hi everyone,

for lase several month I was "constructing" some LEGO compatible parts for suspension. Now I have one question - does anyone know precise dimensions for pin and axle holes that LEGO uses?

Thanks in advance

Igor

From this PickOurBricks webpage, one can see the dimensions (in Lego Units) of the Lego Technic pin hole in a 1x2 Technic Brick. Multiply the dimensions below by 1.6 to get the sizes in millimeters:

There is an easier-to-understand diagram at the bottom of this robertcailliau.eu webpage. The dimensions there are in millimeters. That reference says "The knob [stud] diameter: 4.8mm.

This is also the diameter of axles and holes. Actually a knob [stud] must be slightly larger and an axle slightly smaller (4.9 and 4.75 [mm] respectively, otherwise axles would not turn in bearing holes) but we will ignore this difference here." So, I interpret this to mean that the Lego Technic Axle is 4.75 mm in diameter, but the Technic Axle HOLE is 4.8 mm.

thanks David,

helpful as usual. Now I know that outer "cylinder" for pin is actually 0,9mm long and not 1mm. Everything else my werner scale has measured correctly.

when parts will be finished in nanoCAD software and printed with 3d printer, I'll post a link on forum.

Kind regards

Igor

From this PickOurBricks webpage, one can see the dimensions (in Lego Units) of the Lego Technic pin hole in a 1x2 Technic Brick. Multiply the dimensions below by 1.6 to get the sizes in millimeters:

There is an easier-to-understand diagram at the bottom of this robertcailliau.eu webpage. The dimensions there are in millimeters. That reference says "The knob [stud] diameter: 4.8mm.

This is also the diameter of axles and holes. Actually a knob [stud] must be slightly larger and an axle slightly smaller (4.9 and 4.75 [mm] respectively, otherwise axles would not turn in bearing holes) but we will ignore this difference here." So, I interpret this to mean that the Lego Technic Axle is 4.75 mm in diameter, but the Technic Axle HOLE is 4.8 mm.

helpful as usual. Now I know that outer "cylinder" for pin is actually 0,9mm long and not 1mm. Everything else my werner scale has measured correctly.

when parts will be finished in nanoCAD software and printed with 3d printer, I'll post a link on forum.

Right, these are only the basic dimensions and do not account for actual precise tolerances. For instance, the diameter of a stud is actually slighter larger than its receptable; they are not both 3 LDU. This interference provides the necessary clutch power. Likewise, the width of a brick is not actually 5LDU, it is a little less to allow for gaps between adjacent parts. They minute tolerances need to be known to 3D print parts.

A little bit of trial and error I think will be needed. Even if you match the exact size if there is a difference in material the clutch power will vary. Good luck

A little bit of trial and error I think will be needed. Even if you match the exact size if there is a difference in material the clutch power will vary. Good luck

thanks