I just finished up a custom parallax wheel for my FT rig. I think it turned out pretty good!
I've been using a Nikko Diamond Sterling 10x50x60 and really like the scope. I bought it used more than 10 years ago and it came with a "comma" style parallax wheel. It served me well but I didn't like the design since the effective are of the comma was pretty small. You can see from the pic below I had to transition from the comma wheel to the smaller diameter factory knob for anything much below 35Y. It turned out it wasnt a huge deal because my trajectory was at peak from 25Y-35Y so I didnt really lose much function in that range. None the less, I wanted to upgrade to a larger and wheel that was effective over the whole FT range of 10Y-55Y. The pics below show what I came up with.
This one shows the "original" condition as-purchased.
I started out with a hand sketch to get the general design
Next up was to model it in CAD. I used Fusion 360.
You can see the "tabs" left in to hold the part in place so it didnt come loose and break the end mill.
Next up was to configure the CAM (computer aided machining) to direct the end mill in the right sequence.
The pic below shows the stock bolted to the table and the facing operation complete.
Even with the flood coolant on, the "pocket clearing" operation used to open up the inner holes made a huge mess. I took a break here to vacuum up the chips.
The pic below shows the outline machined. Since some of the facing cuts required removing some of the hold down bolts, I also used powdercoating tape to secure the part to the table. Its about .002 thick. It amazes me that the cutter was able to cut all the aluminum out without cutting into the tape! This is a hobby grade CNC mill but Im pretty damn impressed with the accuracy.
My design uses a non-removable wheel. The Nikko scope parallax rotates in the opposite direction of many scopes. This puts the large portion of the wheel on the bottom side where its not much in the way. I had to get a bit creative to cut the slit in the clamping tab. I used a manual mill and a slitting saw for that operation. My clamping solution was rock solid and with light cuts, I had no problem.
The finished part was in good shape but I wasnt a fan of the end mill tracks so I used a random orbit sander to put a nice matt finish on it.
For the inside holes, I used some scotch brite to give it a uniform appearance.
The drilling and tapping was also done on the manual mill but I didnt snap any pics of the process.
The finished product turned out great. Its rock solid and gave me plenty of room in between the yardage marks at the far end ranges.
Overall, Im very pleased. It was a lot of work though. It doesnt look like it should have taken very long, but I probably put about 10 hours into the whole process.
Hopefully it serves me well. At least until I decide to switch scopes and need to re-invent the wheel!
With as much work as it took, it makes the pricing on the commercially available models seem pretty reasonable.
Anyway, I figured I'd share the pics of the process. I always enjoy looking at projects like these.
All the best,
Brian