Why don't short pins clip through holes in plate-wide System pieces?

[Xfing]

Self-explanatory. I've noticed that 3/4 pins will not securely attach to System plates with holes in them, due to there not being a groove on the rim like there is in 1/2 width Technic beams etc. But strangely enough, when you put 2 holed plates on top of each other, a full-length pin will clip securely. Is that by design? I find it a bit frustrating, since it'd be pretty cool to be able to use half-length pins on plates and such. It's particularly egregious with part 3176, which could work really nicely as a trailer attachment on a half-pin or something to that tune, but seems like you need to stack 2 on top of each other to make it work, and us a full length pin then. 

[M_longer]

39 minutes ago, Xfing said:

Is that by design?

Yes.
That full pin connection comes from overal geometry of system parts. 2 liftarms are thick as 5 plates stacked, so half liftarm is 1,25 plate thick, but thanks to groves it can be attached to 3/4 pins. Plates never had recession for pins to click inside.

[Stereo]

Technic plates and frictionless pins (grey, 2L)  date back to the very first Technic sets, the 3/4 pin and half thickness Technic parts are about 20 years newer, so they didn't change the design to accomodate it I guess.  Some parts like 3651 to 32013 did get modified to accomodate the thin/studless parts.

 

3176 is even older, there were no Technic pins, no axles... it's designed to fit studs or let bars hook through it.

Edited December 22, 2024 by Stereo

[bruh]

Yeah, I agree with m_longer and stereo. The ratios between pin length and plate thickness are different. 

[msk6003]

As far as I know this is only part which has plate thick pin.

[Xfing]

On 12/23/2024 at 4:00 AM, msk6003 said:

As far as I know this is only part which has plate thick pin.

welp my man, you would be right!



I never in a million years would have thought this piece's pins were longer than that of the 3/4 pin. And I find the decision doubly weird given how well 4261 works with indented, half-width beams in the first place. There is some up and down give, sure, but too little to notice. 

Edited January 15 by Xfing

[howitzer]

2 minutes ago, Xfing said:

welp my man, you would be right!



I never in a million years would have thought this piece's pins were longer than that of the 3/4 pin. 

It was released back in 1981 to be compatible with 4262 and other similar parts, which have thickness of a normal plate. 3/4 pin only came in 1996 to help connecting liftarms of half-stud thickness to full-thickness pinholes.

[Xfing]

Just now, howitzer said:

It was released back in 1981 to be compatible with 4262 and other similar parts, which have thickness of a normal plate. 3/4 pin only came in 1996 to help connecting liftarms of half-stud thickness to full-thickness pinholes.

Yeah, but 4261 works with no apparent incompatibility with those too. They're meant to be plate-wide too, albeit with indentations. I think Lego should have kept something that would be plate compatible, since as is, without a compatible piece all you can do with holed plates is put axles through them or only put pins through two at a time.