Locating the centre of a hole tool desired

[Ned Ludd]

Hi Loply,
I agree absolutely, if the hole is big enough to get a normal edge finder in. An edge finder and the halving button on my mill's DRO is the method of choice for the majority of my centring needs. The laser circle one was developed for such things as broken bolt centring, prior to drilling. As to cost, they can be built for price of a small laser pointer(<=£2 the last time I checked) and few pence worth of metal and plastic. Oh, and a few hours in the shop but that does not count, does it?
Ned

[Jonny]

Theyve got a monstrously wide laser beam those cheap and nasty ones, need at least 1/10 the size.
Used to use it to annoy the dog.

Just so happens got another expensive part dont want to replace and needs absolute to thou no runout 3 dimensionally picking up from an 8mm hole. Any runout when undercutting this 8mm hole will render scrap. Guess what i will be using again, i'll tell you an 8mm dia milling cutter.
I do have all manner and other means of finding the centre with lasers, wigglers, dti's and numerous electric edge finders.

Eye sights more than good enough to centre up in a busted bolt hole, done loads never failed even in a pillar drill.
Even drilled out a 1.5mm hardened shear pin in to a blind aluminium hole, cant beat number one eye ball.

[75Plus]

Typical sizes for me are from 25 to 150mm.

 

Joe

[efrench]

An appropriately sized ball bearing will also work well for centering on a hole.

[lockstocknbarrel]

Hi Picclock,

Try this on eBay.
$59.99 USD thats a good buy.
http://www.ebay.com/itm/Co-Axial-Centering-Indicator-CO-AX-250-Axis-Offset-/390533479727?pt=LH_DefaultDomain_0&hash=item5aed9bfd2f

How to on youtube.....................................

Regards Beagles