# laser edge finders



## Icarus (Dec 29, 2009)

Anyone ever used one of these laser edge finders? Are they any good?


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## bluwolf (Dec 29, 2009)

I have one. Here's the homepage for the company that makes it.

http://www.lasercenteredgefinder.com/

I only glanced at the LMS page that you posted. But it seems that the polarizing lense is an accessory, I could be wrong. On the company's page all the lasers come with the polarizing attachment. It really does help. It can make the dot very small. The compromise is that it also get fainter.

I wouldn't use it to build space shuttle parts. But the stuff I make isn't either. It really is great for "quick and dirty" set ups that only need to be within a couple of thousandths.

You have to take your time dialing it in when you first get it. Like anything else, garbage in, garbage out. If you don't spend the time in the beginning it will never be of any real use.

Mike


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## PhotonFanatic (Dec 29, 2009)

Icarus said:


> Anyone ever used one of these laser edge finders? Are they any good?



Does this question mean that you have a lathe? :devil:

I'm sure that the real machinists, such as those on Practical Machinist, will say that there are better and more accurate edge finders that can be used, but if you aren't making parts for NASA, then that edge finder is probably OK.


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## gadget_lover (Dec 29, 2009)

I do not like shining lasers at shiny metal surfaces that I'm staring at intensely.

The traditional edge finders work fine, and they are much cheaper and more accurate. I find the dot too big to accurately find the center.

If I wanted to align a quill with something a few feet away, I might consider lasers.

Daniel


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## darkzero (Dec 29, 2009)

PhotonFanatic said:


> Does this question mean that you have a lathe? :devil:


 
Judging by his mods in the past two years or so, I think Freddy must have a mill & a lathe, or access to them.


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## PhotonFanatic (Dec 30, 2009)

Yeah, good point, but I haven't seen him mentioning his lathe. 

We need pics, of course. :devil:


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## Icarus (Dec 30, 2009)

PhotonFanatic said:


> Does this question mean that you have a lathe? :devil:


Would need a magic staff to make things like this without a lathe and a mill… :nana:


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## precisionworks (Dec 30, 2009)

Nice work, Icarus 

IMO, it's really hard to beat the mechanical offset type edge finder, like those made by Starrett or Hermann Schmidt

https://www.hschmidt.com/productcart/pc/viewPrd.asp?idcategory=8&idproduct=148

http://www.starrett.com/pages/1512_t_and_r_edge_finder.cfm

The Starrett is about $25, the Schmidt is $45. I would cry if the Schmidt got dropped, but have done far worse to the Starrett. 

(Starrett will also email newletters if you want. Here's an archived listing: http://www.starrett.com/pages/1523_last_word_archive.cfm)


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## Icarus (Dec 30, 2009)

PhotonFanatic said:


> Yeah, good point, but I haven't seen him mentioning his lathe.
> 
> We need pics, of course. :devil:


 
Lathe: Optimum D280 X 700 G
Milling machine: Optimum BF20 Vario

 Now, where is yours... :thinking:


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## wquiles (Dec 30, 2009)

Icarus said:


> Anyone ever used one of these laser edge finders? Are they any good?



I actually have that same one, and it has worked great for me for the last 2 years or so, but I use it to locate/align the drill to a center mark on the piece, not for finding the edge of the piece. To me this laser finder is easy to use, fast, and very accurate for the work I have done so far. 

I should also add that I have never used the mechanical edge finder, so I can't compare the two of them.


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## PhotonFanatic (Dec 30, 2009)

Icarus said:


> Lathe: Optimum D280 X 700 G
> Milling machine: Optimum BF20 Vario
> 
> Now, where is yours... :thinking:



I'm sure I've posted this before, but it is here. It can do some milling as well, since the headstock moves up and down.


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## precisionworks (Dec 30, 2009)

Will, since you don't use a laser to find edge, nor a mechanical finder, what do you use? I've used a wiggler on occasion, when the mechanical finder couldn't reach the edge of a large diameter part, but don't know of other edge finding methods.


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## darkzero (Dec 31, 2009)

precisionworks said:


> Will, since you don't use a laser to find edge, nor a mechanical finder, what do you use? I've used a wiggler on occasion, when the mechanical finder couldn't reach the edge of a large diameter part, but don't know of other edge finding methods.


 
How about an electronic edge finder, like the kind that lights up? I never used one, do they require the spindle to spin when finding the edge? Or even an indicator but a conventional edge finder would be easier than this.


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## precisionworks (Dec 31, 2009)

> electronic edge finder, like the kind that lights up


You are right, I forgot about that :sigh:



> Or even an indicator


I don't believe there's any fast or easy way to center the tip of a dial test indicator so that the tip (ball contact) is coaxial with spindle dead center.

There is the optical centering scope that can also be used to find edge. One of those will eventually pop up on eBay & get snagged, but that hasn't happened yet. They are rated +/- .0001"







Another tool (not used by itself) is the magnetic edge finder, also good for +/- .0001"








That model is made by Flexbar. The one on the left (above) is used by touching off both sides of the slot, where the one on the right is used by picking up center of the hole in the tool.


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## wquiles (Dec 31, 2009)

precisionworks said:


> Will, since you don't use a laser to find edge, nor a mechanical finder, what do you use? I've used a wiggler on occasion, when the mechanical finder couldn't reach the edge of a large diameter part, but don't know of other edge finding methods.



Basically, I find the edge the same way I do it on the lathe - I just bring the cutter I will be using towards the edge I want to start cutting, and turn the spindle by hand until it barely touches - that is my zero. Now that I have the VFD and I can have the spindle run at 10-15 RPM's, it is even easier as I can just hear as the cutter is barely touching the part. 

Am I the only one that finds the edge this way?


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## precisionworks (Dec 31, 2009)

> bring the cutter I will be using towards the edge I want to start cutting, and turn the spindle by hand until it barely touches - that is my zero.



That is a common method in Third World countries, but it isn't often done by anyone who can afford a $20 edge finder 

Even the low cost Starrett will find the edge to +/- .0005" or better. If the edge is approached slowly, it's easy to repeat .0002". Not quite as good as the really fancy stuff, but close enough for Space Shuttle parts 

The problem with touching a sharp tool to the part edge is that the tool has to cut just a little to make the faint noise indicating contact. Maybe it cuts .0001", but that could just as easily be .0010". On top of that, if the part needs machining on more than one face, resetting the part adds additional error. The part has to be touched (cut) by exactly the same amount as it was cut the first time. To do that is next to impossible.


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## wquiles (Dec 31, 2009)

precisionworks said:


> That is a common method in Third World countries, but it isn't often done by anyone who can afford a $20 edge finder
> 
> Even the low cost Starrett will find the edge to +/- .0005" or better. If the edge is approached slowly, it's easy to repeat .0002". Not quite as good as the really fancy stuff, but close enough for Space Shuttle parts
> 
> The problem with touching a sharp tool to the part edge is that the tool has to cut just a little to make the faint noise indicating contact. Maybe it cuts .0001", but that could just as easily be .0010". On top of that, if the part needs machining on more than one face, resetting the part adds additional error. The part has to be touched (cut) by exactly the same amount as it was cut the first time. To do that is next to impossible.



Once I get the DRO installed then I don't have to worry about the inaccurate dials on my mill, but until then I am missing something here. 

The mechanical edge finders that I have seen are typically 1/2" dia. Say I use that and I find the edge to within 0.0001". Then without moving anything, I remove the edge finder and install my 1" cutter. Now I am 0.500" too deep from the real edge, so I now have to move the table away "exactly" 0.500" in order to be dead-on the edge again, right? 

I know that the dials on my mill are "not" that good/accurate, so as a newbie, it looks like finding the edge with a mechanical edge finder would work perfectly "only if" the diameter of the edge finder would be exactly the diameter of the cutting tool you want to use. Otherwise you would need a DRO to accurately (say about 0.0002" for glass scales) move the table back to the "edge" to be cut.

I know I am missing something, and this is exactly why I have yet to use a mechanical edge finder. Some help please


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## Atlascycle (Dec 31, 2009)

Typically an edge finder is used to align the center line of the spindle to the edge of the part. You first touch off of the edge of your part with the edge finder and then move half of the diameter of the edge finder to center the spindle and then zero the table dials, if you have a dro installed you can sometimes enter the offset into the dro instead of having to move over and then re-zero. Then you move to acount for the diameter of the cutter, if you are not trying to put any holes on location and instead are trying to square the edge then the edge finder is not really nessecary, you can just touch off with your cutter and then make a light cut, zero the dials, measure and then go from there. YMMV

Jason


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## gadget_lover (Dec 31, 2009)

The idea of a mechanical edge finder is to find the exact edge in relation to the center of the spindle. It's then up to the operator to know the exact diameter of his tools. Fresh tools are supposed to be the stated diameter. Sharpened or used tooling... well, who knows?

OTOH... there is an old trick for finding the edge with a running tool. Put a Zigzag cigarette paper against the edge you will be working on. The paper is a fairly consistent thickness. When you bite into the paper it will be whipped out of the way.

Knowing the true location of the edge will make the DRO even more usable.

Daniel


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## FlaCracker (Dec 31, 2009)

darkzero said:


> How about an electronic edge finder, like the kind that lights up? I never used one, do they require the spindle to spin when finding the edge? Or even an indicator but a conventional edge finder would be easier than this.



I've used this one for some time now and it does a good job. No need to spin the spindle. The only drawback is the workpiece (as well as the vise and jaws) have to be conductive.


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## precisionworks (Dec 31, 2009)

> Typically an edge finder is used to align the center line of the spindle to the edge of the part. You first touch off of the edge of your part with the edge finder and then move half of the diameter of the edge finder to center the spindle and then zero the table dials, if you have a dro installed you can sometimes enter the offset into the dro instead of having to move over and then re-zero. Then you move to acount for the diameter of the cutter, if you are not trying to put any holes on location and instead are trying to square the edge then the edge finder is not really nessecary, you can just touch off with your cutter and then make a light cut, zero the dials, measure and then go from there. YMMV
> 
> Jason





> The idea of a mechanical edge finder is to find the exact edge in relation to the center of the spindle. It's then up to the operator to know the exact diameter of his tools. Fresh tools are supposed to be the stated diameter. Sharpened or used tooling... well, who knows?
> 
> Daniel



That pretty much sums it up. Machinists were using mechanical edge finders for decades before the DRO was invented. DRO's are nice, as they make back lash a non-issue, but a dial can still be zeroed with an edge finder.


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## gadget_lover (Dec 31, 2009)

wquiles said:


> I know that the dials on my mill are "not" that good/accurate,



They should be very accurate, unless your leadscrew or leadscrew nuts are badly worn. The turn of the handle is in a direct relationship to the movement of the nut on the screw. You do have to take out the backlash, but that's a common problem with most things that have screws and nuts for adjustments.

Daniel


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## precisionworks (Dec 31, 2009)

> You do have to take out the backlash, but that's a common problem with most things that have screws and nuts


I worked at a shop with a Bpt mill that was beyond worn out ... about *half a turn* in both the X & Y dials 

Still it was no problem to find an accurate edge location. Approach the edge with the finder until the disc settles down, slow the approach until the disc kicks over, zero the dial. As long as the part is approached from the same direction each time, the zero is consistent.


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## darkzero (Dec 31, 2009)

precisionworks said:


> I worked at a shop with a Bpt mill that was beyond worn out.


 
At shop class I even used the oldeset & abused BP. I'm sure the students have put it through hell over the years. It has crazy backlash too but had no problem finding an edge/center pretty well. Of course it wasn't exact but it was good enough. The BPs are equipped with Mitu DROs but starting off I choose to use dials only to learn. All the old lathes are pretty accurate even though some have very worn gibs. Even my HF8x14 cuts pretty accurate (after adjustments) & the dials are all I use for the cross slide & compound. Many machinists don't have DROs (or even like them) & can still turn good parts. My buddy's neighbor is a retired machinist & doesn't use anything digital, he still does big jobs for the movie industry. My instructor won't use digital equipment either. Will's mill surely isn't junk, I can't imagine his dials are that unaccurate.


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## wquiles (Dec 31, 2009)

As you guys can imagine I have used my mill quite a bit since I got it. My dials are set at 0.120" per revolution, which is a royal pain in the butt to use, so I am constantly having to reset every 0.100", which gets old quickly and of course introduces errors. And I am not talking about back-slash as that is a non-issue with me as I know how to work around that. 

When I am done with my cut on the mill, I am never quite close "enough" to the depth or length I was shooting for. A few mills here and there might not seem like a lot, but to me it is completely unacceptable when I am used to at least 0.001" or better on my lathe. Maybe I am way too spoiled with the 0.0002" accuracy on my lathe's DRO, but I am expecting better accuracy on my mill. 

Either way, that is why I say that my dials are not accurate enough. It will be great once I get the DRO installed/running on the mill so that I don't have to ever use the darn dials again.


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## gadget_lover (Dec 31, 2009)

.120 per revolution? That sucks. Mine are .200. I like that much better than then .100 on my micro mill.

OTOH, .120 per rev gives finer control. You'll love the DRO. 

Daniel


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## dom (Jan 2, 2010)

wquiles Am I the only one that finds the edge this way? :eek:[/QUOTE said:


> Used to use that method years ago -but used a cigarette paper as a guide.
> When it was chopped by the cutter you were within 0.001"
> 
> Spoiled now with digitizing probe on the CNCs but when on the manual mills
> ...


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## wquiles (Jan 2, 2010)

dom said:


> Used to use that method years ago -but used a cigarette paper as a guide.
> When it was chopped by the cutter you were within 0.001"
> 
> Spoiled now with digitizing probe on the CNCs but when on the manual mills
> ...



That is a very cool gadget indeed :thumbsup:


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## precisionworks (Jan 2, 2010)

> it's slow calculating half of the wobblies to get center.



Surely you are kidding 

The "small end" on either the Starrett 827A or the 827B is 0.200". Approach the edge and stop as soon as the disc kicks over. Then zero the dial, understanding that spindle centerline will be 0.100" from edge. 

Install whatever tool is needed, whether it's an end mill of 0.250" diameter or a face mill of 2.500" diameter - or anything else you want to use. Approach the work from the same direction used with the finder and when the dial reads zero, spindle centerline (tool centerline) will be 0.100" from the edge of the work.












It's hard to imagine anything any more simple. Even with a DRO, some method is required to find edge. Lasers & electronic indicators are OK, but nothing today, short of a CNC touch probe, is as precise as "the wobble"


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## gadget_lover (Jan 2, 2010)

It just occured to me that your choice of edge finder can easily be matched to the dials on your mill. My micro mill has .050 per revolution of the hand wheel. A .100 diameter edge finder ( do they make them?) would mean no calculations. Wait for the kick, zero the dial, back it off 1 turn and you have the center on edge.

A quick search showed that most edge finders are .200 diameter (because we can all subtract .100) but some are other sizes. SInce .100 per handwheel revolutoin (or some multiple) is so common, they should work fine for everyone.

Daniel


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## darkzero (Jan 2, 2010)

In shop class .200 dia are the most common & is what I always grabbed for. Some have a pointed end as pictured above. What is the intended purpose for the pointed ones. Would they still be used by subtracting the radius & how? Or are they just used for finding center for a hole?


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## gadget_lover (Jan 2, 2010)

Thanks for asking the question. I realized that I was not quite sure. It looks like you use it like I use a wiggler.

From http://www.starrett.com/pages/1512_t_and_r_edge_finder.cfm




> How To Use an Edge Finder
> Edge finders are easy to use. First, secure them into a collet or chuck. Then, traverse the worktable to obtain contact between the rotating edge finder and the work.
> 
> Upon contact, the contact diameter will shift to concentric position relative to the body -- with very slight additional table adjustment, it will move off center with a decided wobble (see right).
> ...


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## precisionworks (Jan 2, 2010)

> What is the intended purpose for the pointed ones.


As Daniel's link mentioned, the pointed end can pick up a scribed mark or a center punched divot. Starrett mentions that the point should just barely touch the work ... and they do mean JUST barely 

Both ends of the tool have a tiny spring that connects the end to the body. Using the normal (cylinder) end is not a problem, as no pressure is applied to the tip of the cylinder. Using the pointed end means that some pressure will be applied to the point, and more than a few grams can cause the point to stall while the tool body continues to spin. The spring can't tolerate this & will sometimes detach from the body, point, or both ... and those little parts are hard to find when then land in a pile of metal chips 

The pointed end is useful for locating scribed lines & punch marks, as long as a light & delicate touch is used.


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## darkzero (Jan 3, 2010)

Cool, thanks fellas. That would have been quicker to do for the name plate on the c-clamp. Can't wait to try. 

Wiggler I have never used. How is that used, another link? I think I kind of get the idea but what about the longer angled wiggler?


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## gadget_lover (Jan 3, 2010)

The wiggler uses the same basic principle as the edge finder. When rotating, it's easy to push it on center and feel when it's off. 

I use the pointy wiggler to find punch marks. 

Run the maching at a few hundred RPM.
Run something against the side of the tip till it's running true.
Lower it to the punch mark. If it's off center you will see the point deflect as it goes into the punch. I use a magnifier. When I can't see it move in X or Y plane. it's as accurate as the punch.

I use the long angled wiggler to find the center of holes without a DRO. 

Chuck the wiggler. Center the hole by eye. Bring the side of the wiggler probe into contact with the inside edge of the hole nearest you. Rotate the spindle 180 degrees. If it hits the far side, rotate it back. Move the table 1/2 of the clearance. After 3 or 4 tries you are very close. Lock the Y and do side to side the same way. When you are done you should be able to rotate the spindle 360 degrees and have the probe touching the side the whole time.

Daniel


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## precisionworks (Jan 3, 2010)

> Wiggler I have never used. How is that used, another link?


From Little Machine Shop:

http://www.youtube.com/watch?v=RhtBdar4iVg

Note that a pencil is used to true the wiggler point. Real Machinists use their thumb nail, which is why most Real Machinists have a bandage on said thumb nail :mecry:

The pencil really is the better way to do this.

The wiggler with the double ball attachment is handy for finding edge of a large diameter round part. The Starrett 827 finder does not work well on anything but a flat edge. The wiggler ball works better as the spindle & ball can be moved up & down while the work is brought into contact with the ball. As soon as contact is made, the ball deflects & wobbles. It usually takes a couple of tries to find edge with any precision on a round, but the double ball attachment makes it fairly fast.

Starret wiggler kits (Model S828HZ) are around $25 new, often listed for $10-$15 on eBay.

http://www.starrett.com/download/324_p409_412.pdf


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## StrikerDown (Jan 4, 2010)

If you use one of the double end edge finders be carefull not to insert it too far into the collet! The inside end likes to get off center inside the collet and good luck getting it out!


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## wquiles (Jan 4, 2010)

Well, I am biting the bullet. I ordered a Starrett Edge Finder - I will learn to use it even if it kills me !!!


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## gadget_lover (Jan 4, 2010)

wquiles said:


> Well, I am biting the bullet. I ordered a Starrett Edge Finder - I will learn to use it even if it kills me !!!



The only way that happens is if you run it up to 20K rpm and whack the end with a steel rule. The resulting 100 MPH .200 ( +- .00001) bullet just may kill you. 

But seriously, they work really well.

Daniel


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## precisionworks (Jan 5, 2010)

> I ordered a Starrett Edge Finder - I will learn to use it even if it kills me !!!



Once you get used to the 0.100" offset, which won't take long, you'll wonder how you ever lived without it.

NOTE 1: 1000 rpm is about as fast as these like to be spun. Any speed from a few hundred rpm up to about 1000 rpm is good. 

NOTE 2: Be sure to offset the the bottom of the finder (the short end with the .200" diameter post). Any offset will work, something around 1/8" to 3/16" gives a good wobble. This can be done with the spindle stopped, or can just as easily be done with the spindle at speed - touch the post as the finder rotates so you get the wobble you want. 

More wobble is better, as it is easier to see, and lets you know as you are approaching the edge. When the finder is just at the edge of the part, the upper & lower finder body is concentric, then slowly advance the feed dial until the lower part JUST moves to one side. The instant that happens will indicate that the table has been advanced about .0005" too far.

For most every job, half a tenth is close enough. If not, zero the dial (or DRO) dial the table back, offset the post again, and approach the part again, but go more slowly as the two parts come into alignment. 

Starrett says it this way ... _Upon contact, the contact diameter will shift to concentric position relative to the body -- with very slight additional table adjustment, it will move off center with a decided wobble (see right). 

When the contact diameter aligns with the shank, the center of the finder is exactly one-half the diameter of the contact from the work edge. After setting the appropriate machine axis, accurate location relative to the workpiece edge is assured.

_It will be one of the most used pieces of mill tooling :thumbsup:


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## StrikerDown (Jan 6, 2010)

Here is a short tutorial:

http://www.youtube.com/watch?v=f0od-cp_9dg


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