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NGMD

Platinum Premium Member
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Posts posted by NGMD

  1. 23 hours ago, paulmerton said:

    Call me selfish, but I'd rather secure my refund first 🤣

    You got the refund yet because I’m sure we would like to hear the full unfiltered story? You’d not be happy selling that as bullion and the pitchforks are at the ready.
    I believe someone has a PF70UC for sell. Yeah….meeeee.

  2. 3 hours ago, Darr3nG said:

    There's always silver...

    I can go for ages without buying silver and then lots of great designs hit the market at the same time, you know GE, Monarchs, Tudor Beasts. 
    Gold first, silver collectibles to balance out the urge next. Stacking Silver….nah.

  3. Just now, Charliemouse said:

    Which do you mean?  The previous two were Perth and Canada.  They are the only proof coins I have with the Pistrucci design, to compare George's head like with like.

    I am happy to photograph anything I've got with the microscope, but I don't have proofs going further back than the 1980's.

    Love to see like modern Germania/Perth proofs or anything you have under the mattress to see alternative modern processes under high magnification.

  4. 22 hours ago, Charliemouse said:

    Agreed.  The frosting gets more 'frosty' as time moves forward (and more holes), but the definition of the face and detail gets worse.

    What is especially noticeable is that, with the 1984, I could not keep the whole face in focus because the relief was so much higher.  The later coins, especially the 2015, are flatter and easily focused.

    Do you have any close up shots of alternatives mints? Be good to see their process on magnified details.

  5. 1 hour ago, Booky586 said:

    Fantastic photos, keep on posting them!

    I'm with James and NGMD, I wouldn't be surprised if the dies are finished by laser.

    Have a look at the scan I've attached from an 1986 Royal Mint Coin Club Bulletin. It describes how the frosting used to be applied to the dies, historically by Nitric acid etching and then by glass bead shot blasting.

    1986-21 Die Polishing.pdf 493.95 kB · 1 download

    The blasting media is usually done with ceramic now for consistency as glass breaks down to powder easily and has too much colour fluctuations and can hide surface imperfections. 
    Oh hang on, it’s the Royal mint- grit and tarmac sandpaper.

     

  6. 47 minutes ago, Charliemouse said:

    I have no idea.  Hopefully someone with more coin minting knowledge can answer.

    In the meantime, here are some more pics.  Including some missing 'frosting'.

    For scale, those digits are approximately 1.5mm tall.  That makes the 'striations' about 50 microns wide.

    2024_0227_102805_003.thumb.JPG.c8c183569cc313cf56ab31d93788a3cf.JPG

    2024_0227_102822_004.thumb.JPG.0d4b2c13e5634bc70c0cee5b72424e86.JPG

    2024_0227_103238_005.thumb.JPG.8268041f7c7bee774873c83be6b0c435.JPG

    Not CNC. Could be finished with a laser finished with a small aperture. The same as the assay office use.

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