(DISCLAIMER) i honestly dont know much about making or adding step files. ive never bothered with them to know what im doing with them. i made these in tinkercade because im still new to fusion360. please tell me aboout your experiences with these models!

ALSO... im not sure how this will work for r9m boards. i dont have r9m and i dont have the dimensions for it. so im sorry R9M users. use these links.
https://www.thingiverse.com/thing:2956096 by Kilrah
https://www.thingiverse.com/thing:4555317 by ic319
Adapter for regular R9M cases
https://www.thingiverse.com/thing:4151559 by ValeMazzo

ExpressLRS Happymodel 2.4 GHz housing spacer
by Benaresq (ive remixed their top spacer to allow clearance of a fan if you would like to use this spacer with my models.if you need a bottom spacer please use thies and then add .6mm to its height on either side, doesnt matter.) https://www.thingiverse.com/thing:4867657

this is remixed version of both Happymodel's case (https://bit.ly/2S5PbBP) as well as solidware's case (https://bit.ly/3geXp2d). these cases work great as normal radio sized jr modules cases but have been customized to work very well with my new designed jr bay adapter for xlite users. i printed these in PLA but i would suggest something a bit better like PLA+ or petg. these cases should work for 900MHz and 2.4G. i have only tested with 2.4g because i dont have 900MHz board.

the remix work i did was raise and added posts for the board. modified the cases to puzzle piece together nicely with the adapter. increased the holes for the screws so m2 bolts cant be used.

any file listed (A) will work together including the adapter. any file labeled with (B) work together, you cant mix and match A with B. use M2x4 for mounting the boards in either case. use M2x6 or M2x8 for installing the lids for the case. the fan lid accepts a 20x20x6 fan, not entirely sure what screws or bolts to use for the fan but if i had to guess M2x8 and a nut.

infil 20%
.02 nozzle
temps 200/60
supports, yes, mainly touching build plate, i used tree supports.
wall count 3
(your settings will vary based on your preferences and the material you wanna use)