What would be the downside to this?

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estes1953
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What would be the downside to this?

Post by estes1953 » Sun Mar 13, 2016 3:28 pm

Could you use these, mounted top and bottom to a big piece of hardwood to make a long rail for an expansion?

It would of course require a new table and the Y axis rails raised up from it with something narrower.

I'm new to this so will not be insulted if you explain why this is a stupid idea.

Thanx, Alan
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twforeman
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Re: What would be the downside to this?

Post by twforeman » Sun Mar 13, 2016 3:35 pm

You could, though wood expands and contracts with the weather.

Most people mount them to aluminum extrusions.
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JuKu
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Re: What would be the downside to this?

Post by JuKu » Mon Mar 14, 2016 8:05 am

> wood expands and contracts with the weather.

Which will create tensions. then, depending on the relative stiffness of the rail and the wood, you might get deflections ro just tension. I'm guessing that for a machine stored inside, that wouldn't be an issue (furniture doesn't usually crack). Use dry wood, i.e. "furniture grade", "oven dried" or similar, not just something out of lumberyard.

WillAdams
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Re: What would be the downside to this?

Post by WillAdams » Mon Mar 14, 2016 10:40 am

Why not use one of the steel 2x4 extrusions which are often used in the stead of lumber?
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cvoinescu
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Re: What would be the downside to this?

Post by cvoinescu » Mon Mar 14, 2016 9:59 pm

WillAdams wrote:Why not use one of the steel 2x4 extrusions which are often used in the stead of lumber?
The stuff that's used for drywall? The ones I've seen were all fairly thin sheet metal (formed, not extruded, and with lots of cut-outs), and quite flimsy until sandwiched between two sheets of drywall. Being C-shaped, not a box, they had hardly any resistance to twisting.
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dave_the_nerd
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Re: What would be the downside to this?

Post by dave_the_nerd » Wed Mar 30, 2016 9:32 pm

cvoinescu wrote:
WillAdams wrote:Why not use one of the steel 2x4 extrusions which are often used in the stead of lumber?
The stuff that's used for drywall? The ones I've seen were all fairly thin sheet metal (formed, not extruded, and with lots of cut-outs), and quite flimsy until sandwiched between two sheets of drywall. Being C-shaped, not a box, they had hardly any resistance to twisting.
Yeah.

When I've seen them go in, I've noticed the builders will usually put them back to back, rivet them together every 20cm or so, and then double them up across the top too (and rivet those.) The net result is relatively stiff, but they aren't very space efficient. And you're using twice as many as you would use studs. (But they're cheaper, so...)

Not how I'd want to do a shapeoko frame. :? :shock:
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Re: What would be the downside to this?

Post by cvoinescu » Thu Mar 31, 2016 9:43 pm

dave_the_nerd wrote:When I've seen them go in, I've noticed the builders will usually put them back to back, rivet them together every 20cm or so, and then double them up across the top too (and rivet those.)
I'm not sure that's worth the effort. They stiffen considerably when the drywall is screwed onto them -- they can't twist or flex sideways anymore, so they become quite rigid in the direction that matters. But, on their own, they're barely stiffer than cooked fettuccine.
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AnonymousPerson
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Re: What would be the downside to this?

Post by AnonymousPerson » Fri Apr 01, 2016 1:49 am

In a similar vein to the original post, these look interesting, and not super expensive:

http://www.damencnc.com/en/components/m ... near-guide

Ordered some short ones earlier today (single rail, and the pillow blocks) to get a better idea of them "hands on".

For X & Y frame to mount it on, I'm thinking this:

https://www.themetalstore.co.uk/product ... ection-3mm
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JuKu
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Re: What would be the downside to this?

Post by JuKu » Fri Apr 01, 2016 10:32 am

AnonymousPerson wrote:Ordered some short ones earlier today (single rail, and the pillow blocks) to get a better idea of them "hands on".
Please report back with your findings!

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Re: What would be the downside to this?

Post by AnonymousPerson » Fri Apr 01, 2016 10:58 am

JuKu wrote:Please report back with your findings!
Will do. :)
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