Worm gear

[Parazels]

12 hours ago, ukbajadave said:

Mmm, worm gear trivia.

I believe it's also the case that when building for example a brick built linear actuator the old worm gears match up in a line but the new ones don't. 

Unfortunately, actually these 2l worm gears are slightly shorter, than they should be.

I have tryied to combine several worm gears and it doesn't work well due to small gaps between the worm gears.

[ukbajadave]

The worm gears are super sensitive to orientation on the axle. The yellow bushed axle is all lined up correctly. The grey bushed axle has 2 gears 90° out , leading to the slight variation in pitch.

The 2L worm gear has a single dotted line on it to help with alignment just like the slots in universal joints.

I'm not an engineer but I believe the reason 2L gears are not actually 2L is because the pitch is defined by the existing spur gears. If they were a fraction longer for the same pitch they wouldn't line up at the joins. That's also why the 1L worm gears dont line up, there is not enough room in 1 stud to fit 3 rotations at a fixed pitch.

I only physically have one of the 1L gears to play with but I did notice it also appears to have more friction on the axle than the longer ones.

[Parazels]

47 minutes ago, ukbajadave said:

 

It doesn't work.

Place a 8 studs Technic brick between the black beams!

Edited May 22, 2020 by Parazels

[Maaboo the Witch]

1 minute ago, Parazels said:

It doesn't work.

Place a 8 studs Technic brick between the black beans!

Sounds complicated.

[ukbajadave]

19 minutes ago, Parazels said:

It doesn't work.

Place a 8 studs Technic brick between the black beams!

But I never stated it was 8L? In fact I I specifically stated they are less than 2L

1 hour ago, ukbajadave said:

 ...2L gears are not actually 2L...

However, the fact remains if you line the dots up they match perfectly. (Out of system but still...)

[syclone]

43 minutes ago, Parazels said:

It doesn't work.

Place a 8 studs Technic brick between the black beams!

Out of system, but works. The additive slack on long distances would be big, but a few nylon washers on either end should fix it if such a construction would be essential for a build.

[ukbajadave]

That's a cool little video. That is kind of what I had in mind using axles and cross connectors. I tried to make something with what I have but the limiting factor was needing a single axle. Looking on bricklink I see the longest axle is 32L so some kind of crane boom should be possible. I wonder if the additive slack over that length would equal a half bush?

[Parazels]

These systems (above) are useless.

You always have to place a worm gear inside some strong frame or pocket to transfer its power to the next gear.

But any strong frame will be slightly longer than several worm gears combined. The slit between the worm gears makes them useless anyaway.

Edited May 22, 2020 by Parazels

[howitzer]

This is very interesting, because I have lately been wondering if it's possible to build a functional model of a metalworking lathe in Technic. 2L worm gears could be used for it's leadscrew, but it's probably not possible to build a leadscrew that's both long and strong enough for it to work properly.

(There's also the problem of how to drive the spindle as it needs a spindle bore through the longnitudal axis of the spindle, along with bearings around it but there's no lego parts that would easily make it possible, at least not that I know of. I wonder if anyone has succeeded in making this kind of machinery?)

[ukbajadave]

29 minutes ago, howitzer said:

...a functional model of a metalworking lathe...

I assume you mean a model which demonstrates the functions as opposed to a functional model 

Is the leadscrew the long screw on which the carriage moves?  I think worm gears would work for this. Without knowing your scale would a 32L axle be long enough?

Does anyone have a 32L axle and 16 worm gears handy? I suspect the total slack would still not equal a convenient half bush...

[ibessonov]

1 half-bush + a little bit of extra:

[ukbajadave]

1 hour ago, ibessonov said:

1 half-bush + a little bit of extra:

If nothing else I am slightly envious of your parts collection.

So 15 worm gears and a half bush leaves 1 stud at each end for mounting :)

[howitzer]

1 hour ago, ukbajadave said:

I assume you mean a model which demonstrates the functions as opposed to a functional model 

Is the leadscrew the long screw on which the carriage moves?  I think worm gears would work for this. Without knowing your scale would a 32L axle be long enough?

Does anyone have a 32L axle and 16 worm gears handy? I suspect the total slack would still not equal a convenient half bush...

Naturally, for actual turning of metal I have a proper lathe 

I don't know about the scale, the smallest possible which can demonstrate the functions I guess? I have no idea what that scale would be though. I think the problem with the spindle bore would have to be solved before deciding the scale. I have no idea what to use as a bearing for the spindle either, as there are no proper Lego bearings and I don't see how 24121 could be turned into a bearing in this case.