Summary

I liked this idea, but wanted to change the mount to fit in my Bosch Quick Mount Release (https://www.thingiverse.com/thing:2131782). After a few revisions, this is what I came up with. It will probably not be until March before I can actually test it, but everything fits together. If you want to use this with another mounting system, the only part you will probably need to change is the Lip mount.

You can use 4 - metal LM8UU Linear bearings or 4 - drylin Igus RJ4JP-01-08 bearings. Before printing all the parts, I would suggest printing TN_QM_TestPrint_15_2OD_24_2Ht_Rev18.stl 1st. I am using the drylin Igus RJ4JP-01-08 bearings and the cavity they are pressed in needs to be just right otherwise they do not give a slip fit on the M8 rod. If you are using the metal bearings the fit is not as critical. If this test print is not a good fit, in the TN_QM_HalfMounts_Rev18.scad file adjust these 2 variables until you get the fit you want:
Bear_OD = 15.2;
Bear_Len = 24.2;

If you change those variables, you will need to regenerate the STL files TN_QM_MiddleHalf_Rev18.stl & TN_QM_LipMount_Rev18.stl.

I made my own plastic coupling as it has more grab depth for the shafts than the metal coupler I have.

If you do not need to make any adjustments the STL files to print are:

1 - TN_QM_MotorMount_Rev18.stl
1 - TN_QM_LipMount_Rev18.stl
2 - TN_QM_MiddleHalf_Rev18.stl
1 - ShaftCoupler_M5x16mm_M8x20mm_38Ht_rev8.stl
2 - BottomSpringWasher_Rev3.stl

1 - MPCNC_TN_8mmRodBlade_Holder_Only_Rev32.stl (sized for Stanley Box cutter blades)
The blade holder variations that I am working on can be found: https://www.thingiverse.com/thing:2661474

The STL files spring_14_3ODx25_4Lx1_4mm.stl & BoschMount_Rev36.stl are only used for reference in the openscad file.

Hardware you will need is:
4 - M3x50mm Screws to hold parts together
4 - M3x8mm screws to mount nema17 motor
2 - M3x16mm screws to tighten M8 rods to sides of Motor Mount
2 or 3 M3x14mm screws for Coupling connection(M3x12mm might work)
2 - M8x75mm length smooth rod for side rods (80mm would also work)
1 - M8x120mm length smooth rod for Center rod
1 - Spring (I am using this one which I purchased from local ACE store https://www.primeline.net/sp-9728-)

For further info on utilizing this, see the original design: https://www.thingiverse.com/thing:2624654

There is also a thread discussing this design located here: https://www.v1engineering.com/forum/topic/tangential-cutter-in-development/

I added quite a few photos showing the assembly of this. If something is not clear, just leave a comment.

For infill, I used 40% on the Lip mount, 70% on the middle halves & 20% on everything else.