Can't even get it now.
Im reduced to working like a real pattern maker, glueing together lots of small parts, 3D jigsaw.
Ive molded a lot of bondifill blocks to be glued together in the basic shape of the pattern required, then CNC it out. For another aviation gearbox pattern I need to make soon.
Bondifill is relatively cheap in bulk. Like four big tins at a time. I just use a plastic Tupperware container to mold it in. Its real nice to machine and if you make a #/// up you just paste some more bondi in, let it set, bang into it again, don't even need to take it out of the machine.
Back half almost done, front half tomorrow. Might have a clutch cover ready to mold by Monday, maybe.
front half,
Bondifill has to be the best invention, ever.
Can fix multitudes of cock ups.
Now just tidy up and paint.
Happened to be in Broome, WA for a few days and saw this at the airport. The cylinders appear to be turned steel, but unsure of how that was in terms of a bore material…a CI liner?
The head castings are pretty cool with very fine fins. Could they have done this with green sand? I seem to remember that they used linseed oil. Maybe even shell core sand.
Fletto, did your old man or grandad work as a patternmaker way back then?
"Success is the ability to go from one failure to another with no loss of enthusiasm.”
Machined steel cylinders were the standard of the industry for small radials for decades. First used around WW1, if it works don't change it was the industry motto.
The bigger, later ones had cast alloy cylinder and head in one unit. Eliminated head gasket problems.
I've used bog - Bondifiller - for patterns in the past. Yes, it's bloody handy stuff.
BUT - if you're machining it, you need a good dust extraction system. It is after all, only cold moulded chalk.
In the 80's a business partner and I took over a workshop which had been an automotive panel shop. Bog dust several inches deep....
The place got vacuumed - several times - and washed - several times - and painted, before we were happy to move in.
Even then, there was still dust blowing around if the doors were open in a breeze.
Ive go one at my front door.
Lost wax process? Certainly well made castings.
My father and grandfather, probably the closest thing for them to patternmaking was fitting a new shovel handle.
Because this tubular housing overhangs the main pattern, I need to shift the part line up around this overhang. Thats what this insert does, where this wood insert is will leave a cavity that will be taken up by the bottom sand mold.
When Im packing the mold I'll take a picture so you can see what Im talking about.
Sodium Silicate / sand mixing, approx 2%.
Bottom one packed, remove insert.
Cast.
The sand mold split as I removed the pattern. So I ended up having to glue the sand parts together, I didn't want to show this, clearly there was an area without taper or perhaps slightly the wrong angle. Anyway it worked out in the end. Off to heat treatments tomorrow.
Looks nice especially down that bore I'll call it.
Don't you look at my accountant.
He's the only one I've got.
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