Start on a Kiwi ic engine.

[Tjark]

Today I made a test casting off the other crankcase.
At first the pattern released not very well.
After some more sanding and more shellacker it releases well.
Have some working days to go, after that I will cast some more crankcases, left and right who will be heat treated.
The crankcase is not fully cleaned on the pictures.
Next is the cylinder pattern.


    Tjark.

[vcutajar]

That's looking great.

Vince

[Tjark]

Vince, thanks for your kind words.
Some small details I have to correct at the patterns who will be ready for the next week.
I hope also to get the cylinder patterns ready in short time, so I can cast the parts who will get the heat treatment.
After that I can make a start on machining.

     Tjark.

[Tjark]

Made some progress on the cylinder pattern.
At first I made two alignment pins in two blocks off oak.
Then clamped the two blocks with screws and a hose clamp on the top side and turned the blocks round.
After that I cut the cooling fins, only the top fins and base off the cylinder I have to do.
Maybe tomorrow, will see if I have some time left.
Have also coated pattern as far its ready with shellacker .


      Tjark.

[Coopertje]

Hi Tjark,

Looking good, nice to see also something about the patern making! Looking forward to see more...

Best regards Jeroen

[Tjark]

Jeroen, I will try to make more pictures how I make this pattern, have to make a new one so I can make some more pictures from the different steps.

Have made a mistake with the spacing between the cooling fins.
Instead off a parting blade with a 3mm insert I have used a blade with a 4mm insert.
So the pattern is a little to long, its now 55mm and it shut be 50mm.
I can use a longer rod but I would rather use a the original dimensions from the drawing.
So I will make a new pattern with a smaller spacing between the cooling fins.
This pattern misses only the cylinder base.
The new one will have the base off the cylinder straight on the pattern so it will not beak off when I make the pouring mold.

    Tjark.   

[Tjark]

The new pattern off the cylinder is almost ready.
Two new blocks off oak, with alignment pins on the back put first in the mill to get some place for the two wood screws  to hold the two blocks to getter.
Then move the blocks to the lath to turn the wood in the cylinder shape.
Already started with coating the pattern with shellacker and now down to sanding the pattern to get a smooth finish so it will release from the molding sand.

This pattern is 1,5 mm higher than the real cylinder has to be.
So I will have some room for machining.


   Tjark.

[vcutajar]

Following along Tjark.  Hope the fins come out ok.

Vince

[Tjark]

Vince thanks for the interest.
I have made the cooling fins not as deep as they have to be but deeper as the original castings from Hemingway.
I also am in doubt if I shut make the 10° angle direct to the cooling fins.
The pattern has to be very smooth  and i hope I can do this by a lot off sanding.
Will give it a try in the coming week.
When it will not release I have to go to the Hemmingway casting design.


   Tjark.

[fumopuc]

Hi Tjark, I am also following along with interest. Waiting what will by the result with the fins. I am not sure if there is enough  draft angle.

[Jo]

Interesting, Tjark, you might have noticed that I don't have an Aluminium casting for the cylinder I was going to make mine out of either a piece of steel or Cast Iron bar  . 

I am looking on it as being good practise for the 10 I need to do for the Anzani's, I fear I might go a little squiffy doing so many time and again .

Did you not consider making yours out of Iron/steel rather than having to add a liner?

Jo

[Tjark]

Achim, I am hoping that it will release, that’s why I am given a lot attention to the sanding and coating with shellacker.
The cylinder who came out to long I had a draft around three degrees between two fins.
I am hoping to get 1,5 degrees in the shorter cylinder pattern.

Jo, yes I had seen that the cylinder casting on the picture was missing.
I am always a little afraid to make those fins in solid metal.
Have destroyed some parting tools this way.
I have a deep respect for al those people who are making the fins this way.

But it’s a good option to make it from cast-iron, GGG40 works fine and is not hard on tools.
It gives also a good fines.

   Tjark.

[Tjark]

Well I am almost there.
Some little sanding has to be done, but as far it releases the first try I am very pleased with the results.
In the first picture you see the sand mold with  the pattern still in.
The  second picture shows the pattern lifted a little.
The third shows the pattern removed from the sand and the places where it did not release.


   Tjark.

[ths]

Looks good, Tjark. You certainly know how to make an impression! Hugh.

[Tjark]

Hugh, thanks for the kind words.
Still I have a lot to do before all the castings come out as it shut be.

Have made a test pour without a core to see how the sand mold will hold.
Due to turbulence in the flowing aluminum the sand in the bottom off the mold washed away.
On the top off the mold it looked not bad.
There was a big shrinkage default but that is easy to fix.
In the first picture you see the washed away mold, a lot off fins are disappeared.
The second picture shows the top off the casting what looks pretty well.
The arrow in the picture shows the shrinkage defect.
Now I will try to make the pattern as it has to be in real life.
Making a 10° angle to the 5  bottom fins and then give it a try again.
I hoop it will give a more sturdy sand mold.

       Tjark.