LDraw.org Discussion Forums
Is there something wrong with axle holes? - Printable Version

+- LDraw.org Discussion Forums (https://forums.ldraw.org)
+-- Forum: Models and Parts (https://forums.ldraw.org/forum-18.html)
+--- Forum: Parts Authoring (https://forums.ldraw.org/forum-19.html)
+--- Thread: Is there something wrong with axle holes? (/thread-11994.html)

Pages: 1 2


Is there something wrong with axle holes? - Roland Melkert - 2014-01-12

Looking at the radius 4 parts (e.g antenna, tech flex axle endings)

In real life they fit the inside axle holes, but in our library the max radius to fit in axle holes is only 2.8284 LDU ( sqrt(2^2+2^2) ). This seems quite a big margin.

Is this on purpose or is ether the axle hole or the 4LDU bar stuff wrong but accepted over time?

Or I'm I missing something else?


Re: Is there something wrong with axle holes? - Michael Heidemann - 2014-01-12

Hi Roland,
I do not have those parts on hand now to check the real dimension.

I guess that just in the beginning measurements are not very accurate.

Also keep in mind that all the parts we are producing are approximations.

But they should fit like in real. Smile

Maybe you discovered an error that was there just from the beginning. Or maybe parts changed over the time and we can not in any case date a part that we have in our hands.

Anythink is possible - just my thoughts, but maybe there is a reason?


Re: Is there something wrong with axle holes? - Michael Heidemann - 2014-01-12

Are you talking about building possibilities like shown in the attached file?

If yes, where is the problem?


Re: Is there something wrong with axle holes? - Max Martin Richter - 2014-01-12

It's a quite simple reason.
When I take the axle primitive and inline it, is see that each side of the cross is 4 LDU wide. That means 1.6 mm IRL.
But when I measure a random choosen axle, I get 1.8 mm (4.5 LDU) for this wide.

Conclusion our axles and everything else concerning it is about 0.5 LDU too small.
What to do now?
Update all parts or let it as it is?

/Max


Re: Is there something wrong with axle holes? - Roland Melkert - 2014-01-12

No, I would like to put e.g. a gear on that antenna.


Re: Is there something wrong with axle holes? - Max Martin Richter - 2014-01-12

Mike, he is talking about this problem I think. (See attached file)


Re: Is there something wrong with axle holes? - Roland Melkert - 2014-01-12

I don't want to cause such a big change, I don't think it's that big of a problem in daily use.

I just encountered this oddity while tweaking my part snapping code to accept antenna's etc on axle holes.


Re: Is there something wrong with axle holes? - Michael Heidemann - 2014-01-12

Quote:In real life they fit the inside axle holes, but in our library the max radius to fit in axle holes is only 2.8284 LDU ( sqrt(2^2+2^2) ). This seems quite a big margin.

Ok - please define "axlehole". We have a lot of primitive to cover axleholes.
Please tell me a part no. of the part that should fit into that axlehole.

I need to have those data to determine where the problem is.


Forget this post, I just saw the other answer - now I know what you are talking about.


Re: Is there something wrong with axle holes? - Max Martin Richter - 2014-01-12

I saw this some years ago, while building different models. The same problem occurs, when adding a flex hose into something.


Re: Is there something wrong with axle holes? - Tim Gould - 2014-01-12

Gears on bars is a dangerous game, but certainly one the works in real life. If you use e.g. a 4l bar, there's a good chance it willl fuse onto the gear and become pretty much stuck forever.

So probably the minimum cross-diameter of the hole is a bit smaller than 8LDU, but definitely bigger than 5.7LDU.

Tim