Free 186 More Best Homemade Tools eBook:  
Get 2,000+ tool plans, full site access, and more.

User Tag List

Page 1 of 2 1 2 LastLast
Results 1 to 10 of 17

Thread: CIRCLE CENTER FINDER

  1. #1
    Supporting Member Captainleeward's Avatar
    Join Date
    Jul 2014
    Location
    San DIEGO, California
    Posts
    1,097
    Thanks
    496
    Thanked 1,330 Times in 525 Posts

    Captainleeward's Tools

    CIRCLE CENTER FINDER

    CIRCLE & SQUARE CENTER FINDER Made from angle steel,aluminum stock.

    CIRCLE CENTER FINDER-010.jpgCIRCLE CENTER FINDER-011.jpgCIRCLE CENTER FINDER-012.jpgCIRCLE CENTER FINDER-013.jpgCIRCLE CENTER FINDER-014.jpgCIRCLE CENTER FINDER-015.jpgCIRCLE CENTER FINDER-016.jpg

    186 More Best Homemade Tools eBook
    Last edited by Captainleeward; Mar 21, 2016 at 12:18 PM.

  2. The Following 14 Users Say Thank You to Captainleeward For This Useful Post:

    Andyt (Sep 8, 2018), Jon (Mar 21, 2016), jrocasio (Dec 3, 2016), kbalch (Mar 21, 2016), Lee Bell (Sep 7, 2018), Paul Jones (Mar 21, 2016), PJs (Mar 24, 2016), Raytonian (Mar 19, 2019), rlm98253 (Dec 21, 2017), scoopydo (Mar 24, 2016), Scotsman Hosie (May 25, 2018), Toolmaker51 (Dec 24, 2017), tuchie (Dec 23, 2023), werdegast (May 7, 2021)

  3. #2
    Supporting Member Captainleeward's Avatar
    Join Date
    Jul 2014
    Location
    San DIEGO, California
    Posts
    1,097
    Thanks
    496
    Thanked 1,330 Times in 525 Posts

    Captainleeward's Tools
    ENJOY....:O)

    2000 Tool Plans

  4. #3
    Content Editor
    Supporting Member
    DIYer's Avatar
    Join Date
    Aug 2013
    Posts
    3,056
    Thanks
    772
    Thanked 1,850 Times in 1,652 Posts
    Thanks Captainleeward! We've added your Circle Center Finder to our Measuring and Marking category, as well as to your builder page: Captainleeward's Homemade Tools. Your receipt:


  5. #4

    Join Date
    Jan 2016
    Posts
    8
    Thanks
    0
    Thanked 1 Time in 1 Post
    Thanks for another simple to to make, but tough to think of tool. It will go straight to my "often used tool box.

  6. #5
    Supporting Member Captainleeward's Avatar
    Join Date
    Jul 2014
    Location
    San DIEGO, California
    Posts
    1,097
    Thanks
    496
    Thanked 1,330 Times in 525 Posts

    Captainleeward's Tools
    Thank you for your nice remarks.....:O)

  7. #6
    Supporting Member jotasierra's Avatar
    Join Date
    Sep 2015
    Location
    país Argentina, provincia de San Juan
    Posts
    118
    Thanks
    0
    Thanked 13 Times in 13 Posts

    jotasierra's Tools
    Gracias Captain y a copiar el modelito.

  8. #7
    Supporting Member Captainleeward's Avatar
    Join Date
    Jul 2014
    Location
    San DIEGO, California
    Posts
    1,097
    Thanks
    496
    Thanked 1,330 Times in 525 Posts

    Captainleeward's Tools
    for nada :O)

  9. #8
    Supporting Member Toolmaker51's Avatar
    Join Date
    Feb 2016
    Location
    Midwest USA
    Posts
    5,330
    Thanks
    7,041
    Thanked 2,977 Times in 1,892 Posts

    Toolmaker51's Tools
    I've a pile of 1" x 8" steel disk's to center drill, making machine leveling pads. Commercial machinist center heads don't range beyond 5'' diameter ~...
    So make one!
    This will be great. Beats loading them up and chucking in lathe at work.
    Sincerely,
    Toolmaker51
    ...we'll learn more by wandering than searching...

  10. #9
    Supporting Member mklotz's Avatar
    Join Date
    Aug 2015
    Location
    LA, CA, USA
    Posts
    3,433
    Thanks
    357
    Thanked 6,378 Times in 2,116 Posts

    mklotz's Tools
    This is probably a good place to mention the mathematical background of center finders.

    There's a provable theorem from geometry that says:

    The perpendicular divisor of the chord of a circle passes through the center of the circle.

    When you use a center head, the two tangent points where the head touches the circular object define a chord on that circle. The blade is mechanically set to bisect the angle between the arms of the head so it automatically provides the perpendicular bisector of the chord. When two of these chord bisectors are drawn, the point where they cross must be the center.

    The technique is extendable to circles or circular segments too large for any sort of hand-held tool. Simply draw two chords (as nearly perpendicular as possible), construct their bisectors and the point where they cross is the center. Surveyors employ this technique, using their transits to establish the perpendicular bisectors.

    The diameter of a circle is a chord itself. Thus its perpendicular bisector must pass through the diameter at the center of the circle.

    It should also be apparent that this math insight can be used to construct a circle that passes through any three non-colinear points. Construct two chords using the three points. The center of the circle is then the point where their bisectors cross and the radius is the distance from the center to any of the points.
    ---
    Regards, Marv

    Home Shop Freeware
    https://www.myvirtualnetwork.com/mklotz

  11. #10
    Supporting Member mklotz's Avatar
    Join Date
    Aug 2015
    Location
    LA, CA, USA
    Posts
    3,433
    Thanks
    357
    Thanked 6,378 Times in 2,116 Posts

    mklotz's Tools
    Quote Originally Posted by Toolmaker51 View Post
    I've a pile of 1" x 8" steel disk's to center drill, making machine leveling pads. Commercial machinist center heads don't range beyond 5'' diameter ~...
    So make one!
    This will be great. Beats loading them up and chucking in lathe at work.
    The intended application suggests you don't need tenths (or even thousandths) accuracy in locating the center so perhaps a device based on my math post above might work.

    On a metal bar, mount two identical pins about six inches apart on the centerline of the bar. Draw a line on the bar midway between the two pin locations. This is your "chord generator".

    Push it against the circumference of the disk until the pins touch. Lay a machinist square on the top of the bar, align with the center mark and draw the bisector on the disk. Repeat. The center is the point where the two lines cross.

    It's just a gedanken-design but it might inspire you in your build.
    ---
    Regards, Marv

    Home Shop Freeware
    https://www.myvirtualnetwork.com/mklotz

Thread Information

Users Browsing this Thread

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

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
  •