Grind Gages & Physical Test Equipment
Precision Gage & Tool Co. manufactures high-accuracy Fineness of Grind Gages (sometimes referred to as Hegman Style Gages) and testing instruments for a large variety of industries. The Fineness of Grind Gages were originally developed in the early 1930’s for the paint industry by Bernard Hegman of Lowe Brothers Paint and Precision Gage & Tool Co. The two collaborating companies were located within two blocks of each other on East Third Street in Dayton Ohio.
The ASTM D1210 test method is the main ASTM metmhod for Hegman style grind gage. It is referenced in the test procedures of many manufacturers. The paint industries success with using the grind gage to determine that solids are dispersed in a vehicle quickly was noticed by other industries.
Gages by Industry
Precision Gage & Tool Co. adapted gages for use in the ink (ASTM D1316) and other coatings industries. Other industries such as the food, cosmetic, pharmaceutical, nano material, adhesive, petroleum, battery and other slurry products now also use the Fineness of Grind Gages in many areas of manufacturing from QC and R&D applications to on the floor and in process testing.
Precision Gage & Tool also offers a variety of other physical test equipment items that include but are not limited to Wet Film Applicators and Cross-Cut Adhesion Test Kits. For a more extensive product listing download our Grind Gage Catalog or contact us.
Follow this link for a basic grind gage chart showing the specifications and a description of the typical application for each grind gage category.
Fineness of Grind Gages
The Fineness of grind gage is an easy to use, relatively inexpensive production and quality control instrument that enables the manufacturer to check for unwanted agglomerates as well as particles that are too large. Grind gages and scrapers are consumable products and need to be refinished or replaced when they show visible damage to the gaging surface or readings become suspect. Long form certification is available at an additional cost for grind gages and scrapers but is almost always included FREE when you purchase your gage online through our website.
Precision Gage & Tool Co has created thousands of custom gages since 1932 for customers in various industries. Please Contact PG&T and we will be glad to assist you in deciding if one of our standard gages may work for you or if you would be better served by using one of our custom fineness of grind gage.
Hegman, micron, mils and NPIRI are common scales on Fineness of Grind Gages, wedge plates and printing plates. P.C. scale or the N.S. scale (In 1968 PG&T changed N.S. to H for Hegman) are sometimes used on older gages.
Scale and Units of Measurement
Mils – The equivalent of .001 inches, the Mils Scale is the most widely used unit of measurement regarding fineness of grind gaging equipment.
Microns – For a point of reference, 25 Microns is equal to 1 Mil. The commonly used Micron is usually rounded to .00004 inches for practical purposes of measurement.
NPIRI Scale – Designed for ink gages, the NPIRI Scale was developed by the National Printing Ink Research Institute. The NPIRI scale begins at 0 (zero) and extends to 10 at the point of depth equal to .001 inches. Although somewhat arbitrary, the scale is logical in that each division is equal to one tenth of a mil or 2.5 microns.
Bird Style Applicators
Bird style applicators are designed for laying down consistent coatings of various wet films of a precise thicknesses. This wet film thickness is the nominal thickness of the coating when drawn down with the bird style applicator. Bird Style Applicators are single clearance and durable enough for even the heaviest usage and Easy-to-clean. Available lengths include 1″, 2″, 3″, 3.5″, 4″, 5″, 6″, 7″, 8″, 9″, 10″, 11″, 12″.
The bird style applicators are drastically different from other applicators. They are marked with 1/2 the actual path depth (gap clearance) and this is often confusing to people. The fact that bird style applicators are marked with one-half the actual path depth (gap clearance) is an idea that one-half the actual path depth (gap clearance) would be the approximate wet film thickness resulting from the draw-down. This is not the case with many products. Wet film thickness can vary drastically depending on the rheology of the product being tested and also be affected by other variables please refer to (ASTM D823) for more information on this subject.
Each Bird Style applicator comes with a long form certification for trace-ability at no additional cost. Bird Style applicators are machined from 440-C stainless steel and hardened ensuring a long life.
Please specify the film width and bird style path depth which is 1/2 the actual path depth (gap clearance) when ordering bird style applicators . An example would be that a .003” Bird Style Applicator will have an actual Depth of .006”. To purchase a .003” (3 Mils) bird style bar with a 6” film width you would order it using that description. The actual depth of the path is .006” (6 Mils) and we do not need the actual depth information.
Custom Bird Style Applicators are also available with two or three steps in the path.
Wet Film Applicators
Precision Wet Film Applicators lay down a uniform thickness of film for observation and testing and are easy-to-use as well as very accurate . They are a standard used in manufacturing, experimental and quality control situations because of their reliability. Applicators are available in a variety of styles. 2-path “U” shaped chrome plated steel models are available in 2″ through 10″ path widths. 2-path Bar Style hardened 440-C stainless steel applicators may be ordered in 2″ through 14″ path widths. 8-path film applicators in 2″ through 4″ path widths are made of hardened 440-C stainless steel and are in standard depths. Custom depth range 8 path applicators can be ordered at an additional cost. To order these applicators you need to specify the applicator style, film width and actual path depth and if certification is required.
Other applicators such as 1” Cube applicators and the Dow Latex Film Caster are also available. Many custom Applicators have been created by Precision Gage & Tool Co. for customers in various industries. Please Contact PG&T and we will be glad to assist you in deciding between a standard or custom applicator. Long form certification is available at an additional cost for these types of applicators.
Cross-Cut Adhesion Test Kit
The Cross-Cut Kit by Precision Gage & Tool Company provides almost everything you need to perform adhesion and flexibility tests to meet the standards of the ASTM test method D-3359. Each kit includes a blade, a blade holder/handle, a hex wrench for changing blades, an extra clamp screw, a small flaking and cleaning brush, a lighted magnifier and a roll of test tape. Each cross-cut adhesion kit comes in a finished wooden case with instructions.
Testing Materials and Procedure
The information below is taken from the included cross cut adhesion test kit instructions and is also available for download here.
The Cross-Cut Kit by Precision Gage & Tool Company provides almost everything you need to perform Adhesion and Flexibility Tests to meet the standards of ASTM Test method D-3359. In the kit, you’ll find a blade, a blade holder/handle, a hex wrench for changing blades, an extra clamp screw, a small flaking and cleaning brush, a lighted magnifier, and a roll of test tape. You’ll also need a rubber eraser on the end of a pencil.
In the field, you’ll test the actual coated structure or article you want to evaluate. In the lab, you may apply the materials you’re testing to panels of the appropriate composition and surface conditions. Either way, the testing surface must be flat. You can check flatness with a straight edge such as a steel rule.
Make sure your specimen is at room temperature (or other mutually agreed upon temperature) and placed on a firm base.
- Select an area free of blemishes and minor surface imperfections. Under the illumination of the magnifier, use the cross-cut tool tomake parallel cuts as follows:
- For dry film coatings of thickness of 2.0 mils (50 μm) or less, use a fine blade (1.0 mm spacing). For coatings having a dry film thickness between 2.0 mils (50 μm) and 5 mils (125 μm), choose a medium (1.5 mm spacing) or coarse (2.0 mm spacing) blade.
- Make the first cut about 3/4 in. (20 mm) long. Cut through the film to the substrate in one steady motion, using just enough pressure to reach the substrate.
- After making the cut, gently remove any detached flakes or ribbons from the film with your kit’s brush.
- Next, make a second cut at 900 to and centered on the original cuts to create a grid pattern in the film.
- Brush the area again and inspect the cuts to make sure you’ve reached the substrate. If not, make another grid in a different location.
- Remove two complete laps of your kit’s test tape and discard. Remove an additional length at a steady rate (don’t jerk it) and cut a piece about 3 in. (75 mm) long.
- Place the center of the tape over the grid and smooth it into place. To make good contact with the film, rub the tape firmly with a pencil eraser. The color under the tape helps you determine when you’ve made good contact.
- Wait about 90 seconds, then remove the tape. Seize the free end and quickly (without jerking) pull it back upon itself as close as possible to a 1800 angle.
- Using the kit’s illuminated magnifier, inspect the grid area for coating removal. Rate the coating’s adhesion according to the test results classification chart below;
Report the number of tests, their mean and range, and where the failure occurred—i.e., between the first coat and substrate, between the first and second coat, etc. Note the substrate used, the type of coating and the method of cure. If the adhesion strength of the tape has been determined in accordance with Test Methods D 10001 or D 33302, report the results with the adhesion ratings. Otherwise, report the specific tape used.
Precision and Bias
Use the following criteria to judge the acceptability of your results.
Repeatability — If adhesion is uniform over the surface being tested, results obtained for two measurements by the same operator should not differ by more than one rating category.
Reproducibility — Test results obtained by different operators (each the mean of two measurements) should not differ by more than two rating categories.
Bias cannot be established for these test methods.
Sag Meters (ASTM D4400), Leslie Applicator Bars and NYPC Leveling Test Blade (LT1) (ASTM D2801 withdrawn) are multi notch applicators used for evaluating sag or leveling of paint or other coating. Sag Meters come standard in a High Range (14-60 mils), Medium Range (4-24 mils), Low Range (1-6 mils) and Standard Range (3-12 mils). Custom range Sag Meters and Multi Notched Wet Film Applicators are available at an additional cost. Please Contact PG&T and we will be glad to assist you in deciding if one of our standard Sag Meters and Multi Notched Wet Film Applicators may work for you or if you would be better served by using one of our custom Sag Meters or Multi Notched Wet Film Applicators. Long form certification is available at an additional cost.
Slump Flow Test Jigs
The Sealant Slump Flow Test Jig is used to test the slump of a sealant in accordance with ASTM Test Method D2202. Both inch and SI unit scales are on the face of PG&T’s Sealant Slump Flow Test Jig. Scales on face of the PG&T Sealant Slump Flow Test Jig are in .1” (1/10) of an inch increments for a total of 4 inches and 2.5 mm increments (.098425”) for total length 100 mm (SI).
Wedge and Printing Plates
Wedge printing plates are used for quick and easy proof press testing of stocks and inks. (ASTM D6846) They are especially effective in the routine production of standard prints having controlled ink film thickness. Stock ink combinations can be tested for print quality, as well as other performance properties. Impression plates are also available. Long form certification is available at an additional cost for wedge plates and printing plates.
Vacuum Plates hold charts in place for proper draw-down. The PG&T vacuum plate features a 304 stainless steel top, tool steel base. The 300 series stainless steel top Vacuum Plate Gage measures 9″ x 12″. Each Vacuum Plate comes with a long form certification for trace-ability at no additional cost.