K40 Adjustable Focus Head-Quick focus guide tools

When I bought my K40 Laser machine (one of the MANY chinese clones available on the flea bazar) I decided to overhaul it from the start.
It has never been used with the Nasty cracked software or even had the main pcb powered up. It was all removed, totally re-wired and is now powered by a grbl "cnc" nano controller and has 255 grey scale engraving capabilitys and also a few new Safety related UPgrades, Water coolant flow Switch, Door open switch, digital cooland temperature & Current displays, you know all the important stuff that should have been included from the start but was never installed due to chinese profit margin and tight pockets.

I also upgraded the mirrors and cutting head, and that is were a little problem showed up ! how do I now set the correct height. The head is focus adjustable & most of the tools on Thingiverse would not fit or be usable, time to do some measuring and calculate the distances so I could print a nice easy to use guide tool to help me set the correct focal point for Surface etching/engraving and cutting 1,2,3,4,5,6,8,10mm thick acrylic and wood.

The lense in my cutting head is located deep inside the air assist nozzel assembly (40.95mm from the bottom exit hole) and since the focal length is 50.8mm
I now have the starting numbers required to design a simple to use tool with graduated steps for setting the correct depth for cutting different thickness of wood & acrylic etc and the exact level for surface engraving. One tool does it all, possibly

• Important * This may be of no use to anyone else but it is a step in the right direction for anyone else wanting to remix or adjust this tool. No two air assist focus adjustable heads will be exactly the same as my head. they all try to be the same and are produced the same but the rubber O ring between the lens and the body (air seal ring) are not always the same and thats if you even got one with your head so to be exact you need to measure the distance between the bottom of the lens and the exit hole on the end to get the correct numbers to make your own. These tools are for a fixed lens setting of 40.95 mm (one of the pictures above shows the measurement details since 1 picture is worth 10,000 words)
• Important *

The original (w.i.p) tool is available on Tinkercad so you can clone it to your own account ** https://www.tinkercad.com/things/lmg8WSInKae **
or you can just import the stl into a cad package and tweak the settings there before you print it.

Included are 4 (four) different sets
K40_Quick_focus_guide_V is a verticle stacked single block
K40_Quick_focus_guide_H is a horizontal stacked single block
K40_Quick_focus_guide_nn is an individual key style model with a keychain hole
K40_Quick_focus_guide_fs is a full set of the individual key style models ready to print in one go.

This little tool should be printable in fdm (2 shells and 10% infill is what I used) or resin (if hollowed & vented etc "not tested in resin yet")

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