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Posted By: PeteM from the Chaski Machine Forum
January 2002
There have been a few posts inquiring about micrometers for the home shop machinist; and I thought it might be useful to post some information about the desirable features and brands.
FOR STARTERS
- You'll use a 1" micrometer the most and it should be the best and most conveneint you can afford.
- A 0-6 or 0-8" caliper might be the next investment. I'd suggest either a high quality dial caliper(B&S makes an excellent one and Mitutoyo would be my second choice) or a digital electronic caliper if you need metric as well. Mitutoyo would be my first choice in a digital; since quality ones wihtout SPC are now available under $100. The import clones aren't too bad.
- Later you might fill in with additional micrometers and calipers. Because you'll likely use these less often, you might want to settle for cheaper imports, used, or lower-featured items. For example, you might want a cheaper 0-6" set of micrometers, a larger but vernier-reading caliper, or a supplemental set of large micrometers (say, 6-9") that uses interchangeable anvils.
BEST 1" MICROMETER FEATURES?
Like other which-tool-is-best debates you can get a passionate debate on the subject. Some of the variables to consider:
- Are the anvils hardened steel or carbide? Carbide wears longer and is best in abrasive environments. Steel isn't as likely to chip and will last for years with care. I'd much prefer a high quality steel anvil to a cheap non-parallel cemented carbide. As a practical matter, if you are buying a high quality used mic, look for either steel in mint condition or carbide with no significant chips. If it's a new mic, it will probably be carbide.
- Accuracy of the screw and screw-adjusting mechanism. Here's where there are subtle but significant differences between cheap imports and higher quality US and import mics. Some of this shows up in "feel." A cheap mic - most Chinese mics for example - feels squishy and indeterminate as it closes to zero. A good mic has a solid and definate feel as it reaches zero. Of course, you should never overtighten a mic, as it can distort the frame.
- Solid, ratchet, or friction mechanism? Many mics have a sort of slip clutch so that the same pressure is exerted for every measurement. This is especially important in production situations, with different operators, but one QC spec. The ultimate example of this was the Van Keuren light wave micrometer, which used optical fringe bands to assure a consistent measuring force. My personal preference is for a convertable friction/solid mechanism which gives a choice of solid feel or a friction thimble. The ratchet type mechanism can actually have a sort of impact wrench effect, which might show up in .0001 differences. For practical home shop use, you can pretty much suit yourself.
- .001 or .0001 reading? You can probably read a good .001 mic to a couple tenths. You can also mismeasure with a cheap .0001 reading mic by a couple thousandths. Most commonly, .0001 is read through a vernier. The US style vernier has closely spaced lines. The European style vernier wider spaced (easier to read) lines. Electronic mics tend to read to .00005 and can be accurate to .0001. There are also very nice mechanical digital micrometers (e.g. Brown & Sharpe, Etalon) that read directly to .001 and with a vernier to .0001. The bottom line is that mic quality is more important than .0001 reading; but the additional cost of a vernier is so small you'll probably want it.
- Insulated or plain frames? Plastic pads on the frame help insulate them from body heat. This is a nice feature, especially when measuring tight tolerances. A good mic without plastic pads (e.g. an older model) can be held in a shop cloth etc.
- Steel, plated, stainless, etc. thimbles and frames? Many fine quality micrometers are simply high carbon steel - Zeiss for example. Nice if you take care of them. Most quality micrometers have chrome plated thimbles and either plated or painted frames. Good plating will last almost forever; though it will wear. Cheap plating will lift. Most major manufacturers also offer a stainless version for harsh environments.
- Decimal conversions? Don't know about you, but I don't remember every 1/64th " conversion. For this reason, a chromed frame with a carefully engraved (readable!) conversion chart is handy. Charts that are silk-screened etc. will wear off in time.
- Digital electronic or manual? Quality digital mics have three things going for them: instant metric/US conversions, an easy to read display, and various electronic features like over-under reading. Mitutoyo is the share leader. There are also Chinese clones that seem to work, with less precise mechanical actions and uglier looking circuit boards and battery cases. The cons against digital are that they don't suffer abuse, they need batteries, and they are bulkier and heavier. If you can afford just one digital electronic tool, I'd make it a 0-6" caliper.
- Conventional, rapid-set, non-rotating spindle, mechanical-digital, or digital electronic operation? Conventional mics have a screw that advances .025 for every turn. These are the standard; but a little slow to quickly change from small to large size.
Some mics have a speeder on the end (small diameter knob) which is handy. Running the thimble against your palm is a good way to speed things up without undue wear on the threads.
Rapid-set mics advance at double the rate. They have a great feel, but cost significantly more to achieve equal accuracy.
Non-rotating spindles are keyed. Mitutoyo and others make great mics with this feature. This is useful in gaging materials where you don't want rotation. For most home shop uses it adds complexity and cost with no increase in accuracy.
Mechanical digital micrometers have geared mechanisms to advance counters. In general, these add complexity and cost but are easier to read. Mitutoyo and the nearly identical NSK make an accurate but clunky looking version. Brown and Sharpe makes a gorgeous mechanical digital mic; one of my favorites.
As noted above, digital electronic mics use a battery and LED display. These are especially handy if you go back and forth between US and metric units. Battery life has also improved in recent years; don't buy a "vintage" electronic mic.
- Spindle lock. A spindle lock is handy to keep track of a measurement and also to lock the spindle for small lot gaging. Best to have one. Of the two most common locking mechanisms, I prefer the lever type (B&S, Mitutoyo, etc.) to the locking ring type employed by Starrett. The reason is that levers seem to require less attention over the years and are easier to operate.
- Ergonomics. The real test is finding a mic that feels good to your hands, your style of work, and your eyes. There are many intangibles, like satin chrome, clearly marked graduations, light weight (S-T made and makes nice hollow frames in larger sizes), the thimbles, and so on. Ease and stability of adjustment to zero is another factor.
PERSONAL OPINIONS (** = a favorite)
** Brown & Sharpe. B&S has made dozens of different styles, from mundane to space-age looking. Their combination friction/solid mic with slant-line graduations and a carbide anvil is among the best mics you can buy. In the 0-1" size you can get a full chrome plated unit with a fractions table.
-- Central Tool is an old line US maker. I rate them a step below the best B&S, and a half step below the typical B&S, Starrett, and S-T mics.
-- China #1. The original made in China mics with pressed steel frames for the larger sizes are junk.
-- China #2. The more recent made in China mics that are Mitutoyo clones are pretty decent for the very low price. However, they don't come to zero with that definate feel and only time will tell if the chrome plating holds up and the thread maintains its accuracy.
-- Craftsman. Sears and Sears Craftsman mics are made by someone else. At various times this has included Goodell Pratt, Millers Falls, Scherr Tumico and others. Today, some are made in China. The quality varies with the orginal maker.
** Etalon. A fine Swiss mic; often identical in form to a B&S model.
-- Fowler / Helios. Fowler appears to rebrand others mics. A commonly available mic ("Fowler," "Helios," and also "NSK") has a nice friction thimble and is made in Japan. Almost a ** rating, except the friction thimble spring tends to break.
-- General, Hanson, Ace, etc. Beware that "Made in USA" doesn't always mean quality. Hardware stores have sold a cheap US made mic with a die cast frame. The recent Chinese clones run rings around these.
-- Lufkin. For years Lufkin made fine precsion tools, the equivalent of B&S and Starrett. The 1600 series (**) is especially recommended if you find one in mint condition. Very nice feel, larger diameter friction thimble, etc. Most of the other Lufkins have a small diameter thimble, about the same as the Starrett 436 series, which I don't like the feel of.
-- Mahr. High quality mics, but not often seen here and the ergonomics often are just so-so. Their rapid adjusting mics is very nice (**).
-- MG/National. A lower quality US (New York) make. Beats the General/Hanson/Ace die cast mics but a step below Central Tool and two steps below the mic you'll want to own. Accuracy of anvils not to be trusted to better than .001 in my opinion.
-- Millers Falls. MF bought out Goodell Pratt before WWII and has since ceased making mics. Still, you can often find model 112 mics in good condition. I like them as well as the plain Starrett 426.
** Mitutoyo. Like B&S and Starrett, Mitutoyo makes a very full line. Comparable mic to comparable mic, I like them better than Starretts on the basis of "feel." Accuracy is essentially the same, and your preferences may not match. Mitutoyo is probably the world leader in digital electronic mics; though Starret and others also make some nice ones.
-- Moore & Wright is the UK equivalent to Starrett. Nice mics; usually with a handy "measurement reminder" pointer included.
-- NSK. Similar in most respects to Mitutoyo. Probably the same parent company.
-- Poland. Nice mics for the price, as noted by Forrest and many others. Feel and are a little less substantial than the ** rated and other highest quality mics.
- Reed. An old US maker. Decent mic if you find one mint.
- Scherr-Tumico aka S-T. Formed out of two US makers, Scherr and Tumico (aka Tubular Micrometer Co.). These are high quality mics. S-T often won government bids against B&S and Starrett, so you may find some in mint condition from surplus property sales. The large sizes of tubular frame mics are nice and light. A 6-9" or 9-12" interchangeable anvil set, used, is a good buy. Of the 0-1" sizes there is one higher priced model with a very nice feel. This has a friction thimble with a short stubby speeder on the end. ** nice mic.
-- Shardlow. Decent UK brand.
-- Slocomb. Still made to the original 1896 patent design. Very tough US make, but lacking in features. An used 0-6" set in good shape (remember some of these are by now a hundred years old) could be a good way to fill out the larger sizes.
-- Soviet Union. The former USSR made very heavy, very tough, and pretty nice micrometers; mostly in metric sizes. Available cheap, if you need metric (but a digital mic is probably the better choice if you switch back and forth).
-- Starrett. Top market share in the US. The plain 426 series is what most people think of as a Starrett. Pros: it's tough and accurate. Cons: ratchet instead of friction thimble, painted frame instead of fraction chart, no insulation, and a small diameter thimble that's a bit harder to use and read. I wouldn't hesitate to own Starrett 426's in larger sizes; but I wouldn't make it my first choice in the 0-1" size. Most of those cons are handled in another Starrett full chrome friction thimble model (**). Starrett also makes a heavier 226 frame that I like a bit better than the entry level 426. Finally, as with B&S etc., there are dozens of specialty mics.
-- Steinmeyer. Decent German mics.
-- West Germany. Years ago, the US market was flooded with mics labelled "West Germany." The theory was fine German quality at low prices. The reality was a mic with low quality; about the same as the MG/National. Just so you don't get taken; these had a stick-on decimal chart on the frame.
- Scores of others. The micrometer and Crescent-type wrench are probably the most copied designs of all time. You can literally trace the history of industrialization since the late 1800's by following various entrepreneur's attempts to build a better mic.
---------------------------------------
Final thought -- give an interested kid your old mic. You can create a sort of Burke-like (of PBS "Connections" fame) history of industry with accurate screw threads and mics as a starting point. Plus their's fun in learning how thick as "thick as a hair" is. Great way to foster an interest in things mechanical. There are even modern business school lessons about mergers (Starrett was the original leveraged buy out king), product differentiation (B&S tried everything), market segmentation (all the surviving second tier US makers), and commoditization (so you bought an import?) to be learned from the 100+ makers.
January 2002
There have been a few posts inquiring about micrometers for the home shop machinist; and I thought it might be useful to post some information about the desirable features and brands.
FOR STARTERS
- You'll use a 1" micrometer the most and it should be the best and most conveneint you can afford.
- A 0-6 or 0-8" caliper might be the next investment. I'd suggest either a high quality dial caliper(B&S makes an excellent one and Mitutoyo would be my second choice) or a digital electronic caliper if you need metric as well. Mitutoyo would be my first choice in a digital; since quality ones wihtout SPC are now available under $100. The import clones aren't too bad.
- Later you might fill in with additional micrometers and calipers. Because you'll likely use these less often, you might want to settle for cheaper imports, used, or lower-featured items. For example, you might want a cheaper 0-6" set of micrometers, a larger but vernier-reading caliper, or a supplemental set of large micrometers (say, 6-9") that uses interchangeable anvils.
BEST 1" MICROMETER FEATURES?
Like other which-tool-is-best debates you can get a passionate debate on the subject. Some of the variables to consider:
- Are the anvils hardened steel or carbide? Carbide wears longer and is best in abrasive environments. Steel isn't as likely to chip and will last for years with care. I'd much prefer a high quality steel anvil to a cheap non-parallel cemented carbide. As a practical matter, if you are buying a high quality used mic, look for either steel in mint condition or carbide with no significant chips. If it's a new mic, it will probably be carbide.
- Accuracy of the screw and screw-adjusting mechanism. Here's where there are subtle but significant differences between cheap imports and higher quality US and import mics. Some of this shows up in "feel." A cheap mic - most Chinese mics for example - feels squishy and indeterminate as it closes to zero. A good mic has a solid and definate feel as it reaches zero. Of course, you should never overtighten a mic, as it can distort the frame.
- Solid, ratchet, or friction mechanism? Many mics have a sort of slip clutch so that the same pressure is exerted for every measurement. This is especially important in production situations, with different operators, but one QC spec. The ultimate example of this was the Van Keuren light wave micrometer, which used optical fringe bands to assure a consistent measuring force. My personal preference is for a convertable friction/solid mechanism which gives a choice of solid feel or a friction thimble. The ratchet type mechanism can actually have a sort of impact wrench effect, which might show up in .0001 differences. For practical home shop use, you can pretty much suit yourself.
- .001 or .0001 reading? You can probably read a good .001 mic to a couple tenths. You can also mismeasure with a cheap .0001 reading mic by a couple thousandths. Most commonly, .0001 is read through a vernier. The US style vernier has closely spaced lines. The European style vernier wider spaced (easier to read) lines. Electronic mics tend to read to .00005 and can be accurate to .0001. There are also very nice mechanical digital micrometers (e.g. Brown & Sharpe, Etalon) that read directly to .001 and with a vernier to .0001. The bottom line is that mic quality is more important than .0001 reading; but the additional cost of a vernier is so small you'll probably want it.
- Insulated or plain frames? Plastic pads on the frame help insulate them from body heat. This is a nice feature, especially when measuring tight tolerances. A good mic without plastic pads (e.g. an older model) can be held in a shop cloth etc.
- Steel, plated, stainless, etc. thimbles and frames? Many fine quality micrometers are simply high carbon steel - Zeiss for example. Nice if you take care of them. Most quality micrometers have chrome plated thimbles and either plated or painted frames. Good plating will last almost forever; though it will wear. Cheap plating will lift. Most major manufacturers also offer a stainless version for harsh environments.
- Decimal conversions? Don't know about you, but I don't remember every 1/64th " conversion. For this reason, a chromed frame with a carefully engraved (readable!) conversion chart is handy. Charts that are silk-screened etc. will wear off in time.
- Digital electronic or manual? Quality digital mics have three things going for them: instant metric/US conversions, an easy to read display, and various electronic features like over-under reading. Mitutoyo is the share leader. There are also Chinese clones that seem to work, with less precise mechanical actions and uglier looking circuit boards and battery cases. The cons against digital are that they don't suffer abuse, they need batteries, and they are bulkier and heavier. If you can afford just one digital electronic tool, I'd make it a 0-6" caliper.
- Conventional, rapid-set, non-rotating spindle, mechanical-digital, or digital electronic operation? Conventional mics have a screw that advances .025 for every turn. These are the standard; but a little slow to quickly change from small to large size.
Some mics have a speeder on the end (small diameter knob) which is handy. Running the thimble against your palm is a good way to speed things up without undue wear on the threads.
Rapid-set mics advance at double the rate. They have a great feel, but cost significantly more to achieve equal accuracy.
Non-rotating spindles are keyed. Mitutoyo and others make great mics with this feature. This is useful in gaging materials where you don't want rotation. For most home shop uses it adds complexity and cost with no increase in accuracy.
Mechanical digital micrometers have geared mechanisms to advance counters. In general, these add complexity and cost but are easier to read. Mitutoyo and the nearly identical NSK make an accurate but clunky looking version. Brown and Sharpe makes a gorgeous mechanical digital mic; one of my favorites.
As noted above, digital electronic mics use a battery and LED display. These are especially handy if you go back and forth between US and metric units. Battery life has also improved in recent years; don't buy a "vintage" electronic mic.
- Spindle lock. A spindle lock is handy to keep track of a measurement and also to lock the spindle for small lot gaging. Best to have one. Of the two most common locking mechanisms, I prefer the lever type (B&S, Mitutoyo, etc.) to the locking ring type employed by Starrett. The reason is that levers seem to require less attention over the years and are easier to operate.
- Ergonomics. The real test is finding a mic that feels good to your hands, your style of work, and your eyes. There are many intangibles, like satin chrome, clearly marked graduations, light weight (S-T made and makes nice hollow frames in larger sizes), the thimbles, and so on. Ease and stability of adjustment to zero is another factor.
PERSONAL OPINIONS (** = a favorite)
** Brown & Sharpe. B&S has made dozens of different styles, from mundane to space-age looking. Their combination friction/solid mic with slant-line graduations and a carbide anvil is among the best mics you can buy. In the 0-1" size you can get a full chrome plated unit with a fractions table.
-- Central Tool is an old line US maker. I rate them a step below the best B&S, and a half step below the typical B&S, Starrett, and S-T mics.
-- China #1. The original made in China mics with pressed steel frames for the larger sizes are junk.
-- China #2. The more recent made in China mics that are Mitutoyo clones are pretty decent for the very low price. However, they don't come to zero with that definate feel and only time will tell if the chrome plating holds up and the thread maintains its accuracy.
-- Craftsman. Sears and Sears Craftsman mics are made by someone else. At various times this has included Goodell Pratt, Millers Falls, Scherr Tumico and others. Today, some are made in China. The quality varies with the orginal maker.
** Etalon. A fine Swiss mic; often identical in form to a B&S model.
-- Fowler / Helios. Fowler appears to rebrand others mics. A commonly available mic ("Fowler," "Helios," and also "NSK") has a nice friction thimble and is made in Japan. Almost a ** rating, except the friction thimble spring tends to break.
-- General, Hanson, Ace, etc. Beware that "Made in USA" doesn't always mean quality. Hardware stores have sold a cheap US made mic with a die cast frame. The recent Chinese clones run rings around these.
-- Lufkin. For years Lufkin made fine precsion tools, the equivalent of B&S and Starrett. The 1600 series (**) is especially recommended if you find one in mint condition. Very nice feel, larger diameter friction thimble, etc. Most of the other Lufkins have a small diameter thimble, about the same as the Starrett 436 series, which I don't like the feel of.
-- Mahr. High quality mics, but not often seen here and the ergonomics often are just so-so. Their rapid adjusting mics is very nice (**).
-- MG/National. A lower quality US (New York) make. Beats the General/Hanson/Ace die cast mics but a step below Central Tool and two steps below the mic you'll want to own. Accuracy of anvils not to be trusted to better than .001 in my opinion.
-- Millers Falls. MF bought out Goodell Pratt before WWII and has since ceased making mics. Still, you can often find model 112 mics in good condition. I like them as well as the plain Starrett 426.
** Mitutoyo. Like B&S and Starrett, Mitutoyo makes a very full line. Comparable mic to comparable mic, I like them better than Starretts on the basis of "feel." Accuracy is essentially the same, and your preferences may not match. Mitutoyo is probably the world leader in digital electronic mics; though Starret and others also make some nice ones.
-- Moore & Wright is the UK equivalent to Starrett. Nice mics; usually with a handy "measurement reminder" pointer included.
-- NSK. Similar in most respects to Mitutoyo. Probably the same parent company.
-- Poland. Nice mics for the price, as noted by Forrest and many others. Feel and are a little less substantial than the ** rated and other highest quality mics.
- Reed. An old US maker. Decent mic if you find one mint.
- Scherr-Tumico aka S-T. Formed out of two US makers, Scherr and Tumico (aka Tubular Micrometer Co.). These are high quality mics. S-T often won government bids against B&S and Starrett, so you may find some in mint condition from surplus property sales. The large sizes of tubular frame mics are nice and light. A 6-9" or 9-12" interchangeable anvil set, used, is a good buy. Of the 0-1" sizes there is one higher priced model with a very nice feel. This has a friction thimble with a short stubby speeder on the end. ** nice mic.
-- Shardlow. Decent UK brand.
-- Slocomb. Still made to the original 1896 patent design. Very tough US make, but lacking in features. An used 0-6" set in good shape (remember some of these are by now a hundred years old) could be a good way to fill out the larger sizes.
-- Soviet Union. The former USSR made very heavy, very tough, and pretty nice micrometers; mostly in metric sizes. Available cheap, if you need metric (but a digital mic is probably the better choice if you switch back and forth).
-- Starrett. Top market share in the US. The plain 426 series is what most people think of as a Starrett. Pros: it's tough and accurate. Cons: ratchet instead of friction thimble, painted frame instead of fraction chart, no insulation, and a small diameter thimble that's a bit harder to use and read. I wouldn't hesitate to own Starrett 426's in larger sizes; but I wouldn't make it my first choice in the 0-1" size. Most of those cons are handled in another Starrett full chrome friction thimble model (**). Starrett also makes a heavier 226 frame that I like a bit better than the entry level 426. Finally, as with B&S etc., there are dozens of specialty mics.
-- Steinmeyer. Decent German mics.
-- West Germany. Years ago, the US market was flooded with mics labelled "West Germany." The theory was fine German quality at low prices. The reality was a mic with low quality; about the same as the MG/National. Just so you don't get taken; these had a stick-on decimal chart on the frame.
- Scores of others. The micrometer and Crescent-type wrench are probably the most copied designs of all time. You can literally trace the history of industrialization since the late 1800's by following various entrepreneur's attempts to build a better mic.
---------------------------------------
Final thought -- give an interested kid your old mic. You can create a sort of Burke-like (of PBS "Connections" fame) history of industry with accurate screw threads and mics as a starting point. Plus their's fun in learning how thick as "thick as a hair" is. Great way to foster an interest in things mechanical. There are even modern business school lessons about mergers (Starrett was the original leveraged buy out king), product differentiation (B&S tried everything), market segmentation (all the surviving second tier US makers), and commoditization (so you bought an import?) to be learned from the 100+ makers.