View Single Post
  #5   Report Post  
Posted to rec.crafts.metalworking
Bob La Londe[_7_] Bob La Londe[_7_] is offline
external usenet poster
 
Posts: 1,768
Default PM 1440 - First Failure


"rangerssuck" wrote in message
...
On Monday, November 28, 2016 at 12:34:15 PM UTC-5, Bob La Londe wrote:

This brings us to failure number two. After I put it back together I
threw
a piece of stock in the chuck and turned a point to align the tailstock
to.
Then I threw a dead center in the tail stock and started lining up the
points. When I got out my loupe I found the center was blunt. Looked
like
maybe it was dropped. I couldn't see it with just my glasses on, but it
was
clear to see with the loupe. Thinking maybe I dropped it and didn't
remember I got one out of the tool cart that had never been used before.
It
was also blunt. It was a nice tiny dome, but it was blunt. Orders of
magnitude bigger than the tip on my turned point. Atleast it seemed
uniform
so I dialed it in as best I could. I realize even with hardened and
ground
steel handling is coming to take off needle tips from an object that
heavy,
so maybe that's the norm. I don't know. Both centers came with the lathe
so
perhaps they are just lower grade Chinese parts. Do all dead centers have
a
domed tip when looked at under a glass?


* I don't know whether this is common knowledge or not, but an old machinist
* showed me how to get the alignment pretty damned close without a loupe.
* You bring the two points together, and capture a piece of flat stock
between
* them - he used his 60 degree center gauge. Any misalignment becomes
* immediately obvious by the tilt of the metal.

That makes perfect sense. I use a metal scale all the time to set the
height of tool holders. Don't know why I didn't think of doing that between
centers. Nice.