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Thread: Marking Gauge.

  1. #1
    Join Date
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    Thumbs up Marking Gauge.

    Hi Guys,

    Since it has been a bit quiet of late, Christmas preparations and all that. I thought that I would set to and make a marking out gauge.
    I had all the bits and pieces in the surplus metal pile.

    22-12-2017-001.JPG 22-12-2017-005.JPG

    I didn't take any pictures of the offcut of 40 mm round bar before I had put it in the lathe four jaw, centred and drilled it 6.2 mm. The hole is 10 mm offset from centre. The chunk of steel between the chuck jaw is there to balance the offset weight. The piece is turned to leave a 13 mm spigot. I also lightly countersunk the hole to remove any sharp edges.

    22-12-2017-006.JPG 22-12-2017-007.JPG

    This is the finished piece. I drilled a 4.2 mm hole in the spigot and threaded it M5 going into the bore for a pinch thumb screw, before reaming the through hole 1/4" inch to suit the length of chromed steel rod. That clears any burrs from the drilling and threading that would foul the bar that goes through it.

    22-12-2017-003.JPG 22-12-2017-002.JPG

    I had a nice broken carbide drill shank with an 1/8" inch diameter shaft that I intend to sharpen to a point, to make a scriber. After drilling the end of the 1/4" rod with a 2.5 mm drill to a depth of 13 mm, I threaded it M3. I followed this by cross drilling with a 3.2 mm drill and reaming to 1/8" inch. This made the carbide drill shank a very good fit with the M3 screw holding it solidly.

    22-12-2017-008.jpg

    Apart from making the thumbscrew and sharpening the scriber to a point, this is the finished article. The chromed steel rod is 18" inches long ! I haven't decided what length to cut it down to yet.

    Thanks Guys ! I won't be around over Christmas, so Greetings and good wishes to all.
    Best Regards:
    Baron J.

  2. #2
    Join Date
    Apr 2009
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    Ballina N.S.W.
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    Hi BaronJ
    Nice handy tool making good use of the carbide drill shank, I like the way you balanced the offset in your chuck. Having a supply of handy simple tools makes life easy. Here are a couple of tools I made a few years ago that I have often used. The double ended centre punch I made when I had an awkward job cutting a curved access hole in a piece of 12mm thick Aluminium plate on a pontoon. It allowed me to drill a series of holes with very little web between them and then use a pad hacksaw tool to cut it out. The second tool is a metal version of an old woodworking tool. I had a project that needed 150 holes drilled in the centre of 50*50 RHS at various locations. I used a piece of left over carbide in this tool. Hope you have a Good Xmas as well.
    Bob
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  3. #3
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    I like the use of the offset in the design. The reason for this is that it allows for when you need to maximise the diameter of bar utilised.

    Designs based on a central spigot and hole for the bar waste the "depth" of dimension on the upper unused side of the gauge.

    Some metal workers may only have access to bars of x diameter.The offset design allows better utilisation.

    Grahame

  4. #4
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    Hi Bob, Guys,

    I made one of those centre finder punches several years ago, for very much the same reason as you did.
    What I need / could do with, at the moment is one of those centre finders for round bar !

    I want to get the stylus sharpened and the thumbscrew made to finish off the gauge. I'll add pictures later.

    Anyway a slightly belated "Merry Christmas" to all, having just arrived back home from spending Christmas with my daughter and son in law.
    I'm looking forward to a little R&R after being run ragged by a little girl having boundless energy. Shades of Deja vu.

    Thanks all.
    Best Regards:
    Baron J.

  5. #5
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    A possible substitute in case you are unable to access a carbide pin is a cement nail. I have a few left over from shop teaching days.
    Cement nails were a hardware item when I purchased them. I think they are still available. Not as hard but still functional never the less.


    Grahame

  6. #6
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    Hi BaronJ
    I know how you feel, I have just spent a couple of days with our two grandchildren four and eight years old, they are so full of energy.The centre finding tool does work to find centre on round bar you just need a couple of square pieces of stock the same size or a little bigger. Years ago I did make one of those fishtail type devices that you use in your bench drill to find centre but found the results were not accurate.
    Bob
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  7. #7
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    Quote Originally Posted by Grahame Collins View Post
    A possible substitute in case you are unable to access a carbide pin is a cement nail. I have a few left over from shop teaching days.
    Cement nails were a hardware item when I purchased them. I think they are still available. Not as hard but still functional never the less.


    Grahame

    Hi Grahame,

    Yes those hardened steel nails are still around and I've seen them used as scriber’s !

    I have a good number of those broken carbide drills, all 1/8" inch shank. They are commonly used for drilling printed circuit boards and get broken very easily. They make nice miniature lathe tools as well.
    Best Regards:
    Baron J.

  8. #8
    Join Date
    Sep 2012
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    Thumbs up Marking Gauge finished.

    Hi Guys,

    Finally got the last few details of the marking out gauge done, so this project is now finished. Here are the photographs of those as promised.

    30-12-2017-002.JPG

    First a family picture of all the bits. The little plastic piece was added because it fits onto the bar and stops the holder sliding off the end of the bar. Not shown here, but I cut the bar down to 9" inches in length, making the gauge less weildly.

    30-12-2017-005.JPG 30-12-2017-006.JPG

    One of the things that needed to be done was to sharpen the scriber to a point. I did this with the 4 - 6 Facet drill grinder, by putting the carbide drill shank into an 1/8" inch collet and using the edge of the CBN wheel. I only ground enough off to make sure that I had a sharp well centred point. If you look closely you can see the remnants of the flutes from the broken drill. I think that this one was a 0.8 mm drill.

    30-12-2017-003.JPG 30-12-2017-004.JPG

    This is the thumb screw that I made from a very short piece of brass. It was actually one half of a shear pin from a 25 KVa generator. 5/8" inch diameter and about 1" long. You can see what is left of the woodruff key at the bottom left of the second picture. The thread is a single pointed M5, done before I decided to knurl it. Unfortunately I couldn't get close enough with the knurling tool to do the whole width of the knob. Both the knurl and the thread were done with the lathe running in reverse, I used an M5 nut to hold the thumb screw in the three jaw chuck.

    30-12-2017-001.JPG

    And a last picture of the completed tool. The scribe line round the spigot is quite clear in the picture, but barely visible otherwise.

    Thanks for looking, your comments are much appreciated.
    Best Regards:
    Baron J.

  9. #9
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    Thumbs up Centre Finders.

    Hi Guys,

    Just a quickie to post some pictures of my centre finders. Both these were made some time ago ! I can't remember if I’d posted these before but anyway...

    04-01-2018-Centrefinder-02.jpg 04-01-2018-Centrefinder-01.jpg
    These are pictures of a centre finder for bar and tube stock. The punch is a bit of 5mm round silver steel with the end turned to a 90 degree point and then hardened and ground. It is four inches long, 1/4" inch thick bar stock, with the pins 3" inches apart. The pins are 1/4" aluminium bar 3/4" inch long.


    04-01-2018-centrefinder-03.JPG 04-01-2018-Centrefinder-04.JPG 04-01-2018-Centrefinder-05.jpg
    This is a laser centre finder, made with a laser pen that was originally sold by Aldi stores. The body is aluminium with a 1/2" diameter, unhardened, silver steel shaft pressed into it. The laser is angled at 15 degrees, though 20 or 25 degrees would have been better. The hole for the laser is drilled so that its nose just hits the hole for the shank. The idea being that it stops the laser pen from falling right through, and it just lifts out to put in new batteries. The elastic band and the bit of green plastic is there only to press the button to turn the laser on.

    I'm going to make another one of these when I can find a suitable laser. All the other ones that I have tried have been too bright, too big a spot or not a round spot. But they do work very well.

    Thanks Guys.
    Best Regards:
    Baron J.

  10. #10
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    John,
    Is this the theory behind your laser centre finder?

    https://www.centerquic.com
    Chris

  11. #11
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    Hi Chris,

    I got the idea from this
    Laser-CF.png

    Somewhere I have a PDF of this article by "Dick Kostelnicek". There is a Utube video of him demonstrating it.
    There is nothing critical in building one other than finding a suitable laser pointer. But for some reason they seem to be hard to find. I've tried several but you need a small spot size, ideally around a mm.
    Best Regards:
    Baron J.

  12. #12
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    Thumbs up Laser Centre Finder pdf.

    Hi Chris, Guys,

    I found the pfd file for the laser centre finder, However at 7.13Mb the forum software won't let me attach it.
    You can find it at this link. Select: Volume 19 July 2014.

    HMSC Newletter Archive

    Hope this helps.
    Best Regards:
    Baron J.

  13. #13
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    Thanks John. I'll try and track down a suitable laser pointer.
    Chris

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