[How do I?] Whitemetal Casting Question

Thank you to everyone who replied, much appreciated. As this project is a first for me with machining new and restore old parts, it is a huge learning curve and I did a lot of reading and it seems there will also be a lot of trial and error ;-)
My dad always said "I might be stupid but I am not scared " ;-)
 
I pour Babbitt quite a bit (at least compared to most folks). In my free time I rebuild old farm windmills, most of which used poured Babbitt.

What size and kind of engine is this? You did not have to worry about bearing pressure with most of the old hit & miss or throttle governed engines. Keep in mind everything in that link you posted pertains to ship engines ... things are on a bit different scale.

I would try a couple of things. I'm guessing you really won't be running this engine much? or am I wrong? I would take those nice molds you made and instead of putting in the brass/bronze bearings and pouring, I would pour the entire bearing out of Babbitt. Leave yourself some room so you can shim it and have a tight fit, when both sides are completed. If you want a tight fit on the bearing, blacken the shaft with acetylene. If you want a little clearance, wrap your crank/shaft with a single layer of paper taped together at the butt edges. A glossy page from a magazine works well, as does a paper sack from the grocery store (for a bit more clearance). Don't worry about the paper burning from the molten Babbitt.

There are also different grades of Babbitt for different applications. Anywhere from slow speed applications to high speed turbines, lathes, ship engines, etc. At 600 rpm, low load, I think you are fine with a lead based babbitt.

Make sure you seal up any & all cracks and seams in the mold & shaft. Not doing so will result in you doing a dance to avoid the hot molten Babbitt when it pours out of the smallest cracks ... don't ask me how I know this. :)
 
And ... the more I look at them, the more I really like that mold design!! I actually think I have an application that I could make a replaceable insert, instead of having to pour the bearing in place. Did you do those all on a lathe? Just thinking on how I would do that in my shop.
 
Thank you Mister Ed for your response. You also answered another question I had but never asked and that is to only use babbitt for the bearing and not to worry if the babbitt attached itself properly to the brass. The engine is a 3.5Hp Witte Throttle Governed and yes it will probably not run as often as it used to. After restoration it will probably move to the corner of my workshop and only start when showing off to my friends to OO and AA over a beer or two :)
Yes I have cut the mold on the lathe. The center piece was cut first and then I cut 2 big washers from same size material. Then tack welded the washers to the mold and cut it in half. The idea was to have the bearings fit snugly into the mold and also get some babbitt on the sides and machine it down to fit nicely in the crank. The shaft on the mold is smaller than the crank to give me some space and hopefully reduce any bubbles when pouring. I fitted the conrod to the mill bed where I know it is centered when I machined the bearings and stay center when drilling the babbitt afterwards to fit crank.
I made a bit of miscalculation when I cut the mold in half and had to build the one up again to ensure the bearing is below the edge.

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