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1 minute ago, dangerous doug said:

 

sometimes the journey is more important than the destination 

I agree, but in this case I wasn't happy earlier on, instead of wasting time trying to make it work I should have started over, then I would still have a nice length of aluminium flat bar for something else

The joys

Regards Stephen

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On 8/13/2023 at 3:13 PM, dangerous doug said:

 You can flatten it off with a multi setup on the mill or a rotary table

My only gripe ( it's a nice gripe ) with you at the moment is this, you got me thinking and now I have said rotary table coming, and an empty project jar.....lol

Regards Stephen

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I'd echo the comments re expansion. I haven't done any casting for decades either but we had to leave risers to allow molten aluminium to drop down into the cooling object, otherwise there would be a hole. I used to live opposite a bloke who was making a miniature railway (ie narrow gauge) and he used to happily melt pistons etc to cast bogies for the carriages. Outside though, it can be sporty if you spill it. Are you just going to have a huge fire going under that steel plate?

Edited by fmmv
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25 minutes ago, Stellaghost said:

Well a bit of casting fun was had, it's not perfect, might have another  go

Hot, hot  hot

20230903_0222262.thumb.jpg.b0d5c9f7d596fc288022f577751bcd16.jpg

after pouring

20230903_042521.thumb.jpg.9d357f74ef97379d3955f4356589b51a.jpg

Inner dam ring left loose to allow it to move when aluminium contracting during the cooling process , it was still very tight to remove and required a slight adjustment with an angle grinder 

20230903_042812.thumb.jpg.d1e39b4c28e430fe5782ee0206c28b08.jpg

20230903_042820.thumb.jpg.f51334292ee8069549f559ca92c03ace.jpg

Outer removed

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From underneath 

20230903_043155.thumb.jpg.aaf5eebb7a3ba07c1b473e5cd6518317.jpg

A small recess underneath but it is where I need to mill out for starter motor, so not a problem 20230903_043200.thumb.jpg.9265a5fa6b83c401ab8a70aeb1150d5d.jpg

Casting on its own

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then side by side with my previous attempt

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It looks lower but it actually isn't, just a bit of an illusion, having said that I could have done with it being slightly thicker

Previous one sat on top

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this one might be ok, we will find out once machining commences 

Regards Stephen 

 

 

Good work, can't wait to see it milled, and drilled😃

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So managed a wee bit of machining this afternoon ( still on nightshift  )

By shear good fortune I was able to hold casting in my 12" 4 jaw chuck, luckily for me the casting after a wee bit of grinding to take a step out was a knock on fit to chuck body with enough room for jaws to grip it internally and also just clear the lathe bed ( obviously with removable section of bed removed)

Casting on chuck with a fairly crude method of setting it up

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Once reasonably happy I started cutting, worked well only 0.3mm difference in thickness when I stopped machining, that can be sorted in the mill

 

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left in chuck for now so I can cut the recess in for gearbox bellhousing, this will give me a good datum to dial the casting in once on the rotary table

Very happy the thinner section is better than I thought with only about 20% lower than the rest of the casting and that is only on the outside edge. This will get better once external diameter has been milled down

So far nothing tragic uncovered in the casting itself, also any minor discrepancies can be Welded up with spool gun and Machined back

Need to make the extension plate for rotary table now as it will be needed imminently 

Regards Stephen 

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8 hours ago, Stellaghost said:

 

Inner dam ring left loose to allow it to move when aluminium contracting during the cooling process , it was still very tight to remove and required a slight adjustment with an angle grinder 

20230903_042812.thumb.jpg.d1e39b4c28e430fe5782ee0206c28b08.jpg

20230903_042820.thumb.jpg.f51334292ee8069549f559ca92c03ace.jpg

 

 

Shrinkage for aluminium seems to be quoted at 6%-8%, does that mean the diameter of your casting shrank by about 3/4" ? I'm sure I must have that wrong, but it would explain why the inner ring was pretty stuck.

Proper impressed with your casting :)  ...... and your crucible! ;) 

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4 minutes ago, CwazyWabbit said:

Shrinkage for aluminium seems to be quoted at 6%-8%, does that mean the diameter of your casting shrank by about 3/4" ? I'm sure I must have that wrong, but it would explain why the inner ring was pretty stuck.

Proper impressed with your casting :)  ...... and your crucible! ;) 

Those gaps were around 1/4" , if I did it again I would make them 3/8" , outer part of casting shrank by about 1/16"

 Regards Stephen

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1 hour ago, Ed Poore said:

Once you've made a "proper" adapter can you use that in a sand mould to pour more or do you have to make it slightly oversized to allow for shrinkage? 

I suppose you could, but this way has worked, so I will file my mold into the might be used again section of the garage along with Lightweight bulkhead, vent panel and gearbox tunnel formers.....

Regards Stephen

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21 minutes ago, Stellaghost said:

Ha crucible is a deep pan that cannot be used on our new  induction hob, so it is reporting for duty elsewhere...

regards Stephen

This may be the greatest re-purposing of domestic tools ever, certainly way more adventurous than a dishwasher running diesel to clean stuff :hysterical:

Steve

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22 hours ago, Stellaghost said:

Inner dam ring left loose to allow it to move when aluminium contracting during the cooling process , it was still very tight to remove and required a slight adjustment with an angle grinder 

20230903_042812.thumb.jpg.d1e39b4c28e430fe5782ee0206c28b08.jpg

20230903_042820.thumb.jpg.f51334292ee8069549f559ca92c03ace.jpg

 

If you cut the inner ring sections at an angle, they should slip out after it has cooled.

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