Laser cover lift strut replacement problem

[Frederic Gagnon]

I need help for yet another problem... I am trying to replace the gas lift struts on my 1290 laser engraver because the cover is too heavy to be lift repeateadly with the ones installed by the manufacturer.

I purchased a pair of car hood replacement struts. When I received them, strangely, I was not able at all to compress them by hand. I read somewhere that this was normal. So I installed the first one on the left side and tried to close it, but it is really stuck! The cover doesnt close now.

Anyone know what I am doing wrong ??
thanks

[Rich Harman]

Those struts come in all manner of sizes and lift capacities. It could be that the one you have is too strong. Do you know how much force the strut is rated for?

[Richard Rumancik]

I suspect that you have purchased a gas spring with a load rating much different than the original gas spring. Gas springs are made in a variety of force levels, from less than 10 lbs to over 200 lbs. If you just picked something off the shelf not knowing the force rating I am afraid you have a spring that just won't work. I would suggest that you measure the old ones (you can use a bathroom scale to determine the force at maximum compression) and then estimate how much more that you will need. If you buy automotive gas springs they often will not say the load rating as it is designed for a single intended use.

You might be able to find something at an auto supply store but it will be hit-and-miss trying to match them up. If they are packaged gas springs the retailer probably won't want you to experiment in the store. You probably have to order online from a gas spring supplier by specifications. Offhand I don't know who to recommend in Canada but here is an example supplier and how they spec the product.

http://www.guden.com/ItemDisplay/6mm-Chrome-Rod-15mm-Tube

You want to match as many parameters as possible including the type of end fittings. If you hunt around online you might find a suitable supplier.

[Mike Null]

+1 for Guden

[Frederic Gagnon]

They are actualy for lifting a PT Cruiser tail gate. They might be overly strong, but I am sure I should be able to compress them a bit... maybe add some weight on the front of the door if needed?

[Bill George]

They are actualy for lifting a PT Cruiser tail gate. They might be overly strong, but I am sure I should be able to compress them a bit... maybe add some weight on the front of the door if needed?
Send them back for credit and get the right ones.

[Matt McCoy]

Nice website! I enjoyed checking out your work.

I think you might be too close to the problem. From my perspective, it looks like you are unable to compress the springs and close the lid. I don't think adding more weight to the lid is the easiest, cheapest, fastest, or the most elegant solution. I would just replace the gas spring(s) with one that is suited for the load.

[Frederic Gagnon]

Nice website! I enjoyed checking out your work.



Well thank you Sir!

[Jerome Stanek]

try a truck cap dealer the rear glass is closer to the weight

[Frederic Gagnon]

Well I found out the struts I got are rated 161lbs each. That would expline why I can't compress them by hand. (can you lift up your wife with a single hand ? same thing...)

[Ray Scott]

Frederic,

You need to look at the label on the original strut. That label should say the Newtons force that is applied while the gas-strut is properly pressurized. My 1290 laser has a 450 Newton force rating.

You our also need to know the 2 lengths that are appropriate for the gas-strut. How long is it while open? How long is it when compressed?

the next feature to look at is the mounting method. Make sure that the one you buy has the eye-bolt or ball-joint as appropriate to your laser machine.

Many laser machine manufacturers use interchangeable parts, but check to make sure you get what you need.

....

[Scott Shepherd]

....
I have been questioned by my company about, "Why are you giving away tech support for free?"
....
I have been warned by sawmillcreek moderators/administrators that "Ray has a financial interest in participating with other people here." Solving laser problems could lead people to buying parts they need from my company. So... Please buy stuff from wherever you want.

Ray, let's be clear about something. The vast majority of people on this forum are here because we enjoy helping others and sharing our knowledge. It's shared for free, with no obligation, no strings attached. None of us get to sell our wares on here, and none of us do. We come here, we see someone that needs help, we help them. It's really that simple. You aren't being treated any differently than the 1000's of other members on this forum. If you want to advertise your company, there is a mechanism for you to do that. You can become a "Friend of the Creek", which allows you to list your website in that area of the site, or you can advertise and have banner ads for your company displayed all over this site. Those are the same options we ALL have. If you don't believe you should be helping people for the good of helping people, and you think every ounce of help you give here should be compensated back to you, then I think you're going to be disappointed.

If you want to go that route, then maybe some people on here should be paid for solving problems with your machines. There are countless posts by Rabbit owners asking for help here, and they were helped just like everyone else. No one asked for compensation to help them. They don't work for Rabbit, yet they stepped in and helped a user in need. Sure, the user could have called you, but more often than not, problems arise after hours, and that's where this forum shines.

You aren't being singled out, you're being treated just like everyone else, so please stop the non sense about you being treated differently because you own a laser company. It's just not true.

[Mike Null]

Ray

I take issue with your attitude. SMC doesn't owe you anything. You are free to post as you wish within the terms and conditions of SMC.

You get quite a lot of support from a few of your Rabbit owners. It seems to me you would be grateful for that and glad to offer solutions for problems that arise as that can only help your reputation and your company.

[Frederic Gagnon]

I should have mentioned beforehand that I couldn't figure out the specs of the current struts on the machine. There is a label in chinese with no helpful numbers. Plus the website shown on it doesn't work. The photo doesnt show well the white second label but there is only a handwritten chinese character and no numbers, brobably for QC.
303828
My goal was to use a stronger strut than the original one, because it is not appropriate for this hood size in my opinion. I am willing to drill new holes if the new length is not right.

I found some online tools to calculate correct force to use. Will do some maths..
If all fails, also considering using an eyebolt, rope and pulleys, and a big rock to help lift the cover.

[Kevin Braat]

Frederic,

Disclaimer - I work for a gas spring manufacturer as one of their engineers.

As others have stated, you need the extended length, compressed length and the output force. If the current cylinders are not completely shot, brace them upright and add a load until they start to compress. That will give you a minimum starting point for what is needed for the new load.

McMaster-Carr sells a variety of struts. I would expect they have a company in Canada that is comparable.

If you wanted, the end fittings could be reused in most cases. Superglue or loctite is used to secure the threads normally onto an M6 or M8 end of the cylinder. Pray it is not the M7 threaded ends that are almost impossible to find parts to mate with. This would let you purchase any appropriate cylinder without end fittings and just reuse what you have, somewhat simplifying the process.


I should have mentioned beforehand that I couldn't figure out the specs of the current struts on the machine. There is a label in chinese with no helpful numbers. Plus the website shown on it doesn't work. The photo doesnt show well the white second label but there is only a handwritten chinese character and no numbers, brobably for QC.
303828
My goal was to use a stronger strut than the original one, because it is not appropriate for this hood size in my opinion. I am willing to drill new holes if the new length is not right.

I found some online tools to calculate correct force to use. Will do some maths..
If all fails, also considering using an eyebolt, rope and pulleys, and a big rock to help lift the cover.

[Rich Harman]

Something else to consider - if your laser is like mine, when the lid is closed the strut, because of the geometry contributes no force at all towards lifting the cover. I could replace it with a gas spring ten times as strong but the lid would be just as hard to initially open.

The strength of the struts on my machine is more than sufficient for holding the lid open but they got the geometry wrong so it makes it hard to open with one hand. At some point I will relocate the attachment point of the struts so that it makes it easier to open.

[Chris Corwin]

Instead of using 2 struts, could you use just 1 and reduces the pressure need to close the lid by 1/2? Or is that still too much?

[Kevin Braat]

You would probably run into issues with racking the large lid. I would place one on each side.


Instead of using 2 struts, could you use just 1 and reduces the pressure need to close the lid by 1/2? Or is that still too much?

[Frederic Gagnon]

Exactly, the cover is so big it warps easily. I installed 2 extra handles in the front, on the left and right side, but we can't open it using just one of these handles, unfortunately. The problem came when I load a full 4x8' sheet thru the front opening, the center handle is hard to reach, and the body motion required to open the cover in this situation is guaranteed to hurt your back... but that's another issue!


You would probably run into issues with racking the large lid. I would place one on each side.