Metal way covers

Thought I'd share my solution to way covers on my benchtop mill. Most of the suggestions I found were for leather, rubber, or accordion way covers, which all seemed suboptimal to me- they collect chips, or burn, or melt, or get in the way of leadscrews. I wanted basically the fancy sliding metal covers you see on commercial machines, but at a hobby-friendly size and budget. Especially something that didn't interfere with the already-limited travels on the machine. I came up with 2 different designs- one for the Z axis, one for Y (between the table and column). The attached pictures show them installed on my mill as a good overview.

For the Z axis, what I ended up with is a set of nesting panels, with the ends bent at 135 degrees so they dovetail together- so they're more or less constrained to only slide in one axis. This ends up being quite thin- just the thickness of however many sliding panels you need. You can see this in the PNG showing just two such nested panels.

The catch then is you need some way to make them extend and not just slide all the way past each other. The trick is that they edges are bent with a constant radius, not a radius that shrinks as you go further down the nested parts. That means there's clearance in the corners, which you can take advantage of. Hopefully the attached CAD files make it clear, but if you bend a tab outwards at the top of each panel, and inwards at the bottom of each plate, when they nest, each panel can almost slide through the next one further out- until the tabs bent outward at the top of the inner panel catch on the tabs bent inwards on the bottom of the outer panel. I unfortunately don't seem to have a 3D model of this, so see the second PNG with the added lines showing tabs. Hopefully you can imagine the red panel sliding down until it catches on the green panel's tabs.

The very top and bottom pieces are the same, except with whatever additional pieces you need to attach them to the Z carriage/spindle and column. You can see what I did in the picture below + CAD files, but it's machine-specific. The two cap screws you see at the bottom are there to stop the panels from falling off the bottom and interfering with the Y axis.

For what it's worth, all of this was designed around SendCutSend's capabilities- their bending method leaves a constant radius, which is perfect for this. The 4 panels for my mill were $114, made out of 304 stainless. Amazing, IMO. The .zip contains the STEP and FreeCAD drawings for my machine's Z way covers. You'd need to adjust sizes/attachment to make it fit a different mill.

(will put Y axis details in next post)

For the Y axis, I pretty much stole the idea of the Gordillo Bellows: dynatect.com/product/protective-covers/bellows/gordillo/

The problem with those is they don't compress enough- I have very little clearance between the mill column and the table when at the limits of travel, and didn't want to lose any travel. So I made a simpler version. This is just a bunch of L-shaped pieces with accordion material glued between them- see previous post for how it looks in real life, CAD drawings attached.

There are two "tricks" to this- the first is to make sure that the plates overlap some amount when however many folds of accordion material is pulled taught. This helps make sure chips don't get under the plates and stuck between them (though the good news is that accordion material will still stop them from falling on your ways even if that does happen). You can adjust the size of the accordion material, the number of folds, and the geometry of the plates to get whatever extension/collapsed size/ratio you want.

The other "trick" is that this will collapse under its own weight- you need some kind of support. I just 3D printed some brackets to hold a couple 1/4" rods that the covers kinda ride on. The geometry was all eyeballed, so I'm not posting any files for that. You can see it in action in the pictures attached to the previous post.

You obviously also need some way to attach one end to your Y carriage and one to the mill column- that's machine-dependent. On my machine, I just used a chunk of C channel bolted to the column, and directly bolted the opposite end's plate to the carriage. The C channel is glued to accordion material and permanently attached to the L-shaped plate assembly.

Once again, these parts were made at SendCutSend out of 304 stainless. I bought 8 of them (turns out I only needed 7), and cost me $53. Ordering multiples of a single part gets you a discount. The 5' chunk of accordion material I think was ~$20, the glue was... I dunno. So call it $100 for metal way covers for the Y axis. The assembly was nothing special- scuff the metal surfaces, clean with acetone, then put glue/accordion material in there and clamp until dry. The glue I used was Loctite Extreme Glue, but I suspect any number of adhesives would be fine.

Files for the plates attached, though you may want to scale for your machine.

So far they've held up to stainless and aluminum chips, and kept the leadscrews/rails clean. Hopefully somebody finds this useful!

"The 5' chunk of accordion material I think was ~$20,"
Where can we buy it?

Take your pick- Amazon, eBay, Ali Express- just search for "accordion way cover", "accordion bellow", etc. and you'll find it. Random examples I'm not specifically suggesting:

www.amazon.com/uxcell-Machine-Rubber-Acc...Pleats/dp/B0087ZCY86
www.ebay.com/itm/315803295816