Edge finder,do you use one?

I have a selection of 3/8, 1/2 mechanical that are mostly Starrett but the finder I use most is electronic.
Use the mechanicals mainly for plastics.
 
Mechanical edge finders have one distinct advantage over other types of position locators ( electronic, Haimer taster, touch probe, optical, dial indicator, etc.). Properly used, they compensate for runout and so are independent of any spindle runout. The edge finder will automatically center itself on the spindle axis.

I run the edge finder at a medium spindle speed. I initially approach an edge relatively rapidly to get a rough location. I then back off to recenter the edge finder and approach the edge at around .0002"/second. I will repeat the measurement several times until I get a consistent reading to .0001". If you approach too quickly you can kick the trip out prematurely or you can shoot past as it's hitting the edge giving an inaccurate reading but my experience is that it is very repeatable.

For finding the center of a circular boss or hole, I will set the edge finder approximately at the the center of the boss/hole and find one edge in the Y direction and note the position. When using a DRO, I usually zero the DRO at that point. I then move to the opposite edge and locate it. The center of the boss is then 1/2 the distance of that reading. My DRO's re capable of making the calculation so I don't have to do the math. I then move to the center in the X direction and repeat the process to find the edges in the Y direction. If I want to be super accurate, I will repeat the X axis using the Y axis center although I usually find no change from the first position. I now have the true center coordinates of boss/hole. I do use care when moving the edge finder over a boss to return to the same z height for each measurement.

The mechanical edge finder takes longer than some other methods but IMO, it is the most accurate method of locating an edge. It works extremely well with a DRO but I used it for many years with just the crank dials. You do have to take into consideration any backlash in that case.
 
I have a Starrett mechanical 1/2. I use it to get hole #1. after that I use hole #1 as zero.

"Billy G"
 
I have a couple of electronic and a couple of mechanical, use them both. The mechanical ones have a 0.200" and 0.500" ends. I tend to use the 0.500" one.

My mill is a Jet JVM-830, uses step pulleys for changing spindle speeds. I've read someplace that the mechanical edge finders should be used between 500 - 1000 RPM's. If I'm doing something where the spindle is already set to a speed outside of that range, I an electronic edge finder to avoid having to change spindle speeds.

My electronic ones are Fowler's, mechanical ones are a Starrett and an Enco. You can pick up a mechanical one for under $20 off eBay/CDCO/Shars; very handy to have.

Bruce
 
Not much for any electronic gizmos. No DRO in my shop. No digital mics, etc.
Run a wiggler, 1/2" center finder, and a center scope.
Depends on the accuracy I need/want.
Count my handwheel turns. I'm consistently holding .001.
Reduce error wherever you are able on critical parts.

Daryl
MN
 
My used lathe and minimill came with 4 different edge finders along with a laser finder. when I found them in a box of misc stuff, I didn't know what to think of any of them.
Trial and error as well as YouTube "classes" caught me up quickly with what these things were. I use them in one way or the other on just about anything that I mill.
The laser I use primarily for aligning the centerline of the mill with the position that I want to drill or tap. I find all of them invaluable especially if your mill isn't all that
accurate at location finding through the hand dials or even a DRO. This is coming from a really newbish kind of guy.
 
I use a double ended 1/2" edge finder most of the time, .500" on one end & .200" on the other end. I have 2 other mechanical edge finders in different configurations but I don't use them often. Mine are all PEC. Many people over look PEC Tools. Not as nice as Starrett or Mitutoyo but still great tools at lower prices & made in USA.

I have an import Fowler electronic edge finder, the kind that lights up. I don't like the audible ones cause I can't hear them with fans or AC running. I do use it now & then when I have to indicate something where I don't want to mar the finish or if I'm lazy & want to set something up very quick. That's about all I think they're good for as they're easy to damage. Just have to remember that they don't work on plastics or if I'm holding a part using paper or tape. I'm not a fan of the laser ones though.
 
Thank you again for all your comments and your help, I read every one of them and learned a few tips and tricks .my edge finder is on its way.it was in fact cheaper than Amazon usa,paid $22 CDN dollar hope is not going to fall apart on first try.:tranquility:
 
Threw out my Fowler electronic one years ago. Brown and Sharp edge finder, manual model has me within a few tenths with little effort.
 
You must log in or register to reply here.
Back
Top