Niewmismatic Error Coins

Malaya British Borneo 1961H 10 Cents Coins With Rim Clip Errors and Blakesley Effect.
Rarity:RRR/BU
The Malaya and British Borneo 1961 10 Cents coins shown on this page are a good illustration of the Rim Clipped planchet error showing a curve rim clip. Clips are normally curved because the blank was punched from an area overlapping the hole left by a previous punching.
Error coins collectors should  learn the diagnostics of this class of error more than some of the other error types due to the ease and frequency in which they can be faked.Many clips are faked by punching the clip out with a common punch found in almost any die shop or through other cruder methods like the "straight clips" are faked by filing metal away from the edge. No matter what class of clip is involved, in many cases, the rim opposite the clip will be flat and poorly formed. This effect is known within the hobby as the "Blakesley effect".

What is the "Blakesley effect"?
A coin is sent into a circular mill where it rotates while the mill closes around its edge slowly and compresses it. The compressing mill compresses around the coin in all directions, creating the necessary pressure for the rim to be upset. Normally the blank rotates through the mill which becomes increasingly tighter on the opposing sides of the blank as it progresses through.When the blank rotates to the area of the clip the pressure is released and due to the absence of pressure in that area during the upset (or rimming) process, the rim fails to be formed in the area opposite the clip.
The Blakesley effect is a common way to observe if a clipped coin is real or not. A genuine clipped coin usually possessed the Blakesley effect, even for small clips.However, the "Blakesley effect" does not always appear on the struck coin; most probably due to a heavy strike, and collectors must learn to recognize other diagnostics of a genuine clip. Look for tapering at the edge (especially at the extreme opposite edges or lips of the clip where it meets the raised rim) and notice how the metal flows and design details close to the edge stretch or elongate. Not all of these effects always occur and sometimes they are minimal but one or more of these diagnostics will generally be present on a genuine clip.
I am lucky again to inherit two pieces of Malaya and British Borneo 1961 10 Cents coins with Rim Clipped Errors and Blakesley Effect in brilliant uncirculated condition.Thank you Master Tan.