Free 186 More Best Homemade Tools eBook:  
Get tool plans

User Tag List

Results 1 to 4 of 4

Thread: How Small A Gap Can you See?

  1. #1
    Supporting Member rgsparber's Avatar
    Join Date
    Nov 2012
    Location
    Phoenix, AZ
    Posts
    1,321
    Thanks
    777
    Thanked 2,839 Times in 670 Posts

    rgsparber's Tools

    How Small A Gap Can you See?

    As I get older, my vision has degraded. But how bad has it become? Using a pair of parallels and a bit of shim stock, I could test my ability to see tiny gaps.

    If you are interested, please see

    https://rick.sparber.org/SeeingGap.pdf

    Your comments are welcome. All of us are smarter than any one of us.

    Thanks,

    Rick

    186 More Best Homemade Tools eBook
    Rick

  2. The Following 4 Users Say Thank You to rgsparber For This Useful Post:

    mwmkravchenko (May 11, 2019), Philip Davies (Sep 17, 2019), Scotsman Hosie (May 11, 2019), Seedtick (May 10, 2019)

  3. #2
    Supporting Member mklotz's Avatar
    Join Date
    Aug 2015
    Location
    LA, CA, USA
    Posts
    3,519
    Thanks
    362
    Thanked 6,552 Times in 2,157 Posts

    mklotz's Tools
    I'm not sure about establishing tenths accuracy using parallels that probably aren't flat to that accuracy. It might be interesting to repeat the experiment using two optical flats.

    It's generally agreed that the angular resolution of a healthy human eye is about one arcminute or 0.3 milliradians. Thus the smallest separation that could be detected would depend on viewing distance (why we like to hold things closer to the eye when inspecting detail).

    However, I think it would be naive to apply that to your experiment directly since, as an example, distinguishing separation between two lines on a grating just isn't the same thing as detecting when the light "winks out" in your experiment. I'm sure the backlighting in your experiment is very important but I'm not sure how to reconcile it with the one arcminute resolution.

    I know I'm not being very helpful but I appreciate your attempt to quantize something we all do. Keep up the good work.

    2,000+ Tool Plans
    ---
    Regards, Marv

    Experience is always far worse than pessimism

  4. The Following 2 Users Say Thank You to mklotz For This Useful Post:

    mwmkravchenko (May 11, 2019), Scotsman Hosie (May 11, 2019)

  5. #3
    Supporting Member
    Join Date
    Sep 2012
    Location
    Hinchinbrook QLD
    Posts
    323
    Thanks
    44
    Thanked 138 Times in 84 Posts
    If your "finger pressure" is enough to "bend" the parallels, then I dont think they qualify as parallels

  6. #4
    Supporting Member rgsparber's Avatar
    Join Date
    Nov 2012
    Location
    Phoenix, AZ
    Posts
    1,321
    Thanks
    777
    Thanked 2,839 Times in 670 Posts

    rgsparber's Tools
    I suggest you try it. I can bend the head of my mill down by a thou with a hand on top. Bending a parallel by 0.0001” doesn’t take much force.

    Rick



    2,000+ Tool Plans
    Rick

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •