Random Technic Pin Question

[Trainmaster247]

This has been bugging me for a very long time and must say it doesn't seem logical to me. Why is it that some technic pins go in the and can not spin while some can free roll allowing you to use it with wheels, is it something as simple as it being a hairs width thinner or something else. I was just wondering if anyone can let me know thanks.

Edited April 17, 2015 by Trainmaster247

[Boxerlego]

Easy Answer is Friction. Do you see the bumps at the ends on Black this creates friction. Notice how it is smooth for the Grey one.

[zux]

That's because they are designed to be with and without fiction. Other two combinations:

43093 and 3749

6558 and 32556

[RTZX9R]

The design of the pins to have friction or not have friction is done on purpose by TLG (the LEGO group). Sometimes you need a pin without friction, and sometimes you don't. These variations have different LEGO part numbers and some are even hard to find and $$$.

[deraven]

Yes, it's a design feature, not random. I do remember the "good ol' days" when gray pins were frictionless and black pins had friction, and that's all there was to it! It's potentially more confusing now that there are some pins with and without friction in the same colors, but it's easy to tell what you've got if you just look for the ridges as noted above.

Edited April 16, 2015 by deraven

[anothergol]

Yes, it's a design feature, not random. I do remember the "good ol' days" when gray pins were frictionless and black pins had friction, and that's all there was to it! It's potentially more confusing now that there are some pins with and without friction in the same colors, but it's easy to tell what you've got if you just look for the ridges as noted above.

Wait, what? It's totally the opposite, and I hate it!

To start with, I hate how Lego now color-codes everything. Yes, today it's impossible to find a pin/axle connector without friction that not in BLUE (blue is fine.. only if your design uses blue..) or frictionless ones that are not in TAN.

I had to buy overexpensive frictionless pin/axle connectors in BLACK, because those were rare, and it's very unlikely that they will pop up again, now that Lego color-codes everything (even plates now, which is silly IMHO) to make it easier for kids.

So it's totally the opposite, in the "good old days", there was less color-coding, and I'm hanging to the few old-grey frictionless pins that I still have from old sets, because old grey is still better than an ugly blue pin sticking out of your design.

Today,

-black pin=friction

-grey pin=frictionless

-blue pin/axle=friction

-tan pin/axle=frictionless

(& most of the complex pins have friction anyway, so don't need color-coding)

simple for kids, but ugly

They even coded axles now.. black for even lengths, grey for odd ones. Again, easier for kids, but ugly in the results.

(where it's bad, though, is that not all friction pins have the SAME friction)

Edited April 16, 2015 by anothergol

[Paul B Technic]

The answers above are spot on :)

[kinggregus]

You learn something everyday. I feel stupid not knowing that... thanks for the clarification (and the question)

[cgarison]

They even coded axles now.. black for even lengths, grey for odd ones. Again, easier for kids, but ugly in the results.

But the plastic for grey axles is slightly softer than the plastic for the black axles which means for a few of my MOCs I have needed to cut black axles to make them less prone to twisting the axle pieces.

[anothergol]

But the plastic for grey axles is slightly softer than the plastic for the black axles which means for a few of my MOCs I have needed to cut black axles to make them less prone to twisting the axle pieces.

why not bricklink old black axles? There are still plenty out there, for cheap.

[dr_spock]

The old Technic black pins were also stiffer compared to the current black version. They were challenging to pull out if you don't have super strong fingers.

[cgarison]

why not bricklink old black axles? There are still plenty out there, for cheap.

Oh, I bricklinked a bunch of the old odd length black axles as well as bought long black axles and then cut them down to have a square end to hold spur gears on the trains that I build.

The old Technic black pins were also stiffer compared to the current black version. They were challenging to pull out if you don't have super strong fingers.

I have a set os small slip joint pliers to save my fingers when disassembling technic models. They work wonders to save your fingers.

[bonox]

The old Technic black pins were also stiffer compared to the current black version. They were challenging to pull out if you don't have super strong fingers.

there was a great reason TLG stopped using them - and may they burn in hell for all the desctruction they caused to parts and kids teeth.

For the OP, the old ones don't have slots in the middle and would often weld/lock themselves into place. I think you'd cause mass cracking issues if you used them on the new lightweight liftarms.