VSlot - sort of inverted MakerSlide

[ecurtz]

Just saw this new Kickstarter which is similar to MakerSlide but uses channels instead of rails for the wheels to run in. Any engineers want to comment on potential strengths or weaknesses compared to MakerSlide? It looks to me like it might be wobbly but that's not based on any evidence. It should be a little more flexible for designing because you can join the ends without worrying about the rail.

http://www.kickstarter.com/projects/ope ... f=category

[evokanivo]

I think this is going to completely destroy demand for makerslide, which is too bad, since these folks were inspired by makerslide in the first place. Their extrusions fix two problems I've had with makerslide - limited sizes (20x40 only) and the rail overhang getting in the way of various mounting configurations.

One final thought - they could get rid of the groove in the wheels for added strength. I suppose they're using grooved wheels since they're already widely available.

[Seshan]

I like the idea, and it clearly has advantages over makerslide, I just wonder if the removed materiel from the slots would effect the strength when you are mounting something to it.

[vgordin]

I like it. Just bought in.

[orcinus]

I know it's completely irrational, because the contact surface is the same as that on Makerslide and is spread in the axial direction, but i somehow can't shake the feeling this design is somehow less stable. No idea why, might be psychological, due to all those carriage example shots with lots of v-wheels.

[steves]

I get the same feeling but can't pin it down.

If the sides of the v-wheels deflect in under load you'll get some vertical displacement, but I suppose the v-wheels on makerslide could deflect out if equally (over)loaded.

If the VSlot system used a single solid core wheel the two sides of the wheels could not deflect in towards each other.

I wonder what kind of a load it would take for the two sides of the rail to begin to deflect away from each other?

[cvoinescu]

Where VSlot wins big is that the running surfaces are much better protected for shipping. The MakerSlide Vs are very exposed compared to it.

Another advantage is that every slot is a running surface, which makes it more versatile. It's been already mentioned that the MakerSlide Vs get in the way sometimes.

However, my feeling is that VSlot is not as rigid as MakerSlide. The running surfaces are the same size and orientation, but they are connected and braced differently. Without loss of generality, I assume the rail is horizontal and the wheel in question rides on top of it (so it presses down on the rail).

• Aluminum surfaces:
  • MakerSlide: two faces of the V, which is solid, so they can't move relative to each other.
  • VSlot: part of the extrusion "wings", which are less rigidly connected to each other, so they can flex apart and widen the slot.
• Delrin surfaces:
  • MakerSlide: separate halves of the wheel, so they can be pushed apart some.
  • VSlot: with the current design, the V slot in the wheel allows them to be pushed together some. A solid wheel would behave better and may be easier to machine.
• Axial load on the wheel:
  • MakerSlide: bearings twist some, and the Delrin wheel deforms and allows the bearing outer races to move relative to each other, so it's not exactly equivalent to a dual-row bearing.
  • VSlot: bearings twist some, and the Delrin wheel deforms the same as the MakerSlide wheel or more. However, a "filled" wheel (no V slot) may deform less, so it would be a better approximation of a dual-row bearing, giving better ability to withstand axial loads.
• Axial load on the rail: I'd expect to see about the same amount of flex in the horizontal plane. However, in the VSlot, only one side would be pushed outward, opening the slot more and allowing more play. This is especially true at the corners of the profile, which are not braced by multiple webs in the extrusion.
• Radial load on the wheel: about the same for both, although a solid VSlot wheel would fare a little better. However, the MakerSlide wheels can be bolted directly to carriages, with just a washer and no spacers, but the VSlot wheels always need spacers for the carriage to clear the rail. That makes the wheel axles less stiff for the VSlot (much more so if the spacers are plastic, not metal).
• Radial load on the rail:
  • MakerSlide: the V can not bend down easily, as it's braced by the wall of the profile; the V with two neighbouring slots can twist down and out a little (that is, opening the top slot and narrowing the side slot).
  • VSlot: can flex the sides of the slot both down and away from each other; I'd say it has half the resistance of MakerSlide, on average (the two MakerSlide sides aren't the same).

My conclusion is that VSlot is less stiff, but easier to use than MakerSlide. Both will happily co-exist -- it's a gross exaggeration to say that VSlot will "completely destroy demand" for MakerSlide.

[orcinus]

[*]Axial load on the rail: I'd expect to see about the same amount of flex in the horizontal plane. However, in the VSlot, only one side would be pushed outward, opening the slot more and allowing more play. This is especially true at the corners of the profile, which are not braced by multiple webs in the extrusion.

I think this is where most of my "gut-feeling" of instability was coming from.

[vgordin]

I agree re: the deflection concerns above. the big win here for vslot is that it is available in 60 and 80mm flavors, making a large format ord much easier to put together (and why I backed).

[kram242]

Hello guys,
Mark and Trish of OpenBuilds here. We wanted to thank you guys for the KickStarter support and to Bart for the inspiration we gained though his MakerSlide Project. We have gathered together a few of the great projects that have influenced the direction of V-Slot and posted them to the KickStarter campaign to say thank you and to share these projects with others that may be interested.
Its been an exciting few days and the overwhelming support by the community through emails and backer support has been a huge uplifting experience for us!
Thank you so much
Mark and Trish
OpenBuilds Team