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Thread: Screwcutting Charts

  1. #1
    Join Date
    Mar 2001
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    Default Screwcutting Charts

    Been asked to help a guy out in the UK with a Harrison M300.
    He's got one with a bad screw cutting chart and Harrison's do not have any spares for this model.

    Here's a shot of the plate in situ.



    And a close up of it.



    As you can see the lower part is unreadable.

    Took the details and laid a new plate out in CAD, took two nights whist also watching a couple of programs I wanted to watch on TV, not as bad as it seems as copy / paste comes into it a lot.

    So far this is what I have.



    This is a bmp from the CAD program and it looses clarity but the CAD file is 100% clear and I now have this as a DXF.

    Going to do four plates using different methods.
    One is to engrave this normally on some metalised [ true metal ] engraving plastic. This will give a plate very similar to the original, silver with black letters.

    Second plate will be laser engraved on laser metalised plastic which is less durable but will be quicker and interesting to see the differences.

    Third method is to laser engrave on anodised aluminium, this should be a more durable method but it will be reversed, black plate with silver letters as the laser burns the anodising off, it's not powerful enough to burn onto the plate.

    Last method will be to direct engrave onto some stainless sheet using a carbon impregnated spray coat so the laser burns the carbon into the stainless to form the letters.

    Probably take a couple of weeks to fit this in with other jobs and get the plate anodised.
    watch this space.
    .

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.




  2. #2
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    Jun 2011
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    South Wales
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    Default

    John,
    I am sure you will have a lot of folks vying for your wares, I was in St Phillips in Bristol yesterday at the Bridgeport re-conditioners where he showed me an immaculate Colchester lathe about to be returned to it's owner after being fixed up, his main problem was the machines plates tags & screwcutting chart which were badly marked this spoiled what would have been an otherwise superb job.

    Regards

    Paul

  3. #3
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    Oct 2009
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    Louisville, KY
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    Sir John, this is great. I'm waiting for the results. It relates directly to a project of mine.

  4. #4
    Join Date
    Jul 2008
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    Very cool project Sir John. It's going to be real interesting to see the comparison between the 4 methods. Is this something your planning on doing on a regular basis with the new laser and or engraving? If so, that could be mini gold mine considering just how much equipment has unreadable or even missing placards. And after seeing Harrison's built in range of threads and feeds, I'd sure like a new placard and the lathe to mount it on.

    Pete

  5. #5
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    Sep 2012
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    Ontario, Canada
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    John;

    Step 1) for me was to take 2 different Emco Compact-8 plates, and scan them (11mb files per plate), then clean them up with photo touch-up tools;

    Step 2) is to get them printed - so I'm interested in what you have in mind.

    Please remember to post your results/thoughts on this topic. ;-)

    (edited - one plate is from one I purchased in Britain when living there- 50hz metric, the other is an american Sears one I picked up when travelling a couple of weeks ago- it's 60hz, imperial, branded for Sears)

    Another JohnS.
    Last edited by JohnAlex141r; 10-18-2012 at 12:20 PM. Reason: add differences between plates

  6. #6
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    Aug 2002
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    I should get round to the same thing for the imperial conversion chart for my metric Bantam. Not because it's damaged, but because the manufacturers left out three threads - 13tpi for 1/2 UNC, 19 tpi for pipe threads and 26tpi for British cycle and others.

    I think I'd stop at the 'Stick the laserjet transparency on the ally backing plate' stage though.

    I've also got to get around to making up good wall mounted drill and conversiuon chart.
    Richard

  7. #7
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    Getting a bit side tracked here but still useful information.

    Working on a CNC conversion that requires legends on the spindle buttons and the fact I have had to fit an extra switch to swap the spindle from manual control to CNC control.
    The original buttons had the Dymo stick on labels which looked very crude, my idea was to do a complete engraved panel to stick on the original powered coated front.

    Then though, wonder if you can laser engrave direct onto power coating, tried a sample on the inner lip where you don't see it and it came out well, burnt into the powder but not deep enough to hit the metal. A quick wipe with a bit of black paint on your finger tips and it high lights it well.

    Armed with this information I went ahead and engraved on the front thinking if I shagged it up i could always do the full engraved plate and this is how it turned out but not hi-lighted in in black yet.




    Going back to the original thread of the screwcutting charts i was hunting about and spotted a piece of thick plastic sticking out of the edge of a shelf.
    Wondering what it was, pulled it out and it was the number plate off the old van ??????????

    Light bulb went on !!

    These have a reflective layer on the reverse with the letters and numbers sandwiched in between, so cut the end off with no letters and burn the image into the back, then infill with black from a rattle can, don't worry about runs etc you don't see them.



    Problem I have [easily remedied ] is the computer has a basic set of fonts installed.

    The RYT8B in bold in the centre is Ariel heavy, top right is Ariel standard at 25 % power, one below it is 30% power.
    The reflective laminate is quite thick on these plates and although it looks good from the rear it's how deep it goes and the taper of the cut so the front side looks good.

    Blank number plates are dead cheap so this is another form of good plate material as with the lettering being on the back the front is smooth and the letters can't be scratched off.

    Next thing to try is getting some perspex spray painted on the back and then burn this off.
    Attached Images Attached Images
    .

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.




  8. #8
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    Sir John: PM sending.

  9. #9
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    Dec 2006
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    Colorado
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    Quote Originally Posted by John Stevenson View Post
    Third method is to laser engrave on anodised aluminium, this should be a more durable method but it will be reversed, black plate with silver letters as the laser burns the anodising off, it's not powerful enough to burn onto the plate.
    Is there too much bleed to invert the image so the end result is more of a match? (i.e. engrave the field and leave the letters unengraved black anodized aluminum)
    "D'oh"

  10. #10
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    Good point and worth a try.

    Right 5 methods !
    .

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.




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