Reference Tables for Thread Recognition
Tables for determining the type and size of threads, the subject of this paper;
the second part of the series of articles familiar with the types of threads,
fittings and their type determination, will be odorous.
In this section, the reader will be able to determine the size of the gear and its type by having sufficient information.
To avoid the complexity of the word and to preserve the integrity of the text,
some of the cases will be examined separately in the next articles in detail.
In the previous article, how to determine the straight or conical fitting and
measuring the nominal or nominal diameter of the male and female of the fittings were shown.
In this section, by using of this diameter, we will identify the type of fitting thread.
As it is said, the fittings are either conical or straight.
It is also threaded either in the form of a male or a female.
With this information as well as measuring the diameter of nominal;
in accordance with the procedure mentioned in the previous paper,
by using the tables below, the size of the gear,
we determine the size the standard and its type.
1-1 Determine the size and type of conical fittings
As mentioned in the first article, the fittings are either Tapered or Straight.
How to determine is also mentioned in that article.
Also, the method of determining the nominal diameter or of the male and female was discussed in that article.
Now, by using of that information, we will determine the type of gear.
The following is an example of a hydraulic conical gear fittings.
Fig. 1-1 Conic Fittings
2-1-1 Conical Male
The following table shows the geometry and thread screws for conic male fittings.
In the following tables, U, the first letter of the Unified word, W,
the first letter of the word Whit worth and M, is the first letter of the word Metric.
Each of these cases related to the thread type will be reviewed in the future articles.
As explained in the previous paper,
it is possible to determine the type of thread by means of the determinative gauge.
In this table, the type and size of the can be determined by using of the nominal diameter of conic male.
This information can also be used to predict and determine the screw gear.
Table 1-1 Determine the size and type of conic male fittings by using the male nominal diameter.
In the future articles on the type of gear design, such as ISO 7/1 or NPT, will be described in detail.
Note 1: It is important to note that, as a rule, fittings have different fabric tolerances.
Therefore, the above amount may not be accurately applied to all connections.
However, these values are used to identify threads.
Note 2: For ½ and ¾ inch gears, NPT threading and ISO 7/1 are very difficult to recognize.
The reason of this is the similarity of their gear screw.
In these cases, the precaution must be taken by the engineers and,
if necessary, be consulted by qualified persons.
3-1-1 Conic Female
Dimensions given in the table below may not be accurately matched to all fittings.
This is due to the various tolerances in the construction of hydraulic fittings.
After determining the cone and measuring the nominal diameter,
the following table is used to determine the gear.
Table 1.1 Determining the size and type of conic tapered fittings by using its nominal diameter.
Note 2: For ½ and ¾ inch gears, NPT threading and ISO 7/1 are very difficult to recognize.
The reason for this is the similarity of their gear screws.
2-1 Determining the size and type of direct fittings
By using the information obtained from the fitting,
we will determine the size and standard of the fitting.
Below are the tables of male and female direct fittings.
The following is an example of a straight gear fitting.
Figure 1-1 Direct gear fittings for hydraulic
1-2-1 Straight male Fittings
After making sure the thread of the hydraulic fitting is straight and also measuring its diameter,
Referring to the table below, the gear type, its geometry and screw are determined.
Table 1-1 Male direct fittings
2-2-1 Hydraulic straight female fittings
The following table shows the details of straight hydraulic fittings.
Table 1-1 Straight female fittings
In the next article will examine conical thread and its features.
Conical threads include threads NPT and ISO 7/1. In
this article also refers to the standard of these threads.