nd hole being cleanly done. The new device also has a spring guide.
This is still not the device I want. What I really have in mind is cylinder and piston type of gadget where the hop up and nozzle are in a fixed position, maybe even glued, so that I can isolate the variables and confidently attribute the changes in velocity readings to the spring. This device will truly test the fps-velocity that the spring is capable of.
Anyway, as we ACMers make do with what we have I decided to use my spring compression testing (SCT) device to test the strength of the spring (not the fps it is capable of). This device may not be accurate as the markings in the ACM scale shows only readings by half pounds. I will also be the first to question the accuracy of the scale itself and the durability of the spring inside it. However, this SCT device is what I have now so let's MAKE DO and see how it fares. I tested the poundage it requires to compress the spring to 60mm length. The space inside the cylinder, without spacers, being 70mm when the piston is pulled back and ready to fire.
Stock Marui spring (7.5 lbs)
Stock WELL (7.5 lbs)
PDI-170%/M120 (17.5 lbs / PI 230%)
M130/PDI-210% (21 lbs / PI 270%)
PI-170% (EMV350) aka X120 (13 lbs / PI 170%)
PI-240% (EMV400) (18 lbs / PI240%)
The percentage figures in parenthesis with a PI prefix are my comparative ratings versus a stock TM spring. PI stand for Power Index. EMV stands for Estimated Muzzle Velocity based on the PI of other springs. the FPI170% value of the X120 means that it takes 170% more force to compress the X120 than required to compress a Marui spring. Although I haven't tested a M100 or M110 spring I suspect that the X120 is somewhere between a M100-M110 spring and therefore rated it as PI-170%(EMV350) . Many of you may have made that conclusion months back but I want to be a little more scientific.
BTW, a normal TM spring is about 160mm long, the PDI-170% is 150mm, the X120 is 165m, and the PI-240%(EMV400) is 180mm long but is capable of being compressed to 60mm to fit inside the cylinder. And yes, the PI-240%(EMV400) actually comes in many sizes which is a product of poor production techniques. I won't be surprised if the strength varies from batch to batch or maybe within batches. What I rated as PI-240%(EMV400) will be tested.
If my calculations are correct, the new PI-240%(EMV400) spring is every ounce comparable to a M120 and is 40% stronger than the X120 spring. At only P250 shipped (150 pick up) this spring is defintely a must for power-mongers who don't want to spend P900 on an equivalent high end spring.
Now I don't have to resort to high end springs to get the velocity I want for my outlaw series. The PI-240%(EMV400) packs more than enough punch.
