Well, I'm starting a two year Machine technology course at a local technical school. However, for the first six months or so, we'll be doing a lot of projects by hand.
The first project, the one I'm currently working on, is what they call a "screw plate”. It's just a 4.5 inch by 2.5 inch steel plate (about .325" thick), with various sized threaded holes to use for checking bolts.
My problem is a very basic one, but a big one. We're required to file the sides of the screw plate flat and square. We're using a flat-plate and layout paste (they call it prussian blue, I'm not too familiar with terminology) to check for square ness. I'm not too clear with the instructors as to how I'm supposed to interpret the blue markings that are made on my screw plate after I run it over the surface of the flat-plate..
Initially, my understanding was that the blue layout-paste on the flat-plate would mark the high-spots, showing me where to file. My instructor, Hans, then confuses me by telling me that the only parts of the blue dye I should file off are the “shiny” parts, and that I should leave the dark marks alone. I’m not too clear on what he says… There seems to be kind of a language barrier between the two of us. He speaks very good English, but I still find a hard-time understanding him a lot of the time.
Does anyone have any idea about what I’m talking about? I figured that I should probably ask some other people about this, as I’ve been trying to get the side of this screw plate square for two weeks now, and every time I get close, I start gaining low-spots. Every time I ask my instructor about this, though, I just become more unclear on what I’m doing.
I’m using mostly needle files, but I have a feeling that the ones I have are too coarse. I’m mostly using a No. 2 Three-Square, Flat, and Warding swiss file, all double-cut. I’m not too sure on the specifics of the steel we’re using, but it’s fairly soft.  |