Astrophilatelist- Space Cover Collector 01 May 2015 04:38:39pm
When you see the compound perforations, which number is the top of the stamp? I just got my new Scott multi-gauge. Since the gauge is clear, what does one do to make it easier to see and to use? I got a gauge so I can sort some russian stamps which have perf differences.
BuckaCover.com - 80,000 covers priced 60c to $1.50 - Easy browsing 300 categories 01 May 2015 05:31:30pm
re: Perforations
Scott lists perforations by horiz x vert. Gibbons goes the other way vert x horiz.I stand corrected.
I use the gauge by placing the gauge on top of the stamp and lining up the diagonal lines to intersect the perfs in the center of each "tooth". Frequently look closeup with a 10x glass.
Roy
Login to Like this post
"BuckaCover.com - 80,000 covers priced 60c to $1.50- 10,000+ new covers coming Tuesday June 1"
Since some stamps have different perforations on more than 2 sides, the general rule used by Scott is that the measurements are given in clockwise order starting from the top (e.g., for a quadrilateral stamp: Top x Right x Bottom x Left).
Silence in the face of adversity is the father of complicity and collusion, the first cousins of conspiracy.. 02 May 2015 01:57:07pm
re: Perforations
" .... Since the gauge is clear, what does one do to make it easier to see and to use? ...."
Often I'll slip the stamp into a spare GK102BK card so the perfs will be shown against a black background plus it makes manipulating the stamp easier.
If the stamp is mounted with a hinge I have another "102" card that has the cellophane (???) removed and is trimmed so it can be slipped beneath the mounted stamp to again have the perfs shown with the black background.
  1 Member likes this post. Login to Like.
".... You may think you understood what you thought I said, but I'm not sure you realize that what you think you heard is not what I thought I meant. .... "
I also have a clear gauge. What I do is put the stamp on the front of the gauge so I can move it back and forth to line up with the marks on the gauge.
I always measure using the spaces between the teeth because I feel this is more accurate. The teeth may be uneven or broken so this may cause a slight difference in measurement that is not correct but the spaces between the teeth should always be original from the printers.
I do sometimes put it in a holder. In these cases I will put the gauge on top of the stamp. This is good if you are moving around. For example, taking the stamp to the window to get better lighting.
An extra note. I have heard that metal gauges may change slightly in different temperatures due to expansion and contraction. Not sure this is true but I don't use metal perf gauges.
".... You may think you understood what you thought I said, but I'm not sure you realize that what you think you heard is not what I thought I meant. .... "
"An extra note. I have heard that metal gauges may change slightly in different temperatures due to expansion and contraction. Not sure this is true but I don't use metal perf gauges."
This would be a common misconception as we are more familiar with metals and how they act with temperature changes.
To make it simple without engineering jargon;
if steel has an expansion/contraction rate of 1x
then aluminium would be 2x
plastics would be 4x-12x depending on the material
However this is purely academic as the change over 2cm (what the gauge measures) and using an aluminium gauge with a difference in temperature of 65 to 95 degrees F would be:
(now I will get techie) - .02 (initial length in m) X .000023 (the aluminium coefficient of expansion in mm per degree change) X 30(the temperature difference - 95-65)+ .02 (initial length in m) = 2.0014cm.
A change that you cannot visibly measure.
Also the paper changes as much or more than the metal but that is more complicated as the grain, humidity and other factors come into play.
In conclusion, the material the gauge is made of is secondary to its accuracy. Catalogs tend to round off the perforation size so having an accurate gauge can determine the difference between a common or valuable stamp.
EDITED:
" Since the gauge is clear, what does one do to make it easier to see and to use? "
To answer John's original question. I use a clear gauge also with the stamp on top so a dark background like my desk is disturbing so I taped a white card stock to the back of the gauge. A good flexible lighting source and a magnifying glass does the trick.
Silence in the face of adversity is the father of complicity and collusion, the first cousins of conspiracy.. 03 May 2015 11:51:21am
re: Perforations
" .... a dark background like my desk is disturbing ....
That's funny. To me at least.
I find a black background much more efficient except for some very dark stamps printed from edge to edge.
Perhaps the angle that the light strikes the stamp and gauge makes a difference ?
Login to Like this post
".... You may think you understood what you thought I said, but I'm not sure you realize that what you think you heard is not what I thought I meant. .... "