Three Questions about Micrometers

[Joe Piro]

My apologies for starting another thread. I posted these three questions before under a thread called "Ratchet Stop vs.Ratchet Thimble on Micrometer" and didn't really get clear answers.
I guess not that many people saw it on an old thread that someone else started, and perhaps I changed topic just a little too much. I try to read all the existing threads first before I start another but I still have questions, so here goes.
I am shopping for three new micrometers to replace ones I bought perhaps 30 years ago and recently lost by fire (Series 101 and 103 Mitutoyo). I am considering the 293 Series Digimatics because I work on American and metric engines and some Mitutoyo models make the inch/mm conversion digitally. Also I am not young and although I am quite comfortable reading vernier scales, I don't see as well as when I was younger. .
First: Is my impression correct that I can buy a lot more resolution and accuracy at reasonable prices compared to 20-30 years ago?
Second: My Zoro Tools discount recently worked on a Mitutoyo caliper, but it didn't work on the micrometers I had in my shopping cart. Has anyone here gotten a discount on Mitutoyo micrometers at Zoro.
Third: I have recently imported a lot of Japanese tools (Thanks to all the advice and experience here at Garage Journal it was pretty easy from Ehime Machine, Amazon.jp and Factory Gear. Thanks a lot, guys!) I can save about a third on Mitutoyo micrometers from Amazon.jp. Has anyone imported micrometers from Japan?
How did that go? Micrometers are pretty reliable. But would there be a warranty problem with Mitutoyo USA (like people have with Nikon USA warranties on gray market cameras for example.)
OK... Make that Four questions: I prefer well made tools but I have brands from Craftsman to Snap-on. Are carefully chosen but considerably cheaper mics:
less accurate, less repeatable, less durable? None of these or all of these?
Thanks....looking forward to your experiences and advice.

P.S.: Thanks X1 Mike, tube_guy, and Mgdoug3 for chiming in before.

 

[mogandave]

My apologies for starting another thread. I posted these three questions before under a thread called "Ratchet Stop vs.Ratchet Thimble on Micrometer" and didn't really get clear answers.
I guess not that many people saw it on an old thread that someone else started, and perhaps I changed topic just a little too much. I try to read all the existing threads first before I start another but I still have questions, so here goes.
I am shopping for three new micrometers to replace ones I bought perhaps 30 years ago and recently lost by fire (Series 101 and 103 Mitutoyo). I am considering the 293 Series Digimatics because I work on American and metric engines and some Mitutoyo models make the inch/mm conversion digitally. Also I am not young and although I am quite comfortable reading vernier scales, I don't see as well as when I was younger. .
First: Is my impression correct that I can buy a lot more resolution and accuracy at reasonable prices compared to 20-30 years ago?

This is generally correct, if not in absolute dollars, certainly relatively.

Also, I think most of the digital stuff will toggle between inches and mm.

Second: My Zoro Tools discount recently worked on a Mitutoyo caliper, but it didn't work on the micrometers I had in my shopping cart. Has anyone here gotten a discount on Mitutoyo micrometers at Zoro.

I have no idea.

Third: I have recently imported a lot of Japanese tools (Thanks to all the advice and experience here at Garage Journal it was pretty easy from Ehime Machine, Amazon.jp and Factory Gear. Thanks a lot, guys!) I can save about a third on Mitutoyo micrometers from Amazon.jp. Has anyone imported micrometers from Japan?
How did that go? Micrometers are pretty reliable. But would there be a warranty problem with Mitutoyo USA (like people have with Nikon USA warranties on gray market cameras for example.)

I have not, but generally warranties in the US are better than in other countries, and I would be surprised if the imported stuff would be covered. That said, if you can truly save a third, why worry about the warranty?

Saving a third seems suspect, be sure you are comparing apples to apples.

OK... Make that Four questions: I prefer well made tools but I have brands from Craftsman to Snap-on. Are carefully chosen but considerably cheaper mics:
less accurate, less repeatable, less durable? None of these or all of these?
Thanks....looking forward to your experiences and advice.

P.S.: Thanks X1 Mike, tube_guy, and Mgdoug3 for chiming in before.

We had Mitutoyo and Fowler (which are cheap) calipers. The production guys got the Fowlers and tool-room guys got the Mitutoyos, and while the Mitutoyo's seemed nicer and a more robust, I can't say they were really more accurate. I think at the time the Mitutoyo's we're over $200 and the Fowlers were routinely on sale (Enco) for around $20.

I would not buy a mic I could not hold first.

A little harder to trust them, but I always liked the feel of the thimbles.

 

[Mgdoug3]

Whichever route you end up going I would also recommend buying gauge blocks. I occasionally check my micrometers and calipers to make sure they are accurate.

 

[Whitworth]

You can get a Mitutoyo digital micrometer for $150 ish at Amazon.

No brainer.

 

[dr_clyde]

You can get a Mitutoyo digital micrometer for $150 ish at Amazon.

No brainer.

Amazon unknowingly sells a LOT of counterfeit and fake measuring tools on their site through third party vendors. If it's half the price of any other industrial supply house, it's probably fake. This is a very big problem with Amazon that they seem to be perfectly willing to ignore.

Buy your tools from industrial tool vendors. They have accounts directly with Mitutoyo and you'll get the real deal.

As far as OP is concerned, I would think the digital route would be best if you're constantly switching from inch to metric. Mits are about the best out there in their price range for digital mics.

 

[Whitworth]

Amazon unknowingly sells a LOT of counterfeit and fake measuring tools on their site through third party vendors. If it's half the price of any other industrial supply house, it's probably fake. This is a very big problem with Amazon that they seem to be perfectly willing to ignore.

The one I'm referring to is from the Mitutoyo store on Amazon.

Currently $152.25 on sale from $193.

 

[Packard V8]

Amazon unknowingly sells a LOT of counterfeit and fake measuring tools on their site through third party vendors. If it's half the price of any other industrial supply house, it's probably fake. This is a very big problem with Amazon that they seem to be perfectly willing to ignore.

I beg to differ!! Amazon knows well they are allowing counterfeits/fakes to be sold on their site.

I do agree, they aid and abet the frauds. As far as Amazon is concerned, volume will cover all problems. Just sell more and the volume will make enough profit to cover returns and customer complaints about fakes. That it is a huge hassle to the customer, they ignore. Easier to let the system deal with it and laugh all the way to record-high stock price.

jack vines, who in another life saw naked corporate greed at work.

 

[65ranchero]

I have a digital Craftsman caliper ( It was another make on it) and after sitting in the case for years the LCD screen started to bleed across the face.
I can still read it but its annoying and yes it toggles between mm and inch

 

[dr_clyde]

The one I'm referring to is from the Mitutoyo store on Amazon.

Currently $152.25 on sale from $193.

Ok, that's good to know. That's probably a safe bet then.

But just for general knowledge, Amazon WILL sell fakes and they DNGAF about it. Buyer beware.

 

[dr_clyde]

I beg to differ!! Amazon knows well they are allowing counterfeits/fakes to be sold on their site. As far as they are concerned, volume will cover all problems. Just sell more and the volume will make enough profit to cover returns and customer complaints about fakes. That it is a huge hassle to the customer, they ignore. Easier to let the system deal with it and laugh all the way to record-high stock price.

jack vines, who in another life saw naked corporate greed at work.

Ok, so even if they're aware, they just don't care.

I'd rather buy from my local industrial supply house and spend the extra $20 or whatever. I know the owner by name, and they're local. **** Amazon.

 

[X1 Mike]

We had Mitutoyo and Fowler (which are cheap) calipers. The production guys got the Fowlers and tool-room guys got the Mitutoyos, and while the Mitutoyo's seemed nicer and a more robust, I can't say they were really more accurate. I think at the time the Mitutoyo's we're over $200 and the Fowlers were routinely on sale (Enco) for around $20.

One of the unfortunate facts of our global manufacturing world is brands like Fowler, they were for many years a top tier tool brand and is now outsourced China tools of questionable quality. Some of their stuff is actually still made here in America and is top notch but now most of the stuff you see from Fowler are mic's that are basically a copy of the Fowler/NSK mics from years ago. I have some NSK mic's and I would put them right up there with Mitutoyo. Of course, they are probably 25 years old and that's why my suggestion is usually to buy used when it comes to mic's. If a set of mic's on eBay has a recent calibration sticker, I'm in. Most places I've worked we had to hold fairly tight tolerances so to meet ISO standards they would just have us put a little "For reference only" sticker on the mic to avoid calibrating a hundred sets of mic's. If a mic has a calibration sticker on it, you should be golden.

 

[exmaxima1]

I had a Fowler caliper, Swiss-made, for many years and it was an excellent tool. I only replaced it because the it stayed on all the time and would eat batteries. No complaints with Fowler from 30 years ago.

 

[seber]

We always handed out the cheapest mikes we could find to the apes on the production line. Those guys had to handle the raw material all day and got quite strong. As long as they held up those cheap mikes were as accurate as the very best. They are rough working and eventually froze or broke, but I can't say the failure was not due to abuse.

 

[FMB4]

You are over thinking this imo.

 

[Steve_P]

For vernier micrometers, I don't know if you can buy better today vs 20+ years ago for the $. About 25 years ago, back when Enco existed, I bought a 0-6" set of micrometers from them, no name Chinese mfg, for ~$100. I took them to work and checked them on gage blocks and they were dead on. For digital, they are probably cheaper today. For a brand like Mitutoyo, dunno.

 

[mogandave]

One of the unfortunate facts of our global manufacturing world is brands like Fowler, they were for many years a top tier tool brand and is now outsourced China tools of questionable quality. Some of their stuff is actually still made here in America and is top notch but now most of the stuff you see from Fowler are mic's that are basically a copy of the Fowler/NSK mics from years ago. I have some NSK mic's and I would put them right up there with Mitutoyo. Of course, they are probably 25 years old and that's why my suggestion is usually to buy used when it comes to mic's. If a set of mic's on eBay has a recent calibration sticker, I'm in. Most places I've worked we had to hold fairly tight tolerances so to meet ISO standards they would just have us put a little "For reference only" sticker on the mic to avoid calibrating a hundred sets of mic's. If a mic has a calibration sticker on it, you should be golden.

The Fowlers we had were made in China, and this was back when Enco was still in business. My Mitutoyo went south about six months ago (battery contact tab broke off) and I'm now using one of the Fowlers. Both batteries it came with were dead, but with a new battery it's working perfect.

Calibration anyone?

 

[CHI_Tool&Die]

My apologies for starting another thread. I posted these three questions before under a thread called "Ratchet Stop vs.Ratchet Thimble on Micrometer" and didn't really get clear answers.
I guess not that many people saw it on an old thread that someone else started, and perhaps I changed topic just a little too much. I try to read all the existing threads first before I start another but I still have questions, so here goes.
I am shopping for three new micrometers to replace ones I bought perhaps 30 years ago and recently lost by fire (Series 101 and 103 Mitutoyo). I am considering the 293 Series Digimatics because I work on American and metric engines and some Mitutoyo models make the inch/mm conversion digitally. Also I am not young and although I am quite comfortable reading vernier scales, I don't see as well as when I was younger. .
First: Is my impression correct that I can buy a lot more resolution and accuracy at reasonable prices compared to 20-30 years ago?

I don't know about 20-30 years ago, but micrometers today are really affordable because you can shop a wide variety. First, you have MiUSA, MiJapan, and the imports. Second, you have the option of going mechanical, digital, or a hybrid. Third, you can opt for tighter accuracy (.0001" graduation) or go for a more standard .001" graduation. Fourth, you can pick either a ratchet or a friction thimble. There are so many options that it is pretty awesome.

Second: My Zoro Tools discount recently worked on a Mitutoyo caliper, but it didn't work on the micrometers I had in my shopping cart. Has anyone here gotten a discount on Mitutoyo micrometers at Zoro.

Zoro's coupons are weird. I've found that generally, the basic coupons that apply for categories do not work often or at all on micrometers and other precision measurement tools. Those usually say something like "save 20% on hand tools, electrical supplies, etc". Sometimes they work which makes it even more confusing. However, I have always had the coupons that apply to the entire order work for my mics and machinist tools. Those coupons will say something along the lines of "save 15% on your cart" or "save 20% on your next order".

Third: I have recently imported a lot of Japanese tools (Thanks to all the advice and experience here at Garage Journal it was pretty easy from Ehime Machine, Amazon.jp and Factory Gear. Thanks a lot, guys!) I can save about a third on Mitutoyo micrometers from Amazon.jp. Has anyone imported micrometers from Japan?
How did that go? Micrometers are pretty reliable. But would there be a warranty problem with Mitutoyo USA (like people have with Nikon USA warranties on gray market cameras for example.)

I cannot comment on importing the mics. I have bought all mine from industrial sellers here just in case I had any problems upon arrival in the mail. Some even personally delivered my mics or other tools to me at the shop.

OK... Make that Four questions: I prefer well made tools but I have brands from Craftsman to Snap-on. Are carefully chosen but considerably cheaper mics:
less accurate, less repeatable, less durable? None of these or all of these?
Thanks....looking forward to your experiences and advice.

This really depends on what you are looking for in a mic. I work with incredibly tight tolerances so all of my mics read to the tenths and I use ratcheting thimbles. I have put all my faith in Starrett and Mitutoyo because these two brands have given me consistently accurate readings on these tight tolerances. I love my mechanical Starrett mics because they have a very slim profile which allows me to fit the mics into places I couldn't otherwise reach. I also love the heavy knurling around the thimble and that all of the scales on the thimble and the sleeve are actually engraved onto the metal. The locking mechanism is really easy because it's just a circular disk at the base of the sleeve. The downside to Starrett is that they are incredibly expensive. I got a good deal on Amazon of all places. My Mitutoyo mics (I have mechanical and digital) are my most used. They have a switch locking mechanism which isn't my favorite and the scales are printed, but the ratcheting mechanism works flawlessly and they have been incredibly accurate. The digital ones are just bulky. They are also a really good price and manufactured in Japan. For reference, I bought a 0-3" set of mechanical Mitutoyo mics for the same price as my 1-2" Starrett mic. I'm not a huge fan of friction thimbles because the user error is higher since I'm relying on not applying different pressures, but I'll use them all day when I'm not going to such accurate readings. I just don't trust the other brands to the same degree, but I'm doing this all day for work so my demands may not be the same as yours.

Now, if you aren't in need of taking such accurate measurements, you can get away with any of the major brands. Starrett, Mitutoyo, Fowler, Insize, SPC, and the Brownies. Just make sure you take the time to calibrate the mics properly with a gage block or with a quality standard. You can always move the sleeve with the wrench they give you. All of these brands will give you solid repeatability with a .001" graduation.

Personally, if you have the means, I'd swing for the Japanese-made Mits. They are my workhorse mics and have never failed me. The Brazilian ones are ok, but I just don't like them as much. Something about the feel is just "eh" to me.

 

[X1 Mike]

The Fowlers we had were made in China, and this was back when Enco was still in business. My Mitutoyo went south about six months ago (battery contact tab broke off) and I'm now using one of the Fowlers. Both batteries it came with were dead, but with a new battery it's working perfect.

Calibration anyone?

Yeah, Fowler is really sketchy what they put their name on. When I first got in the trade (1985) a lot of the old timers swore by them, but I think they were already starting to outsource. I've never purchased new stuff from them, but I have had good luck with older tools.

 

[X1 Mike]

Personally, if you have the means, I'd swing for the Japanese-made Mits. They are my workhorse mics and have never failed me. The Brazilian ones are ok, but I just don't like them as much. Something about the feel is just "eh" to me.

I thought I heard somewhere that they were only making metric in Japan and everything in inches was being made in Brazil? May have been just dial indicators but it may be worth checking before purchase.



To the OP if I remember right, you were just buying these for engine rebuilds. I didn't think about it, but did you consider one of these?

Starrett T436RLS-3 1/2 Automotive Crankshaft Micrometer, Ratchet Stop, Lock Nut, 1-1/2 - 3-1/2" Range, 0.0001" Graduation, +/-0.0001" Accuracy: Outside Micrometers: Amazon.com: Industrial & Scientific

Starrett T436RLS-3 1/2 Automotive Crankshaft Micrometer, Ratchet Stop, Lock Nut, 1-1/2 - 3-1/2" Range, 0.0001" Graduation, +/-0.0001" Accuracy: Outside Micrometers: Amazon.com: Industrial & Scientific

www.amazon.com

I've never used one, but it may be worth a look for your use.

 

[MKSJ]

Mitutoyo Quantumike Micromters and Mitutoyo 500 Calipers, as well as others. Resolution wise I have seen older micrometers that have similar accuracy, but were very expensive in their time and probably not as robust in a harsh work environment. I also have Igaging Absolutes in both and also had some Fowler's. The newer Fowler and SPI (Chinese) made measuring equipment is pretty crappy, gave erratic reading (making parts wrong) and fell apart. I do not touch any of their newer cheap stuff anymore. Both Fowler and SPI in years past just rebranded other manufactures products, so like my older SPI Precision level is made by E.D.A France.

If you just want to keep simple then I would recommend authentic Mitutoyo Quantumike Micromter, I get very consistent readings due to the thimble ratchet, since it is an Absolute it remembers its 0 calibration point. I do check the it with a calibrator and it always is dead on. I have Igaging Absolute micrometers in larger size mostly due to cost and infrequent use. They are as accurate, but they do not have a thimble or a lock, the have a spring loaded plunger with a liver that pulls back the spindle. If you work in tight places or want to use it locked to verify sizing of multiple parts it is cumbersome. The Igaging Absolute caliper is going on 10+ years and has been a very good work horse, accuracy it compares with my Mitutoyo calipers, since both are Absolutes neither has lost their closed "0" on power up for many years.

My eyes are getting older so harder to read analogue scales, I also flip back and forth from imperial and metric, so the digital display is the way to go for me.

I would not buy from eBay or Amazon, as others have noted the fakes far out number the real ones, and they are very good copies. If it is so cheap to be a good deal it is probably a fake, and even some of the ones close to list price may also be fakes. Zoro and some of the other vendors, it depends on the discount codes. I had a recent 20% off hand tools, it included Mitutoyo, Interapid and pretty much whatever I through into the basket. They also have one time 10% off for new email accounts, many tooling/equipment sites have first time pop-ups. Saving a few dollars buying electronic measuring equipment abroad, not really worth it when you consider years of use and loss of warranty. Even if they did honor the warranty, you would most likely have to pay shipping both ways. I have this with some measuring tools from Germany, if it needs to be fixed you pay both ways plus repairs, so pretty much a toss.

I already made my case about cheap/poorly made tools. I have had my share, and for the most part always got replaced in the long run which cost me more. Doesn't mean spending big bucks will be that much better, but cheap is cheap. If you do not need the accuracy or just need something to knock around there are less expensive alternatives and you also need to consider if you use them for work, damage and if they walk off from your work area. I like the Mitutoyo Quantumike, best I have used. Caliper wise I could do just as well with my Igaging Absolute, been knocking it around for years and has been a real workhorse. I needed a larger caliper, and went with the Mitutoyo Absolute and also like it equally well (it was 3X the price). There are a number of other mid-priced calipers that are probably as good, the cheaper ones the batteries go quickly, the battery doors often fall off, they do not hold "0", etc. Make a mistake with one because it gave a faulty reading and it can cost you big time. Already been there.

 

[MushCreek]

I've been using micrometers in my trade for 45 years. I still have a dirt-cheap 1" mike I bought in the late 70's. I think it was $10 new at the time. It's still accurate! I've used it to measure grinding wheels, and yet it still works fine. I have an Etalon ($$$), and it does the exact same thing. Maybe smoother, maybe a tad more accurate. I have an old set of Fowler 1-4" (Swiss), and a cheap 0-12" set from Poland. I think I paid $130 brand new for the whole set. In skilled hands, they are all dead-nuts accurate. Once I get inside a thou, I have an indicating micrometer, which you set with gauge blocks. Now that sucker is really accurate. Everything really close we measure on a surface plate with gauge blocks. For round work, especially if you don't want to take it out of the machine, the indicating mikes are the way to go.

 

[Steve_P]

I do have some Mitutoyo stuff, and I would have loved to have purchased Mitutoyo 0-6" micrometers. But for home use, a few times a year for anything over 1", I just couldn't justify the price: IIRC it was 5-6X as much $ at that time. The Enco set I purchased has .0001" graduations and as I've said are dead on. After I purchased them, I checked them on gage blocks that were verified at least yearly per our ISO quality program at work. 20-25 years ago, I saw the same set I have in many machine shops. But where to buy the similar set today? If MSC has it, it's probably 2-3X as much now and maybe not such a deal if Mitutoyo is twice as much $. I've said it before, but I miss Enco; and I don't run a machine shop, I'm just a home user.

 

[Joe Piro]

OP'er here. Wow!!! Thanks to all of you. You brought up a lot of good stuff I hadn't thought about and a lot based on personal experience which is just what I needed to hear.

so many options that it is pretty awesome.

So (in today's dollars) more accuracy probably costs a little less than it used to.

coupons will say something along the lines of "save 15% on your cart"

The Zoro 20 % coupons may not work, but the 15% ones probably will. I always play hardball and ignore those (give me 20% or nothing) but 15% is almost as good.

been using micrometers in my trade for 45 years

You can't put a price on the experience you guys bring to this forum.

...local industrial supply house and spend the extra $20 or whatever

Avoid counterfeits and if there's only a little money difference support local supply houses. We would miss those local guys if they were gone tomorrow.

And buy gage blocks !!!!
Someone in another thread mentioned if I'm not mistaken a single 1-2-3 gage block... Seems like a good idea.

 

[CHI_Tool&Die]

Hey OP, I wouldn’t use a 1-2-3 block for checking your mics unless you ground it yourself. I’d use actual gage blocks like these. Every shop I have been in has a set. They can be really, really expensive and that’s why the mics come with a standard. It allows you to check and set your calibration. The blocks are to double check. I’ve only been in the trade just under 10 years, so maybe the older guys could chime in on that.

 

[Joe Piro]

I’d use actual gage blocks like these.

I learned a lot from watching the video on that link. Thanks again.

 

[nbpt100]

Whichever route you end up going I would also recommend buying gauge blocks. I occasionally check my micrometers and calipers to make sure they are accurate.

Guage blocks will work but are expensive. I keep a few dowel pins around to check the calibration on my calipers and mics. The are precision ground .0002 under the nominal size. i.e. a 1/4 dowel is .2498

 

[MushCreek]

1-2-3 blocks aren't really accurate enough unless they've been calibrated. I use gauge blocks. Dowel pins aren't always as accurate as you would think. I was going to use 1/2" dowel pins for roller bearings, but they weren't very round. Even cheap Chinese gauge blocks would be accurate enough for checking mics, and you don't need a great big set. People forget that when you get down to .0001", temperature becomes a factor as well.

 

[bsaint]

It seems you want Mitutoyo. I'm not here to change your mind. At the plant they will buy you Mitutoyo unless I spec out something else which is usually Starrett (Massachusetts raised so I stick with local brands). We have a value brand sold from our carbide dealer called Insized - its like Fowler. Everything always passes inspection because all our tools are calibrated. Anyways sorry to ramble the Mitutoyo are excellent and durable and if you like them stick with it even if you can't get a discount. We have almost every measuring tool from them including some random stuff like wire mics.

 

[nbpt100]

Dowel pins aren't always as accurate as you would think. I was going to use 1/2" dowel pins for roller bearings, but they weren't very round. Even cheap Chinese gauge blocks would be accurate enough for checking mics, and you don't need a great big set. People forget that when you get down to .0001", temperature becomes a factor as well.

I take your word for it. They are likely Chinese made dowel pins. That is a very sad state of affairs if a new center-less ground dowel pin is out of round.
The Pins i use are from the 1980's and USA made. Still keep them around and I have no questions about their accuracy. It is close enough for work at home.

It is never a bad idea to calibrate whatever you are using at home to a good known standard before you put it into service. If you can take it to work or have a friend take it to their shop and calibrate it for you. You are then good to go. If someone is doing stuff at home that requires +/- .0001 they are amazing. I would love to visit that home shop. At least virtually.

 

[Steve_P]

dowel pins typically have a 0-.0003" tolerance; as said, this is not good if you're looking to verify a .0001" graduation mic

 

[Whitworth]

Any good micrometer or micrometer set will come with the necessary precision standards.

Why you'd want to use a dowel pin, or a 3-2-1 block or an old penny for that matter makes no sense.

Why this thread is still going after all this time when the OP could have had what he needs Amazon primed next day to him makes no sense either.

 

[dutchgray]

Any good micrometer or micrometer set will come with the necessary precision standards.

Why you'd want to use a dowel pin, or a 3-2-1 block or an old penny for that matter makes no sense.

Why this thread is still going after all this time when the OP could have had what he needs Amazon primed next day to him makes no sense either.

Moore and Wright, the standards were an optional accessory you bought if you needed them when you bought the micrometers, they were definitely quality micrometers.
This is also why you don't find many used ones with standards, especially in the larger sizes individual machinest's would generally not own.

 

[nbpt100]

dowel pins typically have a 0-.0003" tolerance; as said, this is not good if you're looking to verify a .0001" graduation mic

If you get it calibrated you are good to go. If you are doing .0001 work at home then that is amazing. For a business buy a calibrated Standard. There is a difference between doing work at home vs. for a business. I hope this clears up my thoughts.

 

[dr_clyde]

There is a difference between a dowel pin and a gage pin. I think some guys are getting them mixed up.

Dowel pins are fasteners for assembly of dies and molds. Typically within a few tenths but not accurate enough to be a standard. Gage pins are measuring tools and are ground more precisely than dowels. You could use a gage pin to set a mic. Although micrometer standards are pretty cheap and lots of mic sets come with them.

 

[Steve_P]

If you get it calibrated you are good to go. If you are doing .0001 work at home then that is amazing. For a business buy a calibrated Standard. There is a difference between doing work at home vs. for a business. I hope this clears up my thoughts.

If you want to measure engine parts, like a crankshaft, IMO you should be using .0001" graduation micrometers.

 

[CallumRD1]

As far as micrometer calibration goes, you only need to set one point in the measurement range. A 0-1" mic should be calibrated at zero and will be correct throughout the rest of the range as long as the threads are properly ground. A 1-2" mic should be calibrated at 1" and should have come with the necessary standard (and should only be calibrated at 20˚C because both the mic and standard will grow and shrink with temperature; this matters when measuring in tenths. A classic mistake is measuring a hot freshly cut part on the lathe for a bearing press fit, but when it cools the part shrinks enough to cause the fit to end up a slip fit.). A good Mitutoyo vernier or digital micrometer should be able to resolve half a tenth (0.00005") reliably with proper technique. I've used many different models over the years but by far my favorite to use in the machine shop is the Mitutoyo Quantumike. It has a very fast screw so it's quick and easy to make in-situ measurements of critical features like bearing seat diameters.

 

[X1 Mike]

There are way too many people throwing around 0.0001" tolerance in a thread about micrometers.

If someone claimed to be holding those tolerances with a micrometer, I would throw them out of the shop.

 

[CallumRD1]

There are way too many people throwing around 0.0001" tolerance in a thread about micrometers.

If someone claimed to be holding those tolerances with a micrometer, I would throw them out of the shop.

I'm not sure what you mean by this. I may not be able to consistently machine to a tenth, but I absolutely can consistently measure to a tenth with a good micrometer. That's what they're designed to do. My Mitutoyo micrometers will consistently measure calibrated gauge blocks to plus or minus a half a tenth.

 

[X1 Mike]

I'm not sure what you mean by this. I may not be able to consistently machine to a tenth, but I absolutely can consistently measure to a tenth with a good micrometer. That's what they're designed to do. My Mitutoyo micrometers will consistently measure calibrated gauge blocks to plus or minus a half a tenth.

What I'm trying to say is that I put parts in space and if someone claimed to machine or measure holding those tolerances, I'd question their bona fides.

If I'm measuring that close, I'm using an indicator with gage blocks.
If I'm using a micrometer, I'm using the word "about." It's about 0.7633

 

[Mas78]

I agree with X1 Mike.
Micrometers may have 0.0001 graduation marks, however many Micrometers are not accurate to this tolerance. And allot of the micrometer standards are not at 0.0001" tolerance.
You'd need good gage blocks for that tolerance.
Also you want your measuring tool to ideally be 5-10 times more accurate then the tolerance your given to help eliminate measurement errors.

Granted this isn't always possible though.