PM Research #7 It Begins

I had to do a Google search to find it again. Yes I have seen it and I was trying to find it again.
Thank you!
 
I'm struggling, the machining of the crank journal sets up the datum for the build. .094" below that is the crosshead sliding surface.
I was ready to mill the base before I had established a datum point.
The instructions/plans are designed for a more experienced model maker.
I'm going to go back through Erich's build and check out some other Youtube reference. Measure, measure , measure before cutting.
Here is a start this morning. I had to get the two high opposed corners flat to the base before I could go on.
Set ups and a bit of machining.
I'm comfortable with the base now.
I'll add some pics.
Fortunately I’ve broken cast iron castings in the past so I know to be extremely careful
I found the support from youtube videos (check out people doing a #3, its way more common and really similar!) really helpful. I feel like I leveled up making mine :) Part of the problem, is the base on all of these is the difficult part :/ Most of the other things are only learning a single-trick, the bases are learning a dozen!

The crosshead slides make a REALLY good reference surface, so when I did mine, I milled from the 'top' first. It made things WAY easier to indicate later! You seem to have done the head mounts first. This is going to make drilling the rod-passthrough-thing location REALLY difficult. I'd suggest taking it off your angle plate, placing it flat on the table, and milling the slides NOW, then use them to index everything else.
 
Erich,
I was planning on referencing the slides off the crank Shaft datum. I am waiting for a long center drill, I ordered it a few days ago. That and the small taps and dies required.
I’m pretty comfortable with most of the machining after watching many of the videos.
One of them showed a drill rod through the mains, then measuring with a surface gauge to mill the slides.
That makes it easy. Imho.
I was so afraid of cracking the cast iron I didn’t have the base secured enough. The end mill caught and the BASE jumped off track. (No worries) The boo boo will be fixed, filled and painted.
I’m enjoying this, once the base is done it will be lots of fun.
 

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I'm going to hold off on drilling the cylinder holes until I can conform the datum after I drill the crank journals.
I got ahead of myself. No damage done thank goodness.
Thanks to Erich.
 
I’m pretty happy about the line bore for the crank.
I’m not sure of the depth for the cross head machined surface.
The drawings don’t give a specific value that I can figure out.
The reference off TomW’s post and PM Research have been great but this part is a puzzle so far.
From here I can set up the cylinder mounting holes and set up for the .375” reaming work.
 

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I got it.
It's .094" below the crankshaft centerline. Placing the surface gauge at this point looks like I have about .035" to remove off the deck.
I shall slowly proceed.
I'm posting out of my own interest. My wife doesn't give a hoot.
I need to tell someone.
Shall I continue? Maybe a pic as the progress evolves. This model will take me a few months. I can only work on it here and there. Like many of you, I work for a living. For 2 more years :)
 
Yes by all means continue to post your progress! Did you make the entire bore with a center drill?

Eric
 
Enquiring minds want to know!
We love chips and machines here!

Sent from my SM-G892A using Tapatalk
 
Definitely keep it up! I'm a sucker for a good build thread!
 
I had a ball today.
Using the dial indicator, my DRO and the surface gauge, I feel I successfully milled the cross head ways.
The crankshaft bore went surprisingly well.
I was very careful about the set up. I used an angle plate I recently reground on my surface grinder, it’s square.
I double checked my set up with a dial indicator.
Using my coaxial indicator I verified my center before I center drilled.
I ordered an extended length center drill (under size ) to drill the crank bore but I was able to successfully Do the job with a 1/8”, 3/16 then a .250 chucking reamer.
For my first build, I’m learning a ton. I’m trying to be as accurate as I can.
 

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