Yes, I noticed the double taper on all the Badger needles. On the Iwata and H&S needle, there is only one taper that a naked eye can see. I did not want to stir up another argument for pointing out the difference and just went with the measurement method that Bill Grigg heard from Ken Schlotfeldt. I don't know what to make of the double taper which effectively shortens the total taper length. By intuition, I suspect the second steeper taper angle and a shorter taper can create a larger spray angle. (Just guessing on my part.)
Your guess is as good as mine. But my guess is that the double taper makes the needle less damage prone, and they probably found that it had little or no effect on spray pattern.
I did measure both taper angles the way you did. I have a first taper at 33.2° and the second taper at 8.02°. We seem to agree pretty well again.
Then we agree the main taper of the needle is 8 degrees. I suspect this is the taper that is significant.
But they (direct measurements) are still near or above the high end of the range the Bill Grigg cited from Ken Schlotfeldt. We are measuring the finest needle for the Pro-series. Shouldn't it be closer to the low end value instead? That's why I suspect a different measuring method or definition.
You got me. All I know is what I measure. How do you know the 105 needle is the finest?
I read with interest (a while back) on your web site that the Renegade Rage needle shape is identical to the older Legend series Badger 200 single action needle. So the 200 had been using a small second taper angle for a long time. Why did Badger make the newer Pro-series needle angle larger?
Badger has been making airbrushes for a long time and they know much more about them than you or I. So I assume they chose based on the performance characteristics they were looking for.
Do you know how Badger uses their optical comparator? I would not have expected that an airbrush needle needs that type of accuracy. I will be really impressed if Badger checks the matching of needle angle to the inside nozzle angle in their production. Many suppliers who make precision parts for my projects use the optical technique to certify that their parts meet the specification which are a lot tighter than an airbrush spec.
Optical comparators are very easy to use and it only takes a couple seconds to verify an angle, especially if you have fixturing and an overlay. As an engineer, you know that nothing is perfect. Everything has a tolerance that is acceptable. I spent some time in support of a receiving inspection lab, so I know that. Badger must have tolerances, but what they are is no doubt company confidential.
Let us all hope that this interesting discussion will not turn into another shouting match by the others.
Not on my part. Obviously you are interested in these details. And I think it's fun to think about them too. But, I must say that to the average guy who just wants an airbrush that will do a good job on his models, it doesn't mean much. Most any Badger, Paasche, Iwata, etc. will do that with a little practice.
By the way, one thing you are missing is the effect of air flow, which I suspect is laminar over the needle. Airbrush designs do vary in the configuration of the regulator and who knows what effect this has. It would take something like Schlieren optics to examine it, and that's beyond my resources. Perhaps you have access to something like this.