Selecting Gas Struts for X2

[SScnc]

Today I was milling a part on my X2 and I normally elevate the stock using 123 blocks or using a vice, however today I didn't do that and this required the head of the X2 to go much lower than usual.

It did fine for a few minutes then the stepper stalled on raising the Z during a rapid and this shattered a $12.00 .050" carbide endmill and pretty much destroyed the stock with a very bad gouge.

The ways on the Z have been lapped and look almost like chrome and I had run a warmup program and oiled all the ways just before this. This hasn't been a problem and I really don't want to adjust the gib since it seems to be fine normally.

So I'd like to add gas struts to the head so I never have to go through this again. I've been trying to decide which struts to order but would like some feedback from someone who has done this and a recommendation on which ones to use. I've been looking at McMaster-Carr but I'm still not sure as I don't know how much the X2 head weighs.

My X2 has a modded CNCfusion Z as seen in the pic below. I know this has been done before and I searched but didn't find what is the best choice.

I appreciate any help,

Steve

[SCzEngrgGroup]

There are two considerations: force and travel. You need to make sure the strut, and the mounting, allow the head to move full travel, so the travel of the strut needs to be equal to, or exceed, the travel of the head. Then, the force needs to be less than the weight of the head. How much less is open to debate. I would suggest making the spring force no more than half the weight of the head. You still need enough weight for the head to settle to the bottom of any backlash on it's own, after being moved down. The weight of the X2 head is quite small - even with the motor I doubt it weighs more than 30-40 pounds.

Regards,
Ray L.

[hoss2006]

LMS sells a kit for this.
The complete kit includes the 35lb air spring to lift the whole 38lb head assembly.
Their normal mounting arrangement wouldn't work with my Z setup and may not with yours either.
I used a pair of the weaker economy air springs on either side.
You have to fab your own mounts.
HOHOHO

[The Blight]

How strong are those economy air springs? Will two of these be more powerfull then the one included in the kit?

"HOHOHO" lol

[jstiltner]

FYI most auto parts stores sell the gas struts also. In my area(Va. USA) they all seem to sell Guden brand and usually have a wide array in stock for you to look though to find one you like. Normally they are not the generic style ones like you would find in mcmaster, etc. But some are easily mountabe, and they usually have a book telling the force output by each one, or bring a scale with you. The website for guden gas springs is here
http://www.guden.com/control-dampers.aspx
They will send you a book if you request or you can download one on their website that lists the force rating of each spring etc.
Happy holidays to all (MERRY CHRISTMAS for me!)

[SScnc]

Thanks everyone, Hoss, I knew I had seen the dual strut setup before and couldn't remember where, I just found it on your site here:

http://www.hossmachine.info/projects_8.html

jstiltner, I didn't think about auto parts stores, good job, I'll go look tomorrow.

MERRY CHRISTMAS for me too !

[Bamber]

There are two considerations: force and travel. You need to make sure the strut, and the mounting, allow the head to move full travel, so the travel of the strut needs to be equal to, or exceed, the travel of the head. Then, the force needs to be less than the weight of the head. How much less is open to debate. I would suggest making the spring force no more than half the weight of the head. You still need enough weight for the head to settle to the bottom of any backlash on it's own, after being moved down. The weight of the X2 head is quite small - even with the motor I doubt it weighs more than 30-40 pounds.

Regards,
Ray L.

The force needs to be GREATER than the weight of the head, as during machining the head is forced UP against the screw, so that the head is held on the correct face of the screw so that there is NO dynamic backlash.

Dave