Clamp On Throw Lever for Athlon BTR Gen2 Scope

update 05/20/2026:

Rev 1 is the original file

Rev2 I made the band 1mm taller in the z direction to add a little more material around the head and threads of the screw

Rev 2.1  has a 5% smaller inner diameter requested by bob92553

About a year ago, I was on the hunt for a throw lever that would work with my Athlon BTR Gen 2 scope. It seems like the zoom rings on scopes are always stiff or just hard to manipulate especially when looking through the thing. I stumbled on a design that looked cool, but it turned out it didn't fit my scope. Bummer. Back then, I wasn't the best (totally sucked actually) with CAD software, so I reached out to a buddy who helped me tweak it to fit my scope. Fast forward to today, after taking a couple of CAD classes, I decided to give the project another shot.

I grabbed my calipers and radius gauge and started from scratch. First, I tested the fit of the notch and then designed ring and lever body around that. As a bonus, I added some grippy bits (that's a technical term) at the end of the lever. It uses an M3 square nut and a 10mm socket head screw, and has a nice snug fit when tightened.

I aimed for tight tolerances on this, the ring has a small gap and fit the scope zoom adjustment perfectly. For ease of printing the hole for the screw is tear drop shaped, this allows tighter tolerances, with no supports and gives a snug fit. I may tweak the design for that or to accept a hex nut. It printed great with PLA+ using a 0.4mm nozzle at a layer height of 0.15mm, 0.2mm layer height should be just fine also. this does not need any supports, it will print cleanly without them as it was designed for additive manufacturing. I included a 3MF which also has my anti-ooze start gcode and revo retraction end gcode. (note: the 3mf was from my MK3S days I'm using an MK4S and Core one these days.)

I'm always open to suggestions and feedback. If you have any ideas to make it better or would like adjustments made to it, drop a comment or send me a message. I'd be more than happy to make changes and or adapt it for different scope models.

If you give this throw lever a go, it will totally make my day if you post a make and give it a like! Love seeing other's prints and get some feedback on if it’s working for you. 

Also, I’d like to give a huge shout out to JP for lending a hand and encouraging me to learn some CAD skills. Keep being awesome, brother!