I know the best way to measure a clip is by weight. When I do that, this coin shows it's a 1% clip - obviously, it's larger than that and was struck on an overweight planchet. Does anyone know of a computer based tool that could, easily, determine the missing portion of a circle? Thanks.....
I'll be glad to when I get back to the computer that has the pictures. I'm rather surprised, though, given the metal flow on "LIBERTY" and the obvious Blakesly.
from the G in GOD to the first T in TRUST the rim is not fully formed due to the Blakesly effect. genuine clip...
Incomplete planchet evaluations are based upon what is missing not what "appears" to be missing. For the subject coin, I'd re-evaluate my math if I only came up with 1% or I'd calibrate my scale.
Uhhhh.......yeah but then that would put the "effect" in the wrong location. The Blakeslee effect occurs exactly "opposite" the clip. Not off to the side of the clip as this "effect" is the result of the rim not being raised in the upsetting mill which requires the coin to "roll" around an decreasing radius wheel which raises a "rim" on the blank. "Questionable" at best.
Sometimes I wonder if SOME people on this forum are just plain mean or if their diagnostic capabilities are super lame. In the first place, the genuineness of the clip was not the issue or question. It's real. Period. I can even tell you the counting room where it came from a mint bag. All of the normal diagnostics fit. There is no issue except in the minds of certain people that just don't understand the process. To the guy that suggested I calibrate my scale - OF COURSE I DID. Two of them as a matter of fact. In this case, the planchet is definitely overweight and I thought it might make an interesting discussion of alternatives. I have solved this, by the way, but have no intention of inviting further derision here.
Nice one. Most people forget that straight clips tend to have a much reduced Blakesley Effect, as compared to curved clips.
This link describes the math for determining the area of a circle bisected by a chord (straight clip). http://en.wikipedia.org/wiki/Circular_segment This math might be a beginning of a much larger calculation. A fully struck coin will have significantly different thickness at different radius (ie. edge vs field)and the thickness is also vaiable due to the plethora of design elements. The math isn't that bad if we only consider a flat disc and a perfectly straight clip.
Thanks for the input. For my purposes, an assumption of a perfectly straight clip and flat disk is sufficient. I'm not enough of a mathematician to solve the equations which require knowledge of the angle. I did run across this site http://www.1728.org/circsect.htm only requires the length of the clip and the radius. Using my Harbor Freight calipers, I'm able to come up with a reasonable answer for this purpose. You seem knowledgeable here - does this method make sense?
The Web link performs the math & it looks great! When you calculate the area of the segment [the segment is the green area in the diagram #2], divide that area by the complete area of an unclipped coin of same radius. That resulting number will be the percent clip. This should be the correct calulation for a straight clip on a flat disc. If you assume that a curved clip is perfectly curved, then you could simply double the area of the segment you have calculated & then divide that (2x segment area) by the area of an unclipped coin of same radius. Math is cool. What chord length did you measure or what was the resulting % clip which you calulated for this coin?
I measured the chord at 9.63mm and the diameter at 21.13mm If I calculated correctly, I get slights over a 2% missing area - less than I would have thought.
It is less than I would have thought also. However, this depicts 2.5% of a pie chart. After seeing this, I might concur with a 2% value on the clip.
Good question. I had to check the coin again. This silhouette shot indicates that there are at least four clips. BTW, I actually share your interest in cuds. Nice avatar coin! I'd like to see a CT thread where everyone can post their favorite cuds.
