Gas torch and thermit welding
GAS TORCH AND THERMIT WELDING
BY ETHAN VIALL
McGRAW-HILL BOOK COMPANY, Inc, NEW YORK, 1921
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Gas torch and thermit welding
PREFACE
The beginner, the practical worker, the student and the engineer, will find in this book a great amount of information regarding gas-torch and Thermit welding practice and equipment. No toil or expense has been spared to gather material of real and lasting value. Shops have been visited and data and photographs obtained first hand. Practically every book on welding has been carefully scrutinized for helpful suggestions. The services of experts have been engaged to give the results of long practice and research in their special lines. Each and every plan known to the experienced editor has, been employed to give the reader the highest possible grade of information.
The historical references have been cut to the barest statement of facts as we have been able to obtain them, yet they are ample enough to give the inquiring mind the genesis of each class. Foreign methods and equipment have not been touched upon, except in a few instances, because such treatment would add too greatly to the bulk of this work, without adding an appreciable amount to its real value, since the methods and standard equipment here are, in general, far in advance of anything similar elsewhere.
Great care has been taken to indicate the sources of information and to give the names and addresses of the makers of equipment shown. It is believed that every well known maker of this class of welding apparatus in the United States has been mentioned at least once in these pages. This has not been done with any idea of advertising them, but because it is information every reader is entitled to have without the necessity of making a separate search for it.
Of course no recommendations regarding the best apparatus to use are made in any case. As in any other line, improvements are being constantly made, but in regard to newly invented or unknown equipment the seller should be made to prove his case before an investment is made. Apparatus which does not meet the present day requirements, soon drops out of sight. It is a good plan for a prospective purchaser of equipment to consult some well established firm which is not afraid to advertise its product in open competition. Such a firm will see that its equipment is properly installed and works satisfactorily.
The historical references have been cut to the barest statement of facts as we have been able to obtain them, yet they are ample enough to give the inquiring mind the genesis of each class. Foreign methods and equipment have not been touched upon, except in a few instances, because such treatment would add too greatly to the bulk of this work, without adding an appreciable amount to its real value, since the methods and standard equipment here are, in general, far in advance of anything similar elsewhere.
Great care has been taken to indicate the sources of information and to give the names and addresses of the makers of equipment shown. It is believed that every well known maker of this class of welding apparatus in the United States has been mentioned at least once in these pages. This has not been done with any idea of advertising them, but because it is information every reader is entitled to have without the necessity of making a separate search for it.
Of course no recommendations regarding the best apparatus to use are made in any case. As in any other line, improvements are being constantly made, but in regard to newly invented or unknown equipment the seller should be made to prove his case before an investment is made. Apparatus which does not meet the present day requirements, soon drops out of sight. It is a good plan for a prospective purchaser of equipment to consult some well established firm which is not afraid to advertise its product in open competition. Such a firm will see that its equipment is properly installed and works satisfactorily.
TABLE OF CONTENTS
PART I - GAS TORCH WELDING.
- History and Uses or the Gas Torch
- The Production of Welding Gases - Oxygen and Hydrogen
- Acetylene and Medium, or Positive, Pressure Generators
- Low Pressure Acetylene and Thermalene Generators
- Gas Torches Used for Welding
- Gas Cutting Torches
- Gas-Pressure Regulators and Working Assemblies
- Gas Torch Welding and Cutting Outfits
- Learning to Weld with the Gas Torch
- Making allowance for Expansion and Contraction
- Welding Various Metals and the Fluxes Used
- Examples of Welding Jobs
- Welding Jigs and Fixtures
- Welding Machines
- Cutting with the Gas Torch
- Cutting Machines
- Welding Shop Layout, Equipment and Work Costs
PART II- THERMIT WELDING.
- Thermit Welding: Its History, Nature and Uses
- Making Plastic Process Welds
- Fusion Welding of Heavy Sections
- Welding Crankshafts, Mill Pinion Teeth, Etc.
- Welding New Necks on Large Pinions and Other Heavy work
- Rail Welding for Electric Systems
- Welding Compromise Rail Joints
- Welding Cast Iron and Other Parts
CHAPTER V - GAS TORCHES USED FOR WELDING
The gas torches used for welding in the United States may be divided into two general types, known as medium-pressure and low-pressure torches. Each type is made in a number of sizes, and each size is usually provided with a number of interchangeable tips for producing flames of different size.
The medium pressure torches are also known as positive-pressure torches, and to avoid misunderstanding, they will be referred to as positive-pressure torches hereafter. In these torches, using acetylene and oxygen for welding, the acetylene pressure will range from 1 to 14 lb. and the oxygen pressure from 1 to 24 Ib. per square inch, the pressure employed depending on the thickness of the metal being welded, the make of torch, and the tips used. The pressures given may even be exceeded in some exceptional cases.
A sectional view of a typical positive-pressure welding head is shown in Fig. 23. The oxygen enters at A and the acetylene enters at B. The oxygen goes to the small chamber C and thence out through the center hole. The acetylene goes to the chamber D and also out through the center hole, the two gases starting to mix at the point E, and as they pass out through the channel F to the end of the tip, they are thoroughly mixed. In this illustration, the removable tip is indicated by G. This make of tip has a conical seat and held in its place by means of the lock collar H. Made in this way, there are no threads on the tip itself, although the practice varies in different makes.
The low-pressure torch is also known as the injector type. In this type of torch, the acetylene, or other gas, is supplied under a pressure of a few ounces up to 1 Ib., but the oxygen may have a pressure of from 5 to 30 lb. per square inch, according to the size of tip being used. In some cases the oxygen pressure may be either higher or lower than the figures given.
A sectional view of a typical low-pressure torch is shown in Fig. 24. In this torch the acetylene, or other gas, enters at A and the oxygen at B. The acetylene goes to the chamber C from which it is sucked by the oxygen pouring out through the nozzle at D, and it is carried along with the oxygen into the mixing chamber E in the tip of the torch. From this chamber the gases issue thoroughly mixed and ready for combustion.
As they qualify for classification as either positive-pressure or low-pressure types of torches, the various makes of each type differ principally in form, the general principles of action remaining the same. A few examples of the different makes of positive-pressure torches will be shown first, and these will be followed by others of the low-pressure or injector type.
The Prest-0-Lite Torch. The torch shown in detail in Fig. 29 is made by the Prest-O-Lite Co., Indianapolis, Ind., but is handled by the Oxweld Acetylene Co. This torch is fitted with a long stem through which the gases pass and are thoroughly mixed before issuing from the nozzle.
The stem is fitted to the mixing chamber by means of a union nut, which permits the operator to point the welding tip in any direction, without changing his method of holding the torch. This is particularly advantageous for vertical and overhead welding. Both oxygen and acetylene inlets on the torch are fitted with fine-adjustment control valves. The one on the oxygen supply is so placed that the operator while working can make any slight necessary adjustment with the forefinger of the hand that grips the torch. The handle of the torch is fitted with anti-fireback chambers for both gases, filled with a special material through which it is impossible for a flame to pass.
The torch is easy to dismantle, as all parts are screwed together on metal-to-metal seats and no packing or solder is used at any joint.
For extra heavy work, a special stem 22 in. long is furnished, and for close work a 5 1/2-in. stem may be had in addition to the regular size. The regular stem has seven tips, the largest four being of copper which will stand up against the intense heat radiated from the work better than any other metal. The smaller tips are of a special alloy. A similar torch is also made for very light work which weighs only 3 oz. complete.
In the detailed view given of the torch, A is the hose nipple through which the oxygen passes. At B is a set of 40 strainer cloths for the oxygen filter chamber; C is the oxygen needle valve; D is the acetylene hose nipple; E is the acetylene needle valve; F is the acetylene filter-chamber cartridge; G is the stem. The seven tips are indicated from 1H to 7H, and their openings can be determined from Table IV. This table is especially valuable in that the nozzle openings are shown in regular twist-drill sizes, furnishing an easy method of comparison. The two tips given at the bottom of the table are extras, used for heavy work. The figures quoted in the table are based on straight work on steel plate, beveled when over
1/8 in. in thickness and welded without preheating.
The General Welding Co.'s Torch. A welding torch made by the General Welding and Equipment Co., Boston, Mass., is shown in Fig. 30. Each torch is furnished with nine tips, affording a range equal to all ordinary welding jobs. In addition, stems of different lengths may be had. In the illustration, A is the body of the torch; B is the mixing chamber; C is a short stem, the use of which makes the entire torch 16 in. long; D is a medium stem, making the torch 22 in. long ; E is a long stem, making the total length of the torch 30 in.
Details of this torch are shown in Fig. 31. Here the acetylene inlet is shown at A and the oxygen inlet at B. The body of the torch is indicated by C, and D is the mixing chamber; E is the stem, and F various shapes of tips.
Imperial Torches. Another long-stemmed torch is shown in Fig. 32. This is made by the Imperial Brass Manufacturing Co., Chicago, and differs but little from the one just shown. The gas valves, however are placed at the forward end of the body. Like most of the other torches, these may be used not only for oxy-acetylene, but also for oxy-hydrogen welding work, special tips and regulators being made for the purpose. For oxy-acetylene, the gas pressures are approximately the same as for other makes of torches. For oxy-hydrogen, the pressures used for various thicknesses of metal and different tips are given in Table V. However, neither the size of the nozzle holes nor the amount of gas used per hour are given. This firm also makes a three-way torch which in outward appearance does not differ from the one shown. It is intended to use a combination of acetylene, oxygen and hydrogen.
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The medium pressure torches are also known as positive-pressure torches, and to avoid misunderstanding, they will be referred to as positive-pressure torches hereafter. In these torches, using acetylene and oxygen for welding, the acetylene pressure will range from 1 to 14 lb. and the oxygen pressure from 1 to 24 Ib. per square inch, the pressure employed depending on the thickness of the metal being welded, the make of torch, and the tips used. The pressures given may even be exceeded in some exceptional cases.
A sectional view of a typical positive-pressure welding head is shown in Fig. 23. The oxygen enters at A and the acetylene enters at B. The oxygen goes to the small chamber C and thence out through the center hole. The acetylene goes to the chamber D and also out through the center hole, the two gases starting to mix at the point E, and as they pass out through the channel F to the end of the tip, they are thoroughly mixed. In this illustration, the removable tip is indicated by G. This make of tip has a conical seat and held in its place by means of the lock collar H. Made in this way, there are no threads on the tip itself, although the practice varies in different makes.
The low-pressure torch is also known as the injector type. In this type of torch, the acetylene, or other gas, is supplied under a pressure of a few ounces up to 1 Ib., but the oxygen may have a pressure of from 5 to 30 lb. per square inch, according to the size of tip being used. In some cases the oxygen pressure may be either higher or lower than the figures given.
A sectional view of a typical low-pressure torch is shown in Fig. 24. In this torch the acetylene, or other gas, enters at A and the oxygen at B. The acetylene goes to the chamber C from which it is sucked by the oxygen pouring out through the nozzle at D, and it is carried along with the oxygen into the mixing chamber E in the tip of the torch. From this chamber the gases issue thoroughly mixed and ready for combustion.
As they qualify for classification as either positive-pressure or low-pressure types of torches, the various makes of each type differ principally in form, the general principles of action remaining the same. A few examples of the different makes of positive-pressure torches will be shown first, and these will be followed by others of the low-pressure or injector type.
The Prest-0-Lite Torch. The torch shown in detail in Fig. 29 is made by the Prest-O-Lite Co., Indianapolis, Ind., but is handled by the Oxweld Acetylene Co. This torch is fitted with a long stem through which the gases pass and are thoroughly mixed before issuing from the nozzle.
The stem is fitted to the mixing chamber by means of a union nut, which permits the operator to point the welding tip in any direction, without changing his method of holding the torch. This is particularly advantageous for vertical and overhead welding. Both oxygen and acetylene inlets on the torch are fitted with fine-adjustment control valves. The one on the oxygen supply is so placed that the operator while working can make any slight necessary adjustment with the forefinger of the hand that grips the torch. The handle of the torch is fitted with anti-fireback chambers for both gases, filled with a special material through which it is impossible for a flame to pass.
The torch is easy to dismantle, as all parts are screwed together on metal-to-metal seats and no packing or solder is used at any joint.
For extra heavy work, a special stem 22 in. long is furnished, and for close work a 5 1/2-in. stem may be had in addition to the regular size. The regular stem has seven tips, the largest four being of copper which will stand up against the intense heat radiated from the work better than any other metal. The smaller tips are of a special alloy. A similar torch is also made for very light work which weighs only 3 oz. complete.
In the detailed view given of the torch, A is the hose nipple through which the oxygen passes. At B is a set of 40 strainer cloths for the oxygen filter chamber; C is the oxygen needle valve; D is the acetylene hose nipple; E is the acetylene needle valve; F is the acetylene filter-chamber cartridge; G is the stem. The seven tips are indicated from 1H to 7H, and their openings can be determined from Table IV. This table is especially valuable in that the nozzle openings are shown in regular twist-drill sizes, furnishing an easy method of comparison. The two tips given at the bottom of the table are extras, used for heavy work. The figures quoted in the table are based on straight work on steel plate, beveled when over
1/8 in. in thickness and welded without preheating.
The General Welding Co.'s Torch. A welding torch made by the General Welding and Equipment Co., Boston, Mass., is shown in Fig. 30. Each torch is furnished with nine tips, affording a range equal to all ordinary welding jobs. In addition, stems of different lengths may be had. In the illustration, A is the body of the torch; B is the mixing chamber; C is a short stem, the use of which makes the entire torch 16 in. long; D is a medium stem, making the torch 22 in. long ; E is a long stem, making the total length of the torch 30 in.
Details of this torch are shown in Fig. 31. Here the acetylene inlet is shown at A and the oxygen inlet at B. The body of the torch is indicated by C, and D is the mixing chamber; E is the stem, and F various shapes of tips.
Imperial Torches. Another long-stemmed torch is shown in Fig. 32. This is made by the Imperial Brass Manufacturing Co., Chicago, and differs but little from the one just shown. The gas valves, however are placed at the forward end of the body. Like most of the other torches, these may be used not only for oxy-acetylene, but also for oxy-hydrogen welding work, special tips and regulators being made for the purpose. For oxy-acetylene, the gas pressures are approximately the same as for other makes of torches. For oxy-hydrogen, the pressures used for various thicknesses of metal and different tips are given in Table V. However, neither the size of the nozzle holes nor the amount of gas used per hour are given. This firm also makes a three-way torch which in outward appearance does not differ from the one shown. It is intended to use a combination of acetylene, oxygen and hydrogen.
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