Technic question: What is the difference between the purposes of the gray technic pins and the black ones with the slots in them? I know the description says something about “with friction.” Does that mean the gray ones are meant to spin and the black ones don’t? If I am using them just to hold technic bricks together, other than availability, does it matter which ones I use?
I just opened a rather new LEGO motor from a sealed bag and with or without a no load, it is rather loud. It seems to be working fine, but it makes a high-pitched sound when it is running. Are the new motors all like that?
Everytime I’ve built a MOC with a LEGO motor, Ive found that the motor goes really fast and exerts very little force. So I have to “gear down” MOC’s by using a small gear directly attached to the motor to drive a larger gear that spins more slowly. Often you have to do several in sequence going from a smaller gear to large gear to slow down the rate of spin and increase the output force. The fewest steps in gearing down involve using a worm gear, as can be seen in the gear ratios on this table: