# How To Use an Edge Finder



## HMF (Nov 3, 2010)

From the Starrett Web Site:

http://www.starrett.com/pages/1512_t_and_r_edge_finder.cfm

Edge Finders are simple, effective and accurate tools for locating workpiece surfaces.

Flat surfaces, straight edges, grooves, shoulders, round work, dowels, studs, center points and scribed lines can all be accurately located with this tool. 
How To Use an Edge Finder
Edge finders are easy to use. First, secure them into a collet or chuck. Then, traverse the worktable to obtain contact between the rotating edge finder and the work. 

Upon contact, the contact diameter will shift to concentric position relative to the body -- with very slight additional table adjustment, it will move off center with a decided wobble (see right). 

When the contact diameter aligns with the shank, the center of the finder is exactly one-half the diameter of the contact from the work edge. After setting the appropriate machine axis, accurate location relative to the workpiece edge is assured.

To locate center points and scribed lines, put a rule or pencil tip along a scribed line. Then, carefully bring the edge finder's pointed contact to the center point or intersection of scribed lines and adjust the table so that it barely touches the work.

Best,

Nelson


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## EmilioG (Nov 1, 2014)

How do you get the pointed end to spin concentric? Is it done under power or do you do it by feel?
Thank you.  Great info. I'm new so I need more clarity.


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## catoctin (Nov 1, 2014)

I am new at this but from the instruction on the web the pointed center finders are used without spinning.  Simply position the center finder in the hole close to center and move the table until you can "feel" the upper and lower portions are aligned.


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## Pontiac Freak (Nov 1, 2014)

You would do it with the machine spinning.  Here is a video showing it in action.  https://www.youtube.com/watch?v=aUa_B6YIt_M


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