The 7 Best Feeler Gauge Sets in 2021: Types & Uses Analysis

Tensed about valve adjustment or wooden curved object depth? Well, in this case Steel or hardened material made feeler gauge sets counting on versatile blade numbers is the perfect solution. Designed such instrument in a way not only for measuring gap thickness but also to avoid the inaccuracy by the caliper and Vernier scale where the ruler gets restriction to reach to the object. Moreover, in a dispute of calibration vs validation vs verification, all in all you will receive with the bucks spended package of feeler gauge. However, it is quite confusing to determine how thick is a number 12 feeler gage. Well, it is similar as the other thin sheets of different ranges. 

If you want to expand the functions of this movable, portable and durable device, this is 101% possible. How? As well as we see the regular tasks, for instance, musicians, mchinsists, engineers, plumber and more require the adjustment of valve or gaps while mating another object. In this article, we are going to provide well-informed and experienced feeler gauge sets details including some feeler gauge size charts, 7 popular ones, and FAQ section one after another. So, happy reading! 

best feeler gauge sets

What Exactly Is a Steel Feeler Gauge?

Feeler gauge or Steel made feeler gage is a rapid tool to measure gap widths like a height gauge is useful for measuring height, length and corners too with holes of any object if it has. In particular, speaking of this tool’s construction, Steel blades of different thickness which are well-known as feeler gauge size chart. However, it may differ with a single brass blade for some prehistoric reasons, for instance, decades and decades back the electronic ignition processed tools required enough air gap between the pickup part and the reluctor which was being set with non-ferrous objects on the top. 

Sometimes instead of flat blades, wires with specific diameters the manufacturer used to integrate to fix the gap in between spark plugs to ensure the correct size. In particular, this type of construction happens by decreasing or increasing the air gap until the designer matches the specific size to fit inside the gap.   

Why Need Different Types of Feeler Gauges? 

Such a tool is an assembly of mechanical parts to measure the accurate depth of another material. In particular, the reading one can get if this instrument fits between 2 parallel surfaces, for instance, two machines in-between parts. But how to use it, and this is the first common question. Well, before answering that and regarding the rest of the questions, let’s have a short introduction with its physical types which are available in global shops or your next to the road ones. Read more: Stylus Force Gauge Analysis

Straight or Straight Blade: 

Comes with uniform blade shapes with High Carbon Steel in its construction. An in-built set of these blades is used to wrap certain dimensional values. To serve specific purposes, the standardization in designs may vary from professional to novice. 

Offset or Blend: 

Include changes to Steel blade lengths ( short and long). Especially, in space-constrained applications or in a wide range of areas which has restricted movements. To get access to those gaps, down to the earth this damn awesome instrument is the perfect one. 


This type of feeler gage set has similar metals in construction, such as High carbon Steel or Carbide with narrow shapes. The shape can get access to narrowed widths toward the blade tip, however, possibly can prove to be the best assistant to evaluate the space restrictions wherein the work areas. 


Such designs utilize longer blades including 2 precision thickness steps. Across their entire length, this categorized gage simplifies the illustration of the gaps by eliminating the feelings of users all along the way to evaluate the reading, for instance, the greater/less than tolerance window. 

Shim Stock: 

Similar to the previous metallic blades include exceptional calibrated wires with bent edges to the right-angle. In terms of a spark plug, or a wire feeler gage, this is very common for combustion engines gaps measurement by setting this in between the paralleled gap. 

For grabbing the answers of your curious mind, check out the People Asked section including the listed feeler gages above that part. 

Most Popular Feeler Gauge Sets

1. Precision Brand 19740 Feeler Gage Poc-Kit Assortment

Precision Brand 19740 Feeler Gage


Blades Amount 20
Inch 0.001″, 0.0015″, 0.002″, 0.003″, 0.004″, 0.005″, 0.006″, 0.007″, 0.008″, 0.009″, 0.010″, 0.012″, 0.014″, 0.015″, 0.016″, 0.018″, 0.020″, 0.022″, 0.024″, and 0.025″
Weight 9 pounds 
Material High Carbon Spring Steel 
UPC 698158197408 
Length 5” 

Notes on Experience

It is a hella nice set, including different thicknesses ranging from .0001” to .025”. Sounds great without delaying the proper reading as if the sharp blades can reach the machine portal by the consisted .5″ wide high carbon spring steel and C1095 close grain. Though etched each in decimal and inches, however, inches is the right measurer. All included in a rigid case which is made with vinyl as long as separate pockets.   


Wide range of thickness for hard depth measuring feeler gauge need? Our first pick is 19740 Precision Brand model High Carbon Steel Made feeler gage. As well as the length is good enough to enter within 2 parallels of the object.  

Number of Leaves or Blades

Unlike other feeler gauge models, this one offer no in-built handles. So, in lieu of altogether attached in a handle shape, comes as a pocket kit holding 20 blades in 20 separate pockets. But there is an option to buy a single handle to attach and carry in a single bag.  


Speaking true of the in-built materials, we have never experienced such smooth and sturdy blades of High Carbon Spring Steel to get the measurement jobs done within seconds. As long as we have experienced each one of .5” width close grain metal, not that much of heavy-weighted to single-handedly. However, S.S. is a good resistant to high temperature, yet not possibly can show anti-corrosive performance every time. The manufacturer has packaged altogether the 20 kits in a vinyl case which is well enough sturdy that eventually and conveniently folds flat.  

English vs Metric Sizes

This feature depends greatly on the number of blades you are purchasing and materials in construction too. For example, this model concludes with 20 S.S. blades, as well as the regular feeler gage set of more than 20, and approximately 25 combines both inches and millimeters. In terms of being only 20 pieces as a set, serve inch sizes. 


So far, it is good news as each blade ranges 5-inches and convenient in case of smaller reading of too short machines depth or fix in the gap. If the user requires much shorter ones, spend bucks on specifications wherein ¾ – 1 inch has mentioned on the package covers.  


The final feature you should never avoid or consider put in the corner. This model comes with each straight blade which has uniform round edges with solid sharpness. 


  • Including .0001-inch size;
  • Accurate thickness;
  • Simple use;
  • Dual design, both handle and separately;
  • Solid vinyl storage case. 


  • Nothing noticeable. 


2. Starrett 66B Thickness Feeler Gage Set 

Starrett 66B Thickness Feeler Gage Set


Blades Amount 31
Inch 0.0015-0.035″
Weight 8 pounds 
Material Tempered Steel 
Length 3.75”

Notes on Experience

We give a second startup with a 66B model, manufactured by Starrett. Formed as L.L. Satrett in 1880 to manufacture precious tools and such metrology instruments to help engineers and machinists, especially for the novices. More than their consumer market popularity, we love mostly this locking device which can also ensure security to the great match with one more number of leaves in a single position.  


Our team member has chosen this ultimate feeler gage model to take the novice experience easy to accelerate to the intermediate level. Such an imperial thickness concluded gage give optimists not only in automotive aviation but also diesel and farm equipment measurement. The uniform style makes it more convenient, for instance, 2 types of blades and sizes.  


Among 31 leaves, 1-5 and 27-31 are tapered types, in particular, shaped bend edges. The rest of the blades confirm straight shapes. Ranging in thickness from 0.03-5mm and .0015-.200″. However, possibly everyone can move each blade at ease. 


Unlike the previous one, these feeler gauge blade sets have the finest tempered steel. If one takes a look at each finishing, amazing to correct thickness and individual blades have been tested and marked from the manufacturer’s factory. Lightweight, yet powerful to access the gap of smaller or larger machines. 

Leaf number

This one evaluates the compatibility of how long one can accomplish the task whatever the tool size is for measuring. 31 leaves with a locking mechanism to ensure the setup security in one position, even if the user wants to move one per work, then it is no more hassle at all. 


A complete set of leaves has been manufactured in 3 cubic inches which are approximately perfect for standardization. And, if you keep it in a damp environment, it may rust as soon as possible. 


We have measured each blade in 3 places, the first one at the center end in its width, yet backed off only about 3mm. The second is while inserted straight on, any burr present can mislead the measurement. The last one is the blade end left corner. All measuring instruments’ faces range from 0.275 and 0.375 in diameter. In terms of overlapping, users will find some areas and somehow we have found a +/- 0.00004 range error. 


  • Complete set of 31 blades;
  • Locking device;
  • Great thickness and useful;
  • Blades are movable;
  • Thumb slot. 


  • Hefty-priced. 

3. Hotop Dual Marked Feeler Gage Set

Hotop Dual Marked Feeler Gage Set


Blades Amount 32
Inch 0.0015, 0.002, 0.0025, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.010, 0.010, 0.011, 0.012, 0.013, 0.014, 0.015, 0.016, 0.017, 0.018, 0.019, 0.020, 0.021, 0.022, 0.023, 0.024, 0.025, 0.026, 0.028, 0.030, 0.032, 0.035
Millimeter 0.04 – 0.88 mm
Material 65 manganese steel
Length 3.75”

Notes on Experience

Hotop blade has the greatest exception for its golden or yellow blade which is measured approximately 0.010mm or .25mm with the rest of the silver blades about 0.04 – 0.88 mm. We have experienced the most expensive and different feeler gauge sets including different sizes. 


Jumping to the next one and this one is from Hotop which has 32 blades, means a single one more than the previous feeler gage set. The prettiest and noticeable thing is its foldable compatibility including different types of blade adjustments.  


Single numbers according to the types have been etched on each blacet side. But it has a uniform shape or type, as long as we have experienced it, it was straight along. Not too heavy, not too small just to measure the filled gap. Instead of a straight shape, may it have tapered edges at the end to make it compatible with the valve adjustment? 


A bunch of 65-grade Magnese Steel blades polished with machine oil including the aroma gives the strongest feeling to spend your bucks on it. The polished, as well as varnished leaves, create an anti-corrosive environment as if wherever you put it or use it, not a big deal will happen if the surrounding is enough humid. 


Each blade has the well capacity to measure the depth at least 3.75”. 

Size range

The size range includes how the reading will be taken as per the object you have. Includes both English and metric measuring methods, for instance, decimal 0.04 – 0.88 mm and .0015” – .035”. 

Blade number 

Great for 3D printer calibration. Is not it stunning? Well, this model contains the accurate feeler gauge sets to use on paper to create starters’ very first layers, especially with the .007/18mm blade.  


  • SAE standard;
  • Oily blades;
  • Locknut;
  • Equipped with 0.010” thickness. 


  • Manganese Steel. 


4. CTA Tools A308 Valve Tappet Gauge Set

CTA Tools A308 Valve Tappet Gauge Set


Blades Amount 11
Inch 0.004” to 0.014″
Handles 2
Material Stainless Steel 
Length 3.75” 

Notes on Experience 

Nothing can beat such feeler gauge sets if changing the oil on our team member’s tractor or ‘68 Corvette. We have enjoyed the most the 2 handled system while one possesses .013” and another .014” to continue our inserting process and measure the depth.    


Aiming for a complete and accurate feeler gauge set which will become the single answer on what happens when valves are out of adjustment including if you don’t have a decimal millimeter system to workout? Then jump to the CTA Tools A308 model to explore something fresh and apart from common designs. 


Though this set does not comprehend straight blades like the previous models, the tapered shapes or offset we can say is better to solve the valve adjustment issue. 


Stainless Steel in construction makes it rustproof to prolong its life either to insert blade easily into the paralleled space or to adjust the valve. Indeed,, ashe S.S. in construction is highly magnetic graded which can sometimes create problems. But the single screw is enough capable of holding all feeler gage to the 2 types of handles. 


3.75” matters nothing like the previous one. Whatever the length is, the sharpness and tapered valve adjustment intake the 3.75” without handles is damn stunning. 


Not bullseye accurate, it causes due to the difference of the handheld blades size range. As long as we have used 11 sizes for certain valve clearance jobs, however, the tolerance rate was not that good, for instance, the required rate was +/- 0.02mmyet we are sure will improve later on. But the decimal ranges from 0.004” to 0.014″ is quite different than other ones. 


  • Durable;
  • Offset blade type included;
  • 2 handles;
  • Frequent competency of the single blade;
  • Reasonable. 


  • Too limited size;
  • Not conquer expected accuracy rate. 

5. Zuzuan Straight and Offset Feeler Gauge Sets 

Zuzuan Straight and Offset Feeler Gauge Sets

Specifications for Straight Blades 

Blades Amount 32 
Inch 0.0015 inch to 0.035 inch
Millimeter 0.04 mm to 0.88 mm
Material 65 manganese steel 
Length 5” 

Specification for Offset Blades

Blades Amount 16 
Inch 0.005 inch to 0.020 inch
Millimeter 0.127 mm to 0.508 mm
Material 65 manganese steel 
Length 5” 

Notes on Experience

If you require to enjoy a blend of accurate feeler complete gauge set to get the entire day jobs done, especially when you are a machinist then both 32-sizes straight blades package and 16-sizes offset blades package will become the great assistant. And obviously, such good packages are from Zuzuan. 


In the 5th position of this tool listing, Zuzuan refers to the highest blade types within a single pack. Each variant comes with an in-built Steel handle with a lock mechanism to secure the movement and position of blades that it is holding from the midpoint. The core design is very unique as if configured with a thumb notch for safe and easy expansion and selection. 


Yes, the most perfect selection this designated manufacturer company is producing by considering all pro-graded and newbie machinist and tool operators to measure the instrument’s accuracy. Why? Not only because of easy identification but also for both offset or rectangle shape and straight shaped blades, respectively 16 sizes and 32 sizes. Such identical bent blades include changes to each length. Moreover, you can apply each one in certain space-constrained applications. 


Constructed with 65 Magnese Steel, however, quite different from the genuine Steel ideology yet the manufacturers have provided a polished look with oils neither to let scratches nor to leave burr behind to happen unnecessary accidents.  

English vs Metric Sizes

Hardness and precision are other specialties of this feeler gauge set, but the legibility comes in much better forms, for instance, both decimals measurement systems marked on each blade. While inch is ranging between 0.005 inches to 0.020 inches and a millimeter is ranging between 0.127 mm to 0.508 mm. 


Including elasticity, for convenient usage, all can move 360 degrees and concludes with a good length of about 5”. 


  • 2 types of blades; 
  • Higher breaking strength;
  • 360-degrees movement capacity;
  • Bent freely;
  • Prevent scratches.


  • Not anti-corrosive;
  • No longer existing marks.  


6. Proto J000TL Long Feeler Gauge Set 

Proto J000TL Long Feeler Gauge Set


Blades Amount 25
Inch .0015”-.040”
Metric Yes 
Material Steel 
Length 12”

Notes on Experience 

Blades are etched with both decimal inches and metric and this works as an eye-catching feature. Also, 0.040” is the thickest one to get the precise reading of flange gaps inside the pipe stresses.  


Let’s introduce another unique design, the specialty comes with the highest length of blades with greater elasticity. Yes, talking about Proto J000TL which has performed as a lightweight tool to measure depth with higher breaking strength. See also: What Are the Best Digital Height Gauges


Unlike previous models, this feature sounds much better with almost 12” length. It may be a difficult job to employ measurement towards a far-to-reach object. In terms of that hard reaching to confined areas, such extra-long blades are also well enough for valve adjustment.   


Besides those jobs, extra-long straight blades are excellent for flange gap measurement. So, yes, strong and 360 degrees movable blades of 25 sizes to serve your explicit and various needs.  


Not only the blades are Steel made, but also the holder and lock mechanism are as well. But in terms of weight with Steel construction, works like High Carbon Steel to measure pipe stress. 


25 blades of multiple sizes to serve with satisfaction, but this is not true enough. Well, this one serves better than that with much precision compared to other models, however, it holds only 25 but looks like more than 30. Moreover, the only lack is the measurement scale offers in inches and metrics with lower points.  


  • Thumb slot;
  • Removable blade;
  • SAE order maintained;
  • Longer blades;
  • Lightweight. 


  • Incomplete blade set;
  • Pricey rather than quality. 


7. Camway Dual Marked Blades Steel Feeler Gauge 

Camway Dual Marked Blades Steel Feeler Gauge


Blades Amount 32
Inch 0.0015 inch to 0.035 inch
Millimeter 0.04 mm to 0.88 mm
Material 65 Magnese Steel and lube oil coating 
Length 4”

Notes on Experience 

Now the question is how to suit this heavy design? Well, if you are an engineer or mechanic, or designer, then the tappet clearance’s thickness, bearing clearances, piston ring gaps, and the rest of confined areas you can take this to measure with enough accuracy. However, it comes up with a smaller length, yet the removable advantage with each piece.  


If the previous tapered feeler gage set is too expensive rather than quality, you can move to this alternative choice. However, the bent facility is the most eye-catching tool part that we have ever experienced. Also, the greatest measuring range gives a plus point. 


Precise calibration is a great additional point for this designed model and some hobbyists as well. From our team member’s experience, once one of them tried to apply these in air gapping through the compressor piston and got that job done according to the marked calibration. 


Apart from the calibration competency, this model is very lightweight due to the in-built 65-graded Magnese Steel to identify both metric and imperial gaps in between tools. Also, create non-breaking strength for repeated usethe Hardedend tempered Steel and lubricating oil coating prevent corrosion. 


Already you have acknowledged the 32 blades type, including the 360-degree spinning capacity, removable feature, and group of thin steel sheets to get bent for valve adjustment. You can take a gamble on this damn straight yet thin group of sheets for convenient purposes. 


32 pieces of Steel thin sheets offer dual marked, either use measuring range from 0.04 mm to 0.88 mm or from 0.0015 inches to 0.035 inches. 


  • Affordable;
  • Complete blades;
  • Enough durable;
  • Thin sheets with oil polished;
  • Prevent scratches; 
  • Easy yeat rigid carrier;
  • Compatible with all hard-to-reach object purposes. 


  • Cheap plastic nut. 

People Also Asked 

How to Apply Feeler Gauge Sets and Most Popular Applications?

From its name “Feeler”, indicates the exact use of your sense to make it perform the level of resistance you want. As per your desired friction, set in that way. For better acknowledgment of gap width, after setting the tool you may feel the friction level should be moderated. 

Want to expand your needs? Apart from measuring gaps of the 2 mating devices, you can employ it across automotive, pharmaceuticals, aerospace, general industrial machining, and oil and gas.

How to Read a Feeler Gauge?

Take any attached 20-30 leaves at a pivot point to slide the gauge in any gap. If none of these fit, try to put one over another to avoid the need for longer leaves. Now pull it out. Have a closer look at the side of the thickness measurement. 

Therefore, a wide range of methods are available, however, this one is the easiest and perfect one. 

Do You Find SImilarity Between All Gauges?

This is sometimes true, yet different from manufacturer to manufacturer production style. Different sets perform and offer different blade lengths, decimals, and metric sizes. Already it has mentioned it mostly relies on the leaves numbers. So, expanded sets have one material in a similar set on its offer.

Are NGK Spark-Plugs Pre-gapped?

A few decades back, it was necessary to create gaps in betwen spark plugs. But now in general, it is found pre-gap. While one installs spark plugs, it is highly advised to double-check if the gap is in its place or not. 

As well as NGK plugs are also available in pre-gapped condition, however, the gap sometimes require a few adjustment with the feeler gauge set. 

How to Select a Complete Feeler Gauge Set?


Wanna discover that your feeler gauge provides accuracy or not? For example, we cannot carry such micrometers. Perhaps of doing this, we can rely on ease on the certificate. If it does not a tool manufacturer offer, this must be a deception to the prospective customers. Fortunately or unfortunately, the products we have experienced and mentioned above are certified.

Since any metallic object is reactive to heat, selecting the heat-resistant material is harsh. This feature invalid the blades from expanding or extending, as well as effective to accuracy. Eventually, if you are using the gage set in a hot emitting environment to measure the pipe gap inside the hot machine, then it is a guaranteed false result. 

Measurement Range

The feeler gauge set standard measurement include charting from (0.001mm) to one millimeter (1mm). The wider the range, for instance, Zuzuan and Camway, the better it gives results. In general, a typical set has a range under 1mm, yet for valve adjustment rocker arm, we suggest Proto J000TL with lengthy blades and patterns for easy processing. 

The quantity of blades often fixes the range. As long as we have tried with higher ranged one, for instance, 0.88mm or 0.035”, and we got separate accuracy. In general, each set may contain more than or less than 25 blades, but the higher the blades range between each one reduce, the precision validity increase. 

Unit System 

Most feeler gauges which are available in stores next to the roadside, graduate each blade in either inch or mm and sometimes both which are known as English vs Metric units. Yet the inch measuring system is common. The Metric graduation means mm to convert in inch is equivalent to valued terms. This is not a headache, in fact, the dual or single value engraved on the blade’s either side will help.

In terms of dealing with metric measurement, this process is a need indeed. You will find simple numbers on each blade except for the imperial feeler gauges and need to convert the unit to an inch if you know the formula. 


As we have mentioned earlier about the accuracy dependency on the construction material. The material is something that gives each blade the ultimate potentiality and individuality. Even competency in different levels, for instance, non-breaking strength while working and trying to remove the blade from the center. Therefore, such characteristic makes it much more flexible. 

Tough material yet make the blade durable and flexible enough is the best solution, for example, 65-graded Manganese Steel and High Carbon Spring Steel. Even help to insert itself to the restricted areas. Apart from these 2 material types, renowned hard tempered Steel is popular and adequate, yet needs some oil polish after every application to keep rust-free. 


As long as with a wide range of types, the feeler gauge contains a specific length per set, not per blade. A complete feeler set contains 13, 15, 25, 31, 32, and till 100 leaves. Whatever the blade count you may purchase, a typical blade length can extend from 3” to 5”, but this may vary if the set offers more leaves in a packet. So, check your object first that you have to take for measurement, and then purchase. 

However, instead of such short blades and to deal with a bigger gap of materials, spend bucks on at least 12-inches longer leaves to perform with better distance.  

Final Thought 

Either for clearing valves between rocker arms or wall slot size in any reactor vessels always need a feeler gauge set to perform within moments with excellent accuracy. Is this the end? No! This is the start-up and the rest of the regular applications put an emergency call for such a toolset. 

Durability, non-breaking strength, 360-degrees rotating features, or other relevant info that will help you to spend worthy bucks on the certain one, you can put one from our experienced checklist to use them in lieu of vernier scale or caliper one.  

Relevant Resources:

About Gavin Ford

Hi, I am Gavin Ford. I am a full-time power tools salesperson and a part-time mechanic. I help my friends and neighbors with their tools. Which one to buy, how to buy it, how to use it, methods to fix broken tools, and so on. In I will do the same for the rest of the world. You will get everything you need to know about tools for regular and professional use.

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