centering / edge finder camera

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Mat

-- Myford Mat

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Think it was issues 121 & 122 of MEW (Dec / Feb 2006) Articles entitled 'Centrecam'

hth Mike

Andrew

I built the Hemingway microscope, partly as an excercise in building it. I find it extremely useful and very accurate, though havig to put it in the mill then change to the chuck can be a bit fiddly. It's extremely good for locating marks, but also unbeateble for centering the rotary table. I have a taper that drops in the centre hole and has an accurately centered mark on it - focus the microscope and move the table to bring the mark under the centre of the graticule and its aligned.

Most people seem to manage perfectly well without one, but I like mine and am pleased I built it.

Incidentally, the graticule is about the only difficult bit. You can use any old objective from a microscope and the eyepiece is a standard X10 job. The prism is essentially a front surface mirror. As I remember, the kit used to be a lot cheaper - its quite pricey now. You do need to get the thing anodised - I got mine done by a local company for about a tenner but had to wait a while.

For those not looking for quite the same degree of accuracy, the most useful thing I've picked up this year is one of the new laser edge and centre finders. Roughly one inch and a half long by half inch dia barrel, which contains a couple of button batteries, with a small additional spigot for chuck/collet mounting at one end. The opposite end has a pin hole aperture for a 'safe' red laser. Mount in chuck of mill, for example, twist micro switch on barrel side, centre resulting red dot on work below and it's aligned. No more 'take away half the diameter of the number you first thought of' etc....! Switch laser for tool and off you go.

There's an optional add-on, a Polaroid filter cap can be slipped over the business end and be used to change the diameter of the marker spot. I find initial rough setting of 4-jaw lathe work is much easier, hold laser in tailstock chuck, and move work until work ref point and laser dot coincide. The other way round, laser in 3-jaw SC chuck in headstock switch on and locate ref on work clamped to cross-slide table, or even check tailstock set-over etc etc etc.

It's an extremely versatile bit of kit and I seem to use it every time I go in the workshop. I'm sure I'll find lots more applications as time goes on.

ISTR it cost about £30-£40, with an additional £25? for the filter. Highly recommended. --

Chris Edwards (in deepest Dorset) "....there *must* be an easier way!"

Could you please tell the brand and where to buy this laser?

I got mine from here

-- gn3d

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A great idea! I'll buy a laser pointer next time I see one.

Nick

The laser edge finder is from my experience a waste of money. May be ok for the 4 jaw idea, but hopeless on the mill, especially without the Polaroid filter, and nowhere near as accurate or repeatable as the good 'ole wobbler Bob

Ansatt,

It's badged as a US manufactured item, but I think I got mine from Chronos - see

Chris Edwards (in deepest Dorset) "....there *must* be an easier way!"

The one I bought a year ago was from the American site and pre all the modifications as stated on the recent web page. Maybe its better now? Bob