--> This is the PERFECT tool to set your brass inserts straight and makes assembly easy!!

There are different sized iron head inserts to fit your needs!

I followed the links from people who adapted the jig and printed an interchangeable head with a thicker spring. I also used some washers on each side of the spring to allow easier movement of the iron - 18 and 20mm, with options for tightly screwed-in versions and snap-ons instead.   

The rail to which you will attach the MGN7H block and linear rail (150mm) comes in 2 versions:  V1 is very tight, and the second one, V2, is much looser.

Parts you will need: 

  1x Soldering iron

  1x 150mm rail with MGN7H block

  6x M2 nuts

  10x M2x6mm screws

  7x M3x5x4mm heat-set inserts  -- you need 2 extra for the interchangeable head to swap irons if you choose that variation

  1x M3x6mm screw

  4x M3x10mm screws -- I used 14mm screws and 8 washers for the springs

  2x M3x12mm screws  -- add 2 more for the interchangeable head

  3x zip ties -- to tighten the wire at the back

I printed everything in PETG using a 0.2mm layer height and 0.4mm nozzle - I used 3 walls and only 10% adaptive cubic infill.  I used supports for the main body - you can use "blocker" shapes to avoid supports in the three small holes at the back for the zip ties.