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9Nov/10Off

Master Setting Discs

Master Setting Discs are ideal for calibrating and setting comparators, snap gages and other precision measuring instruments. Master Setting Discs are furnished with insulating grips to prevent heat distortion from handling. They are available in gagemaker tolerances from class XX thru class Z. Master Setting Discs are offered in high quality tool steel, chrome and carbide materials for longer life. They are available in 3 styles for various applications. Master Setting Discs conform to ANSI B47.1. They are ring lapped to size, and polished. Roundness and taper of all gages does not exceed 50% of the applicable gagemaker’s size tolerance and are non-accumulative. Sizes are available up to 23 inches in style #3.

4Nov/10Off

Reversible Style Thread Plug Gages.

Thread Check, Inc. offers a complete line of AGD – American Gage Design, metric working reversible style thread plug gages. The reversible thread plug gage style allows for one end of the gage to be rotated so the user gets two gages in one. A worn gage end can be turned around by simply opening the collet of the handle and turning the gage and bushing around so the opposite end essentially becomes a new gage. The reversible thread plug gage is ideal in high volume inspection applications. Thread Check’s reversible thread plug gages are manufactured per ANSI/ASME B1.16M. Thread Check, Inc. reversible style thread plug gages are manufactured to an X tolerance in class 6H. Reversible thread plug gages are available in M, MJ and specials. All standard reversible thread plug gages are stocked in hard chrome coating which extends the wear life of the gage by more than a 100% thus providing dramatic savings in replacement costs. All Thread Check, Inc. gages are manufactured to the high end of the tolerance to ensure longer gage life. Thread Check, Inc. manufactures reversible thread plug gages in carbide, ceramic and other types of specialty steels. Thread Check manufactures many types of special gages including pre-plates, multiple starts, special leads, acme threads, buttress threads, square threads, extra length thread gages, and custom gages to print. All thread plug gages are traceable to N.I.S.T.

3Nov/10Off

UPDATE ON ASME B1 THREAD COMMITTEE REPORT FROM AMTMA NEWS LETTER

The ASME B1 threads standards meeting was held May 13, 20l0 in Miami Beach Florida.

Following is the report on these meetings.

B1.1 60° product threads: new standard is available from ASME

The revised B1.2 is still in draft form at this time.

Sections have been reviewed and approved.

B1.5, acme threads: no new activity

B1.8, stub acme threads: will be revised soon

Bl-9, buttress threads: some changes proposed for symbols and wording.

BJ.20. pipe threads: David Kats brought up the issue of using 3 dimensional drawings in

the specification.

 Angel Guzman stated he had not seen this in other documents. It was agreed if they need to be used to show a clearer picture, we would incorporate if possible. There was a discussion on the letter submitted by Guy Cuccio on changing of gage point from end of pipe to last scratch of thread. Guy passed out a copy of his proposed change for review. There was a discussion on the specification and whether to revise it. David Katz pointed out that section 8.1 refers to the "End of the Pipe" as the gauging reference. Section 8.1 and 8.2 refer to the "End of the Thread", but also refer to figure 6, which shows gauging to the end of the pipe. David Katz referred to the specification NI.5, section 1.7.2.1 which describes how to handle chamfer size on the product. It describes that the purchaser and supplier should agree on gauging points if chamfers exceed major diameter of the internal nd minor diameter of external, Alan Sheppard brought up the turns engagement method, Guy Cuccio stated that the turn's method is not an accurate way to check pipe threads. David Katz said this part of the Specification will be put in the appendix of the new revision.

It was discussed that some manufacturers' practice is to make large chamfers on external threads to protect the thread, especially on large fittings. They feel that the threads are good and the specification should allow this practice by not counting the excess of chamfer when gaging the parts. Additionally, this would better ensure adequate thread engagement. Some manufacturers have had auditors not agree with this practice because it is not allowed in the specification.

Al Barrows explained the following tasks that still needed to be done

• Review non-threaded gages in the current B1.2, table 12 items 8-16, table 13, items

8 thru 15 and table 14.

• Wording for progressive set plugs

• Wording for the calibration of the new vs. used gages

• Incorporate table 12,13 & 13 notes from current B1.2 document

• Integration of appendix A from current B1.2 document

B1.10 unified miniature screw threads: The Bl.l0-2004 unified miniature screw thread

document is current and available from ASME.

NEXT ASME B1 MEETING

October 19-21 2010 in St. Louis, MO

The American Measuring Tool Manufacturers Association is looking for new members. Visit www.amtma.com for information on becoming a member.

2Nov/10Off

Dimensional Inspection of Parts Using Fixed Gages

Choosing the proper inspection instrument is a critical quality control decision; the wrong device or method could produce inaccurate results, and also affect the cost and performance of the parts that are inspected. Additionally, the parts should undergo a comprehensive inspection in which all aspects of the part's performance life and functions are considered. The importance of the part's function should directly correlate to how extensive an inspection might need to be performed, ranging from a simple scale to the utilization of complex measuring instruments.

It is also important to realize that when inspecting parts, gaging and measuring are two different terms. The primary distinction between the two relates to a count of units: gaging refers to whether the part features are within a specified limit, and measuring refers to the number of units in the specified dimensions of a part.

Measuring devices can be relatively costly and complex, but may be necessary depending upon whether an accurate count of units is needed. In contrast, gages are typically inexpensive, simple devices, and require little set-up. The choice of inspection devices (measuring or gaging) is usually determined by what type of measurement is needed. If the actual dimensions of a part are not required, then the less expensive gaging method is the optimal choice.

Benefits of Fixed Gages

Fixed gages are typically simple devices like plug gages or ring gages that contain no moving parts and are easy to use. As such, their use is very common. They are also easily portable, do not suffer breakdowns in service, and do not require power.

Because fixed gages are available in an extensive range of sizes and tolerances and offer increased assurance of a fit between mating parts, it is easy to see why fixed gages are the most widely used inspection device.

Setting Gages and Limit Gages

Fixed gages are usually regarded as either a Limit Gage or a Setting Gage. Setting Gages are used to set the zero position of a particular instrument, while Limit Gages determine either the maximum or minimum material condition of a part's features. Limit gages are typically utilized as a full-form or 3D simulation of the mating part. This serves as the basis for the gaging practice known as "Go, No Go," which is often used with ring, plug, and snap gages.

The Go, No Go Inspection Practice

In this gaging practice, a Go Gage is used, serving as the equivalent to one of the part's specified features. If the Go Gage fits into the part, then it stands to reason that the mating part does not have excessive material and will also fit, ensuring proper assembly. Likewise, if the No Go Gage does not fit into the part, it shows that the feature under inspection is not lacking material or is not too large and consequently too loose.

The Go, No Go Gaging practice is a quick, efficient, and cost-effective verification that part dimensions meet drawing requirements and will assemble and function properly.

Using Plain Plug Gages

Plug gages are available in many different types and are utilized for a variety of inspections. Reversible wire plug gages are held in a collet-type handle that forms either a single-end or double-end Go, No Go Gage Assembly. Reversible wire plug gages are available in a range from .004"-1.000", and in a tolerance range from class Z-XXX. Most often utilized for checking hole size, they can also be functional for setting masters, locating pins, calibrating laser micrometers, and other high precision demands. Wire type reversible plug gages also referred to as pin gages have become very popular, due to their low cost and availability in thousands of sizes.

To inspect hole size of a part, the Go gage is inserted into the hole. If the gage can be entered into the hole, then the hole is considered to be above its low limit. Following that, the No Go gage is used: if it enters the hole, than the hole is too big.

Using a series of plugs in various diameter steps will result in a high repeatability rate. Gaging should be performed under optimal conditions so as to have little effect upon the inspection, such as cleanliness of the part and proper temperature control. Work tolerance might also be a factor to consider, in which a gage wear allowance may be used. In this case, a wear allowance is added to the Go Gage diameter.  A tolerance should be specified so that the total gage tolerance does not exceed 10% of the part tolerance.

For very fine tolerances, a carbide plus gage is often the most effective and practical gage to be utilized. Additionally, many gage users also elect to use plugs in addition to air gaging or electronic inspections, in order to ensure that the parts will mate.

For more information regarding fixed gages or any other gaging questions contact Thread Check ‘s  sales engineering department.