Balanced Air Brakes from Scratch: Difference between revisions
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=== Air Tank === | === Air Tank === | ||
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File:FreightTruckAirBrakes1.jpg|I started with the air tank. It is constructed using 2 inch diameter PVC pipe (schedule 40) with a pair of caps. A hole was drilled and tapped for 10-32 threads to accept a Clippard fitting. An adhesive dot was placed over the hole before painting. | File:FreightTruckAirBrakes1.jpg|I started with the air tank. It is constructed using 2 inch diameter PVC pipe (schedule 40) with a pair of caps. A hole was drilled and tapped for 10-32 threads to accept a Clippard fitting. An adhesive dot was placed over the hole before painting. | ||
File:FreightTruckAirbrakes2.jpg|PVC glue was applied to the threaded hole before inserting the Clippart CT4 1/16 hose barb fitting. Be careful with the glue. As you can see it will remove paint. | File:FreightTruckAirbrakes2.jpg|PVC glue was applied to the threaded hole before inserting the Clippart CT4 1/16 hose barb fitting. Be careful with the glue. As you can see it will remove paint. | ||
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=== Brake Pads === | === Brake Pads === | ||
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File:CabooseTruck BrakePadMaterial.jpg|Brake pad material from McMaster-Carr. | File:CabooseTruck BrakePadMaterial.jpg|Brake pad material from McMaster-Carr. | ||
File:CabooseTrucks AttachingBrakeShoes.jpg|The Brake Pads are cut and glued to the aluminum Brake Shoes with JB Weld. The Brake Shafts are pulled tight using rebar ties attached to the axle. This holds the shoes tightly to the pads and forms the curve in the shoes. | File:CabooseTrucks AttachingBrakeShoes.jpg|The Brake Pads are cut and glued to the aluminum Brake Shoes with JB Weld. The Brake Shafts are pulled tight using rebar ties attached to the axle. This holds the shoes tightly to the pads and forms the curve in the shoes. | ||
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File:CabooseAirBrakeTrainLineValve.jpg|Clippard TV-2S toggle valves were selected because of their small size, low cost, and reliable operation. Note the eye hooks for safety chains, as required by some railroads. | File:CabooseAirBrakeTrainLineValve.jpg|Clippard TV-2S toggle valves were selected because of their small size, low cost, and reliable operation. Note the eye hooks for safety chains, as required by some railroads. | ||
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=== Plastic Shoes === | |||
In 2019 I replaced the aluminum shoes with more realistic shoes printed in black PLA. See [[Brake_shoe#Plastic_Brake_Shoes|Plastic Brake Shoes]]. | |||
== Video Demo == | == Video Demo == | ||
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< | <youtube>6xFOI4LY6Vs</youtube> | ||
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Latest revision as of 23:20, 5 January 2021
Fall 2015
During the summer of 2015 I began studying air brakes and how live steam modelers incorporate working air brake systems on their trains. I was well into building a Kitsap Live Steamers caboose kit and decided to add a fully operational balanced air brake system to the caboose.
This is my first attempt at building operating air brakes, and I am quite pleased with the results. Air brakes will certainly be added to my other equipment.
Summary: This article describes how to build Pull-to-apply balanced air brakes.
Equipment
- Clippard parts:
- UDR-17-1 : Stainless steel double-acting cylinder, 1 inch stroke, 1-1/16 inch bore, 5/16 inch shaft
- CT4 : #10-32 to 1/8” ID Hose Connector, designed for Clippard's Polyurethane hose
- T44-4 : Tee fitting, 1/8 inch ID
- URH1-0804-BKS : Urethane tube 1/8 inch ID
- TV-3SP : 3-Way Toggle Valve, ENP Steel Toggle, 1/8" NPT
- MCV-2 : Check Valve, #10-32 Ports
- 15090-1 : 1/8” NPT to #10-32 “L” Fitting
Tools and Supplies
The following tools were used in the construction of the truck brakes:
- Drill Press
- Low-cost wire welder (110 Volt AC) from Harbor Freight
- Lincoln Innershield NR-211-MP flux core welding wire, 0.035 inch
- Lathe (for turning brake shoes and brake shafts)
Build Gallery
Air Tank
Brake Shoes
In an effort to save money I decided to cut brakes from a ring of aluminum purchased from McMaster-Carr. The pipe has a 4 inch inside diameter and a 6 inch outside diameter.
A 1/2 inch width of the aluminum pipe was parted off on the lathe. Here it has been blued and marked for cutting.
Mechanical Drawings
Assembling Brake Shafts
Brake Pads
Final Assembly
Plastic Shoes
In 2019 I replaced the aluminum shoes with more realistic shoes printed in black PLA. See Plastic Brake Shoes.
Video Demo
This video demonstrates the failsafe operation of the balanced brakes, along with how to disable the brakes once activated. Video by Daris A Nevil, August 2015.