Hello community!
I just introduces myself shortly on the new members thread today. I gave also a few impressions of my workshop there, and how I got the various tools to work correctly.
For me the HMEM community is a rich source of inspiration and a vast collection of projects with an exhaustive and well made documentation by the members. I can spend hours reading the discussions and take up the tips, hints and propositions on the way you do things - and also the fails including the remedies to it.
The news: I have finished a Moriya Major Fan too! Staying with the dimensions of James' booklet, i had to make a few changes due to livings in Germany and being metric. Taps, drills, ball bearings, bar and tube stock, all will be metric for me. Wher the aluminum parts are all to the book, especially the hot end and displacer, as well as the power pistion and cylinder are crtical parts with close tolerances. I had to take what's in stock and keep as close as posisible to the original dimensions.
This done and said, I finished with a lovely fan, running at about 360 rpm after a few minutes of operation.
(-): Take may excuses for the poor paint job. I think the quality of the heat resistant spray paint I used is pretty poor. It doesn't like silicone spray too - which i used in the break in phase for the power cylinder. It doesn't stick to well to aluminum, neither to steel. Albeit everything was throroghly cleaned with solvent prior to painting. Anyways, I'll take her apart again and redo all painting - or better, have it done by a friend of mine (a professional).
I'm not too much concerned about the looks, more by the function. This said, I put a bit of pain in the fan guard to have it look "vintage".
Technical details: Also, all moving parts have ball bearings, apart from the displacer rod by design. Down to 3mm ID, 8mm OD 4mm wide for the displacer yoke.
The fan blades are stainless steel 1.3mm thick. Quite heavy, which doesn't do any harm to the fan as a flywheel.
An interesting thermodynamic detail: Knowing that aluminum is by far not the best material for the displacer tube, I had nothing else suitable in stock. So i gave it a try and turned down a piece of tube down to 0.5mm (20mil) wall thickness and OD 37mm. And guess what - it does work, against all my expectations!
Changes to come (soon): I'll rebuild the crank shaft including the counterweights in the crank webs. For now, the fan is still not well balanced, albeit I added the (good looking) bronze counterweigts externally. Which will statically balance the whole engine part, but dynamically doesn't make it significantly better (maybe worse). I bolted the fan on a pretty large piece of granite plate for now, but would like to ged rid of this in the future. I'll use Fusion 360 CAD software to calculate the center of gravity of the whole arrangement and optimise the crank webs this way.
Coverage: See the photos and short videos attached (I'm not a great photographer, and even less a maker of decent videos. I'll have this done by a pro too, but I was eager to show off a bit right now)
Before you ask: The engraving on the starter whell is NC made. See my introduction in the new member thread.
To come: I have 100+ photos of the making of - and the fails too. I'll post some of these if you are interested in a future post.
Happy chip making!
Wolf