Spring constant is approximately (all dimensions mm and for steel springs):
10^7 * wire diameter^4 / (outside dia-wire dia)^3 / number of coils
to give the newtons per meter spring constant. Change 10^7 to 10^4 to give newtons per mm
so 2mm wire with outside diameter 22mm and 20 active links (ignore ends) is
10 000 000 * 16 / 8000 / 20 = 1000 Newtons per m or 1 newton per mm. Too weak for an air rifle. Most air rifle springs are 5000 to 12000 Newtons per m spring constant.
Thicker wire, lower diameter and less coils = stiffer.
For your formulas that model spring gun behavior...do you need this spring constant or is spring rate needed? Or both?
I have wanted to try this but never dealt with the tools involved. I have read about the shadetree method of putting a bathroom or other scale down on a surface or press and using that to measure the force.
But I'm reading about tools like these. Anybody use one? What pressure/force scale or rating would be appropriate for the springs inside a springer (a TX200 in this case). Seems like one of these in a vise or drill press (chuck a guide of some sort in the press and slip the spring over it) would do the trick.
http://iyrs.org/Portals/0/Uploads/Im...log2%20139.jpg
http://iyrs.org/Portals/0/Uploads/Im...log2%20141.jpg
http://www.youtube.com/watch?v=tVsrky0cpDs
Good deals: davida6212 jimmer u.k.neil
New HW80: 28 coils 3.1mm wire 21mm OD 240mm long.
John
Law of any kind only affects those willing to abide by it.
Chaps,
To tie in with Airsporter 1st's thread on HW80 mainspring spec, I thought this'd be of relevance, again.....
THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
NEXT EVENT :- August 3/4, 2024.........BOING!!
Only me!!!!!
Just thought I'd ping this thread back up, to tie in with that excellent current thread on different springs and springer tuning!!
Jim, could this go into the "Useful Info" section, yet?
Ciao,
Tone.
THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
NEXT EVENT :- August 3/4, 2024.........BOING!!
As I've run out of springs for my mk2 stroke TXs, I'm going to buy a #1 and #9 titan to try, based on the info is this thread they should both be suitable. In fact I think the #1 should be perfect
Thanks again for posting...
Opportunity is missed by most people, because it is dressed in overalls and looks like work.
I have gathered a lot of spring info in an Excel-sheet, but am not able to upload it...
I coul e-mail it to someone?
Has anyone got details of the diameter, length and inner ID of Titan 13, 14 & 15 springs.
Hw77+7
As promied, the measurements from a recent SFS HW95K
SFS spring HW 95K
30 active coils
3.46mm wire
3.95mm gaps
19.75mm o/d
13mm I/d
223mm free length
16mm preload gave 790fps with 8.4gn .177 JSB
Cheers
John
Last edited by Snooper601; 12-11-2014 at 05:32 PM. Reason: typo due to sausage fingers on phone
Snooper601 Suspect a simple fault, or a simple engineer He who dies with the most toys wins!
QHAC Official lubricant development engineer.
just ordered a hw97k .22 from Netherlands he never had the uk spec rifle in stock so I ordered the standard its on its way with the spring removed so I have the problem of cutting this 14.7ftb spring down to make it 11.6ftb, the specs on the spring is as follows, Energy (Joule / ft.lb) 20 / 14.7.
Link to gun
http://www.krale-schietsport.nl/en/w...ch-hw97-k.html
I have a chrono but I want to be able to cut it so i don't over cut and end up having to pack the piston out with delrin washers.
watching videos of 97 uk 12ftb strip downs it seems that when spring block is removed the spring guide and spring seem to be flush with the threaded chamber should i use this as a guide?
I have no idea what type of spring is in this gun as I don't get it until this Tuesday and would appreciate any help I will upload spring dimensions when I get the gun on Tuesday.
Last edited by kingsnake; 01-05-2015 at 06:30 PM. Reason: typo
Believed to be the standard spring. Ends closed and nicely square and ground:-
Free length 214mm
Wire diameter 3.2mm
OD 19.2mm
Active coils 28
THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
NEXT EVENT :- August 3/4, 2024.........BOING!!