starrett edge and centre finder

[thezetecman]

Hello

I bought a starrett edge finder at the week end.

It has 2 ends one cylinder end for finding the edge. I understand how to use this end. It works very well.

How do you use the pointed end to find a hole centre?

Thanks for your help
Paul

 

[DickDastardly40]

I'm not sure if this is the exact 'proscribed' method but how I'd do it, having seen what you mention but not used one personally.

Power off the machine
Chuck the tool and fix the job to the table of your mill.
Move the table until the centre pop is roughly under the point.
Come down on your Z/quill and move the point so it drops into the pop mark.
Move the table until the edges of the tool are flush all round, rotate the spindle by hand to ensure concentricity.

You could prolly pick up a small diameter existing hole by the same method.

Hope this makes sense, happy to be put right if I've made any glaring errors.

Al

 

[lugnut]

At the risk of sounding totally stupid here I have to ask: Is your edge finder the same as what is called a "Wiggler"? if so, here is a link to Little Machine Shops instruction of the use of that tool. http://www.littlemachineshop.com/reference/wiggler.php

I hope this helps I know it sure helped me find the use for mine.
Mel

 

[DickDastardly40]

The description I posted was for how I believe you use one of these:

http://www.jlindustrial.co.uk/STC-53063E/SEARCH:KEYWORD/product.html

Al

 

[Bogstandard]

I would just like to point out about the type of finder Al is on about.

If you are going to buy one of these, go for the Starrett one. The far eastern ones haven't quite got the spring pressure and friction right, at least on mine it didn't, and you can sometimes get rather spurious results. The cost is only a few £'s ($'s) extra for one that is spot on.
This is one time I will thoroughly recommend a home grown item.

John

 

[thezetecman]

Yes that is the one I bought it is a genuine Starrett

 

[zeusrekning]

I use it for finding center of large round parts that you can not reach the center line with a regular endfinder. Just keep your quill height the same (so you are touching the same tangent point on the part to the edgefinder) and touch both sides.
Tim
I'm trying to post a pic but it says upload folder is full, I'll try later.

 

[dave e]

I use it a lot for quickly lining up to layout marks on my workpiece. I mark up the work piece with Dykem Blue and a surface gauge. Put the center finder in the chuck and push any handy edge against it, for example an edge of my vise or a scrap piece, while the machine is running at a few hundred RPM. This gets the point nice and concentric with the spindle bore. Then turn the machine off, and using a 5x magnifier just visually adjust my work under the point to line up with my layout marks. With the 5x magnification, even and old half-blind duffer like me can get within a few thousands in about 30 seconds or less.

 

[rake60]

The machine I operate for a paycheck is a highly sophisticated computer driven
CNC turning center.

I use a $21 Starrett wiggler held in a collet holder to "teach" the computer drives
the exact ZERO for the C axis during a set in many applications.

Sometimes the old technology is the best technology.

Rick