Nuts to Me
August 14th, 2009Machining Woes
Heather’s mom is having kidney problems, and Heather is asking for prayer. Here is the link.
I had an interesting day. I was determined to check my Parlec vise and see if it needed adjusting. The parallels were sliding out from under parts when I tightened it. I went out and started moving the table to an appropriate position, using the power feed. The power feed slowed down. I figured it was defective. Then I heard a noise, and I looked up and realized I was trying to move a workpiece past a cutter which was not rotating.
Naturally, I lost my mind for several minutes. I could see that I had knocked the head out of tram. No dial indicator needed. I assumed I had destroyed the mill’s entire head. But it turned out to be okay, and I got some more valuable experience in tramming. Man, I felt like an idiot.
I put the vise back on the table and aligned it, and I put two 123 blocks in it, one on top of the other. I centered them in the vise and tightened it, and the lower block didn’t come loose. So it appears that the vise is okay, although it doesn’t work that great for parts that don’t press against the lower parts of the jaws.
I finished up one T nut. Had a couple of issues. First, I tapped the nuts by hand, because the alternative was to spend a year putting each one in the lathe and centering it in the 4-jaw chuck. The mill’s lowest speed makes me nervous, so I didn’t want to use it for tapping. When I was done, it turned out the threads were not perfectly perpendicular to the top surfaces of the nuts. I don’t think it matters when they’re in use, but it’s a bummer. Second thing: I made a subtraction error and made one of the nuts the wrong size. It will work, but I wanted it to be right. Guess I’ll make new ones.
It sounds nutty, but while I had no problems with advanced math and physics involving tons of variables, addition and subtraction of actual numbers drive me crazy. In higher math and science, mistaking plus for minus is usually a trivial error which is easily fixed. If you make the same error with numbers, it can cause real problems.
I will make nuts until I get them right. You watch.
August 14th, 2009 at 9:08 PM
Thanks Steve!
I totally agree with your previous post about travel with family. Several of my friends keep asking me to go on cruises, etc. with them. I keep telling them-‘you like me now, if you travel with me, you will grow to hate me-let’s stay friends.’ Needless to say, I do not travel well. 😉
August 15th, 2009 at 1:06 AM
I worked in a machine shop for a while making parts for Boeing aircraft.
Using anything but a calcualtor for arithmetic, even something as simple as subtracting .020″ on the control of a mill was a firing offense.
I watched as one nitwit was told twice then canned. He never did “get it”.
Use your calculator, it is more accurate than you are and will lower the incidence of errors.
By the way, the most popular calculator was the $10 Texas Instrument 30X scientific.
Gerry N.
August 15th, 2009 at 7:45 AM
A trick people use for hand tapping a hole they’ve just drilled in a mill is to raise the drill out of the hole, place the tap in it, and bring the drill point back down into the dimple that’s in the end of the tap. That keeps the tap upright while you start it with a wrench.
August 15th, 2009 at 9:42 PM
Ed beat me to it. You can also take a piece you’ve drilled elsewhere and use the drill press to hold the tap straight. I’ve threaded brass this way by turning the chuck by hand, but for most things you need a wrench.
Or, Brownells sells a tapping fixture made for this; it chucks into the drill press and has levers so you can turn it like a tap wrench while the press keeps it straight.