3" Burrell Traction Engine build.

   Cutting The Modified Square Thread-Brake (Part 4).  Me aged: 53 Software Engineer Machinist, with zero tolerance to mistakes.. Simple Idea: Making a Tap from a Threaded Rod Hello everyone—just sharing a simple idea I’ve been trying. Instead of scrapping a brake rod, I decided to practice screw cutting and then use the best threaded piece to make a tap. The goal is to create a matching internal thread for a nut. The brake rod has been completed (As above) but this has taken a few practice goes before committing to this. The results of which I am very pleased with and the square threads look the part as compared to just cutting a metric thread of say 8mm.  What I did Cut an external thread on the rod Used a 4 mm ball-end cutter to make three flutes Offset the cutter slightly to give a bit of rake Cleaned up the edges with a file Case hardened the tool The idea behind it If the external thread is correct, turning it into a tap should produce a matching internal threa...

  Screw Cutting The Square Thread-Brake rod (Part 3). Hello again. (To put a face to the Blog)   The brake rod threading is still very much in the practice stage—we’re now on part 3. Screw cutting is proving to be a real skill to master, especially when it comes to achieving the correct thread form and overall appearance. The latest attempt (shown above) still isn’t quite right, but it will be used as the basis for making a tap. The plan is to produce a clean, symmetrical thread, then mill flutes into it and case harden it. This tap will then be used to cut the bronze nut so it matches the thread that will be machined onto the brake shaft. The current issue is with the pitch-to-width ratio. I used a 1.5 mm cutter for this test, but in hindsight it really needs to be closer to 1.25 mm to achieve a proper 50/50 tooth-to-gap ratio, which I wasn’t able to get here. The drawing specifies 10 TPI (2.5 mm pitch), and while I’m close at 2.55 mm, the groove width of 1.6 mm is too larg...

Screw Cutting The Square Thread-Brake rod (Part 2). Hello again, this time I intend tackling the screw cutting problem, head on. Previously I eluded to the thought of cutting an acme thread but through some useful feedback, I've learnt that a square thread is, as the name suggests (square) and not acme form. The 2nd thing I have found out is my previous thinking of a pitch 0.108" is also incorrect. 1. Why the first lathe change gear setup didn’t work I selected from the longitudinal feed section of the chart instead of the threading (metric pitch) section. These feed settings are designed for fine carriage movement per spindle revolution , not for synchronizing the carriage with the spindle to cut a thread. So the gear train I spent hours installing: 24T stud 72–18T compound 80T 60T screw was creating a very small feed ratio , which explains why: ten turns of the chuck certainly wasn’t giving 1" of carriage movement That’s expected — feed rates are ...

  Screw cutting Acme Thread - Brake rod (Part 1). Welcome to this month’s traction engine build update. With the weather not helping motivation, I decided to tackle some straightforward lathe work — the brake rod. The drawing specifies a 3/8" × 10 TPI left-hand square thread. While anticlockwise operation to apply the brake would justify a left-hand thread (as seen on some full-size engines such as those by Aveling & Porter and Burrell ), cutting an internal LH square thread at this size would be challenging. A right-hand thread will be perfectly adequate for the model. My plan is to screw cut a trial thread in silver steel, mill flutes to create a tap, harden it, and use it to thread the bronze nut. I’ll then cut the matching screw so both parts mesh correctly. Since the nut is bronze, machining should be manageable. Although the Boxford metric lathe is the easiest machine to set up for screw cutting, producing true 10 TPI would require imperial conversion gearing. Instea...

  3" Burrell Reversing / Brake Lever (Year 7)! First of all — happy 53rd birthday! 🎉 That’s a proper milestone. You could go out and buy a finished engine for 7K. But that wouldn’t be your engine. It wouldn’t carry the hours in the workshop, the problem-solving, the remakes, or the “that went well to plan” moments. The value isn’t just in the finished article — it’s in the Model Engineering. Having completed a 1" Minnie to steam up when you want that instant satisfaction is actually a perfect balance. It keeps the joy alive while the bigger build continues at its own pace. Planning shows is a smart move too. Events like: The Midlands Model Engineering Exhibition Welland Steam Show. They do  — spark conversations, ideas, photos, and that little internal nudge that says “Right… back in the workshop.” Long projects aren’t about speed. They’re about momentum. And momentum doesn’t mean dramatic progress — it means not letting it quietly fade away. The engine will b...

 Happy New year 2026 !! (Year 7) Build Log – Reversing Lever General Update Happy New Year. It’s been a while since the last update, and now the festivities are out of the way it’s time to report on what’s been happening in the workshop. Time in the Shed I wouldn’t say machining stopped altogether. Odd bits were done here and there just to keep things ticking over, but between getting older and the fairly grim weather we’ve had, standing in a cold shed for hours isn’t always that appealing. More than once the pub won that particular argument. Most of the recent effort has been on the reversing lever, which turned out to be more awkward than expected. I first tried working straight from the drawing and made a paper mock-up to check the folded shape. That quickly showed the angles were nowhere near right once folded up. Revised Drawing As a result, I went back and produced a proper drawing with all dimensions added, along with a flat pattern that should be useful for anyone el...