28 June 2025

I AM An Expert You Know

D-P-355a refers to a set of drawings.

Rock Island Arsenal last updated them in 1960.


This is some OLD SCHOOL drafting!  They don't make drawings like this any more.  They didn't make drawings like this when I was still drafting.

Of note is the use of geometric tolerancing.  That was state of the art in 1960.

I'd suspect (guess) that Rock Island was told to take the 1928 prints that all M1911A1's were made to and get them up to current engineering standards in case war were declared.

Now, this print tells you WHAT to make, not how to make it.  The processes of how to make this part to this print is called a "technical data package".

Colt, historically, has been VERY reluctant to part with that documentation.  In WW2 they basically had to be forced to give it up.  Even so, Remington Rand lost almost a year's production of parts that were nominally to the print, but wouldn't interchange with other makers guns.

4 comments:

  1. That's how I got started as a drafter in 1983; I took a drafting program in upstate NY, affiliated with GE, and performed well. Being a veteran helped me get in the door, and things went from there. I spent @5 years on the boards with occasional brushes with CAD(Applicon, Cascade V), before getting a contract at Kodak in 1994, doing manual drawing updates on the Corona project. I was given the opportunity to learn UG, and went on from there for the next 3 decades.

    I love the old manual drawings and drafting; I still have a drafting board and tools, although I haven't touched them in years. Projected views using points, blue construction lines, HB through 4H leads in lead holders.

    The drawing above looks as if most of the text was done with a Leroy lettering set, not manually, and probably not not by using templates.

    ReplyDelete
    Replies
    1. I went from manual in 1993 to Microstation at the vending machine company then to AutoCAD for almost the rest of my career. One place I worked as a temp used an HP cad program; they did valves.

      Delete
  2. There are still places that use manual drawings, or at least did as late as the time @2018. Two clients had manual drawings that were J size, roughly 4-12 feet long, on vellum. Incredibly complicated, and the cost to convert to #D CAD was prohibitive. The assemblies, involving drive trains for vehicle transporters, were still in production.

    Lastly, try understanding railroad equipment drawings dating back to the late 1870s-1890s. I worked several months on doing assemblies in UG of these old drawings, only because the American Association of Railroads insisted on it. Fractional dimensions mixed with decimals, some German text mixed with English.

    Thank you for posting this drawing, and the remarks. If my comments are out of line, feel free to delete them.

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    Replies
    1. I started out as a manual drafter as well.

      I love these old drawings.

      My most irritating job was working for a water treatment plant company and a Quebecian city that wanted all the dimensions in metric when the contractor they'd hired to rolled their eyes and said, "we order in inches because we use the same pipe standards as you Americans."

      Water treatment plants are interesting work.

      So is bulk material handling.

      Delete

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