Malaysia Parliament Series 1968 20 Cents With Straight Clip Errors And Blakesley Effect.


Straight Clipped Planchet Errors 

The Straight Clipped Error occurs in the process of cutting blanks from metal strip. When cutting blanks, long strips of metal are fed through a machine which cuts the blanks from the metal strip. When the strip runs out it is possible for a blank to be cut when there is not enough metal strip left creating an incomplete blank with a straight edge. Then if it is not removed through the quality control process it will be struck into a coin and a small number of these reach circulation.

Blakesley effect

Blakesley effect (named for the American numismatist who first described it) occurs diametrically opposite the missing segment.

The so-called Blakesley effect occurs on most genuine error coins of this type and is characterised by a rim weakness directly opposite the main fault. Coin blanks are put through a rimming machine before being struck.

The rimming machine comprises a concave curved wall and a roller set slightly off-centre so that the gap between the roller and the leading edge of the wall is slightly more than the diameter of a blank and the gap between the roller and the trailing edge of the wall is slightly smaller than the diameter of a blank. Blanks are fed in at the wider end, are progressively squeezed across their diameters as they roll around the curve and emerge from the narrower gap as planchets.

Now when a blank with a missing segment is fed into the rimming machine, all goes well until the missing segment comes into "contact" with the roller or wall. At that moment, the squeezing pressure drops to zero. Obviously no rim is formed on the inside curve of the fault, but also, no rim is formed on that portion of the blank opposite the fault. Subsequently when the coin is struck, a rim may be formed by the action of the collar but it will generally be much weaker than normal.

This is the Blakesely effect and is quite visible on the 1988 10 Cents specimen shown here.


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