[Dylwad]

Anyone have any pictures or info on retrofitting the fineline/cncrp designs to use 15 and 20 mm linear rails without a complete redesign?

I have Iko 15 mm rails for the x and z, 20 mm thk's on the way for the y. Machine is loosely based on the 2x3 fineline machine.

Thanks!

Dylan

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[roundrocktom]

Dylan,

Photo's would really help. One photo of current design, second showing the rails you plan on using.

I'm really not sure what you currently have, always remember the first part of the design is 20% or the work, getting everything up and running with a new design is 80% of the work.

Having said that, I suspect a simple 1/4" steel adapter plate will to the trick
to allow the linear bearings to be bolted to the bottom and the gantry to be bolted to the top.

My Gantry has a hidden nut it's design, in hind sight I should have changed that to a different design to tighten the nut snug.

In the process of adjusting the gantry, I had removed the gantry stops to reach the hidden nut better. My gantry slipped back, and had I not moved as quick as I did I would have 300 pound gantry between my finger and a the edge of a 1/4" steel plate. Ya, not good.

[Dylwad]

I'll have to take some pictures when I get the 20 mm rails in. I just figured someone had done it before and was looking for inspiration or something clever to add to my thought process. Sucks to overhaul a good working machine, but it's time to get rid of the skate bearing setup

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[roundrocktom]

I'll have to take some pictures when I get the 20 mm rails in. I just figured someone had done it before and was looking for inspiration or something clever to add to my thought process. Sucks to overhaul a good working machine, but it's time to get rid of the skate bearing setup

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Just think of it as being "major maintenance".

I do wonder how long the skate bearings will hold up on my machine. It has a pretty good "song" when running, so easy to hear something amiss.

I'll run my machine for a while, but already have a few idea's on lowering the gantry and improving rigidity. Just need more hours on it before doing anything else!

[harryn]

Surprisingly, even fairly large profile rails will follow the shape they are mounted on. The ideal situation is to mount them on a 1/4 or 1/2 in thick ground plate, and then mount this on your 8020.

THK and similar sites refer to milling a straight edge profile into the steel plate so that the mounting is straight on one side, and then indicating off for the other.

Depending on which version / preload you purchased, the tolerance for misalignment can be pretty small.

No doubt, this approach is a significant upgrade from skate bearing setups though.

[Dylwad]

That is kind of what I was thinking I would have to do, not too keen on bolting them straight to the 80/20. I will have around .40" of space to use for mounting plates on the rail and blocks unless I redesign and widen the gantry, which will actually be pretty easy and cheap to do, gotta love 80/20!

Here are the rails I purchased SR20W2UU 1480mm THK Used LM Guide Linear Bearing 2RAILS 4BLOCKS CNC Route | eBay Not a bad deal?

I have 15mm IKO rails and blocks for the X and Z standing by, and a ground C3 NSK ballscrew assembly for the Z

Dylan

[Dylwad]

Heres what I'm working with now.

[Dylwad]

Rails came today, 48 hours door to door from Korea, not bad!

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[RicknBeachcrest]

I sandwiched a piece of 1/8" alum bar between my rails and 8020. I made my own t-nuts.

Here is a link to the page that shows a little more detail
http://www.cnczone.com/forums/1141165-post123.html

Rick

PS.
You might check out SteveSpo's build thread. He mounted is rails on the side of the 8020

http://www.cnczone.com/forums/cnc_wo..._steppers.html

[Dylwad]

Thanks Rick,

I remember Steves build, even posted in his thread a few times

I have around .4" of space to work with between the machine sides and inside of the gantry after the rails and blocks are in place. I was thinking of having some .25" 1018 steel water jet cut to cap the sides bolted to the 80/20, with 6mm holes tapped for mounting the rails, and using the same .25 plate with pockets machined for the blocks that bolt to the inside of the gantry frame. I may have some thinner stock cut to bolt under the rails to act as a shelf for alignment. I would love to have a pocket machined for the rails but don't think that would be a cheap job. I have a hook up in water jet cutting, and know someone who could machine the block interface plates.

My machine has a slight sag in the center, about .015" due to the 5 foot long 1530, so mounting the rails to the t slots probably isn't the best idea.

It's a major job no matter how you look at it, and the machine is making my living so I need as little downtime as possible.

Im not great with 3D cad, but I think this would be a good exercise to draw up in Rhino

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