Jared,

Is this the same thing as a Center Square advertised in Micro-Mark's latest catalog on page 17 (items # 82285 and 82280 )?

Ken Montero

----- Original Message -----
From: "JaredH"
To: STMFC@yahoogroups.com
Sent: Thursday, January 17, 2013 7:13:25 PM
Subject: [STMFC] Re: Establishing Tank car top and bottom locations






You can do this more easily using a center finder. It has an angle that sits on top of the cylinder with a straight edge that goes down across the cylinder and bisects it so you can mark the center top and bottom.

Jared Harper
Athens, GA

--- In STMFC@yahoogroups.com , Andy Carlson wrote:

Bill Welch mentioned the importance of establishing lines for the tops and
bottoms of the tanks during the construction of our tank cars. While machinists
have great tools for this purpose, there are alternative ways to get good
results. Here is one which I use:

On a level surface (such as a pane of glass) support the tank cylinder securely,
enough that the tank won't roll around. I use two steam engine cylinder
castings, but modeling clay will work well too. With a machinist's square, mark
the top location where the top of the tank is tangent to the horizontal. Repeat
by marking the tank at the point of tangentcy at the lower location. Duplicate
these actions on the opposite end of the tank, as well.

You now have 2 marks on each end of the cylinder for a total of 4. Draw a
longitudinal line joining the top two marks, and then the bottom two marks. The
tank cylinder need not be exactly horizontal to the working surface, as long as
the cylinder can't move, the technique will establish two lines 180 degrees
apart. Any error from eyeballing the marks should not be consequential if effort
is made to closely mark the top point of tangentcy.


-Andy Carlson
Ojai Ca


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