Results after computing some SecSavr concerns:

• Spend the £17 extra to change 2x27mm cylindrical tubes into 1x40mm box tube that is 1m long
  • I can get them cut to size, but unlike tubes, they are bought in fixed sizes.
    • If I want a length more than 1m, I'd have to get like 1.5m and ask them to cut it down
  • Also, 1m of 40mm costs like 50% more than 2m of 27mm
  • There are benefits though.
    • For the low low price of £17 total (as in, for both gantries), I save 1.54kg on each Z axis, translating into 752g saved on each Y axis.
    • There's more material further away from the axis lines where it counts, so I assume that the second moment of area would be larger. 
      • The diagonal is 56.56mm, which is the equivalent of having the horizontal and vertical orientations of the 2 27mm tubes at the same time.
    • Easier to build as there's just 1 tube instread of 2
    • The X and Y sliders should be smaller, meaning that the cantilever for the Slime's center of mass is shorter, further reducing vibrations.
    • I was thinking that using 4 beams for the "hulkbuster" equivalent of the Slime (for metal CNCing) was kind of excessive. 2 square beams is probs fine.
    • The bearings have more contact area.
• Look into ways to get cut (and bent?) sheet metal cheaply
  • https://hackaday.com/2020/03/10/forming-sheet-metal-parts-with-3d-printed-dies/
  • I want to look into other manufacturing methods that could still be done easily but would produce a part better than a 3D printer.
  • I was thinking of making a vice that clamped onto the bicycle racks I was walking in a circle next to, then printing equipment to do the folds or cut tubing
    •  (I don't have a workshop/garage)
• Find a 24V motor that will do 10K RPM
  • https://hackaday.com/2014/08/03/brushless-dc-motor-used-for-high-speed-cnc-spindle/
  • I'm thinking that there might be a different Slime variation that has the spindle motor instead of the Nema17 motor, or perhaps the spindle motor is a tool that also has another degaussing electromagnet to clip on different bits as tools.
    • Motors are expensive and I'd rather look into a system that allows me to change drill bits without having to buy a motor (and ESC) for each one.

Concerns I still have:

• Should I now use 42.4mm tube for the Y sliders for higher stiffness?
  • Positive:
    • Stiffer, possibly increasing the usable acceleration even though peak acceleration is lower.
    • Same as Z axis and frame, so would look more consistent and be easier to source
  • Negative:
    • Would negate the weight savings of using 40mm box tube for the X axis
    • Y Slider increases by 13mm in height, which could mean that the effective Z height reduces by the same amount.
• Should I look into making the Slime body out of sheet metal, metal trusses or continue with the fully printed idea?
  • I'm thinking of fully printed as that would still acheive a minimum viable product.
• The procedure required to swap the Slime for the beefier equivalent, and if the beefier equivalent would even be necessary for the materials I want to cut.
  • An answer to the latter would require a MVP anyway, so I'm going to assume it isn't until proven otherwise.
• How will the bed be attached to the rest of the frame?
• Is the Mozzle heatsink enough to cool the cold end side of the SecSavr Slight, and if so, can it be modified to thread 5mm into the heater block?