New to castings

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Hello

I’ve brought a Kennions Tina casting set and I’m  very disappointed with them so far. I’ve finished six castings and found no room for errors. These two have 1/16th to play with from the base to the top, the eccentrics  gave me problems as hardly any room for error.

Kennions seem helpful as the base feet don’t align with the castings but after adjustments with the measurement I got it reasonably central for the castings to sit on.

I must admit I prefer to make engines from bar stock so far .

1. Is it me or is this the standard for a casting, watching Joe pie with his beautiful castings for a engine.
2. 

[bernard towersParticipant @bernardtowers37738]

Could be three things, poor patterns, poor tolerances, poor foundry.

[JasonBModerator @jasonb]

Or poor understanding of how they were cast. To me the feet not being at right angles to the casting is not something to worry about. What really matters is that there is enough metal to fully clean up the top and bottom to the drawing size. If there is enough metal where I have shown then the rest is machined off so not critical.

One needs to study the casting and understand how it was cast and what the pattern was like. The tell tale with these is that the fettled parting line does not run centrally up the sides. You can clearly see it coming in from the thick side and following the line I have marked.

If the pattern is to be removed from the sand then the sloping top and bottom will need draft angle and that is what is making you think the foot is not cast square. The patterns would have been cast with teh arrow upwards.

They look about average for what you might expect.

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Thanks for the replies,

I’ve got 1/16th of material to play with, I always new where I was on bar stock, first castings new learning curve.

Bob

 

[JasonBModerator @jasonb]

Worth going through al lthe castings to see if any are tighter than others before starting to machine. Sometimes, if one is going to end up undersize you can leave a bit more on the mating part to even things out. For example if your bearing pedestalls look like they will come up short you could not take as much off the pads on the base casting which would keep ctr height of the crankshaft correct.

 

What I will say is it looks like your casting has been done with a coarser sand than the individual castings shown on the Kennions web site. Quite possible they are older Kennions photos and EKP are using a different foundry.

[DalboyParticipant @dalboy]

As Jasons suggestion above also you could put a thin shim under the casting after machining the square and flat on the mating surfaces.

After painting they would not show

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