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Super-duper gas struts!

PostPosted: Fri Jul 17, 2009 10:28 pm
by bbarry
I received my gas springs today from McMaster. I ordered ones with 120lbs force each on the recommendation from several members here. I am completely unable to compress these springs by any non-mechanical means. I'm not a hulking gym-junkie by any means, but even putting one end on the ground and using my entire weight (160lbs) I couldn't get them to budge a bit.

Is this normal? I tried turning the plunger end in case there was a threaded lock of some sort...no dice. I can always put a pipe clamp on them to make certain they compress, but I don't want to force anything. I for sure don't want to install them until I know they're okay.

Ideas? Thanks!!!

Brad

PostPosted: Fri Jul 17, 2009 10:51 pm
by MCI1969
yes, its normal. I work with gas props used on canopies and tonneau covers. Even a 40lb is hard to compress by hand (tonneau props range from 90 -180lbs). Just confirm your prop poundage and use it to your specs. Alot of them are marked in newtons so make sure the numbers you are using are pounds. Hope this helps.

:thinking:
PS - Rememberyour anchor points have to be strong enough to support the prop pressure. They (props)do contain oil and have an up side when installing. Inverting them will lead to premature failure. in the cl;osed position you want the steel stem low and the body high. They may inver when in use but 99% of the time the door will be in the closed position.

PostPosted: Fri Jul 17, 2009 11:37 pm
by bbarry
MCI1969 wrote: Even a 40lb is hard to compress by hand (tonneau props range from 90 -180lbs)


Hmm, I would have thought that 160lbs of me balancing on the spring in my living room (picture that!) would have been enough to compress a spring rated for 120lbs. I did double check the rating and they are marked "120 lbs."

Brad

PostPosted: Sat Jul 18, 2009 7:31 pm
by Jiminsav
Brad, the weight rating is the weight the strut can hold in the open position. it takes quite a bit more then the rated weight to make it close. your puny 160 pounds is fluff to a 120 lbs strut....
girly man. :lol:

Re: Super-duper gas struts!

PostPosted: Sat Jul 18, 2009 7:42 pm
by mikeschn
bbarry wrote:I received my gas springs today from McMaster. I ordered ones with 120lbs force each on the recommendation from several members here. I am completely unable to compress these springs by any non-mechanical means. I'm not a hulking gym-junkie by any means, but even putting one end on the ground and using my entire weight (160lbs) I couldn't get them to budge a bit.

Is this normal? I tried turning the plunger end in case there was a threaded lock of some sort...no dice. I can always put a pipe clamp on them to make certain they compress, but I don't want to force anything. I for sure don't want to install them until I know they're okay.

Ideas? Thanks!!!

Brad


Yes, that's normal.

We used 90 # springs on one of our other builds, and we could not compress them manually either. but once we installed them in the hatch, they worked perfectly.

that reminds me, I gotta get some too. How do you like the ones from McMasterCarr? got a good close up photo of the end where you screw on the fitting?

Mike...

Oh, fwiw...

Image

and

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PostPosted: Sat Jul 18, 2009 9:08 pm
by bbarry
Jiminsav wrote: your puny 160 pounds is fluff to a 120 lbs strut....
girly man. :lol:


:lol: I'm working on that beer gut. I'm on a strict regimen of 12 ounce curls.

Brad

Re: Super-duper gas struts!

PostPosted: Sat Jul 18, 2009 9:11 pm
by bbarry
mikeschn wrote:How do you like the ones from McMasterCarr? got a good close up photo of the end where you screw on the fitting?



They seem well-made at first inspection. I'll get a picture for you soon. I ordered them with ball fittings pre-installed. They were the same price as the spring with no fitting.

Brad

PostPosted: Sun Jul 19, 2009 7:10 am
by bbarry
Thanks for your help guys! I'll go ahead and install them and see how it goes!

Mike, here's a couple closeups of the spring. Like I said, the fittings were installed already. $14 each from McMaster.

Image
Image
Image

Brad

PostPosted: Sun Jul 19, 2009 7:18 am
by mikeschn
I like them...

Is that the model number, the C16-24215?

Mike...

PostPosted: Sun Jul 19, 2009 7:31 am
by bbarry
mikeschn wrote:I like them...

Is that the model number, the C16-24215?

Mike...


I would assume so. The McMaster part number is 4138T587 which they describe as GAS SPRING WITH BALL−JOINT END FITTING, 120 LB
FORCE, 20.12" EXTENDED LENGTH, 8.27" STROKE.

Brad

PostPosted: Sun Jul 19, 2009 10:51 am
by Jiminsav
the problem is, thats the wrong end for what you want to do. you need a end like these.
Image
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Image

PostPosted: Sun Jul 19, 2009 1:02 pm
by bbarry
Jiminsav wrote:the problem is, thats the wrong end for what you want to do. you need a end like these.
Image
Image
Image


Those are just brackets. One can directly thread this fitting into the wall, or use a washer and nut to bolt it to a bracket such as you show.

Brad

PostPosted: Sun Jul 19, 2009 1:07 pm
by starleen2
bbarry wrote:
Jiminsav wrote: your puny 160 pounds is fluff to a 120 lbs strut....
girly man. :lol:


:lol: I'm working on that beer gut. I'm on a strict regimen of 12 ounce curls.

Brad


So - How much pressure does it take to collapse a wooden prop rod?? :roll: :thinking: :lol:

PostPosted: Sun Jul 19, 2009 3:06 pm
by Jiminsav
starleen2 wrote:
bbarry wrote:
Jiminsav wrote: your puny 160 pounds is fluff to a 120 lbs strut....
girly man. :lol:


:lol: I'm working on that beer gut. I'm on a strict regimen of 12 ounce curls.

Brad


So - How much pressure does it take to collapse a wooden prop rod?? :roll: :thinking: :lol:


well, I don't know about that, depends on if you collapse it across someones head or backside..I'd say about a 75 MPH force might do it.. :thinking:

Re: Super-duper gas struts!

PostPosted: Sun Jul 19, 2009 3:44 pm
by planovet
bbarry wrote:Is this normal?


Yep, I thought the same thing. Mine are 150# and I tried and tried to compress them manually. Could not do it. I thought they would be way too stiff. But I went ahead and mounted them and they worked great. I think 120# would have been perfect but I have no complaints with the 150#.

mikeschn wrote:that reminds me, I gotta get some too. How do you like the ones from McMasterCarr? got a good close up photo of the end where you screw on the fitting?


Mike, I got mine from McMaster and I am very satisfied. In fact I bought a pair and had to switch them out for a shorter pair. They took them back with no questions asked. I used a bracket like the one below to mount mine.

Image