Laser edge finders

[FMESParticipant @fmes]

I have three tools for edge finding, the 'wobbler' is a nice easy one to use PROVIDED you accurately measure the stub to calculate the offset.

The laser doesn't have the offset problem but it can take a while to get it accuarely zeroed, and then of course it doesn't like bright workshop lights, But it IS very accurate if the polarising lens is used to fine down the beam.

My favorite for really accurate edge and spot finding is my quill mounted optical microscope from Titan Tools in the States which according to the certificate, is accurate to 0.0001"

Only problem with the Titan is that a small centre pop takes up over half the microscope viewfinder.

[Mark CParticipant @markc]

lofty,

I have an optical center finder (microscope) that is a cracking bit of kit but I do hate it when I bang my head on the down feed handles – you might imagine you would learn not too but I get that engrossed in the location and impending milling operations that I forget the handles are there and then they get me! Andrews instrument would be much better and probably easier to use but I hate to think what it cost (my microscope cost me £75 second hand which is probably a lot less than the probe on Andrews bit of kit).

Mark

[FMESParticipant @fmes]

Mark, which one do you have? mine is one of these **LINK** which sticks out quite a way from the machine.

I paid $150 for a tool sale item which turned out to be unused in its original box with all the paperwork, I think they retail for around $1300.

I was at the time more annoyed with having to pay the Mount Pleasant charges for import duties and VAT

[Mark CParticipant @markc]

Lofty,

Mine is an antique! I will try and remember what the makers mark is when I go into the shop tomorrow. I had to get a new reticule and objective as the old one had some damage. It also only has compensation in one plain rather than two like you have but other than that it is reasonably similar (as they all tend to be). The tube on mine is at 45 degrees which is why I bang my head, the Titan can be had with the tube much closer to perpendicular which I imagine is helpful.

Mark

[Mark CParticipant @markc]

Lofty,

It turns out I have a copy of the instructions for it and it is a "Centerscope" made by MSE (Machine Shop Equipment Ltd. London). I think it was probably made in the 50's or very early 60's but can't be certain. It is easy to use and set but I could do with the adaptor that allows you to turn the eye tube through 90 degrees for obstructed use.

Mark

[John Stevenson 1Participant @johnstevenson1]

I have tried all sorts over the years. Got a Haimer [ too big and bulky ]

Co-ax centre finder for holes [ even more bulkier ]

Toolmakers microscope, very, very expensive Russian one but too much of a pain to use. One advantage as coming from the Belarus area of Russia you don't need any background lighting.

4 or 5 sets of wigglers in various holders [ work Ok once you get used to them ]

But for years I have used a variation of what Phil has but simpler as mine is a 20mm bearing on a 6mm piece of silver steel. Have an accident and all it costs is another 2" of silver steel. I use a 20mm bearing as I'm all metric and 10mm is a nice figure.

However something I have found is if you use a 2RS rubber shielded bearing as you make the initial contact it slows by half due to the drag on the seals and that is the exact point.

I ran some checks once by finding the edge, zeroing the DRO and then checking with other methods.

Must admit I have bought two of the laser finders, both different and broken both of them. I regard them as gimmicks

[Jesse Hancock 1Participant @jessehancock1]

Well when I brake my laser I'll make a set of Dam Buster type lights and see if that works.

[Douglas JohnstonParticipant @douglasjohnston98463]

What I love about this site is the little gems of information that I never thought of. The length of steel and 20mm bearing for an edge finder is just brilliant- now off to my workshop to see if I have a suitable bearing.

Doug

[KWILParticipant @kwil]

My MILL DRO allows me to measure holes by any three points of contact and it does the calculation but I do like JS's 20mm bearing!!

[Anonymous]

Posted by Mark C on 27/02/2015 18:36:19:

Andrew,

That doesn't look like it came out of a lucky bag!

Mark

Sadly it didn't. I bought a Haimer Centro at the same time, so it left rather a big hole in my wallet. Although not as big a one as it might have been. It looked like it was possible to order direct from Haimer, so I filled in the website forms and waited. I got a terse note saying contact their UK distributor. The distributor converted the euro price one to one to pounds and then added UK VAT, which at that time was more than German VAT. I argued about exchange rates but the distributor said take it or leave it. So I made it clear I was leaving it.

Eventually I discovered the company in the link posted by Murray. Much more reasonable, as they took into account the pound/euro exchange rate.

Andrew

[martin perman 1Participant @martinperman1]

The method I use is the one I was taught as an apprentice, it involves a piece of 6 mm silver steel and a thin piece of paper on the side of the job, its cheap and accurate

Martin P

[Mark CParticipant @markc]

Andrew,

You can't expect the poor importer to do all that paperwork and handling for nothing. Was it R Turpin and Sons by any chance? There are a lot of his daughter companies in the UK I find.

Mark

[Bob Brown 1Participant @bobbrown1]

The method with a bearing seemed so good I made one, took all of 5mins, used a 6002 bearing as it was what I had 15mm id 32mm od. Wibbly wobbler may end up confined to the draw.

When I get a chance I'll check the accuracy with a bar in the mill (DRO on the mill) measure edge from both sides and see how close it is, and repeatability.

Bob

[CrocadillopigParticipant @crocadillopig]

Am I missing something ? Don't these methods rely on the concentricity of the chuck whereas the wobbler automatically works off the centre line of the spindle.

Russ

[martin perman 1Participant @martinperman1]

if the concentricity of the chuck is incorrect what centre does the wobbler use.

Martin P

[Michael GilliganParticipant @michaelgilligan61133]

Posted by martin perman on 28/02/2015 16:00:21:

if the concentricity of the chuck is incorrect what centre does the wobbler use.

.

Martin,

The wobbler [or a simple 'sticky pin'] is trued to the axis of rotation of the spindle.

This is somewhat similar to the way that lenses are centred on a 'wax chuck'.

MichaelG.

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