Member postings for Thomas Pawley

Hi. Bri, thanks for the ebay tip, I'll have a look. Material is steel, should have said!! Tom

Hi. Does anyone know of information on making a boiler tube expander please, tube sizes are

1 1/4" and 5/8"...Tom

Hi all. Thanks for your advice and assistance. The valve in question is as the drawing shown in Paul's comment. As regards the making of the rings, I followed the information in Prof. Chaddocks article to the letter, including the heat treatment, for which he specifies a temperature of not more than 560'C followed by slow cooling. I am using continuous cast Mehanite bar of stated good quality.

Whilst I can easily "screw" the first ring into its grove, it has proved quite impossible to move it on to the next one, it always breaks when I have tried. Also, having made a tool for expanding the rings, they break before opening sufficiently to slip them over the piston head...I can only assume that; 1, the annealing process is not working or, 2, the material is not all it's supposed to be! I will try the heat treatment again, holding at the temperature for longer than the recommended 10 minutes and see what happens... Thanks to you all, I'll let you know what happens!!. Regards, Tom.

HI. I'm having problems with CI piston rings! I am currently building Martin Evans Highlander design. Having finished the piston valve as the drawing, I then made the rings. I followed the methods as set out by Tubal Cain and others, after machining I carried out the full annealing process as recommended. So far, so good. I made six spares, but have now broken seven rings in attempting to fit them! The valve has three ring grooves, I can get the first one in ok by "screwing" it into the groove, but then that prevents fitting the others in the same way.. Trying to expand the rings far enough to ease them over the piston head simply breaks them. I should really apreciate any suggestions before I run out of Mehanite bar, or my patience Tom.

Edited By Thomas Pawley on 14/02/2012 20:47:10