Making a Steam Whistle

Steam whistles, the icon of the by-gone era of steam. There is nothing like the shrill, the moan, or the sound. The steam whistle was synonymous with the snorting of steam locomotives to the clattering steam tractor, it was the machine’s voice. The art of traditional whistle making has almost been lost to time with the passing of steam engine, as the roar of gas and diesel engines came on to the scene. There are still many whistles left but with the problem being that the original desirable ones have a high price tag or others ones are broken beyond repair and are only show pieces. Hello everyone I am Joseph Throener, I have been involved with the Steam hobby for a number of years and have had the wonderful opportunities to run steam tractors and steam locomotives. In leu of this there was a locomotive that needed a different whistle. Since the current one is an industrial single chime, it has a horrid sound and when large crowds are concerned it is startling. I have tried constructing whistles in the past and each one was a failure. This one is successful from those failures. The other hederal that was confronted was the search for information that can’t be easily found on the internet, this includes critical dimensions and the way parts are shaped. So, this here will bring the information to light in a way for the builder to have the capability to make a chime whistle but also have the complete freedom of the final shape and sound of their whistle. 

What is presented is a 6in diameter 4 chime whistle with a 13in long bell but the construction can be changed to make a 3, 5, or 6 chime without much of a problem at any bell length desired. On the contrary the diameter is more difficult to change since different dimeters require different bowl to lip gaps to make the whistle sound properly. It is highly recommended to purchase the book The Engine’s Moan: American Steam Whistles, this book has a wealth of information when it comes to whistles. It also has the necessary charts for the critical dimensions so the whistle has the highest chance of working properly with minimal tuning. 

Before going further here’s a few informational bits. First, it is understood that the builder has or has access to a lathe, mill, other associated equipment and tools for metal working and has the knowledge to use them. Second, the builder must be able to set up their own tolerances since the prints supplied are for a general guide and are not to be used for final dimensions. Third, there are many different ways to make the same component, that can be either made out of one-piece of metal or built up from different pieces welded together. This will show one way of constructing the whistle but is up to the builder on how they want to build it. Lastly, to give the whistle the best chance of success of working correctly take the time to plan out the machining processes and make sure to keep everything concentric and square as possible.

This project requires the use of a lathe, mill and general meatal working tools. Metal would also needs to be gather up or purchased at the builders discretion. Again it is almost a requirement to get the book The Engine's Moan: American Steam Whistles, since the information presented by the book cannot be found anywhere on the internet.

After the acquiring the metal it would be best to start off by cutting the Whistle Bowl Pipe from its respective pice of pipe. Next go the lathe to face and square up the Bowl Pipe. If seamed pipe is used the internal dimeter will have to be bored out to make it round. The part can be removed from the lathe and set aside.

Next the main Stem Pipe needs to be built up, start off by cutting a piece of thick wall pipe and go to the lathe to face the ends off and bevel one end for welding, remove part from lathe. After that cut a piece of solid round stock of the same outer dimeter, go to the lathe and face both ends off. Next would be to turn a smaller dimeter on one end of the stock to be a press fit in the hole of thick wall pipe. Now bevel the larger dimeter for welding. Remove part from lathe. Take both machined parts and press together with bevels facing each other. Take the weldment back to the lathe, chuck up and set up a live center on the other end for support. Turn the part down to a uniform diameter. Remove the stem from the lathe and go to the mill. Set up the part in such a way to mill out the 4 slots in the stem as shown in the print. Afterwards deburr and set aside.

The bowl plates are next. First, take the 2 blanks to the lathe. Drill and bore out the centers to be a tight fit over the stem pipe, bevel one inside one edge of each for welding. The one plate can be set aside since it needs to be solid. The other plate needs to be opened up to allow the passage of steam. The ideal way to make the part is to remove 4 quadrants as shown in the print, that can either be done with a mill or by other means. Be sure to leave enough material between the outer edge of the quadrant and the outer dimeter (O.D.) of the plate so it can be turned down to fit in the Bowl Pipe. After the plates have had their center holes made and the one quadrated out it is time to weld both of them to the stem pipe. The solid plate goes on the bottom and the other just over the top of the 4 slots machined earlier, refer to the print to aid in the placement. Weld them into place. Now go put the assembly in the lathe, be sure that the stem pipe is running concentrically. Turn the O.D. of the plates down to fit in the Bowl Pipe. Remove the assembly from the lathe, install the Bowl Pipe and weld it in to place. Take the assembly back to the lathe, after letting it cool, to face off the front of the assembly and turn the Stem Pipe O.D. and the I.D. of the bowl pipe so they are centric and square. Be sure to clean up the top of the quartered-out plate to have a flat square surface so the language plate can rest squarely in place. Remove the center and drill a hole through the solid portion of the stem pipe for a ¾ in thread. After threading the assembly can be set aside. The Whistle Bowl is assembled.

The Language plate is next, to start off take the round blank to the lathe and open up a hole in the center. This will be used as a way to register the other component. Remove and set aside. Next take a large piece of round stock put in the lathe and face off. Turn a register on the end that is a tight fit in the hole of the previous machined blank. Bevel the O.D. of the stock for welding. Take the part out of the lathe and take the two parts press together, and weld. After cooling, take the assembly back to the lathe and make sure that it runs concentric and square as possible. Face the front of the plate. Reverse the part around so the plate is in the chuck, face off the stock side and size the length to the measurement from the Top Plate to the top the Stem Pipe so the language Plate sits flush with the top of the Bowl.   Turn the part back around. Now drill and bore out a hole through the center of the assembly to fit over the Stem Pipe in the Bowl. After that turn the O.D. of the plate down to be slightly smaller than the I.D. of the Bowl Pipe to create the gap for the steam to go through. Now the create the bevel on the back side of the plate be sure to make the flat surface length correct form the top of the plate to where the bevel starts. After removing the assembly from the lathe, the Language plate is complete. Now take the time to put the Language plate in the Bowl in its Respective place. If it sits too high the Language Plate needs to be machined shorter. If it sits too low it needs to be shimmed up so its sit flush with the top of the Bowl. 

The time has come to start on the Bell of the Whistle. First is to make the main stem of the Bell. Take a piece of round stock to the lathe. Face and drill in center holes on each end to allow the Bell Stem to be turned between centers. After resetting up in the lathe clean up the round stock. Now reduce the I.D. on each end to leave .020 thou for final turning. To determine the lengths of the reduced dimeters, refer to the print. Remove the part from the lathe and take it over to the mill to make the 4 slots as shown in the print. With the slots completed the part can be set aside.

The bell tube is to be made of the same dimeter pipe as used in the making of the bowl. This can be cut to length and set aside if it is seamless, if not it will need bored out to make it round.

 Next is to make the Vein plates that will be affixed to the Stem. Use material that is an acceptable width so there is room for turning them down. Cut to the same length of the slots in the Main Stem. After cutting insert the vein plates in the slot of the stem and weld them in place. The assembly can be set aside. Now with the stem with the vein plates cool it can be taken back to the lathe to be ran between centers. By the nature of the assembly being machined it is going to be loud it is recommended to wrap rags or put rubber bands on the assembly to quell the incessant ringing. Bring the dimeter down to be around .100 thou above the I.D. of the bell tube. Remove the part from the lathe. Next is the creation of the chime stop plates to make the different chamber lengths thus the different notes of the chime whistle. Cut out the rough shape out of steel that is needed for the chime stop plate to fit between the vein plates, allow for some clearance between the back of the chime stop plate so it doesn’t foul on the main stem. After determining the chamber lengths weld the plates into place. Back to the lathe and do the final turning to bring the assembly to be a mild press fit in the bell tube. Don’t forget to face the ends of the vein plates. The assembly can be removed. Take the assembly and the bell tube to the press and press together. Take the assembly back to the lathe and turn the bottom reduced dimeter so it can be threaded 3/4in. the same can be done at the top. the assembly can be set aside

Now the bottom washer can be made. Take the respective sized puck to the lathe, face the front off and drill a ¾ in hole trough. After the hole is drilled and deburred the washer can be fitted to the bottom of the main stem. Then weld it to the veins.

With the washer now attached take the assembly back to the late, run it between centers. Face the washer off until it is square with the rest of the assembly. Now to create the gap needed between the lip of the bell and the top of the bowl. This is around 1.5 inches measured from the bottom of the washer to the lip of the bell, in this whistle’s case. Refer to the book for other sizes. After that machine the bevel that is shown in the print. Remove from the lathe and test fit the bell to the bowl.

Now the last part is to be machined is the cap plate of the whistle. What is shown on the print was not done in this case. Take a puck of steel and drill a ¾ in hole through and face. The puck can be remove and a mandrel need to be turned to machine O.D. of the puck so it fits in the bell tube. After that the puck can be fitted on the whistle held in place by a nut on the machined stud.

The whistle is more or less completed, there may be the need of tuning the whistle but that can only be found out when under air or steam. The condition that can be herd in the video is overblowing, characterized by the high pitch squeaks and squeals. This is corrected by changing the position of the bell tube on the veins, that be either up or down. After testing / tuning the cap can be welded into place.