KC2IXE
Flashaholic*
I always thought that once your tolerance level got to tighter that +-.005, you really shouldn't be using calipers anyway. That's what your mic is for
Somebody else like the "old school" vernier calipers ...
- Thread starter wquiles
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Russel
Enlightened
That is true, but with a little experience, vernier calipers with the fine thumb screw adjustment can be used to consistently measure to 0.001"
KC2IXE
Flashaholic*
Oh yeah, a Master Vernier can be quite accurate, no doubt about it, but as I rarely work above 6", and have mics to 6", in general, once the numbers get tight, out comes the mic. BTW, even with digital mics, I've found a big difference between say a cheap set and my Miti 6" absolutes (which do have a thumb screw)
Russel
Enlightened
Most of the measurements that I take with my calipers are under 2 inches. Mostly for measuring materials when making rough cuts. It surprised me that I was getting such good results with a cheap vernier master (with thumbscrew) caliper. Measure, calculate rough cut, cut, measure again for finish cut, and have the numbers work out consistently. Of course, you have to develop a feel for the calipers.
I do, of course, use micrometers when I need to be as accurate as possible. It's kind of funny, I was always the guy swearing up and down that you can't measure to .001" with calipers consistently until I discovered that I could when I started using them over and over.
Edit: Wow, I must be blind. I just noticed you're an amateur extra.
--... ...--
I do, of course, use micrometers when I need to be as accurate as possible. It's kind of funny, I was always the guy swearing up and down that you can't measure to .001" with calipers consistently until I discovered that I could when I started using them over and over.
Edit: Wow, I must be blind. I just noticed you're an amateur extra.
--... ...--
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KC2IXE
Flashaholic*
Well, I don't doubt most are under 2". I saw a real interesting stats chart on the size of most work done in machine shops, and if I remember right, 90% is under 1", which is why the 5C collet is so popular for turned work. If I remember right, for turned work, something like 45% is under 1/2"!!
precisionworks
Flashaholic
My Mitu mechanical mics run from 0" - 12" & they're hard to beat for good OD measurements. Where the Master Vernier really shines is ID measurement because the jaws are dead parallel (unlike most digit calipers where the ID jaws are offset so they can slide by each other). The best ID measurements are made with tri-mics (not a single one in my shop) or with the Starrett or Mitu inside micrometer caliper: http://www.starrett.com/metrology/p...and-Tools/Micrometers/Inside-Micrometers/700A
But - the Starrett inside mic calipers measure only .2"-1.2" or 1" - 2" (700B Starrett). The Master Vernier allows dead nuts accurate measurements limited only by the length of the caliper (Starrett claims .0005" per foot & there isn't a disco caliper made that can equal that).
Other ways to accurately measure ID ... sure, telescoping mics (use them a lot), solid rod mics (quite often) expanding gages (every now & then), pin gages for tiny bores, etc. The Master Verniers are the go to instrument when there's nothing else that fits the bill & the bore has to be on the money the first time around - because there isn't a second chance to hit dimension.
But - the Starrett inside mic calipers measure only .2"-1.2" or 1" - 2" (700B Starrett). The Master Vernier allows dead nuts accurate measurements limited only by the length of the caliper (Starrett claims .0005" per foot & there isn't a disco caliper made that can equal that).
Other ways to accurately measure ID ... sure, telescoping mics (use them a lot), solid rod mics (quite often) expanding gages (every now & then), pin gages for tiny bores, etc. The Master Verniers are the go to instrument when there's nothing else that fits the bill & the bore has to be on the money the first time around - because there isn't a second chance to hit dimension.
KC2IXE
Flashaholic*
Yeah, inside measurement is a bear, no matter what you do. Like I said, nothing against verniers, and have a pair (but really want a set of 12" masters, but so far not enough to actually, you know, BUY a pair, but they are getting close to the top of the list). So far an inside mic (and yeah, I don't have any tri-mics either - the price - shudder) and or expanding gages has been 'good enough' for what I need to do (gad, do I hate doing bearing press fits). I probably have better shop gear than my skill level needs.
I tend to treat Master verniers (when I've had the use of a set) as a standard/more precise tool for when they are NEEDED. The digis are 'good enough' for 90% of what I do, then I have way way too many sets of Mics. I've bough enough used lots of tools that I can't tell you how many mics I've GIVEN away to guys/girls just learning. Heck, I had one beat up old pair I even used to use as a C-clamp just to freak people out (totally beat .001 General brand that I painted red). I even keep a 1" mic in the glove box of the car
I tend to treat Master verniers (when I've had the use of a set) as a standard/more precise tool for when they are NEEDED. The digis are 'good enough' for 90% of what I do, then I have way way too many sets of Mics. I've bough enough used lots of tools that I can't tell you how many mics I've GIVEN away to guys/girls just learning. Heck, I had one beat up old pair I even used to use as a C-clamp just to freak people out (totally beat .001 General brand that I painted red). I even keep a 1" mic in the glove box of the car
KC2IXE
Flashaholic*
Just remember there was a job I was putting off for the lack of a good long caliper (need measurements in the 9" range). Guess what I decided to shell out the cash for. Nope, NOT a 12" Master - a 24" Yep, just bought a 24" Starrett Master vernier
Russel
Enlightened
I'm going to buy a Starret master vernier, one of these days...
This is the cheap one that I've been using.
http://www.centraltools.com/all_images/products/6421cat.jpg
This is the cheap one that I've been using.
http://www.centraltools.com/all_images/products/6421cat.jpg
