Have you ever looked at your old hunting scope and though “I just wish you were that little bit better” ?
I have; specifically relating to turrets - I love the light package of my trusty Zeiss Terra 4-12 scope (I know it's not everyone's cup of tea), but it has a Plex reticle and no ballistic/target turrets! If I need to take a longer shot, I either need to guess a hold-over, or take off the caps and count clicks (no numbers on the dials), this is frustrating…
I scoured the internet looking for options to convert / upgrade what I have, but unfortunately nothing came up. Then decided to see what a new scope would cost, but most of the options that have target turrets are just a bit too expensive for me at the moment (not to mention bulkier than my Zeiss).
So, I set off to design a conversion of my own! Took apart one of the dials and decided that this shouldn’t be too hard, fired up Inventor and went to work on creating my new masterpiece.
I finally landed on a design that required 3 separate parts: one outer turret (obviously), one sleeve part to engage the threads of the previous caps, and one to allow the new turret to clamp to the existing dial.
Interestingly, the most difficult part was to try and decipher the existing threads on the scope caps.
Now the hard part starts – finding someone to manufacture this at a decent price-point… Tried local machinists in NZ, and those that quoted were quoting close to 70% of a new scope, and others said this is too small of a job…
Finally found a JLCCNC in China to make these for what I think is a decent price and worked with them to finalise some smaller aspects of my design. I wanted to have the whole thing anodised and the markings laser-engraved, but unfortunately their laser engraver doesn’t have a rotary indexer and the markings would be inaccurate. We finally agreed to CNC engrave the markings on the outside of the turret, I adjusted my file and sent it off for machining.
I just received my order, and I couldn’t be any happier! All parts fit together seamlessly, and the CNC engraving looks very professional. I think in time I’ll will the engraving in with some kind of white paint or white epoxy, as it isn’t THAT easy to read.
What I’ll do different in the future is to select a polished+anodised finish, I selected bead blasting+anodising, which is just a bit too rough for my liking (you live and you learn, right).
Next steps are to tap M3 threads for the setscrew and locate a 23x1mm gasket / O-ring to make this whole thing watertight. I’ll also need to laser engrave a reference line on the Sleeve part, was kind-of impossible to know where this should be without fitting the part to the scope.
I can also customize one to my own ballistic drop in the future, just wanted to keep it relatively straight forward at this point.
If anyone wants to make the same upgrade to their Terra’s, I’d be happy to share the files around (send me a PM).
Snips of the basic design below, will get some photos of the real deal tomorrow some time.
I have; specifically relating to turrets - I love the light package of my trusty Zeiss Terra 4-12 scope (I know it's not everyone's cup of tea), but it has a Plex reticle and no ballistic/target turrets! If I need to take a longer shot, I either need to guess a hold-over, or take off the caps and count clicks (no numbers on the dials), this is frustrating…
I scoured the internet looking for options to convert / upgrade what I have, but unfortunately nothing came up. Then decided to see what a new scope would cost, but most of the options that have target turrets are just a bit too expensive for me at the moment (not to mention bulkier than my Zeiss).
So, I set off to design a conversion of my own! Took apart one of the dials and decided that this shouldn’t be too hard, fired up Inventor and went to work on creating my new masterpiece.
I finally landed on a design that required 3 separate parts: one outer turret (obviously), one sleeve part to engage the threads of the previous caps, and one to allow the new turret to clamp to the existing dial.
Interestingly, the most difficult part was to try and decipher the existing threads on the scope caps.
Now the hard part starts – finding someone to manufacture this at a decent price-point… Tried local machinists in NZ, and those that quoted were quoting close to 70% of a new scope, and others said this is too small of a job…
Finally found a JLCCNC in China to make these for what I think is a decent price and worked with them to finalise some smaller aspects of my design. I wanted to have the whole thing anodised and the markings laser-engraved, but unfortunately their laser engraver doesn’t have a rotary indexer and the markings would be inaccurate. We finally agreed to CNC engrave the markings on the outside of the turret, I adjusted my file and sent it off for machining.
I just received my order, and I couldn’t be any happier! All parts fit together seamlessly, and the CNC engraving looks very professional. I think in time I’ll will the engraving in with some kind of white paint or white epoxy, as it isn’t THAT easy to read.
What I’ll do different in the future is to select a polished+anodised finish, I selected bead blasting+anodising, which is just a bit too rough for my liking (you live and you learn, right).
Next steps are to tap M3 threads for the setscrew and locate a 23x1mm gasket / O-ring to make this whole thing watertight. I’ll also need to laser engrave a reference line on the Sleeve part, was kind-of impossible to know where this should be without fitting the part to the scope.
I can also customize one to my own ballistic drop in the future, just wanted to keep it relatively straight forward at this point.
If anyone wants to make the same upgrade to their Terra’s, I’d be happy to share the files around (send me a PM).
Snips of the basic design below, will get some photos of the real deal tomorrow some time.
