Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2436559.
Getting a perfect 90° cut on PTFE tubing is a royal pain in the .... yeah. If it's not perfect, you are just asking for leakage, which is NEVER good in any situation, especially in a 3d printer hotend. You could take the heatblock apart and trim the tubing flush against the metal sleeve, but that requires disassembling the hotend which isn't particularly fun, either. What you need is the PTFE Tubing Guillotine! Simply slide your tubing through the hole until it sits firmly inside to rear pocket and slice. Easy peasy.
You will need a 25mm (1") long 3mm bolt, a 3mm nut and two (at least) 6mm long 3mm bolts as well as a standard Stanley-type knife blade.
UPDATE As requested, I have added another version of the base that has the PTFE tubing hole cut all the way through to aid in removal of the scrap piece. This is v3 of the base.
UPDATE PART 2 As requested. I have added another version of the base that has a 45° angle guide in addition to the straight through guide. This is the v4 of the base.
NOTE Due to either a Thingiverse bug or (more likely) shadowbanning, my models no longer show up under the [Newest] listings. If you want to see more of my models, please be sure to 'follow' me.
Another Sketchup Model - Debunking the Myth that Sketchup is Useless in 3D Printing