Does the Tan Axle 4 with Center Stop Really Add Something?

[merman]

The part is used extensively in 42009 and to a lesser extend in 42008 and I am not sure it serves a purpose not present in other parts. The dark bley axle 4 with stop prevents gears from sliding off axles. Can anyone point me the exact benefits of the tan axle? Like, 42009's B Model starts with the tan axle and a 20t Double Bevel gear. This might as well have been a regular 4 axle right?

[mahjqa]

Perhaps for a B model, but tan axles when used correctly can stop axles slipping out where 4-axles with stop wouldn't work.

Edited July 14, 2013 by mahjqa

[Junpei]

Since I don't buy sets and haven't made a BL order, I'm sorry to say I don't really know much about this piece. Does it really have a stop ring or is it just the cylindrical part?

Sorry for the late edit Mahj, thanks for editing your comment.

Edited July 17, 2013 by TwentyLeggedHen

[DLuders]

The 87083 "Dark Bluish Gray Technic, Axle 4 with Stop" can be inserted into a Lego Technic Liftarm only from one side, while the 99008 "Tan Technic, Axle 4 with Center Stop" is sandwiched in between Liftarms.

[dhc6twinotter]

To be honest, I don't really see a point to the new part. The only thing I can think of is it makes the building process more mistake proof.

You know how at the beginning of each instruction book there is a diagram that tells you not to squash a beam between a bushing and 24 tooth crown gear? This new part prevents a beam from being squashed between a bushing and a gear, or two gears, etc.

That's the only thing I can think of.

Question for the engineers amongst us: Does the round part of the axle produce less friction in a beam hole than the cross axle section would?

Edited July 15, 2013 by dhc6twinotter

[rm8]

This axle can not be pushed out from differential, of course, if you use it right

[maxxens]

A good example where this part is usefull is in the 9398 motor. There it is connected like this:

motor | beam | gear | beam

In this configuration the 4L with stop would not help the axle from slipping out, but because the center stop is in the first beam even if the axle slips it will never fall out because the gear keeps the axle in place.

[Jeka Jackson]

I've used this axles in my Jeep Wrangler to prevent sliping of the axles from rear hubs. Very useful details.

[Lipko]

I found it to be a good placer in structures. You don't have to add an extra bush.

[allanp]

It's original purpose was to prevent the axle from sliding out of something, particularly out of a diff, where it's held in place by only a thin bevel gear, right on the end of the shaft. Even with the new axle it's still a bit ropey due to the rounded end of the axle. I think in most cases where it's used after that it's just a case of "well we have this part now, might as well use it!"

[merman]

Call me stupid, but I still don't get it. Take a 5x7 frame and put in a differential. Using two tan axles won't make a difference. They are not stuck inside the frame and can be pulled out easily. Ijust built 42008 and of the 4 tan axle used I don't see a reason why not to use regular axles...

[allanp]

For a specific example you need to look at the crawler. On the output tan axles you have a 12t double bevel gear, with an axle connector block holding it in place so that the tan axle cannot slide out. Probably wasn't needed anywhere else although a round shaft acts as a better bearing than a + shaped shaft.

[DLuders]

[Blakbird]

I talk about the purpose of this part extensively in my 9398 review including showing a few examples of why it works.

[N-4K0]

A clever new part. Upon seeing it for the first time on pics here, I immediately thought of a good use for it