springs

[tydra]

hi cody,

i have to buy springs for my arm, but i have some problems finding them.

my sled, complete with all components, is 24.22 pounds weight (11 kg) and following your instructions, i should use 4X .75" x 4.5" x .093 springs.

searching on the net i've found this

Type

Extension Springs

Material

Steel Music Wire

Ends

Machine Hook Ends

Overall Length

4"

Outside Diameter

47/64"

Wire Diameter

.092"

Load

38.01 lbs.

Deflection at Load

2.00"

Rate

12.98 lbs./inch

Initial Tension

8.72 lbs.

that corrispond to the 9654K384 product on Mcmaster-Carr.

what do you think, can it work fine?

thank you

[Cody Deegan]

Those might be a bit strong for your needs, being 1/2" shorter.  You could probably make them work though, if you get a spring tensioning system working, or if you drill the holes in the bones a little closer together (the ones for the bolts that the springs mount to).  I get all my springs at Century Spring online.  Some people have difficulties ordering from them however, so the McMaster Carr ones might be a good choice if you're up to making a few modifications..  







Cody

[Jonathan Cohn]

sorry to bring this up again, but did anyone confirm if these springs actually work?

It's not easy ordering from century springs since they have to make an account for you.  I'm also not sure what the prices will be from century

[David Delaney]

I have the same problem.  I went to ACE to buy my springs, but they only had 2 of  the 8 that I need.  I am finding the springs the biggest and last challenge on this project.  I feel for you and know that I am going to the same...

[Jonathan Cohn]

i bought these springs and installed them in my arm... but I havent loaded everything up yet to test the weight.  We will see

[David Delaney]

Where did you get the spring from?

[Steve Bernard]

http://hbsboard.com/index.php/topic,2973.0.html

I just got off the phone with the one of the engineers at Century.  I listed the part numbers on the thread above.