Mainspring data thread

[Black Beard]

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.

[DoctorBoudreau]

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

[JLB]

New HW80: 28 coils 3.1mm wire 21mm OD 240mm long.

John

[TonyL]

Chaps,

To tie in with Airsporter 1st's thread on HW80 mainspring spec, I thought this'd be of relevance, again.....

[TonyL]

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.

[Shed tuner]

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...

[MattyBoy]

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...

I stuck a number 1 Titan in my .177 Diana 52 and it made 17 ft lb. I had to cut 3 whole coils off it to get 11.4 ft lb

Bloomin stiff spring

I'll be interested to hear how it goes john and how many coils you end up lopping off

Matty

[bigtoe01]

Jon

what length spring and what coil count and wore thickness do you need?

[Shed tuner]

I stuck a number 1 Titan in my .177 Diana 52 and it made 17 ft lb. I had to cut 3 whole coils off it to get 11.4 ft lb

Bloomin stiff spring

I'll be interested to hear how it goes john and how many coils you end up lopping off

Matty

hmmm... chopping is easy, but I don't want it too stiff... it looked less stiff than the #9 (more coils, same len), and the #9 is meant for a mk2. Maybe I should try the #10 but it looks too thin wire and possibly a bit short

Is the #1 really stiff, or just too long ?

[evert]

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?

[HW777]

Has anyone got details of the diameter, length and inner ID of Titan 13, 14 & 15 springs.

[Snooper601]

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

[Phil Russell]

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 890fps with 8.4gn .177 JSB

Cheers

John

Thank you for this information. I note, however, that you would be running a tad hot if your figures are correct. Have you recorded the requirements for 'not hot' version?

Cheers, Phil

[Snooper601]

Thank you for this information. I note, however, that you would be running a tad hot if your figures are correct. Have you recorded the requirements for 'not hot' version?

Cheers, Phil

Typo fixed 790fps

J

[TonyL]

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

Excellent info, John.