Technical question about coin surface

MtMan

There has been a lot of talk recently about how dipping can remove the flow lines that give a coin its luster. I was wondering if anyone knew what the characteristic dimensions of these flow lines were? How deep, how wide from peak to peak etc.

MtMan

hughesm1

Flow lines are caused by the planchet metal moving against the surface of the die during striking. Flow lines are as unique to any coins' surface as snowflakes. There are no particular standard dimensions, though the longer a die has been in service, typically the flow lines become more dramatic.

Hope this helps.

DHeath

And interrupted by die polish.

Cam40

Die scratches.Hairlines from wire brushing.Flow lines..at that level of magnification there are at lot of things that can be seen.
Only after viewing alot of different coins in all conditions with a 10x loupe you start to tell the difference between
all these things.
One tough one is seeing / noteing the difference between hair lines on the coin from a harsh cleaning with a wire brush and the tiny raised lines that are die scratches.
Then there are the flow lines.These nearly always extend from the center of the coin outward towards the rim.
And the size or demensions of the flow lines depend on the age of the die or how the die was prepared.
Flow lines on a Proof coin for instance are extremely fine and can hardly be seen even with a super strong glass.
Conversely ,an aged business-strike die may produce a coin with HUGE flow lines easily visible with the naked eye.
These look funny sometimes like the coin has a human skin-like appearance.