Technic Pins: To friction or not to friction...

[S_Bartfast]

I'm new to Lego and while I've been designing MOC (or is that "a MOC"??) in Lego Digital Designer I see there are two types of Technic Pin notably, a "Connector Peg with friction ridges" (2780) and a "Connector Peg without friction ridges" (3673). Just wondering why they have two types. For MOC (man it's hard not to call it "my MOC") I have exclusively used pins without friction ridges because I couldn't really see the point of them but am wondering if I should have used a mixture.

While many of the pins I have used are intended to act as swivel points several are being used as rivets like this:

Of course the actual pins used here are "Long Pins" (32556) rather than the shorter ones discussed above.

I kind of figured that given that arm looks pretty rigid frictionless pins would be fine but might have I been better off opting for ridged pins in this instance?

[samlr]

You would rather use pins without friction to connect moving parts and with friction with fixed parts. The pins with friction will hold much more strongly. The ones without may get loose, especially if you have a lot of constraint on them. With physical part, you would really feel the difference.

On your example, if you have just little constraint on the direction of the pins, they will break loose. Same thing if you have to much constraint perpendicularly to the arms and the pins, the connectors will bend due to the splits on there ends and they will break loose.

So yes, you would be better off using pins with frictions :-). I never use the other ones.

Edited May 13, 2015 by samlr

[Captainowie]

If your creations are going to remain digital, then it really doesn't make a lot of difference (for that matter, you could probably just use 2L and 3L axles). However, if you are going to physically build it, then you'd want the friction pins everywhere that is not an active pivot point.

Check out the instructions for any technic model - the friction variety is used almost exclusively unless it's a swivel point in the model.

Owen.

[S_Bartfast]

If your creations are going to remain digital, then it really doesn't make a lot of difference (for that matter, you could probably just use 2L and 3L axles). However, if you are going to physically build it, then you'd want the friction pins everywhere that is not an active pivot point.

Check out the instructions for any technic model - the friction variety is used almost exclusively unless it's a swivel point in the model.

Owen.

Hmm, fair enough.

I have just ordered the parts to bring this into 'meatspace' but perhaps I can add some extra friction pins to the order.

Edited May 13, 2015 by S_Bartfast

[Balrog]

Even for pivot points, sometimes pins with friction are more useful than pins without friction. The reason is simple: The pivot mechanism gets more stable and often the friction of the pin is easy enough to overcome.

[dr_spock]

If a pivot point needs to spin freely like a wheel, then pins without ridges. If it needs to pivot and holds it position like posing arms on a mech, then pins with ridges.

[S_Bartfast]

If a pivot point needs to spin freely like a wheel, then pins without ridges. If it needs to pivot and holds it position like posing arms on a mech, then pins with ridges.

I think I'll just order two copies of all of them and see what seems best when I build it.

By the way, I'm building a dice tower which has a lever arm mechanism:

(the blue pins are 'rivet pins' while the yellow ones are 'pivot pins')

The idea is that you put dice in that tray then press the lever down which will lift the tray and pour the dice into the tower.

There is a trapdoor inside the tower and when the tray is lowered again the trapdoor is permitted to open allowing the dice to fall through and roll into the tray again.

While it would probably be easy to overcome the friction of the pins in the lever arm the pins that deal with the tilting of the tray will no doubt need to be as free as possible.

Here's a link to a thread I started with more details if anyone is interested: http://www.eurobricks.com/forum/index.php?showtopic=109113

Edited May 14, 2015 by S_Bartfast

[Boxerlego]

Most of the time you want to use the friction pin for your connections. Only the frictionless one comes in handy when it has motion involved in it something like a tire specifically. An axle sometimes can work as well if not better as a frictionless pin.

Even for pivot points, sometimes pins with friction are more useful than pins without friction. The reason is simple: The pivot mechanism gets more stable and often the friction of the pin is easy enough to overcome.

That is very true. In some case it better to use friction pins over the one with out friction.

[deraven]

Well, I think the pins question has been pretty well answered, so I just wanted to pop in and say that I think your dice tower looks pretty cool!

[S_Bartfast]

Well, I think the pins question has been pretty well answered, so I just wanted to pop in and say that I think your dice tower looks pretty cool!

Cool, thanks.

Now here's hoping it actually works

Edited May 14, 2015 by S_Bartfast

[DrJB]

I see this tower easily converted into a GBC.

[S_Bartfast]

I see this tower easily converted into a GBC.

Huh, I'd never heard of GBCs before so just looked them up.

Some of those things are pretty cool!

[GoldCivetta]

cool MOC!!