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  1. #1
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,444

    Talking Indicator Point !

    Hi Guys,
    A recent thread "Adjusting a test indicator point" reminded me of this little project I completed recently. I wanted to use a "Mercer .001" dial indicator in the vertical position but to have the probe at 90 degrees. So I made this adapter from bits of scrap that were laying about.

    Indicator_1.jpg

    This is the aluminum bracket lying on a 50 mm diameter slitting saw, to give an idea of size. The aluminum is 1/2" thick. I cut a piece with a hacksaw and cleaned it up on the mill with a 16 mm diameter four flute cutter. The clamp screw is a stainless steel M4 Torx head cap screw and the pivot screw is a short length of 6BA brass all thread with the end threads crushed to lock the nut in place. As can be seen in the other photographs, I drilled and reamed an 8 mm diameter hole to be a good fit on the dial gauge spigot. I then hacksawed a slot so that the clamp screw would cause the bracket to grip the dial gauge. I must admit that I should have used the slitting saw instead, because it looks terrible in the pictures.

    I turned the top down so that the bracket cleared the adjustable rim on the dial gauge. Since the slitting saw is 50/1000" thick I found an old brass box with 45/1000" thick walls and cut a 1" square piece to use for the lever. I also needed a piece 6 mm wide for the dial gauge probe to run on. For this I simply bent a 6 mm wide strip of the brass plate in half and soldered it to the top edge of the lever for the probe to run on. At the other end I made a probe from a 6 mm long bit of 2.5 mm round brass rod. I hacksawed a slot in one end and rounded off the other in the lathe. Again I soldered the pin probe to the bottom of the lever.

    The picture of the lever is before I had cleaned it up. The brass box was silver plated which is why you can see the copper under the plating where I have been a little heavy handed with the brass brush. The two close up pictures are showing the dial gauge probe at the extended end of its travel and the little brass pin used as the probe at the other end. As near as I can measure the ratio of horisontal to vertical movement is 1.5:1. In other words the dial gauge reads 1 thou for each 1.5 thou of the horisontal probe.

    Indicator-24a.jpg Indicator-24.jpg Indicator-22.jpg Indicator-23.jpg Indicator_5.jpgIndicator_4.jpg Indicator_3.jpg Indicator_2.jpg Indicator-24b.jpg

    Next job is to make a jig to sharpen that slitting saw.
    Best Regards:
    Baron J.

  2. #2
    Join Date
    Aug 2010
    Location
    Near Bendigo, Victoria, AUS
    Age
    72
    Posts
    3,102

    Default

    Very nice and ingenious.
    The bottom one on this page came with one of my old dial gauges:
    http://www.mytoolstore.com/starrett/dial04.html
    Note that you introduce a sine or cosine error (can't recall which one) if you go too far away from 90deg.
    Cheers, Joe
    retired - less energy, more time to contemplate projects and more shed time....

  3. #3
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,444

    Default

    Hi Joe,

    Thanks for that interesting link.
    It gives me some ideas for other uses. I see that the arms are exactly the same length on the Starrett one and that the shaft size is 9.5 mm. The shaft on my Mercer is 8 mm. But what a price they want. Still if it gives someone else a clue.
    Best Regards:
    Baron J.

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