Thanks guys!  I was worried when the hobbing started, given how much work went into the parts to get them ready, but it went very easily. The hobbing still seems like magic!
 

  Great looking hobulation process, and a fantastic result Chris. The fit looks good. 

Great result (in more than one way) 

Per     

I have admittedly not chimed in yet - But as I'm very much an IC man myself - this is one of the more interesting builds here 

I'm already paying attention to how you make and use the Jigs needed to build this Engine 

Per   

The below was written over a year ago and held back for lack of photographs. You will notice there are not any!

A year has passed without me posting a progress report. I have been making slow progress but life, not health, has returned with a vengeance since lockdowns were removed. I have not helped matters by taking on more responsibilities and starting another project.

Having made all the piston rod and connecting rod another trial assembly was made. This time it was to determine the position of the piston rod guide which sits in the fork of the connecting rod. Although the piston rod lined up with the crankshaft the guide was nowhere near its bosses on the adjacent standard [photograph attached]. Since everything else lined up the only way I could see how to cure this was to lift one foot of each standard and slide them across the bedplate. This struck me as an awful lot of work with new parts probably needed along with a lot of thought. There was an alternative, accept the misalignment and use a plate between the standard and guide bosses to offset the guide. The model would not look right to anyone who knew the engine but it would allow me to finish it. So a plate was produced with its own bosses silver soldered in place. The bodge was successful but quite a bit of delicate filing had to be done to prevent the connecting rod from hitting the guide bosses (this was with a couple of horribly blunt files that had never seen steel).

The final bits of the model were then tackled, the steam supply throttle plate, its rod and bushes along with the governor die block and various linkages. This work allowed me to use my nice new little lathe. The only difficult bit was the throttle plate, I gave it a lot of complex through and realised all it was was a slice cut from bronze bar at an angle of about 30o, drilled for the rod and filed to shape.

Finally the steam and water pipes were bent to shape and silver soldered to their flanges. I found there was not enough room on the water pump for one of the flanges so the pump will have to be modified.

At this point, last (now 17 months ago) autumn (fall) all the bits were put back in the box since another model had priority.


I have posted this out of shame. The model is dismantled and some time ago I started painting it. Other things have got in the way including two models, a 5" steam loco (which I will never finish), and a Saturday model, a Stuart compound marine engine.

AVTUR