efferman

Efferman's Custom Parts

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On 8/4/2021 at 1:33 AM, efferman said:

I will generate .part files in the next days.

Thank you very much! That would be amazing.

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@efferman have you tried printing a part like this  92907.png but with a towball socket in it instead of the pinhole?

The closest I could make in Studio part designer is this:

400x300.png

And I have been thinking about using it in an axle like this, where the width of the axle could be adjustable by replacing the thin 5L liftarms to 4L or 3L versions.

Steered%20Axle.png

Do you think that such a construction would be strong enough?

BTW, I have checked out your Shapeways parts, lots of interesting stuff there. Was wondering if a diff with 20z gear is possible, it seems you have tried it already, although your desing is 2L wide, and I was thinking of a 3L wide version to fit into a 5x5 frame. How sturdy is that with those small gears inside? I guess they may be a bit weak for heavy-duty RC cars?

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Hi, will make a Sketch this evening about jour Part Idea. I think yours is Not really Solid under Load.

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Somewhere on this site I recall seeing a similar suggestion, but maybe more robust.  It was basically a 2L thick liftarm (with two axle holes instead of pin holes), with the tow ball socket at the end.  Imagine one of the 5L arms with 2L cut off the end and the pin holes converted to axle holes.

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2 hours ago, efferman said:

Hi, will make a Sketch this evening about jour Part Idea

Thanks!

2 hours ago, efferman said:

I think yours is Not really Solid under Load.

Do you mean the part or the axle construction? Sure, I guess the part itself can be improved (and the axle construction obviously needs more connections to be solid).

8 minutes ago, Hrafn said:

It was basically a 2L thick liftarm (with two axle holes instead of pin holes)

Sure, I can imagine that, but then the mounting becomes more problematic, and it protrudes more towards the center and you start losing ground clearance..

 

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On 9/15/2021 at 5:36 PM, efferman said:

My idea is this .part

Thanks for making this!

On 9/15/2021 at 5:36 PM, efferman said:

2 crossholes are more solid than only one

I agree, actually this was my first idea too, but as I started thinking how I would build with it, I found that the second crosshole could be in the way in a couple of cases, either for the steering, spring mounts or some cross-connections, that's why I simplified to the single crosshole version. However, I really like the pin-hole on the back of your version, that has some potential of using it to fix it more solid if it's needed, even if there's only one crosshole, for example like this:

400x300.png

On the other hand, I started playing with your version, and came up with this construction, which could be a solid one, if there existed a male CV joint with an axle (have you tried that?), as the top and bottom bars could be connected in the center, close to the wheel (no need for more connections on the front/back side):

400x300.png

What do you think about these?

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10 minutes ago, gyenesvi said:

a male CV joint with an axle (have you tried that?)

Printing crossaxles is the last way, the nylon is to soft against load in Torsion, but it should be possible when only the last stud is a cross. An other Way would be a crossblock with a 9mm Hole, the the standard CV connector could fit.

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38 minutes ago, efferman said:

Printing crossaxles is the last way, the nylon is to soft against load in Torsion

That's a pity, I didn't know that.

39 minutes ago, efferman said:

but it should be possible when only the last stud is a cross

So if the one stud after the ball would be circular, that could help? That would also be okay for this use case and others too I guess (an axle joiner is only connected to the last stud).

40 minutes ago, efferman said:

An other Way would be a crossblock with a 9mm Hole, the the standard CV connector could fit.

If I understand correctly, the middle part around the hole would need to be wider by half studs on both sides to make that possible. I guess that would be a strange part, and maybe not too useful for other use-cases.

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1 hour ago, gyenesvi said:

wider by half studs on both sides

more a quarter Stud, but yes, the usecases seem to be limited

51489717648_33aeb922bb_z.jpg

.part

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On 9/18/2021 at 6:06 PM, efferman said:

more a quarter Stud, but yes, the usecases seem to be limited

I do like the part itself though, it doesn't look as off as I thought it would, thanks! I will play around with it a bit it Studio.

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General question for anyone here who has made custom bevel gears, what bevel profile are you using? Spur gears are easy enough to design, I have all the relevant information needed for parametric modelling, but I'm more interested in bevel gears due to their versatility, and I have yet to find relevant information on their additional design constraints. 

I went into Stud.IO and compared the various bevel gears, and noticed a lot of inconsistencies, unless the LDraw models are incorrect but I doubt this is the case; the only consistencies seem to only appear in the older double bevel gears. Each of the single bevel gears seem to use a different profile, and from what I can tell this profile isn't consistent with each other. The single bevel 28 tooth differentials seemed to introduce a new tooth profile altogether, the largest change being the angle of the bevel, which the new 28 tooth double bevel gears follow this new design, but they're not based on the same radius, the differentials have a slightly smaller gear; to further this, the 28 tooth double bevels also have a different spur profile in the center of the gear. Because of these differences, each gear outside of the set of the old double bevels has a different tapering on the bevel portion itself.

I was wanting to draw up some gears, but then noticed this issue. Lego's bevel gears are also far different from what standard bevel gears typically are like, so I'm not having luck finding a parametric script to generate the correct profiles. Is it common practice to just borrow the tooth profile from other gears and hope they mesh well? As an example, if I wanted a 16 tooth single bevel half gear, would I just borrow the tooth profile from the 12z or 20z gear? Or is there a program or parametric script I haven't come across yet that generates a profile that's compatible with Lego's bevel gears? Also, would it be better to follow the older profile or newer profile of the teeth, because the newer 28 tooth gears do have a significant difference in design. 

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to be honest, i have used a caliper and copied the Lego shape with a lot of chamfering. Mathematics for real gears are not yet in my brain.

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On 4/24/2021 at 5:28 PM, efferman said:

51135356861_e9c09ca6c6_c.jpg

@efferman, do you maybe have .part files for the white custom towball socket arms on this image? And that top cross beam that holds the towball pin also seems interesting. I could use them for some experimental Studio builds.

BTW, what software do you use to design these parts? I guess it's not Part Designer, it seems too limited for these.

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55 minutes ago, efferman said:

These should be the parts, made with autodesk inventor 2016

Thanks!

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