# Center finder suggestions for a rookie?



## heliyardsale (Mar 17, 2013)

Looking for advice, something I can use with my Bridgeport and Sherline mill. For big holes I'm guessing a dial gauge on some type of holder that goes in the spindle? How do the Starrett wiggler sets work? How large of a bore can they center?


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## DMS (Mar 17, 2013)

I have just used a DTI in a collet. Center the spindle over the hole by eye, then bring the indicator tip into contact. Rotate the spindle (by hand!!!!), and adjust X/Y until there is no variation. It can get a bit cumbersome reading the dial when it's facing backwards; some people use a small mirror. For larger holes you could make a longer arm to hold the DTI.

Of course, if you have money to burn, or you do this sort of thing enough to justify the price, you could buy a co-axial indicator.

http://www1.mscdirect.com/cgi/NNSRI...re=ItemDetail-_-ResultListing-_-SearchResults


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## ScrapMetal (Mar 17, 2013)

There are a couple of other tools for doing the job as well.  A couple of them are pretty easy to fabricate yourself.   There is the Indicol holder which attaches to the spindle without having to remove your tooling first ...




as well as a couple different designs of a "zero-set".  Here's one made by one of our members - http://www.hobby-machinist.com/showthread.php/9655-Zero-It-Indicator-Holder-Finished




You can also look up a Noga-flex.  It's a simple articulated arm that can mount in the spindle using a collet...




Lots of options.

-Ron


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## darkzero (Mar 17, 2013)

I ditched my indicol & replaced it with one of those Noga NF1018 holders, couldn't be happier. But like Ron mentioned, the indicol allows you to hold an indicator without having to remove the cutting tool from the spindle.

Another option is to use a co-ax indicator. Some like em, some hate em, but they can be ran with the spindle under power & would account for any spindle runout if it was an issue. 

Blakes will cost you but there are less expensive imports. I only used an import one a few times a while ago so I'm not sure how they compare to a Blake that I have now. But for us home shop machinists I suspect it'll do just fine. 

Fowler & SPI also offer them.


If the bore is large enough, you could also just use a typical edge finder to locate center or a wiggler as you asked about.


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## heliyardsale (Mar 18, 2013)

Just ordered the Noga 1018! Thanks for the great advice everyone.


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## Splat (Mar 26, 2013)

Love my Nogaflex arm!


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