Anatomy of a .18 micron needle

Robbyrockett2

Air-Valve Autobot!
Since I had to do a lot of measuring to make matches I figured I might as well share. Could be helpful for making an exact repair.

So our main angle 6 deg;
The secondary angle stubs off about 1.1mm of what it would be if it continued.

1545870373196.jpg

Secondary angle 12deg
Again stubbed off flat , cutting about .3mm of what it would be;
1545869738211.jpg


The flat tip is about .05mm across, these are .1mm divisions;
needle2.jpg

A common method called centerless grinding is likely used, it a bit difficult to fully control so the angle actually runs slightly off parallel from the needles axis even though the point is centered.
(Imagine balancing a cone on a rod and tilting the bottom of it a bit)
This is why the taper length is different depending on which side it's measured on, as you see here;

needle6.jpg

This means the taper length can measure 11.1-11.5 mm.

So, to blueprint this needle tip I used a little applied trig.
I'll put that in the next post.
 
This is not done to real angles or scale just somewhere to visually hang the numbers. Doesn't matter much but basically by calculating only half the taper I get to work with right triangles.

Starting with a triangle of 6deg and a length of 1.4mm I know the secondary angles height is .07357mm.

So the main angle must go from there to .6mm at 3 deg.
Height of .52643 at 3 deg.

That makes the main angle 10.05 mm long.
Add the 1.1mm the second angle is stubbed down to and that makes the total proper length of taper 11.15mm.

Also means the flat on the tip is actually about .064mm across, though the best I could mic an actual measurement was .07 , of course I personally don't have steady enough hands to mic the very edge of the tip so I'm satisfied my numbers are good.

You can allow for quite a big margin of error (.5mm on lengths, .5deg on angles) here without any human being able to detect a difference in spray characteristics, but it something good to aim for.

IMG_20181226_205529.jpg
 
Last edited:
Of course the easiest and most important checks, in order are
1.how far it sticks out the nozzle

2. How long approximately is the taper.

3. Does it have about a 1mm second angle, and does it have just a bit of a flat on the end.

I've found that flat tip important not only to deter damage but also for spraying. A perfectly sharp point actually doesn't work as well for some aspects.
 
Last edited:
Of course the easiest and most important checks, in order are
1.how far it sticks out the nozzle

That's how I measure my custom treated needles:)

I've found that flat tip important not only to deter damage but also for spraying. A perfectly sharp point actually doesn't work as well for some aspects.

My way is to make an arch shaped second tip. It's something in between "flat tip" and straight one stage sanding (Olympos). Works well.
 
That's how I measure my custom treated needles:)



My way is to make an arch shaped second tip. It's something in between "flat tip" and straight one stage sanding (Olympos). Works well.
They generally end up that way when you polish anyhow. At least with soft lapping.
Like a rifle bullet.

Though, when I refer to the flat tip I'm referring to the blunt portion .064 wide , not the second angle.
 
Last edited:
They generally end up that way when you polish anyhow. At least with soft lapping.
Like a rifle bullet.

That's it! It becomes that way anyhow. The only thing more I do to the tip is giving certain arch shape, not just as it is.

I think this shape is better than double angled tip for both paint and air flows to get finer line. Besides the tip becomes much more bend proof then the straight one.


Though, when I refer to the flat tip I'm referring to the blunt portion .064 wide , not the second angle.

Didn't understand you correctly.
 
Nice post. See this is the only reason I think Micron needles are double the cost of all other iwata needles, that secondary angle. Also why I think that SharpenAir thingy wouldn't work on micron needles. I emailed the people at SharpenAir that specific question about the double taper on Micron needles, and they wouldn't even respond. :thumbsdown::rolleyes:
 
Have you measured both .18 & .23? I'm curious to the difference. I have both sizes in my parts stock still sealed in the package, I should take pics with my 36mp D810 and macro lens of both.
 
Nice post. See this is the only reason I think Micron needles are double the cost of all other iwata needles, that secondary angle. Also why I think that SharpenAir thingy wouldn't work on micron needles. I emailed the people at SharpenAir that specific question about the double taper on Micron needles, and they wouldn't even respond. :thumbsdown::rolleyes:
Try again, Chad is very responsive to questions - maybe on holiday? The Sharpenair is designed to work at 4 different angles to repair a needle tip, and works fine on Micron needles.
 
Nice post. See this is the only reason I think Micron needles are double the cost of all other iwata needles, that secondary angle. Also why I think that SharpenAir thingy wouldn't work on micron needles. I emailed the people at SharpenAir that specific question about the double taper on Micron needles, and they wouldn't even respond. :thumbsdown::rolleyes:
Eclipse needles have a pronounced double taper.
The micron needles I'm pretty sure cost double just because they can.

Sharpenair has four angles to use.
I think 6 and 12 are in there.
How well you use it to actually copy the original profile I think is kind of on you.

Part of why I figured I'd share the info.
 
I always thought the sharpenair (SA) was designed for people who bent a needle, and needed to get the job done. I never thought of it as a factory reman in a can. It turns out, that the profile it creates will work very very well in most situations.

Maybe somebody who is super-tuned into the brush doing micro fine detail could pick out a new vs. reshaped SA needle, but so far I've found it will do a very adequate job. I don't like the surface finish of the 1200 stones and the 600 stones are like dragging my needle on concrete outside.
 
I always thought the sharpenair (SA) was designed for people who bent a needle, and needed to get the job done. I never thought of it as a factory reman in a can. It turns out, that the profile it creates will work very very well in most situations.

Maybe somebody who is super-tuned into the brush doing micro fine detail could pick out a new vs. reshaped SA needle, but so far I've found it will do a very adequate job. I don't like the surface finish of the 1200 stones and the 600 stones are like dragging my needle on concrete outside.
With the measurements here if you were finnicky about it I'm pretty sure you could use a sharpenair to where almost noone could tell between factory and the repair.
 
The only problem is you do get a totally different finish when you just rotate something in one position on 1200 grit (or any grit) then you would if you moved the abrasive around.
You don't get random cuts like abrasive is supposed to do.

Each grit particle settles into a rut and 1200 effectively gives a 600 finish.
 
Back
Top