How to use a set of Digital Calipers
I measure things. Constantly. As a woodworker I am always making sure my offsets on my dovetails are right. When I am using the CNC machine, it’s dimensions of material. In my laser business it is, well almost everything, cups, hat patches, just everything. And to top it off, they reason I do all three is that I happen to be gifted in Computer Aided Drafting (CAD) so my brain thinks in thousandths and ten thousandths of an inch sometimes. When you have the measuring problems I do, you have to have digital calipers.
Digital calipers are a very smartly designed and accurate tool that are designed for measuring a variety of objects, including outside dimensions, inside dimensions, depth, and step dimensions. I believe in ANY shop or business, right along side the measuring tape, should be calipers. As we are approaching 2024, the digital version is the way to go with many having large screens and long lasting batteries. They are easy to use, and with a little practice, you can get very precise measurements.
If you have ever wondered about the magical(they are really pretty wild) world of calipers, just read on!
What are the basic steps to using Digital Calipers?
- Turn on the calipers and zero them out. This is important to do before each measurement, as it ensures that the calipers are calibrated correctly. To zero the calipers, I simply close the jaws together and press the zero button.
- Select the appropriate jaws for the measurement you want to take. Digital calipers have two sets of jaws: outside jaws and inside jaws. The outside jaws are used to measure the outside dimensions of an object, such as the width of a board or the diameter of a rod. The inside jaws are used to measure the inside dimensions of an object, such as the diameter of a hole or the depth of a groove.
- Place the object between the jaws and close them gently. I am always careful not to overtighten the jaws, as this can damage the object or the calipers.
- Read the measurement on the digital display. The measurement will be displayed in either millimeters or inches, depending on the setting you have selected.
What are some tips for using Digital Calipers?
- Zero your calipers. Every single time I use my calipers I zero them. It will save you so much headache if they happen to be a tenth off!
- Keep your tool clean and treat it delicately. This is a precision instrument, and the last thing you want is to be getting false readings based on damage or neglect. I very lightly oil mine and keep them wiped down.
- Use as much of the measuring surface as possible. If you can, use the flat surfaces in the jaws to make more contact with the item. This makes for a better measurement in almost all cases.
Do not overtighten the jaws of the caliper. Overtightening the jaws can damage the object being measured or the caliper itself.
Truth-In-Lending
This is my truth-in-lending (probably not the right term) more like disclousure. I am an affiliate marketer, just like every other blogger out there. It is literally how I pay for this website. With that said, I ONLY recommend tools I use and that I believe are good or great values. I have used several calipers, and I totally believe the Kynup 12 Inch Digital Caliper is the best on the market.
Outside Measurements
To make an outside measurement with a caliper, follow these steps:
Ensure the caliper is zeroed. Before taking any measurement, I make sure the caliper is zeroed. This means that the jaws should be closed and the display should read 0.00 mm or 0.000 inches. If the caliper is not zeroed, the measurement will be inaccurate.
Select the appropriate jaws. Most calipers have two sets of jaws: the larger jaws for outside measurements and the smaller jaws for inside measurements. For outside measurements, use the larger jaws.
Position the object to be measured. Place the object between the jaws of the caliper. Make sure that the jaws are parallel to the surface of the object and that they are contacting the object firmly but not too tightly.
Read the measurement. The measurement will be displayed on the digital display of the caliper. If the caliper is set to millimeters, the measurement will be in millimeters. If the caliper is set to inches, the measurement will be in inches. Some calipers like the one above will also show inches in fractions!
Repeat the measurement to ensure accuracy. Measure twice, cut once! It is always a good idea to repeat the measurement to ensure that it is accurate. If the two measurements are not the same, take a third measurement and average the three measurements.
Inside Measurements
To make an inside measurement with a caliper, follow these steps:
Make sure the caliper is zeroed. This is important for any measurement with a caliper, but it is especially important for inside measurements, as it can be difficult to get the jaws perfectly seated against the object being measured.
Select the inside jaws. Most calipers have two sets of jaws: outside jaws and inside jaws. The inside jaws are smaller and are used to measure inside dimensions, such as the diameter of a hole or the depth of a groove.
Insert the inside jaws into the opening to be measured. Be careful not to force the jaws, as this can damage the object or the caliper.
Gently open the jaws until they contact the walls of the opening. Be careful not to overtighten the jaws, as this can damage the object or the caliper.
Read the measurement on the caliper display. The measurement will be displayed in either millimeters or inches, depending on the setting you have selected.
Repeat the measurement to ensure accuracy. It is always a good idea to repeat the measurement to ensure that it is accurate. If the two measurements are not the same, take a third measurement and average the three measurements.
Depth Measurements
To make a depth measurement with a caliper, follow these steps:
- Zero the caliper. This is important for any measurement with a caliper, but it is especially important for depth measurements, as it can be difficult to get the depth gauge perfectly seated against the bottom of the hole or groove being measured.
- Select the depth gauge. Most calipers have a depth gauge that extends out from the bottom of the caliper. To use the depth gauge, simply slide it out until it contacts the bottom of the hole or groove being measured.
- Gently push down on the depth gauge until it seats itself against the bottom of the hole or groove. Be careful not to overtighten the gauge, as this can damage the object or the caliper.
- Read the measurement on the caliper display. The measurement will be displayed in either millimeters or inches, depending on the setting you have selected.
- Repeat the measurement to ensure accuracy. I always repeat the measurement to ensure that it is accurate. If the two measurements are not the same, take a third measurement and average the three measurements.
Step Gauge Measurements
To make a step gauge measurement with a caliper, follow these steps:
- Zero the caliper. This is important for any measurement with a caliper, but it is especially important for step gauge measurements, as it can be difficult to get the jaws perfectly seated against the steps being measured.
- Select the outside jaws. Most calipers have two sets of jaws: outside jaws and inside jaws. For step gauge measurements, use the outside jaws.
- Place the caliper on the step to be measured with the fixed jaw resting on the lower step and the sliding jaw resting on the upper step. Make sure that the jaws are parallel to the surfaces of the steps.
- Gently open the jaws until they contact the steps firmly but not too tightly. Be careful not to overtighten the jaws, as this can damage the object or the caliper.
- Read the measurement on the caliper display. The measurement will be displayed in either millimeters or inches, depending on the setting you have selected.
- Repeat the measurement to ensure accuracy. It is always a good idea to repeat the measurement to ensure that it is accurate. If the two measurements are not the same, take a third measurement and average the three measurements.
Comparative Measurement
You can do a comparative measuremet with any of the styles listed above, this is just an example.
To make a comparative measurement with a caliper, follow these steps:
- Zero the caliper. This is important to do before each measurement, as it ensures that the calipers are calibrated correctly.
- Measure the first object. In this case we are measuring the first hole as we are trying to determine the exact placement distance of both holes. Place the object between the jaws of the caliper and close them gently. Be careful not to overtighten the jaws, as this can damage the object or the caliper. Read the measurement on the digital display.
- Zero the caliper WITH the jaws open. This will subtract half the circle on both ends of the complete distance giving you the exact hole placements.
- Measure the furthest point of each hole. If you do this right, the measurement you end up with is an exact interpetation of the hole placement.
- Read the measurement on the digital display. The measurement on the digital display will be the difference between the two objects.
The Vernier Scale
I am not going to try to explain this one in this article, but know it is a more accurate way to measure with your calipers if the screen isn’t working. I have added a great YouTube video on the Vernier scale here. Really worth the watch.
Short story, if you look at the picture directly above you will see two different measurements. Those extra measurements help with manually measuring the thousandths place.
To use the Vernier scale, you first need to line up the zero point of the main scale with the zero point of the Vernier scale. This can be done by gently sliding the jaws of the caliper until the two scales are aligned. Once the scales are aligned, you can read the measurement from the main scale. The number of lines on the Vernier scale that are between the main scale reading and the line that is closest to the Vernier scale zero point will give you the tenths of a millimeter or tenths of an inch.
For example, if the main scale reading is 12.3 mm and the Vernier scale line that is closest to the zero point is 15 lines away, then the total measurement is 12.35 mm.
Again, this is difficult to explain, so I would go watch the video, it is an excellent explanation.
Whitworth Scale
Whitworth calipers are typically used to measure the diameter of threads. They have two sets of jaws: outside jaws for measuring the outside diameter of a thread and inside jaws for measuring the inside diameter of a thread. The jaws are marked with Whitworth thread pitches, which are the number of threads per inch.
To use a Whitworth scale caliper, you first need to identify the thread type that you are measuring. There are two main types of Whitworth threads: coarse and fine. Coarse Whitworth threads have a thread pitch of 1.25 mm, while fine Whitworth threads have a thread pitch of 0.75 mm.
Once you have identified the thread type, you can use the caliper to measure the diameter of the thread. Place the object that you are measuring between the jaws of the caliper and close them gently. The markings on the jaws will show you the thread diameter.
My final 2 cents about Digital Calipers
As I said before, I am an affiliate marketer, but I really do use the products I recommend. As a general rule, I do try to buy American, or at least Canadian, but alas, this is a product I just can’t find a good one from either.
I strongly recommend the Kynup 12 inch Digital Caliper. It is by far the best I have used in ever category.
I have a Woodcraft store around the corner from my shop so I have in a pinch bought a few calipers there. My experience, and they sell a few different versions, is that the internal gear slider inside always goes out which leads less to inaccurate measurements(you can still get a good measurement), but more so to frustration of getting the measurement on the first try. I have given up on all of theirs.
Starrett Tools makes a couple, and Starrett makes mostly “made in the USA” tools. But as of my research, they don’t make a made in the USA digital caliper. They have one that looks that way, but if you dig you will see it is in fact, not. They are also fairly expensive. ranging from $75 to $425 dependent on the version.
I have owned the Kynup now for about 5 years (I have 2, one for inside at my computer and one for outside in the shop) and they have NEVER failed me. The batteries last forever (well over a year- probably 2). The finish does not corrode or blemish. And the internal gearing does not slip. This really is the number one tool I stand behind in my shop and probably why I spent to much time writing this article.
Make sure to check out the rest of my website and blog! My store has many of the common items I personally use and the WHY behind it.
Have a great one!
Royce
Hill Country CNC & Woodworking is an affiliate marketing business, but it is one with ethics and morals. We only promote the items that we use in our daily business. Let’s help each other! I will give you my experience (and discounts sometimes) and you can help me grow.
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