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Thread: How well can you see a cutting edge of bit?

  1. #1
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    Default How well can you see a cutting edge of bit?

    How well can you see a cutting of a bit. I have a stereo microscope so I have no problem. But before that I used one of these:

    http://www.use-enco.com/CGI/INPDFF?P...MITEM=890-1363

    About midway down the page is the Fowler pocket scope. Mine is the 20 power. It works extremely well if you have good light source. It is also graduated (maybe I should say mine is). It was helpfull in reallying seeing what was going on with an engraving chisel.

    You do need good light to see under while using it. If I didn't have the scope I'd be using the pocket scope once again.

  2. #2
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    I started the machinist camera project to look at drill bits, a angle on the screen to compare tip center and angle. I have a cnc drill shapener drawed up to use the tool height setup.

    No pictures available.. Right now I am up to my armpits in the cnc bender redo. I bolted a quadrature encoder onto the indexer only to find out I didn't have enough resolution, I should've done the math. Now I get to make a mount for a different style.
    Excuse me, I farted.

  3. #3
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    I'v had to start using magnification this year, I got a set of loupes off ebay, then a cheap handheld microscope, I've now picked up this:

    http://i135.photobucket.com/albums/q...r/DSC00578.jpg

    I'm in the process of adding LED illumination, a micrometer stage for linear measurement and a USB camera eyepiece to allow use of a PC for viewing.

    It's rubbish getting old but the toys do keep getting better
    Nick.

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    I've got a pocket comparator with a zoom function (8x to 16X). Only have the one plate for it but works quite well. I have even used it to take pictures in combination with a Sony floppy disc camera. Sometimes you just can't see what you think you need to see.
    The optimist says the glass is half full, the pessimist says it's half empty. The paranoid in me says somebody put a hole in it.

    Remember pessimists are at heart opptomists. They know things can and will get worse.

  5. #5
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    Quote Originally Posted by Spin Doctor
    I've got a pocket comparator with a zoom function (8x to 16X). Only have the one plate for it but works quite well. I have even used it to take pictures in combination with a Sony floppy disc camera. Sometimes you just can't see what you think you need to see.
    Hmm, sounds handy, but I've never heard of such a thing. I've been thinking I'll pick up a small comparator if I ever see one cheap at auction, just hasn't turned up yet.

    Edit: Just found them on Enco. Neat. How well do these work in general. Obviously you like the one you have, but what all can you do with it?
    Last edited by BadDog; 12-08-2006 at 12:52 AM.

  6. #6
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    How well can you see a cutting edge of bit?

    Without magnifiers?
    Well you can if you look to see what is not there!
    Look for any light reflection from the cut edge.
    If you see light, it's dull.
    Thats because a sharp edge has no reflection, but once it is rounded, it is able to disburse the light and conveys the looks of a shiney edge.

    You see a variation when turning shafts in a lathe.
    Say you wonder if the toolbit is getting duller when you are in the middle of a cut.
    Just look at the light reflection off the shaft.
    If the light reflection is wider , the tool is duller and your finish is rougher.
    As you get close to a "mirror finish, notice that the "light line" reflection gets narrower, until it becomes a very fine line left to right, which is significant of a beautiful smooth finish.
    Rich

  7. #7
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    Quote Originally Posted by Magic9r
    It's rubbish getting old but the toys do keep getting better
    Nick.
    Well put!

  8. #8
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    As a young lad following my grandfather around, he taught me that all that was necessary to check the edge of a knife was to hold it in such a way as to get it to reflect light from any source. His words were,"A keen edge reflects no light". This metheod has worked well for me for many years now, and I trust it without question. If you're looking at any "edge" and you can see light reflecting off of it, it is not sharp. It is possible that it may feel sharp, but I trust my eyes more than my sense of touch. Works for me. Of course, if you need to verify the accuracy of a cutting profile, then a comparator or similar device is needed, but if you are confident of the profile, then nothing beats the human eye.
    Last edited by Ed Tipton; 12-08-2006 at 05:58 PM.
    There is no shortage of experts, the trick is knowing which one to listen to!

  9. #9
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    Lathe tools & milling cutters I check with a light - if I can see the edge - it needs sharpening.
    With knives / chisels etc. same but you can also rest the edge vertically on a finger nail - if it slide off it need sharpening if it does'nt it's probably sharp enough (try it !)
    Mark

  10. #10
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    A rolled edge, you can drag across your fingernail backwards, if the edge has rolled over it will cut into your fingernail. Why everyone used to strop razors with leather, knock the feather edge off.

    Tattoo needles after going sterile with the solution, before autoclaving I'd give them a quick check like this. After cooking them 45 minutes under dry steam you'd want to check them with a loupe afterwards as you built your tattoo machine for a customer. Too late to drag them on a fingernail then, ya got gloves on.

    Funny, sometimes a needle would quit carrying the ink, look, and some of the multiple points would be "gone".. where? lost or wore to nothing.

    I got a real good page on drill bits.
    http://www.tpub.com/steelworker2/121.htm
    To drill a really deep hole, as in a barrel, you need a perfect drill bit. Both edges cutting evenly so it does not arc off in a tangent.
    Excuse me, I farted.

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