This is best suited for the cheep soldering irons on the internet's grip shape (see the cross section pic). must remove the rubber grip to fit well.

Recommended to first only print ‘round’ and ‘fastener’ to check they grip the solder iron well and that the parts can close around the rails. there is a tolerance tester rail if you wanna see the fit before printing the entire base.  

Needed hardware for assembly:
3 sets of: [608 bearing, M5x20 bolt, M5 nut, M5 washer)
4 sets of :[M3x10 bolt, M3 nut]
some CA glue to attach the Spine to the base, full assemble and then glue to make sure you are ‘on plane’ and everything can move freely.

Printing notes:
the print has some tolerances built in but I still used 0.15 XY hole compensation.
this way the bearings are press/loose fit and can add tape to fine tune tolerance.
(if your printer is accurate can reduce this to exactly press fit)
I used 0.4 nozzle with 0.2 layer height. 

Strength: on the rails especially going to 4 perimeters is much better for stiffness then more infill, can go even at 20% but 4-5 perimeters is preferable.
other parts are under less stress and don't need to be as exact.

this is the onhape project link: (if you want to adjust the clamps to diferent soldering irons)
https://cad.onshape.com/documents/e55fd6f8364b7b7aeea12e0a/w/7c748eb15f1f958ec2b21669/e/5204d1d89fe8a56c387615b7
*if you prefer to avoid random links the dock name is “Heat Insert Fixture V2” by “EitamR”.

All feedback is welcome (positive is nice, but improvement suggestions is best)