M42 thread to Canon EF mount adaptor STEP

Built as a .STEP file based on this EF mount bayonet and inspired by the aperture ring of this adaptor.

Main improvements over the previous adaptor design:

• Increased clearance of the aperture pin actuation ring in order to accomodate a wider range of M42 lenses that may have previously bottomed out prematurely on the aperture pin actuation ring. Previously, some M42 lenses would not achieve infinity focus because of this.
• Tested on various M42 lenses including the Helios-44-2 and 44M-4: The lens markings are now right side up!
• Redid the overall adaptor design and exported as two different .STEP files. Inner threads/aperture ring is a separate model from the outer EF bayonet/flange. This allows the user to rotate the inner thread to their desire and achieve perfect timing with other lenses I haven't tested.

Files:

• M42-EF: The ready-to-print files, available in both .STL and .STEP.
• EF Mount: An EF socket with a hollow centre. 
• M42 Thread and Aperture Ring: Goes inside of the EF Mount file. You can rotate the M42 Thread relative to the EF Mount in any CAD program of choice then exporort them as one file, in order to achieve custom timing independent of flange distance.

Snug, normal support worked the best for me when printing flange side down.