This is Steamworx, a Model Engineering channel. This is a second in a series of basic Model Engineering tools that are easily made in the workshop.
Being able to machine a simple profile can save hours of filing and sanding, not to mention adding accuracy to a machined surface. Here I show a simple method of creating a half round profiling tool for use in the lathe or shaper to cut a bead edge. Although this tutorial describes a specific shape the process can be used to produce some quite complex profiles, for example globe valves such as used in many Stuart Turner models.
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If you are interested in 2 ½” gauge locos please visit ‘The National 2½” Gauge Association’ at https://www.n25ga.org/ or the Guage 3 society at https://www.gauge3.org.uk/
Castings for Dyak and many other locos available from Kennions at https://www.kennions.co.uk/
welcome to Steamworks I’m Tim this is Tim’s top tool tips I’m going to use this piece of 1 in thick gauge plate to make a half round profile cutter the profile will be a 1/16 of an inch in diameter and I’m going to shamer the corners so that I can get a nice neat cut using a shot made gauge the piece is set in the mil viice at a 5° angle this will give a front cutting relief of 5° the end is M Square to give me a flat face to start working from this cutter sounds a little bit blunt I zero each axis so that I can get the hole in the center and have an accurate start point for me to machine from the center of the hole is exactly 100 th from the edge of the cutter cutting fluid is used to get a clean profile from the drill I’m taking it nice and steady so I don’t get any uh hard spots caused by overheating I can now machine away exactly 100 thou from The Edge and that’ll take me to the center of the hole that I’ve just drilled the cutter doesn’t sound too sharp so I’m just dropping to a fresh Edge this is the final cool another homemade gauge is used to cut the 45 degree shampers this is one of those I could do with three hands operations each side is milled to the same angle the size is stamped on prior to hard you can just make out a little bear on the edge of the hole this will snap off after hardening I machined another profile on the other end of the tool for heat treating the tool is brought evenly to a cherry red color it’s quite difficult to gauge but cherry red is somewhere in between dull red and bright red the key is to try and keep the heat even looks like I’ve got a leaky seal in the burner it’s starting to color up now so it’s important to keep the heat even along the L this is around about d red and we’re getting to about cherry red now I drop the tool into the oil on its Edge to stop bowing there are a number of ways to stop oxidization during heat treatment on this occasion I’ve not bothered I just polish it off on some fine wet and dry paper using oil as a lubricant it takes a little effort but it’s not long before you get a good finish tempering makes the tool less brittle color is used to judge the temperature of the steel I’m after a dark or medium straw this should give me a good cutting tool but it needs to be a bit more flexible as it’s only 1/8 of an inch thick it’s heated gently and again trying to play The Flame evenly along the length here I’ve just m catch it in the middle that’s not a bad thing I can see that the temperature of the steel is nearly where I want it to be so I’ve move the flame further away and being more gentle gentle heat is required as the color chain sneaks up on you we’re very close in fact there it goes medium straw just what we’re after quick polish and as you can see that little birs disappeared so does it cut does it do what we actually want it to do well it takes a little bit of lubrication oil but yeah this is looking good I’m taking it steady it’s only a thin cutter e final bit job done that’s spot on
2 Comments
(6:40) When you heat by passing a flame back & forth across a rod or bar, think about what is going … you are traversing the center twice for every time you reach an end (you are applying 2x more heat to the center). Thus the idea "heat evenly" which is the main point, is being violated. To be "even" in heat application you would pass over the bar then off the bar & skip back to the beginning and pass again, repeating.
All good info.
I have to do things differently, it being my nature, i harden first and cut the radius after with a tapered carbide end mill. The taper slows you to choose the radius and give cutter relief at the same time.