How to Make the Most Out of Your Height Gages

height gages

Height gages are used to measure a lot more than just heights. These useful measuring tools trace their origins back to the 16th century when Pierre Vernier developed the vernier scale. This scale allowed mathematicians and engineers to measure accurately. So good was his system that the scale became the standard of quality measurements for the next four centuries. From this, the vernier height gage and the gear tooth vernier height gage were developed and became widely used throughout various industries.

The height gage as since come a long way and a lot of other useful functionalities have been added to it. Its basic design has not changed much though. It looks like a hand-held caliper that rests on a heavy base that keeps the tool aligned to the surface. In the original machines, the scale had a movable jaw that was used to mark a part to indicate a measurement. Here is how to get the most out of your height gage.

Setting it Up

Before you can use your height gage, you will need to set two references. The first of those is the zero-reference which the tool is able to set automatically. It does so by moving to touch the surface to set a reference point. Machining experts recommend that you do this process twice so as to ensure that no dirt or other anomalies interfere with the reference.  The other point of reference is correcting for probe ball diameter. This reference does not matter very much if the gage is only being used to measure heights. 

If, however, the gage will be used to measure grooves or diameters, then it is important to take the probe ball diameter into account. For most modern height gages, the probe ball diameter is measured automatically and its dimensions automatically factored into all readings. The machine takes a fixture that comes with the gage which sets up a plane. This plane is measured from the two opposing directions and the difference between the two measurements is taken as the ball diameter.

How to Measure

Modern digital height gages make it easy to take any measurement. All the operator needs to do is to slide the measuring carriage across the part that is being measured and press a button. The gage will move the carriage from the top to the surface and print out the height reading on the display. Modern height gages allow the operator to manipulate and share data. They come with data ports and other useful connectivity options that allow for the transfer of data to computers and other platforms for analysis and storage.

Things to Look Out For

One of the most common sources of bad readings from height gages is when an operator takes higher than recommended height measurements without changing the base. When this happens, the gage wobbles (although this may not be discernable) and this influences the measurement.

Maintain Proper Air Supply And Tooling Maintenance For The Best Air Gaging Results

air gaging

Air
gaging is similar to mechanical gaging in several ways, e.g., they are best
used in dry, clean, and tight conditions. Although air gages are more reliable
and durable than mechanical gages, it does not mean they don’t need scheduled
maintenance. This means that air supply vigilance and proper tooling
maintenance is required to enhance air
gaging
accuracy. Below are some tips on air supply
and tooling maintenance to help you achieve the best possible results:

Check
for Balance Errors

Balance
error tests are often performed by first rotating the air
tooling
to allow the jets to be mounted vertically.
The master is then placed on the plug, and if done correctly, it will rest on
the top jets and note the reading. Remember to lift the master so that it restricts
the lower jet as well. Oftentimes, the two-jet air plugs will automatically
balance themselves (one jet will be closer to the workpiece than the other). If
you notice one of the orifices or jets is worn or damaged, it means that the
test has demonstrated that the gage cannot maintain that balance.

Because
plug gages contact the workpiece across a broad surface area, they tend to be
pretty durable. This, however, does not mean one can ignore the possibility of
poor balance or lack of centralization. It is important to perform these tests
as part of one’s annual gage calibration plan.

Be
Mindful of the Air Supply

The
process of compressing air is known to produce moisture. As compressors also
need to stay constantly lubricated, oil mist is often found in the line as well.
That’s why shop air is significantly difficult to keep dry and clean. When
water mixes with oil, these elements act as an abrasive and can cause premature
part wear over time. With that in mind, avoid letting air continuously run
unless it becomes necessary to do so. This is a good way to prevent mist from
entering the gage and damaging the jets.

To
keep air supply quality in check, it is recommended that one employs proper air-line
design that intercepts moisture before it enters the meter. Consider pitching
down the air main lines from the source by installing a proper trap on the end;
placing filter in operating gages; bleeding air lines before they are connected
to the gages; and taking air from the top of the mains.

Inspect
for Signs of Wear

Although
air gaging does not involve metal-to-metal contact between the workpiece and
gage component, air gage tooling typically makes contact with the workpiece and
may show signs of wear after repeated use. To inspect for wear, below are some
simple steps to follow:

  • Secure the gage with the jets in horizontal
    position.
  • Place a master on the plug, release it, and
    take the reading.
  • Steadily raise the master until it contacts
    the plug’s lower surface.
  • If the readout moves from one chord (through
    the maximum diameter) to another, it means that the plug is worn.
  • If the reading exceeds the part tolerance by
    10 percent or more, it means that there is excessive wear.

Top Tips For Handling Digital Height Gages

digital height gages

Digital height gages are used to perform a
variety of measuring tasks quickly and reliably. Digital height gages are made
up of a base plate with a measuring station and a control display. The
measuring station is designed to measure one-dimensional coordinates
vertically. For this reason, digital height gages are great for measuring
distances between two points on an object or for measuring diameters. Over the
years, operators have discovered other ways of using digital height gages. For
example, if the object being measured is tilted to an angle of 90 degrees, then
measurements can be taken at this angle as well. Here are some tips on how best
to use these useful measuring tools.

Keep
the Gage and Work Surface Clean

Before using a digital height gage,
ensure that the work surface, the contact probe, and the space around the
equipment are clean. This is because dirt and particles on the surface where
the gage rests or on the contact probe can affect the measurements taken by the
gage. It is also important to ensure you zero the gage before you use it. This
is done by switching the gage on and letting it set its reference location.
After a minute or two, repeat the process again and compare the first result
and the second.

Mind
the Temperature

Sometimes, operators using digital height
gages convey their body heat on to the instruments. This causes various
elements of the tool, such as the base plate, test piece, or the stylus to heat
up. This, in turn, produces inaccurate readings due to heat expansion. Operators
should be careful about what they touch and how long they remain in contact
with the elements of the gage. It is also recommended that operators use gloves
when touching the test piece.

One should also avoid placing the digital
gage anywhere near a draft or direct sunlight to avoid cooling or heating up
the gage elements. It is also important to avoid testing parts that have been
transported in a cold or hot facility. Experts recommend letting them ‘rest’ in
ambient temperature for a while before using the digital height gage to measure
them.

Keep
the Gage Working Properly

It pays to constantly inspect the gage for deflections
on the contact points where they touch the part. This happens when the contact
point is long and this can affect the accuracy of the measurements that are
taken. When deflection is noticed, one has the option of building a
reinforcement bridge on the contact so as to minimize the effect of the
deflection

Other Tips

Machine operators can improve the measurements they take by avoiding radiators in the proximity of the digital height gage. It is also important to use the air bearings to position the height measuring instrument. If you are using a digital height gage with a motor drive, one can improve the accuracy of the measurements by using a constant gaging force when the test piece is being measured or inspected.

How to Measure Counterbores And Blind Holes with Air Plug Gages

Air plug gages

Air plug gages are used to perform a
variety of tasks around the workshop. Some of these tasks include measuring
blind holes (also known as counterbores). An air plug gage is made up of a
cylindrical body that provides the guide for air jet positioning in the bore.
The nozzles that release the air are contained inside this body and this
essentially makes the air plug gage a non-contact measuring tool. The internal
nozzles also help to protect the air jets from being damaged. Air plug gages
also clean out the surface of the object being measured through the air jets,
leading to greater accuracy when measuring. So, how does one use these air plug
gages to measure blind holes?

Measuring
Blind Holes

When measuring blind holes with an air
plug gage
, one must ensure that the hole is free of any contaminants.
Debris and pieces of wood or metal in the blind hole can lead to false readings
from the air plug gage. One must also ensure that they are using the right size
of the tool and that the gage is properly maintained. Typically, the air jets
clear most of the debris away but it is useful to regularly inspect the nozzles
to ensure that they are clean.

When using air plug gages, the gage will
automatically center itself in the hole being measured and reduce (if not
completely eliminate) the probability of angular error. This makes the gage easier
to use for operators who have limited experience in using air gages.

Take
Note of Tolerances

Apart from selecting the correct air plug
gage for the blind hole you want to measure, there are a number of things to be
on the look-out for. The first is to be aware of the tolerance that you are
measuring for.

Consider Different Surface Finishes

The other thing is to be aware of the
surface finish of the blind hole that you are measuring. Various surface
finishes can give different readings. This is because the air plug gages
measure the average of peaks and valleys that the air jets encounter.

Avoid Rushing to Take Measurements

The other thing to note when using air plug
gages to measure blind holes is to be patient with the readings. This is
because all air gages measure the backpressure created by the air inflows that
‘bounce off’ the part. If the backpressure takes a while to fill up, then
taking a reading immediately will probably give you bad results. This is
unlikely to be a problem when measuring blind holes in a simple workshop but if
this is happening as part of an automated manufacturing process, then bad
timing can result in wrong results.

Air plug gages are effective in measuring
blind holes provided that they are used properly. Willrich Precision Instrument stocks a
variety of high-quality air plug gages for all your precision measurement needs.

5 Golden Rules of Air Gaging

Air Gaging

Air gaging is a useful and effective method to measure hard to reach spaces such as small holes. Air gages have the additional advantage of being easy to use and are very flexible. Air gages are non-contact measuring devices and they are useful for measuring objects and surfaces that are extremely sensitive. When you are using air gages, there are some things that you need to keep in mind in order to produce the most accurate results possible.

Understand What You Are Measuring

Although this sounds obvious, it is not always the case that operators are clear on what they are measuring. Air gages can measure a variety of things including diameters, partial diameters, squareness, straightness, and more. Understanding what you want to measure will determine the usefulness of the data you get from the process.

Where Are You Measuring?

Air gages and the air jets that they use can measure a wide variety of spaces. One of the rules of air gaging is that the air jets have to be covered by the surface that it is measuring. When using an air gage, it is critical to understand that the air needs a path in order to accurately measure the dimensions of a hole. When you are measuring a blind hole, it can pose certain challenges.

Consider the Surface being Measured

When using an air gage, the finish (or roughness of the surface) will also have an effect on the reading that you get from the measuring device. If you were to use a contact-type gage to take the same measurement, there is a possibility that the two readings will be completely different.

Backpressure May Delay the Process

For an air gage to work properly, it is essential for the air channels and the air pipe in the machine to fill up due to the back pressure. This back pressure is created when the airflow from the jets are restricted by the part being measured. If the air pipes are long, this process can take a while, and in certain applications such as high-speed automated gaging, it might lead to incomplete results. One way to solve this problem is to bring the converter as close to the surface being measured as possible to reduce the length of the air pipes. The second way is to ensure that the air in the tool does not flow out of the part between measurements. This means that the air hoses take a shorter time to fill up as they would already have a significant amount of air from previous measurements.

Altitude Matters

The height of your location plays a part in the performance of your air gage. This is because air is thinner at higher altitudes and this can affect the performance of the equipment. Since most air gages are custom made for specific tasks, ensure that you ask your supplier to take the altitude of your location into consideration when calibrating the machine. This is also something to keep in mind when moving the equipment from one manufacturing plant to another.

How To Deal With Height Gage Challenges Like A Pro

height gage

Technicians may encounter some challenges when using larger height gages. The cause of those potential problems is not due to the height of the gage but its relationship to the size of the base. If there are errors in how the gage is set up, it can potentially distort a carefully planned height measurement procedure; that said, what can you do to get perfect measurements for every job and overcome said height gage challenges?

Keep and Use a Well-Maintained Surface Plate

A majority of height gages are typically used with surface plates. These surface plates are designed to provide the reference for both the height gage and the part that’s being measured. It is imperative that these plates are well-maintained and clean. When measuring a workpiece that has a height of approximately 10 inches, a strand of hair or a small metal chip is enough to throw off one’s measurements by 0.020 inches.

In addition to minute dirt and debris, the surface of the granite plate also plays a major role in performance of the height gage. The slightest imperfections can be amplified if the surface between the workpiece and height gage is not smooth enough, is uneven, etc. This may cause problems if the measurement gets higher. Here’s a quick scenario:

  • The surface plate of your height gage has a flatness spec of 50 microinches
  • The base has a length of six inches
  • Imperfections on the granite plate’s surface can cause a 50-microinch error to grow over 0.0003 inches

Lengthen and Widen the Base

A height gage is designed to measure a specific height. That’s the point where it performs at its best. If the height gage model you are using is designed to measure 24 inches, you can’t simply extend the post to measure a part that’s three times that height. If the cross area of the measuring post or base design is not modified, the gage can start to flex and/or wobble, affecting the final measurement. Oftentimes, it is hard to spot if these problems are occurring at that moment. For example, a 0.001-inch wobble is invisible to the naked eye.

To prevent the post from flexing or wobbling, some technicians may focus on “strengthening” the column of the height gage. Unfortunately, this is not a viable solution for resolving the problem. If pressure is applied to the measuring contact when it’s nearing the maximum upper position, the gage may tip over. If the same amount of pressure is applied horizontally against the gage’s measuring contact, the gage may start sliding along the table.

The correct way is to focus on decreasing the ratio of the base to the post. One can achieve this by making the base wider and longer. In addition, build in some mass. By doing this, one can expect to see significant improvements in the height gage’s performance.

Looking for a reliable height gage? At Willrich Precision, you can purchase high-performance height gages online at the best prices. Feel free to contact us if you have any inquiries.

Getting A Retrofit Controller For Your CMM?

CMM retrofit controller

Before we delve into why getting a retrofit controller for your CMM is a good idea, it will help to start with the basics as to what a CMM is and what it does. A CMM or coordinate measuring machine is a tool that measures the geometry of the surface of an object by sensing the points on that surface with a probe. CMM machines come in many forms. Some are computer-controlled while others are controlled manually by an operator.

CMM machines also use various kinds of probes to sense surfaces. For example, there are CMM machines that use laser probes, mechanical probes, optical probes, and white light probes. CMM machines use a reference point in order to specify a probe’s position. Some CMM machines allow for probe angling in order to measure hard-to-reach surfaces. Hence, CMMs generally offer greater precision than other measurement tools such as micrometers and calipers.

CMM machines allow for parts to be upgraded and one of the parts that are likely to be upgraded is the CMM controller. There are numerous benefits to upgrading your CMM controller which we are going to explore in this article.

Reduce CMM Downtime

A worn-out controller can easily lead to serious measurement errors or worse, complete breakdown of the CMM machine. For this reason, it is better to catch the problem early and change the controller before it gets to this point. Even though the changes will necessitate some downtime, this is short relative to the downtime that would be occasioned by a breakdown. Proactively changing the controller leads to fewer errors and eliminates any chance of the complete breakdown due to a malfunctioning controller.

Take Advantage Of New Technologies

The technology around controllers is always changing and replacing your CMM controller allows you to take advantage of modern technology without having to get a completely new CMM. Better controller technology leads to more accurate readings and helps to keep the CMM machine operating at optimal levels.

Prepare For The Future

Related to the previous section is the fact that changing your CMM controller will put you in a better position to prepare for next-generation CMMs. What this means is that by upgrading your CMM, you are ensuring that your machining process can keep up with modern technologies and prepare for future expectations.

Extend Your CMM’s Capabilities

By upgrading your CMM controller, you ensure that your CMM can do more. For example, upgrading to some of the new CMM controllers can transform you CMM and give it new capabilities such as touch-trigger and also add non-contact measurement capabilities. All these changes lead to more precise measurements and greater flexibility when using the CMMs.

Lower Your Training Costs

Newer CMM controller technologies come with simulation capabilities which mean that you can effectively train machine operators via modern digital technology. This translates to significantly lower training costs and shorter training time.

As you can see, there are quite a number of benefits to retrofitting your CMM controllers. If you notice that your CMM controllers are reaching the end of their shelf life, don’t be afraid to upgrade and install new controllers. It will give your CMM machines a new lease of life as well as offer you many other benefits.

How To Avoid Buying The Wrong Bore Gage

bore gage

Bore gage is a collective term that refers to tools that are used to give very precise measurements of holes. There are many reasons why a manufacturing process would want to have a very precise measurement of holes. For example, the quality control process of a manufacturing plant might be very interested in measuring holes in a given part that is being produced, especially if that part is designed to fit into another part.

Any deviation from the set size would have costly implications for the manufacturer and therefore the quality control process has to use very precise tools to ensure that all the parts have the right size/shape of the hole. To this end, companies invest in bore gages and the choice of what type of gage to buy is determined by various factors that we are going to explore.

Consider The Manufacturing Environment

Various bore gages work in various environments and it helps to understand where exactly the bore gage that you want to buy is designed to work in. For example, if a manufacturing process will require the quality controller to move around randomly checking samples, it might make sense to get a bore gage that is easy to use and portable. Such a manufacturing process might discourage some of the non-contact gages that tend to be bulky and very expensive to maintain.

Consider Their Application

Various gages have varying capabilities. For example, some bore gages come with digital read-outs that allow for data collection. Other manufacturing processes don’t really care much for data collection as long as the bore gages can help them ensure that there is no variation in the parts being produced. With this in mind, it would be important to get a gage that has a digital read-out screen and a data collection port if data processing is important to your manufacturing process. If not, you might be ok with a simple bore gage which typically tends to be more durable and easy to use.

Level of Flexibility Required

Some bore gages offer greater flexibility when it comes to calibration than others. A good example is the two-three point contact system that is calibrated to a reference master. The implication of this is that only the setting ring on the reference master needs to be calibrated and this offers a much easier and faster process of keeping the gages calibrated. For a manufacturing process that requires precision as well as fast calibration (such as a large and busy manufacturing plant), these kinds of gages might be more ideal.

Type Of Holes Involved

Holes come in different sizes, shapes and depths and all these factors play a part in determining the type of bore gage to be used. For example, air gages work well with holes that are tapered. Where they are located on the part and how accessible they are will also play a part in determining the type of gage you select. Air gages again are easier to use on holes that may be in positions that make it hard to use mechanical gages.

There are many factors to be considered when selecting a bore gage. Understanding your manufacturing process and what you want to measure with the bore gage are the first steps in determining what kind of bore gage to buy.

Understanding The Importance Of Air Gage Maintenance

Air Gage Maintenance

Handling large production runs? Need to take high-resolution measurements? An air gage can help! Air gaging currently represents the method of choice for these tasks. Compared to mechanical gages, air gages are pretty reliable and durable. Air gages, however, require a higher level of maintenance. That’s just part of the deal.

Proper Air Gage Maintenance Ensures Accurate Air Gaging

There are two main things you need to do to achieve accurate air gaging. Be mindful of the air supply and properly maintain the tooling. Although you (the gage user) can’t control the factory air supply, you must ensure that the air that reaches your gage is clean, stable in pressure, and dry. It has to be this way because the air lines and compressors may be shared by dozens of other users. Tooling is directly under your control, so there’s no reason not to maintain it!

The Basic Requirement of Maintenance

Air gage maintenance involves keeping the tooling dry and clean inside and out. You cannot let contaminants such as cutting fluid, coolant, dirt, and chips to be picked up from work pieces. Oil and water are known to originate from the air source itself. So, be very careful.

Some air gage users depend on air flow to clear out certain air passages (this can happen on its own). This is not always recommended. You should keep in mind that some contamination may still occur in the measuring jets and master jet. You can throw off the measurement if you allow even a few millionths of an inch of contaminants to accumulate. If you master repeatedly and it produces inconsistent readings, it’s a sign of dirty jets!

Prevents Air Leaks

Air gage inaccuracy is typically caused by air leaks. To confirm your suspicions, observe the indicator needle after covering the measuring jets tightly with your fingers. If the needle does not remain stationary, check all of your connectors, tubes, and fittings for leaks.

Avoids Damaging Sensitive Tooling

Although most factory air lines run at approximately 100 psi, the final amount still depends on other air users’ demands. Air gages that are properly designed should be able to operate reliably between 40 psi and 150 psi. A small amount of fluctuation is acceptable.

It is important to check the sensitivity of your air gages. A part of maintaining them includes isolating them from fluctuations via a semi-dedicated or dedicated air line. With that in mind, sensitivity checks can be conducted by leaving a master in place on the tool. Next, take note of the indicator’s movement while other air line users facilitate normal tasks.

Prevents Moisture Build-Up

The accumulation of water mist and oil can cause moisture to build up. When they do, these elements can act as an abrasive and accelerate part wear over time. Will air dryers work? If you compress air, the process produces moisture. Additionally, the compressor will need lubrication, which will generate oil mist in the line. A better solution is to employ an air line design that intercepts oil and water mist before they enter the meter. You can also consider taking air from the top and not the bottom of the mains. This will prevent moisture from draining into the feed.

How To Use Air Gages To Measure Squareness

air gages measure squareness

Right angles—perpendicular intersection of surfaces and lines—apply to many things such as manufacturing, agriculture, civil engineering, and architecture. There is an array of terms utilized to explain this relationship, including squareness, normalcy, 90 degrees, and perpendicularity.

When it comes to engineering products, some of them do not feature perpendicular surfaces. In this case, perpendicularity when engineers and technicians need to create dimensions via rectangular coordinates. In the manufacturing industry, the measurement and implementation of right angles are never perfect. It is whether you achieve a higher degree of perpendicularity or not.

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