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Igaging micrometer
- Thread starter Poconolg
- Start date
I don't know of anything against IGaging. However, I find I don't use my Mitutoyo ball-end micrometer very often. The problem is a lot of brass, especially Lake City and some other makes, don't have perfectly smooth surfaces. For that reason and because the anvil measures thickness at a single point of ball contact, you can go all around the neck making multiple measurements and have the results jitter up and down around the average. That makes you spend extra time on the measurement. If you do go ahead with it, get a micrometer stand of some kind. It makes the measurements easier to take and more consistent.
I am currently using one of the Redding Case Neck Concentricity Gauges. It makes it easy to measure runout and then note (or spin the dial to zero) when the case it turned to where I want to measure the neck thickness and then see how much it moves when I withdraw the case. That said, this Sinclair tool is less expensive and appears to do the same thing and not require you to provide a separate base or to screw the tool to a bench, so the Sinclair is what I would get today.
I am currently using one of the Redding Case Neck Concentricity Gauges. It makes it easy to measure runout and then note (or spin the dial to zero) when the case it turned to where I want to measure the neck thickness and then see how much it moves when I withdraw the case. That said, this Sinclair tool is less expensive and appears to do the same thing and not require you to provide a separate base or to screw the tool to a bench, so the Sinclair is what I would get today.
I suggest you mic or caliper the neck diameter of a loaded round then use a bushing .002" smaller. After about .001" spring back, there'll be an interference fit of about .001 inch.
Half the difference between the round's neck diameter and bullet diameter is the neck wall thickness.
You can use calipers to measure how thick necks are measuring the last fourth inch of the neck.
Half the difference between the round's neck diameter and bullet diameter is the neck wall thickness.
You can use calipers to measure how thick necks are measuring the last fourth inch of the neck.
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if I were setting up a machine tool for a commercial production run I would not trust a cheap micrometer. For turning a neck or choosing a bushing I am not worried about whether the neck thickness is .0120 or .0121 or .0119. I use a RCBS I bought off Midway for about 50 bucks, it seems to work fine for the purpose I use it for.
Poconolg said:I have the Sinclair concentricity gauge. I want the micrometer just to get a numerical measurement of the neck wall thickness.
As I described, though not clearly, you can do that on the Sinclair gauge. Try it a slightly different way: Let the plunger of the dial indicator rest on the cylindrical case neck portion of the neck pilot. Loosen the thumbscrew that locks the dial bezel in place and rotate the bezel until the zero on the scale is lined up with the indicator needle and re-snug the screw. Slide the case on and observe how far the needle has moved from zero when the plunger is resting on the case. That is your neck thickness. It's not in tenths of a thousandth, but you can learn to read those between the graduations on the dial by eyeball when a measurement is small like that.
If you still want the tubing wall micrometer, in shooting, even if the precision were off by ±0.0002", you will still close enough comparison and it's not likely to be off that far if you zero is carefully. And, as I mentioned, a micrometer stand makes the measurements both faster and more repeatable.
Look at the RCBS Case Master tool
It has a setup to measure neck absolute neck thickness as well as variation.
It has a setup to measure neck absolute neck thickness as well as variation.
Aguila Blanca
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"Any good" depends on your expectations, and your needs. What level of accuracy and precision you you think you need? The micrometer you are looking at is made in China. I have a story about that.Poconolg said:Are Igaging tools any good? I see they have ball micrometers for under $100. Are they worth it or am I throwing my money away. I am only going to use it periodically,.
A number of years ago I bought a digital caliper from Harbor Freight Tools. It seemed to be okay, but it ate batteries. Plus ... I'm a dinosaur. I never really warmed up to using a digital, so it sits on the shelf and I use my dial calipers on an almost daily basis.
Several years ago I had a visit from a friend from Europe. He is a firearms aficionado. He expressed a desire to get a genuine Lyman digital caliper while he was in the United States. I don't remember where we ordered it, but we ordered one, and it arrived while he was still staying at my house. At one point I took his Lyman digital caliper and compared it to my Harbor Freight digital caliper (which cost about half what the Lyman had cost).
They were the same. I don't mean "similar." I don't mean "pretty much" the same. They were identical. I don't care what aspect I looked at -- the casting marks, the lettering, the construction inside the battery compartment -- everything was exactly the same. And that's the fundamental truth about most consumer-grade Chinese tools. They ARE all the same. They all come out of the same factory, and they just get a different name slapped on at the end of the assembly line.
You're looking at a digital ball micrometer that sells for around $65. Is it worth $65? Not to me. Being a dinosaur, I'd spend $35 and get the analog version (which, in fact, I have). I know how to calibrate the analog version so that it reads zero when it should read zero. I know the digitals calibrate by pushing a button, but I don't know how that works so I'm not sure I trust it. The Igaging digital ball micrometer I found on Amazon claims to read to 5 ten-thousandths (.00005). Is it really that accurate? I doubt it. Does it matter? I doubt it. Using a mechanical, analog micrometer I've found that a spec of lint from a tee shirt is enough to affect the reading, and that's only reading to the nearest thousandth. Even if this thing does read accurately to .00005" -- that's clean room accuracy. You aren't working in a clean room.
Bottom line, the Chinese mike is not the equal of a Starret or a Mitotuyo. On the other hand, you're making ammunition, you're not in the aerospace industry. Is it "good enough"? Again, it depends what your standards are. The Chinese calipers and micrometers are "good enough" for my purposes. I don't know if they are good enough for yours.
I will note that I have a Chinese 1" micrometer, and I also have a good Brown and Sharpe analog 1" micrometer that's now about 60 or 65 years old. The Chinese mike matches the B&S for everything I have measured with both. That's good enough for me, and it gives me a degree of certainty that my other Chinese measuring tools are "good enough."
That's actually half a ten-thousandth or 5 hundred-thousandths (50 millionths). And if you switch to mm, you get 0.001 mm resolution or one micron (.00003937"). I never know exactly how far to trust that last decimal place, either. It's not hard to change temperature enough to move it with a lot of materials.