New Olds (boat tail speedster)

[Olds]

Err,  thanks I think. No pressure then.

[Olds]

Had a go at making 'green sand' and a sand mold but wasn't happy. The only sand I have is really too coarse .
Thinking out of the (sand)box a little I figured that perhaps as this part flat bottomed I might be able to make a three piece steel mold.
I have absolutely no idea if this will work, but there is nothing to loose in trying.
If anyone knows of a reason why this won't work please shout.

[Mendalot]

Steel is used for pressure casting aluminum, I presume that you will have to get the mold good and hot before casting and then let it cool down slowly.
Good fun

[Manky Monkey]

I'm just impressed you made such a perfectly formed mould.

[Sid_Vicious]

From what I've learned about casting (mostly from other forums and youtube), the only problem I can see is that the middle core should not have straight walls to make it easier to remove from the casting. I would use a smaller diameter on the side you press the core out from the casting. And maybe use some powder of some sort to make the mould more slippery to release the cast.

[Olds]

I will heat the mold to prevent chilling of the aluminium on pouring but it shouldn't need to be too hot. I figure around 200 C should be fine.

It's really not that perfect Andy. It's a little oversize on the lugs to allow them to be machined to size.

The taper on molds (mould) or patterns is called the draught angle. On patterns it's so you can get it out of the sand and as you say on hard molds its to allow removal of the casting.
With this mold it all comes apart. The central core is a wrap of sheet steel with a washer tacked on top, so should be fairly easy to remove. We will see.
It will all be dusted in graphite but I wouldnt expect much sticking anyway.

Melted down some scrap tonight using the propane torch. As expected, can't get it hot enough to pour this way but it was mainly done, because estimating scrap volume is difficult. If I get a chance I will fire up the forge tomorrow. That should certainly provide enough heat.

[BikerGran]

It's absolutely fascinating seeing all the things that clever people on here can do!

Mike and I (being rather old) were just having a discussion about how cars (even his 23 old Jag) and particularly my VW T5, are so complicated now, and even the stuff that's not complicated you can't DIY any more, you just have to buy replacements.  New brushes for your starter motor - buy them off the shelf and fit them yourself, likewise the starter dog, and if the winding failed you could take it to a man along the road and he'd rewind it.   I even had the generator for little RXS100 rewound in the next village by a bloke in a shed in his back garden in about 1999 - but when he got too old the business closed.

Brake cylinders - buy a seal kit and DIY.  Windscreen wipers - just buy the rubber and DIY.  And so on.

I know youi can still get this stuff but only if you know where or who - you can't even nip down to the local garage for a ... whatever ...  cos it's not a garage any more it's a filling station and the workshop's a Spar shop now.

Sometimes I wish I still had a Morris 1000 - only problem I had with that was the carb and I could take it off, clean it and replace it at the side of the road!

[Olds]

  I'm not so clever, rather I've been around and done a bit of this and that. I too hanker for times when things were simpler.

Well that went well. fired up the forge at 11.00 finished by noon. But damn that was hot in hat, big boots, gloves and overalls. I know it wasn't a lot of aluminium but I knew a guy who had half his scalp burnt off by molten metal, so I'm very cautious.
Aluminium melted well with not too much dross and once that was scooped off it poured fine. Not many pics as I was sort of busy.

[Sid_Vicious]

That came out nicely.

[Olds]

Very pleased with it.   Came out far better than I could have got it with a sand mold. A fair bit of effort but it was well worth it.

[poprodder]

wow, truly amazed at everything your
doing on this.

[Olds]

  Thanks Chris.
Just about got as far as I want to go with this, until I get the other parts made. No porous areas or cavities discovered during machining. 
Figured as this was probably the bit most likely to go wrong, I'd attempt it first.

[Olds]

Milled the outside diameter of the base to size, using the pillar drill and made the cap section. This was made from 3mm thick aluminium, hammered over a steel former, then tidied up on the lathe.

[Olds]

Not used to making things this size. Pivot clevis made from brass prior to parting off from bar.
While it possibly doesn't need to be rounded due to it's position, I figured it's easier to do so now while making it, than to modify it later (plus I like the shape  ).

[Olds]

Clevis finished and cap arm roughed out. A mis-measurement means that the arm is couple of mm short but should be OK.