Best Micrometers

Best Outside Micrometer

Micrometers are accurate measuring instruments that are available at an affordable price. They are designed to measure to an accuracy of .0001” or .0025mm.

This is achieved using a precision ground thread with 40 threads per inch (T.P.I) on the spindle.

There are many different types of micrometer available with many specialised uses, but In this article I will be reviewing the most common and most useful, the outside micrometer.

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If you just want to know what micrometer I recommend then here it is,
Anytime Tools Premium 0-4″ outside micrometer set

anytime tools micrometer set

Should You Buy a Starrett or Mitutoyo Micrometer?

It isn’t always necessary to buy from the best, most reputable manufacturers. For some products such as Digital Calipers I would recommend buying from the most reputable companies.

There are some good micrometers available from more affordable companies.

Read on for certain points to consider when deciding which micrometer to buy, such as…

Digital micrometer or a mechanical micrometer?

Digital micrometers have several advantages over ‘traditional’ mechanical versions because they can be used to read both metric and imperial measurements.

They also have higher resolution readouts than is available with a mechanical micrometer.

But you have to consider that the accuracy of a micrometer is very dependant on build quality.

Just because a digital version has a higher resolution readout doesn’t mean it is more accurate than a traditional mechanical micrometer.

What are the Benefits of a Mechanical Micrometer?

The two main benefits of a standard mechanical outside micrometer are its cost and its reliability. 

They cost less than their digital cousins and just by design there are no delicate electrical components that can fail or get damaged. They can last a long time regardless of build quality.

If you buy a mechanical micrometer with a vernier scale on the sleeve you can accurately measure to .0001”.

This accuracy is good enough for anything you are likely to make in a home workshop. 

Even without a vernier scale it is possible to read them to within a few ‘tenths’ of thousandths of an inch.

Having to decide between metric or imperial isn’t a deal breaker, you can easily use a calculator to convert the units if needed.

What Size of Micrometer?

Micrometers only have a 1” measuring range so you will have to consider which range of sizes you are likely to need, you may have to buy more than one. They are generally available in sets of 3, which would be an ideal option. 

Making parts on smaller hobby cnc mills and lathes don’t often require large measuring instruments.

What features make a good Micrometer?

  • Ratchet stop

Most micrometers are equipped with a ratchet stop or friction stop on the rear end of the spindle. This feature prevents you from over tightening and gives you consistent readings.

  • Vernier Scale 

Having a vernier scale on the thimble enables accurate reading of tenths of a thousand of an inch, instead of having to ‘eyeball’ the tenths.

  • Carbide Tips

Carbide tips on the anvil and the spindle end is an advantage, this will reduce the wear over time and prolong the useful life of the tool. 

What to watch for with a budget micrometer

If you have the budget for buying a Mitutoyo or Starrett micrometer you are guaranteed to get an excellent product that will be accurate and reliable for many years. 

If you don’t have the cash there are some cheaper options available, but with it the possibility that you will get a lemon. 

There are some simple ways to check if your Micrometer is working well.

  • Check it for accuracy and calibration
  • Check for a parallel anvil and spindle
  • Check for smooth operation
  • Calibrate for zero

How to Check a Micrometers Accuracy

Micrometer standards are used to check accuracy and calibration.

‘Standards’ are metal rods that are accurately ground to length with each end being parallel.

They can be used to check a micrometers accuracy and calibration at its two extremes of travel. For example a 1”- 2” micrometer can be checked with 1” and 2” standards. 

How to check for a parallel anvil and spindle

When a micrometer is tightened against the standard using the ratchet stop the standard should feel tight yet still be able to slide out smoothly in any direction. If it doesn’t then there is a defect with the micrometer. 

This problem can be a symptom of a ‘dropped’ micrometer, basically it has suffered an impact which has distorted the frame.

The anvil and spindle are no longer parallel to each other.

Poor build quality with a budget priced product may also cause this problem.

How to improve a ‘sticky’ spindle

A new micrometer should feel very smooth and free when rotating the spindle.

Some budget Micrometers can feel tight and ‘gritty’ when rotating the spindle.

If this is the situation you will need to disassemble, degrease and lightly oil the thread in the spindle.

Calibrate for a zero reading

Your micrometer should come with a small wrench, this is used to adjust the zero position of the sleeve to match the thimble.

Use the ratchet to tighten the spindle against a standard then lock the spindle.

There is a tiny hole at the rear of the sleeve, this is to engage the wrench to twist the sleeve to line up the zero position.

The sleeve should be a tight friction fit but should move with the wrench. Once adjusted, your micrometer should now read accurately at both extremes of travel. 

Storage Temperature

An important point to note when storing and using a micrometer is that temperature changes can affect the calibration. 

The typical temperature to calibrate and use a micrometer should be 20 deg C. 

In fact, some are made with plastic insulation plates on the sides of the frame to prevent the heat from your hands distorting the reading. 

This is only usually a factor in an industrial environment when the micrometer is being used constantly throughout a full working day.

Product Reviews

Anytime tools 0”-4” outside micrometer set

This set contains four micrometers enabling you to measure up to 4”. They come in a protective box which also contains wrenches and three standards. 

anytime tools micrometer set

These micrometers feature carbide tips for wear resistance and they all have a vernier scale. This lets you measure to a tolerance of .0001”.

The standards will let you regularly check and zero your micrometers to keep your measurements consistent.

This set is very economically priced, especially for four micrometers with standards included.

My only concern would be taking a chance on the build quality and how accurate the standards are.

Ideally you should use a high quality set of standards from a reputable manufacturer to calibrate them, at least initially. 

A measuring tool is only as good as the standards you check them with.

I really think the value of this set is too good to pass on, the 4” measuring range is perfect for the home machinist.

My main concern would be with the standards, if you had some gauge blocks you could check the standards against those to confirm their accuracy.

This set gets my recommendation.

Pros

  • Zero to 4” measuring distance
  • Excellent value
  • Includes protective case
  • Carbide tipped anvil and spindle
  • Vernier scale for .0001” accuracy 

Cons

  • Taking a chance on build quality
  • I would want to check them with quality standards

Mitutoyo 0” – 3” micrometer set

If you want the best and you want guaranteed quality then you do not need to look any further than this set of three micrometers from Mitutoyo. This set comes with wrenches and two standards for zero adjustment. 

mitutoyo micrometer set

The Micrometers have carbide tips for wear resistance and ratchet stops for consistent readings. 

The marketing information claims a resolution of .0001”, i’m not sure that means that they have vernier scales or not.

But what I do know from experience is that they are not essential, you still can read to within a few tenths without them. This is more than good enough for 99.9% of work you will do.

A protective case keeps everything organised and clean when they are not being used.

Even though this set only measures up to 3” this range would still be enough for most if not all home or hobby machinists. 

I would definitely recommend this set if you want professional quality, although the price may be prohibitive to some.

Pros

  • Zero to 3” measuring distance
  • Guaranteed quality and accuracy
  • Includes standards you can trust
  • Carbide tipped anvil and spindle
  • Marketing info claims a vernier scale for .0001” accuracy  

Cons

  • Higher cost

Anytime tools 0-1” micrometer

If you are only looking for individual micrometers and not a set, anytime tools offer this option as well. 

anytime tools o-1 micrometer

The information provided by the manufacturer claims they have a balanced frame and thimble design to ensure easy handling and better readability. I’m not sure what they mean by this, it appears to just be marketing nonsense.

That aside, they are the same product that comes in the set, so the main advantage is being able to buy them individually if you only need one for a specific task.

If you check out this product on Amazon, you will also see that there are sizes available all the way up to a 5”-6” micrometer size.

Pros

  • Excellent value
  • Includes protective case
  • Carbide tipped anvil and spindle
  • Vernier scale for .0001” accuracy 

Cons

  • Taking a chance on build quality
  • I would want to check it with a quality standard

Mitutoyo mechanical 0-1” mic

If you want to buy a professional quality micrometer, buying individual instead of a set will help bring down the cost. This one micrometer will set you back nearly as much as the set of four ‘anytime tools’ micrometers, but this is definitely a ‘get what you pay for’ tool.

mitutoyo 0-1 micrometer

This particular micrometer does not have a vernier scale for accurately reading to tenths of a thousand inch.

The micrometers I own and use regularly don’t have vernier scales and it has never been an issue.

Most milling machines, especially hobby cnc machines, are unlikely to achieve that small a resolution anyway.

Pros

  • Guaranteed quality and accuracy
  • Buying individual micrometer reduces cost
  • Carbide tipped anvil and spindle
  • Includes protective case and wrench 

Cons

  • No vernier scale

Mitutoyo digital 0-1” mic

I have never personally owned a digital micrometer but I do use them at work. They are more expensive and definitely have advantages over a traditional mechanical micrometer.

digital micrometer

They are easier to read and have a higher resolution.

But the most useful function, in my opinion, is the ability to change the unit of measurement from metric to imperial.

Digital micrometers in machine shops are used almost exclusively in dedicated inspection departments, they are not necessary for a machinist to use every day. 

Any machinist I know that has bought one did so for vanity reasons, basically so they can say theirs is better than yours.

Anyway, if you do want one, they are awesome, and Mitutoyo is the brand to get.

Spend the money and you will receive an accurate and reliable micrometer that will last for a lifetime of careful use.

Pros

  • Guaranteed quality and accuracy
  • Easy to read
  • Coolant proof
  • Measures in imperial and metric
  • Carbide tipped anvil and spindle
  • Includes protective case

Cons

  • Expensive vanity purchase, unless you are a machine shop inspector or have a specific need for a higher accuracy measuring tool.

Rexbeti digital 0-1” micrometer

Buying an inexpensive digital micrometer is a risk. You do generally get what you pay for when buying digital tools so I would advise against buying this or any of the dozens of similar clones.

0-1 digital micrometer

If you do get one don’t expect it to last too long.

Pros

  • Easy to read
  • Measures in imperial and metric
  • Includes protective case
  • Less expensive than the Mitutoyo

Cons

  • Questionable build quality and reliability

Conclusion

Using a micrometer when making accurate parts is really helpful. Anyone who has had experience using digital calipers and micrometers will tell you how much easier they are to get reliable, repeatable and accurate readings. 

If you have never used one before, learning to read them takes a little getting used to.

A lack of practice can lead to an incorrect reading. I have an explanation and show a few reading examples in my article ‘How to use machinist measuring tools’.

If you haven’t already, check out my recommendation of the Anytime Tools 0-4″ Micrometer Set.

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