Ever wanted a workspace that's reconfigurable?

Do you want to move equipment/machinery safely and easily into unused spaces, then move it back so it's in arms reach or in a comfortable position?

Imagine you have a workbench/office desk/sewing table, and several devices on it. Now, assume you can't really move your chair around that much, and so you need a reconfigurable desktop workspace.

Or perhaps you have a 1 car garage, and you'd like to slide your mitre saw sideways so you can cut longer lengths of timber, but then put it back for easy storage.

Sound interesting?

Now, Gridfinity is all good and well, but it's not going to help you switch between a sewing machine and overlocker/serger when your sitting position is fixed. Neither is it going to help you move a lab power supply, isolating transformer, oscilloscope, and signal generator out of the way when space is an issue. Gridfinity can't help you with a mitre saw either.

So here's a low cost, 3D printed linear rail system (fit only for horizontal, table top applications) for making a linear "lazy Susan" (who was Susan anyway, and can't we call her something other than lazy? I'm sure she has feelings.. but I don't know how else to describe this function).

Now this set comes in three different 3D printable parts:

1. The linear rail sections. (number depends on the desired length)
2. The carriage block (print 4 per carriage)
3. The breaking bracket. (one per carriage)

You'll also need:

1. 16-18mm (say, 3/4") thick board roughly the size of your largest device (well, it's base at least). The reason I say largest, as it's safer to build an oversized "carriage" for a smaller device, than it is to build a smaller carriage for a larger device.

2. A plank of wood to screw your rails to. The dimensions depend on the length/width you need the rails to be (build the carriages first to ensure rail alignment).

BUILDING THE CARRIAGES:

Once you've got a plank of wood that your device can sit on safely. You'll need four (4) carriage blocks per "trolley/carriage" you intend to have. So if you have a sewing machine and an overlocker/serger (two carriages) then you'll need eight (8) carriage blocks for both carriages. We've toyed with the idea of having both machines on one big carriage.. but my partner found that being able to separate them was extremely important when pushing large amounts of fabric through. I'm sure there are many tools and test equipment where breathing room is a good idea too. :~)

To install the bearings, you'll need sixteen (16) 608ZZ bearing (easily obtainable online/eBay/etc) per carriage. So again you need thirty two (32) for both a sewing machine trolley, and independently movable serger/overlocker trolley.

Naturally, you need the same number (32) M8 machine screws/bolts (20mm or 3/4" long) to connect the bearings into the pre printed M8 threaded holes of both carriages.

MOUNTING THE CARRIAGE BLOCKS TO YOUR CARRIAGES:

You'll need pieces of wood (large enough to support your equipment base that you'll put on top. I highly recommend keeping the front-back dimension consistent across ALL carriages, so the rail width is consistent and easy to install. I ALSO highly recommend placing the carriage blocks in the corners of your pieces of wood to avoid tipping hazards.

Built your carriages so they're basically identical? Now it's time to "lay down that track".

BUILDING THE TRACK:

The inverted V-shaped linear rails are self-aligning, like a train track, you'll need two parallel rails, and each section is 200mm (20cm) long to suit a common printing build volume.

So if you want your track to be (say) 1.2m long you'll need (6x 200mm) sections to get that length, then double that so you have enough for both rails.

I recommend using a plain (flat) board like MDF sheet to screw them to so you don't have to screw the rails into your shiny table. You can easily move the whole linear rail assembly if you ever need to. Remember, you need the board thick enough to handle the screws you use. Or conversely, you need screws short enough to NOT go through your wood and scratch your desk. It's pretty hard to get wood screws smaller than 12mm (1/2" or so) so please keep this in mind. The head has to be wider than 4mm or 5/16" at a bare minimum to stop the head going all the way through. In fact, if you can find flatter "button head" screws rather than countersunk models, it'll be less likely to "drive through". If you use countersunk headed screws, then I suggest installing them by hand after pre-drilling (preferably with a self-centring or "Vix" bit), to prevent damage.

LAY ONE TRACK USING A STRAIGHT EDGE TO ENSURE STRAIGHTNESS & SCREW IT DOWN, THEN USE THE CARRIAGE TO LAY THE SECOND RAIL IN THE RIGHT PLACE:

It might seem weird to build the track AFTER the train.. but we're actually going to use the carriages and V-shaped bearing systems we've built to align the rails. But we lay a single contiguous track down first, screw it to a piece of thin-ish (1/2" or 10mm MDF) with little M4 screws of appropriate length, then once we've done the first, we sit the second rail (about) the right distance from the first, then place the carriage on top so the rail is moved into the right position. Screw that down around the carriage, and work it along until you're satisfied. It's probably a good idea to try screwing the opposite ends of each rail section down, and if any adjustment needs to be made, you can easily do that with the unused holes and a self-centering bit.

ADDING BRAKING:

Well.. braking is perhaps overstating it a little. It is simply screwed into the edge of your carriage wood. I've added slotted holes so you can align the vertical hole (using another M8 bolt.. or something slightly smaller for easier use) to drop through the braking bracket and stick into the various holes in the rail.

THE BUCK STOPS... WHERE?.... BEWARE SLOPED TRACKS

Unfortunately, at this point there's nothing to stop the carriage(s) from rolling off one end of the rail or the other. I chose to glue a couple of scrap pieces of wood to the rail board to prevent this... but you could also leave a protruding bolt in the end holes of the rail to stop further travel. Or 3D print a stop block too. It's up to you.

TO CONCLUDE:

It works well for my partner's sewing table. I hope it's useful to you too.

Anyway, I'd love to see how you use this rail system, and if you have any constructive feedback, please let me know!

Be safe, have fun, and make something fun!
Ham.