Starting in to the "machining" process.

 In my previous post you got to see the casting and a few little machining operations, but I changed my mind on how I wanted to do the second stage. I decided to leave the casting as a finished part and then make a derived part from it to do the machining.  The benefit of this is that it provides a disconnect between the cast part and all it's hundreds of features, sketches, and legacy data and the work I'll be doing going forward.  This allows me to make changes to the casting that will, for the most part, remain completely disconnected from machining.  If I notice I forgot something in the casting, I can go back and fix it and it won't cause a cascading failure in the feature tree when it updates all the features that are below the change in the tree. The new part is little more than a dumb solid with no legacy data, however if I make a change to the original casting part it will update that dumb solid with the new geometry.  I'm also going to highlight the new work for the ease of viewers like you so you can actually see what is changing by making it a blue color during this stage of the work.  Eventually I'll change that to a more realistic machined texture to make it look nice for rendering.


Here's what I've been up to since last time.  First I noticed I had missed a boss on the back of the bell housing:


So I added it in:


And then combined it and filleted to suit.

does that say fillet 191? how many freeakin' fillets did you use?!?!

Next I went back to adding machining to the rear of the crankcase. I need to remove the overcasting on this boss and add in a rather long drill hole that will act as an oiling channel for several components.


Here is the completed hole in cross section:


Next I added in a couple of holes that will connect the oil channel to a couple other areas.


Next I added a small bearing cup with it's associated oiling channel:


This is the point at which I decided to leave the casting as a matte aluminum texture and make the new machining a color called blue anodized aluminum (it was the closest highlighting color at hand being in the same folder as the rest of the aluminum colors). Next I added in a bunch of the bolt and stud screw holes that are on the face of the rear flange.  Sorry I didn't take individual screen grabs of every hole, I figured it'd bore you.  get it? Bore? Hole?  Bore hole?  okay I'll shut up.



In the last one there you can see some of the other machining that has gone one, the big machined flats are the base for the mounts. Here is a view from the front with the rest of the machining I've done highlighted.


I also tried to show the parts tree of the derived part so you could see how the derived part looks different from the original part.  The original part has a tree longer than your arm and putting the casting into a derived part does away with this for the work going forward.

That's about it, for this update, but there was one other thing I wanted to mention.  I am working on a Bill of Materials for the -7 Packard Merlin.  It's on google sheets.  You can see it here:


As you can see, it's just something I am updating as I work to keep track of what I'm doing. If you are a fan of the Merlin and want to help me put the BOM together and you have access to either the real BOM or the Aircorp Library drawings then let me know and I'll add you to the sheet as an editor. Help would be appreciated, but I'll get it done eventually either way. Anyway, thanks for reading and following along, I really appreciate the support I've received here and on WIX and WW2Aircraft.net and have a great day!

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