Laser edge finders

Hi,

Has anyone got experience of the laser edge finders as sold by Chronos and others?

I am not getting the accuracy I want with traditional edge finders and wondered what sort of results these give?

Thanks

Michael

I use one of these electronic ones that light up as they touch the surface, accurate enough for me.

I just use a wibbly wobbly one

Bob

Michael, What accuracy are trying to achieve? What type of edge finder have you been using?

One of the best and most accurate methods is to use a test bar and slip gauge, the test bar should preferably and for best accuracy fit directly in the machine spindle but being realistic for most ME use a suitable bar held in a collet will suffice. It is easiest if you use a bar that suits the machine scales, for example on an imperial machine a 1" bar used with a 1/2" (0.500") slip gauge will set your spindle precisely 1.00" from the edge of your work so move the table 1.00" and your spindle centre is over the edge.

Stating the obvious you use the slip between the work or vice jaw and the test bar and "feel" the position of the table until it is in the correct position then zero the scale.

This was the preferred method I used when setting work on a jig borer and we were more often than not working to a few tenths limit. One has to.accept that the machines most of us use will not hold the tolerances of a jig borer but nevertheless you will achieve the best setting but be aware if you clamp the table or quill there will be some movement. There are ways around this if need be by making an "allowance" for this movement.

Hope this helps John

Edited By JohnF on 26/02/2015 20:23:52

I have one but haven't used it much as yet. After marking out the block of the Sealion I'm building I then marked a datum in a corner to see how I measured up against the laser.

It's more accurate than I can see with a rule but of course the the overall accuracy of the part depends on how accurate I placed the datum in the first place. Also the dot defuses on any reflective surface so I'm thinking I might under coat with a light spray of grey primer and see how that goes.

They aren't cheap so I'm hoping it pays in accuracy.

Not a lot of help I guess but there may be other's who have found better ways of utilising them than me.

Properly used a decent edge finder will get you within .001" of your desired position and there are other more accurate methods which can in theory give better accuracies but using hobby machines rather than Swiss jig borers costing many thousands of pounds a .001 positional tolerance is good going.

I myself think laser edge finders are better left in the retailers, they look flash but I don't think good accuracy can be achieved with them but I am sure some will disagree.

Tony

Spot on Tony, my thoughts are the same, not that I'm against new technology but I think I would have serious doubts about the ability of these tools to give the best results against the old tried and tested methods, plus the alternatives are considerably less expensive.

Having said that I have no experience of using one so it will be interesting to here the views of others who have.

Edited By JohnF on 26/02/2015 21:05:38

Edited By JohnF on 26/02/2015 21:05:57

.

I have one from Machine DRO

I think it's a great bit of kit. (although unfortunately not cheap) I not only use it in the mill but they are also very handy for putting in the lathe tailstock when helping to center a scribed line or punch mark on work in a 4 jaw chuck.

I would advise getting one that has a polariser fitted as these can be rotated to adjust the size of the dot and and intensity. They also effect the best viewing angle.

I use one in this video **LINK** (about 11 mins in) This video is filmed on an iphone and the focus is not pukka. This seems to show the laser dot much, much larger than it is in reality to the eye.

In short. If anything were to happen to it. ( god forbid . ) I would replace it.!

Nick

Edited By Nick_G on 26/02/2015 21:30:46

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Michael,

There's a lot to be said for blue Rizla cigarette papers.

Approximately one thou' thick ... Damp a piece on your tongue & stick it [the paper ] to the job. Carefully run the rotating cutter towards the work,and when it whips the paper off the surface, you're about one thou' off.

MichaelG.

Edited By Michael Gilligan on 26/02/2015 21:41:19

The method I use in my milling machine for finding an edge seems (to me) to be more accurate then the one thou mentioned by Tony, but this thread has now got me wondering....

I put a 4.000mm diameter rod in the ER collet and tighten the nut with fingers only. My ER set is not super precision and with the speed at about 50RPM I can easily see it has run-out (maybe about 0.05mm). Using a light I view the gap between the rod and the edge of the job as I move the work closer. When the rod first touches the job the light passing through the gap varies as it rotates. By closing the gap very slowly Its possible to detect the point where the light (and the gap) is reduced to zero. Half the rod diameter then tells me the datum position. The light happens to be an IKEA Jansjo LED on a flexi mount so its easy to position at the opposite I am viewing from.

Because the collet is not dead tight, when the rod is in alternating contact it can 'give' slightly so it is not rubbing hard against the work. The rod I use is a precision ground and polished shaft out of a VCR motor and after two years use is unmarked. The 4.000 diameter I mentioned is real and reflects the manufacturing tolerance that some of the VCR components are made to.

This method seems to work for me but I would be interested any comment or criticism of it. I have no real feel for what level of accuracy I get but it seems very consistent.

Ian P

I am on my second one same as Jasons, had it years ago from J&L think £17 because what I wanted wasn't in stock. Don't spin them that's how I wrecked first one.

Electronic ok for conductive materials ie aluminiums, steel, brass. No good for plastics.

Plastics and anodised parts I have to use a Wigler hoping it wont mark the surface. Careful theres a lot of junk out there and all look the same.

Lasers total waste of time unless eying up a marked hole. No more accurate than putting a centre drill in or milling cutter within a hole. The laser spread is way to large and of course they have to be zeroed in. Mine I imported from California about 14 years ago when first came out, listened and watched the sales blurb new then about £67 never used since.
Also useless for clocking up vices I need accuracy that amounts to 1/4" at 100 yards. DTI best.

Ian sounds good I do similar at times. If know say 10 dia hole can just peck with 10 dia cutter lining it up, great way to do the rear fixing backing plates on to rear fixing chucks, works every time and is as accurate as your eye sight often better than electronic.

Michael

I was seduced by the idea of the Laser Edge Finder with Polariser years ago, but after buying it I realised that it still relied on the mark one eyeball for accuracy and is not really suitable for edge finding. If you are working to reasonable tolerances you would be better off with a wobbler pin or fag paper and use the laser for woodworking.

Russ

Edited By Crocadillopig on 26/02/2015 23:31:04

Thanks for all the input. Thinking about the problem I an having I think it it not the accuracy of the edge finding but a problem with my mill, a Warco Super Major. I think there is an issue with the quill and the column not being aligned, need to do some checks. Incidentally when I was tool making for a living the favourite way of edge finding was a 1/4" dowel pin in the drill chuck run at a moderate speed, touch with a marker pen and then offer up to the workpiece until the marker is just wiped away, move .125, good enough for most work. Jig boring and grinding used optical center finders.

Michael

Quite fancy one of these TBH. This is actually a relatively good price for them although it excludes VAT. You dial the work in towards the spindle until the gauge reads zero and at that point the spindle is exactly in line with the edge of the work. Works in all 3 axes, so pretty handy for CNC work. Knowing me I'd leave it in and turn the spindle to full speed or fast jog it into the vise......

I use a std edge finder. Once I'd finally figured out how to use it, I find it is deadly accurate and I can't imagine how you could visually position a laser spot to anything remotely like the same accuracy.

As for those wiggler wobbler things, I can't imagine anything more annoying. Who invented them?

Murray

[ As for those wiggler wobbler things, I can't imagine anything more annoying. Who invented them?

Murray ]

The beauty of the simple wobbler is that it normally comes with three types of sensor rods (cylindrical, round and point.) enabling it to be used on round bar diameters, block edges, and pick up centre dots.

Russ

I have one of those laser edge finders, and am still not convinced as to how accurate it is.

I also have a Haimer 3D taster which is absolutely superb but too bulky and awkward to use on a regular basis.

And I am always worrying that I might drop it or something.

On my Alexander Miller and the Boley (BCA) jig borer I use these most of the time.

The one on the right is my 'everyday' edge finder and is no more than a 1/2" OD ball race loctited to the end of the collet adapter for the Boley, the one I use on the Alexander is even simpler and is just a plain bar with a bearing on the end which is then held in the machine collet.

In use you simply run the job gently up to the bearing with the spindle running, and when the outer race stops spinning you know you have just touched the job with it. Then use the DRO in the usual way taking into account the 1/4" radius of the bearing.

It is such a simple tool to make and use, to the point I rarely need anything else for most jobs these days.

Phil

Edited By Phil P on 27/02/2015 14:52:26

Edited By Phil P on 27/02/2015 14:57:35

I like it.!

So easy, simple to use and cheap to make. I shall be 'constructing' as a very useful addition to the laser one I have.

Nick

Dooball Boost made a video about this. Why aye, bonnie lad.

Phil - if you can't make good use of the Heimer, perhaps you might consider selling me it at a knock down price?

Merry

Edited By Muzzer on 27/02/2015 16:03:02

Laser edge finders are over rated and not worth the money, if I hadn't had it bought for me I wouldn't have bothered. I use a dress makers pin in a holder, gets me within a thou or two of where I want to be. Keith.