TLDR: refinement & simplification of my stiffened linear rail design - only adds 1kg rather than 2, uses the original linear bearings, uses a variation of my Turtle Clamps, fewer bits to print and adds a few expansion options, uses 25mm rather than 30mm bolts in most places. Still retains the significant stiffness boost over the stock Maslow4.
My linear rail conversion (I linear rails-ed my Maslow) did what I wanted - upped the stiffness a lot. But it was at a cost of quite a bit of weight gain, and complexity of assembly. I’ve spent a bit of time refining that as I knew it was overkill really, and there was a lot of scope for simplifying and saving weight.
The first thing I wanted to fix was the clamps - hence the Turtle Clamps (Turtle Clamp (non-split clamp design)). But further than that, I wanted to see if I could refine it a bit from over-engineered back to just…engineered. Although I like the linear rails, the linear bearings a stock Maslow comes with are sufficient for a router based CNC and the loads we’re likely to put on it. In time I aim to get a fat spindle going, and I suspect I’ll need the linear rails at that point, but for now this gives me everything I want for a trim-router based Maslow.
Although you can use three bits of 2040 with printed brackets:
I don’t think this is necessary so i’ve just been using it with a single 2020 cross piece and some alloy brackets, which saves a few hundred grams.
Refinements and comments
I can do a step by step build guide if needed, but largely it will be the same steps as the linear rail one . So I’ll just do a list of points about this:
- The 2040-to-sled printed brackets are now single-piece and sit lower. Which means…
- It uses 25mm bolts where the liner rail version used 30mm (they seem easier to get hold of).
- Although in the photos you can see I’ve used 300mm rods for the linear bearings, the stock ~200mm ones work fine.
- The rod holders are design so the 2 through-bolts can be used to set the exact spacing when assembling, but then the brackets can be slid out and off via the t-nuts for maintenance without having to reset the spacing each time.
- Similarly, the stock posts with the bearings are used (i’ll include variations of my own design in 1.1)
- With the Turtle clamp the router-collet-to-base-gap now sits at ~8mm.
- Maintenance - one aim was a bit of design-for-maintenance. It’s still a bit of a faff to get an arm out for example, but I have put some though into several of the common things I do.
- Router out - as with the linear rail design, using 350mm 2040 sides means removing the router is a case of:
- Make sure the cage is at the lowest Z-travel.
- Unplug the control board.
- Loosen the Turtle clamps.
- Slide the router up and out.
- Note the Turtle clamps have cutouts for the button pusher anyway.
- Taking the whole cage assembly out is a case of:
- Loosen the side t-nuts of the cross-piece, and slide off.
- Loosen the t-nuts on the rod holders, and the rod-clamp-bolt
- Slide the rod-holders up and out.
- Do Z-travel up until the cage is free and lift out.
- When re-assembling, you shouldn’t need to re-adjust and spacing this way, just tighten the loose nuts.
- And to just remove one arm it’s a case of:
- Router out as above.
- Raise the cage / Z-travel to the top but not off the nut.
- Unscrew either the top or bottom post depending which arm it is you’re removing.
- Slide the arm out - watch out as you often get both the arms on that side slide out and you need to remember the ordering.
- As you can see, the aim is that nothing that needs spacing-adjusting during assembly should need loosening for general maintenance.
- Router out - as with the linear rail design, using 350mm 2040 sides means removing the router is a case of:
Files to follow shortly once I’ve done a PR for them.
