[TC28] Metal Lathe

[2GodBDGlory]

I was a little hesitant to join this contest, given that I'm deep into another project at the moment, but Eurobricks contests are too good to pass up!

The plan is to build a model of a lathe for machining metal, something like this:

It's not something I've built anything like before, and there seems to be a lot of room for interesting gearing. The rough plan is to include:

• 6+ gears to choose from for spindle drive
• Universal chuck
• Sliding, adjustable tailstock
• Manual (crank), motorized (rack gear), and motorized thread-cutting (worm gear drive) carriage movement
• Manual crosslide
• Manual top slide

It would be definitely cool to make it actually capable of machining something, but I don't think I have anything of softness so extreme that I could machine it with a Lego cutting element. It might be worth trying to mount a razor blade in a 3D printed part, but that's obviously outside the Lego-only stipulations for the contest rules, so that wouldn't be a part of my entry.

I really have very little experience with lathes, being limited to playing with them for a few days in high school Machine Shop, and then watching a guy for maybe half an hour last summer, so hopefully I can pick up a good enough understanding of them to make a quality model.

Anyways, this is the progress I've made so far, which is pretty much limited to just the chuck. It's a 4-jaw universal chuck, for gripping objects of various shapes, and like a real-world one, each jaw is manually adjusted using a screw. This requires some care to ensure that the material you're machining is properly lined up, but allows for gripping non-round shapes easily. I chose it, mainly because it seemed like the simplest one to accurately translate into Lego at a reasonable scale:

The sliding jaws of the chuck are actuated using sliding worm gears, controlled by the yellow half-bushes on the outside of the ring. These worm gears engage with locked 8T gears on the main frame. To prevent the worm gear from being crooked, as they would be if both 8T gears were at right angles, one gear in each pair is locked in place via its axle, while the other one is technically free to rotate, except that a beam on its other side takes some of the space between its teeth, locking it in a position where a gap is meshing with the worm gear, rather than a tooth.

I look forward to continuing this model!

[Davidz90]

Another great idea, so exciting! Nice jaws structure.

Indeed, finding something that can be machined with Lego could be challenging. Styrofoam? Butter? 

[howitzer]

Hey, you stole my idea!  I'm also in the process of designing a metal lathe for this contest, but didn't post anything yet because I'm waiting for a few crucial parts to arrive in mail.

Anyway, my plan is in larger scale and custom main bearing so it'll be interesting to compare your approach and mine.

[2GodBDGlory]

7 hours ago, Davidz90 said:

Another great idea, so exciting! Nice jaws structure.

Indeed, finding something that can be machined with Lego could be challenging. Styrofoam? Butter? 

Thanks! Probably some kind of Styrofoam type thing would work (I think I've seen it on other Lego machining projects), but I don't really have any in a suitable shape, and I don't especially want to buy any.

 

5 hours ago, howitzer said:

Hey, you stole my idea!  I'm also in the process of designing a metal lathe for this contest, but didn't post anything yet because I'm waiting for a few crucial parts to arrive in mail.

Anyway, my plan is in larger scale and custom main bearing so it'll be interesting to compare your approach and mine.

Sorry about that! There's definitely room for two lathes with different approaches, though