So I've had this kid working for me for a while now. He does not have
the same work ethic I had at his age. But he is getting better. He is
absorbing information. Last week I had him single pointing threads for
the first time. First item was a 1 1/2 aluminum pipe nipple. I needed
the aluminum pipe cap to thread on loosely so that the end of the
nipple would bottom out against a rubber gasket. After showing him how
to pick up the threads and doing one my self his job was to do the
same thing. First on a solid blank without any threads to get a feel
and then the real thing. He did a good job. This was easy though
because the nipple only had to be a loose fit in the cap. After doing
the first one I discovered that I had ordered the wrong threaded
fitting for another part of the same project. The fitting is made of
brass and is for a gas connection involving a metal to metal seal. The
threads for this part are 5/8-18 left hand on one end and 1/4 female
tapered pipe on the other end. The metal to metal seal part on the
fitting is part of a .250 radius sphere. These are common fittings.
So, I made a sketch and showed him how to cut left hand threads. Most
important was that since the threading tool starts in the thread
relief if the half nuts are not engaged at the right spot he wouldn't
have time to disengage them before the part is scrapped. He practiced
cutting air until he was ready to do the real thing. He made a good
part the first time! He used a thread mike and I had him make a class
2 thread. The PD was in tolerance when he was finished. After the part
was done I smeared a little prussian blue on the contact surface and
threaded the fitting into the mating part. After unscrewing the
fittings he was able to see the line contact where the bluing was
squeezed away by the two mating surfaces coming into contact. It sure
made the guy feel good to make a part completely on his own that
matched the print and looked better than a store bought part. Since
this fitting is now installed in the water cooler line for the TIG
machine every time he TIG welds he'll know it's his part that finished
the job and that keeps the torch cool. He was so pleased with himself
I think he'll tell all his friends about it. Made me plenty happy to
see him do a good job too.
Eric R Snow,
E T Precision Machine