Monday, March 8, 2021

Machinist Rage

 I don't know who you are......

                    But I will find you........

                                And when I do.......




For the love of all that is holy, or just because some poor dipstick is going to take it apart someday, put a flat on ANYTHING that is gonna get a set screw driven into it.


I mean, how hard is this.... really....

These are hard won lessons.  No charge today.  Unless you did this......

Flaming skull backgrounds - SF Wallpaper

Oh, and I got to break in a vise I bought about 5 years or more ago.  Yay!


I even painted it passably  :)



  1. Your post reminds me of my father's directions as I modified a generic electric motor to replace one in a window air-conditioning unit. It required cutting the shafts to length, filing a flat for the squirrel cage set-screw, and using a hacksaw to cut a slot for the retainer clip on the fan blade. It took a big part of of an afternoon, but I learned a lot that day, and was rewarded with air-conditioning in the bedroom of my apartment.

    1. If no one else ever needed it, it was still the right thing to do. I'm glad you remember that. It makes all the difference down the road.

      And thanks for stopping by! Visit anytime.

  2. Oh yeah, how many times have I tried to get a pulley off a shaft some nitwit put on that didn't have a flat on it and the pulley had spun on the shaft?
    The set screw machines a groove in the shaft when it does that and you more often than not end up breaking the pulley getting it off.

    1. I wasn't even thinking about it, until I needed it off. Then it was "Why?!?!?!??!" I'd forgotten about doing that, but this drove it home like never before.

  3. I never thought about it STxAR, but that totally makes sense. This is not common knowledge or practice?

    1. It is on manufactured goods.... normally. What I'm working on has no backstory. It's kind of a one off, not at liberty to divulge.... But suffice to say, it shows real ignorance of common industry standards, and some really brilliant designing too. I'd like to find out who did this. Not to just off him, but to pick his brain first! :) Yeah, I didn't even think to do this until I ran into it... Then it was a solid "Oh yeah!"

  4. I don't remember what I was taking apart, but I remember removing the setscrew, thinking that it seemed short, (much like me) and finding another setscrew in the hole.

    My adventure in metric threading with an imperial leadscrew was successful.
    Things I learned.
    If you follow the chart, the change gears and the quick change gearbox lever will deliver the thread count you want.
    A piece of 3/4" PVC pipe makes a great test piece for checking your threading setup.
    Stainless steel is hard to machine.
    The threading dial cannot be used when cutting threads and when you lock the halfnuts you leave them locked.
    I also learned that just because the internet says that the stainless steel nozzles you ordered from China that will allow you to spray latex paints through your Harbor Freight HVLP spray gun will fit, they won't fit, and you will have to do some fair amount of learning, and lathe work before they fit.

    The good news is that I now know I can cut metric threads, and I now own both an internal threading bar and an external threading tool that both use the same carbide inserts.

    I cut the threads until they were of a size to fit where I needed them to fit.

    And as to adding the flat, once in a while I have done something to make it easier for the next guy, and it turned out that I was the next guy.

    1. That last line is exactly where I'm thinking I'm at. If it works out, I wouldn't mind servicing these things. Just a long commute to get to them.

      I've seen Mr. Pete use pvc to demonstrate internal threading. It was VERY clear.

      What kind of lathe are you using? I don't have a lathe that would do metric. I remember there being a 127 tooth gear in the train, and maybe a 39 tooth? Going by memory....

      It's good to be somewhat self sufficient!!

    2. I have a Grizzly 9" x 19" lathe.
      The lathe has a chart for both imperial and metric threads.
      I followed the chart to cut metric 1.0 mm.
      The magic conversion from imperial to metric seems to be when you stack the 127 and 120 tooth gears.
      I'd done my first internal single point threading to make a lampshade adapter for my wife.
      The only things I needed to change from that job's 20 tpi to cut metric 1.0 mm was to pull the 120 gear, put the 127 gear in its place, and then stack the the 120 onto the 127.
      The leadscrew gear remained a 30 tooth, but I had to pull it put in a spacer and then reinstall it.
      And switch the quick change lever.
      It took some head scratching because I want to understand the process.
      And it took a little bit of backlash adjusting to get the gear train to settle down and be quiet.

      I learned a good deal, and I continue to marvel that a certain combination of gear teeth, and a lever selection on the gearbox, will enable accurate thread cutting.
      We own a lot to those in our past.

      What lampshade adapter you ask?
      I will get back to that subject after errands.

    3. I can hardly wait. Sent a pic to email ifn you want.

    4. I sent the photos a couple of seconds ago at around 0850 EST on the 11th.

  5. Hmmmmm. If that is for a pulley or sheave set... wouldn't ya run a keyed shaft...?

    1. Good call. These things aren't transmitting power, they have collars, and hold things in a set spot. The collars have set screws, and the shaft has no place for displaced metal to move to. I just about tore up a collar and shaft to find out what was happening to another part.

      Coming behind a guy that is equal parts bright and dim is maddening...

  6. STxAR,

    Another though is to drill and ream a cross hole in each for a taper pin. That way, it will always stay timed if taken apart unless someone decides to re-ream the hole with the two pieces out of time. I can definitely see that happening.