How good/bad/useful are laser pointers for Zeroing?

A friend of mine has a cool red laser-pointer throwing crosshairs on his SB table.

Seems these cool gadgets are not particularly expensive - $40?
How truly useful are they?

Most comment on the subject I've found (in Archives) dates back five years
so I'm wondering what the state of art...of thinking is.. re. these wonderful gadgets.. today in 2011
now you guys have had a chance to mess around with them

Are they as wonderful as they look?
Does any particular make/model stand head and shoulders above the crowd?
How to get power to them? (batteries inside the unit?)

you have to use an offset to use one and the beams are pretty big. if you just want to use it to find an edge it is ok. but I use a laser to find a corer and show me where a cut would be to relocate material when needed.
http://www.lasercenteredgefinder.com/main.html

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Originally Posted by knight_toolworks

http://www.lasercenteredgefinder.com/main.html

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That's a nice-lookin unit, but not cheap
(you get what you pay for?) :D

Thanks for the link -it's a start!

I just went out and bought a cheap barrel type (like a pen) laser pointer for a few bucks at big lots or some place like that and chuck it up in my 1/2 collet.

But even that was a PITA to bother with so i don't use it much. It just shoots a dot not crosshairs.

I don't use it a lot anymore but if you use a lot of jigs or don't use a jig to locate material it is handy. it's handy to check to see if the material is square to the machine too.

You can buy a small laser for under $5.00.

As others have said - the beam gets to be too big to be useful. The other ones that chuck up into the router are okay - but may require a collet change.

I like a nice sharp v-bit - or better yet - the shank of a broken carbide or HSS tool that you sharpen to a nice sharp point.

-B

I use a laser regularly as an installation tool in the field. After checking out what was available and comparing features I laid out sever hundred dollars for one from Pacific Laser. I chose it because it is accurate and true, as opposed to all available at the big box stores. You can't get a good laser for "a few bucks". The small cheap ones are good for presentation pointers and that's about it.

David,

Below is a link to the way I set mine up over a year ago. I had a job where I needed to cut out some pre-printed plastic signage - and I needed to be able to get within .010 to find the corner and align the sheet - before cutting. This setup worked great at the time, but in hind sight, I would do one thing different.

This setup was mounted to the router. Since the router creates a lot of vibration - over time the pointer would vibrate enough to create an error on zeroing. I intend on changing it some time using a bracket mounted to the same aluminum extrusion that the router is mounted onto. It will add a little more structure to my setup, but that area seems to minimize the vibration.

http://www.talkshopbot.com/forum/showthread.php?t=8419

Above-mentioned friend sent me this link..

http://www.dealextreme.com/p/red-las...-16mm-5mw-5942
(turns out it's the same unit mentioned in Scott N's link, above..)

..says this is the one he got... for $3.95 ?? :eek:
and apparently you can focus the thing too!


I'm thinking that -for $4- this unit can make a start even if it dies in six months
then buy something a lot better, having gained some experience with it..

David,

That is the one I bought and it works great.

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Originally Posted by sailfl

That is the one I bought -and it works great.

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I stopped thru at my friend's workshop while on the way to work this morning
and took a few quick photos. See attachments below.

He's been using this $4 laser for a few months now
solidly mounted on a lil right-angle bracket on the Y-car
(see the second pic) -and it seems to be working just fine.

Geez, at $4 a pop, you order 3 of them - one to use right away,
and keep the other two for when the first one dies!

He tells me they came in from China direct
with China stamps on the package he picked up from the local Post Office
and shipping was free! Beat that. :cool:

I have mine set and installed on the machine as three lasers - vertical line, horizontal line and the cross hair. Idea was to help line up the corner with the horizontal and vertical lines and use the cross hair to align with a feature.

I still have to set up the offsets to get the scenario complete, but the $4 lasers have a twist focus adjust, but seem to spin with the machines movement. I may have to replace the internal spring with a stronger one to get them to hold properly (or a dab of hot melt to allow for future adjustments). The location of the cross hair intersection stays true from the initial experiments, but the 'lines' rotate (+ to X and anywhere in between).

I mounted mine to the side of the gantry with a scrap of HDPE or Delrin. Wired in a nice control project box with an on/off switch and some AAA batteries.

I spent the money on a laser center/edge finder unit with the cross hair, from SDA. it isn't cheap, but the accuracy is impressive. the polarizer on it allows you to cut the dot size down to a few thousandths, way better than my $8 Chinese made laser. The first unit I received did not focus correctly, but they replaced it in 3 days with one that is perfect. It paid for itself on the first job where I needed to get an exact re-alignment with a partially cut part.

You can focus the laser shown at http://www.dealextreme.com/p/red-las...-16mm-5mw-5942; however, be aware that the focus is achieved by rotating the front lens (light output) part of the barrel. This rotates the crosshairs as well. It makes mounting it a bit awkward. Still, as a relatively crude offset zeroing device it's not bad. It's probably good to + 0.020" and it provides a warm feeling that things will be cut properly.
The focus causes one other issue - where to fix the focus. I focus mine on the bed, not on the top of the material. After a few resurfacings of the bed, I need to refocus and compute a new offset.
I think I'm going to modify mine to have a switchable intensity. At high intensity, the human eye gets saturated and it is almost impossible to determine the exact location of the beam. At low intensity, the visible part of the crosshair does not extend more than a couple of inches.
Paul Z

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Originally Posted by paul_z

You can focus the laser shown at http://www.dealextreme.com/p/red-las...-16mm-5mw-5942;
however, be aware that the focus is achieved by rotating the front lens (light output) part of the barrel.

This rotates the crosshairs as well. It makes mounting it a bit awkward.
Still, as a relatively crude offset zeroing device it's not bad.
It's probably good to + 0.020" and it provides a warm feeling that things will be cut properly.

The focus causes one other issue - where to fix the focus.
I focus mine on the bed, not on the top of the material.
After a few resurfacings of the bed, I need to refocus and compute a new offset.

I think I'm going to modify mine to have a switchable intensity.
At high intensity, the human eye gets saturated and it is almost impossible to determine the exact location of the beam.
At low intensity, the visible part of the crosshair does not extend more than a couple of inches.

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Will bear all that in mind! ;)

The Boss has ordered 6 of them! ..some with points, some with crosshairs.
We'll be using them one at a time of course...
Multiples were ordered because Barbados is a long way away from China,
and keeping spares in stock is a good idea
plus.. at $4 each, this approach is within anyone's financial means.

Accurate to 20 thou is all we need, really.
It's just to help get close to where the action will be, in less time
and besides, it's cool as hell -and impresses visitors to our workshop.

My post somehow deleted an underline. It was supposed to read + or - 0.020". Still, it's very useful and I do agree that it impresses visitors.

Paul Z

my boss bought a lazer cross hair for a drill press at a wood working show we mounted it to the spindle and aimed it it works brilliantly
we had to use a different band clamp but it works great we use it because we do a lot of different projects

http://www.woodcraft.com/Product/208...ttachment.aspx

that looks like it would fall apart with so much vibration.

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Originally Posted by Coleman Becker

my boss bought a lazer cross hair for a drill press at a wood working show
we mounted it to the spindle and aimed it it works brilliantly
we had to use a different band clamp but it works great
we use it because we do a lot of different projects

http://www.woodcraft.com/Product/208...ttachment.aspx

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I'm assuming the two little red things out on the corners -are two lasers?
Why two? -helpful to have two?


How long has this $40 item been in use? I'm assessing long-term durability..

I agree with the other poster that, mounted directly to router/spindle
it must suffer some considerable vibration...

With two lasers, you don't have to use an offset. One laser produces the x line and the other produces the y line. Geometrically speaking, one laser fan beam is in the x=0 plane and the other is in the y=0 plane. The intersection of the beams is x=0, y=0 for all z values.
You can't do this with a single crosshair laser because it would have to be located where the router/spindle is or canted at an angle. If it is canted, then it would work for only one height below the carriage. That's why most crosshair users make sure the beam is vertical and they compute an offset.
BTW an easy way to compute the offset is to peck the spoil board with a v bit, and set x and y to zero. Make sure that the crosshair is dead on vertical. Then move the carriage so the crosshair is dead center over the peck point. The offset is the current x,y. The offset does not vary with z.
Paul Z

How wide is the beam?

g.

The crosshair pattern is about 12" wide when the laser is 12" away. Beam width at this distance seems to be about 0.015".

The beam is very intense at 12" and easily seen on wood with the shop lights on (my shop lights are very bright). If anything, the laser is too bright for accurate alignment (which is easily corrected by using a resistor in series).

The line lasers have the same angle and beam width.

(I bought a few of each about two years ago and I can't find where I put the spares!)

Paul Z

it has been there for about 6 months and i have only had to change the battery. i dont know exactly what the tolerances is but it is a lot better than a v-bit in the spindle eying your offset

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Originally Posted by Coleman Becker

it has been there for about 6 months and i have only had to change the battery.

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Speaking of battery life, I just noticed that we installed our laser July 24th. 2011
-and we're still using the first set of CopperTop AA batteries, nearly a year later
with no obvious signs of battery failure.


Around that same time we also installed a small Genius keypad on a 10+ ft. USB cable
for easier finding our X/Y zero point
and together with the laser, this combo has made it a lot easier!
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If you use a crosshair laser, mount it on the router/spindle holder and make sure it points straight down. If it is not vertical on both directions, you will get different results as the Z axis goes up and down. Using the Z travel is a good way to verify that the laser is pointing straight down.

Using a V bit, cut a very slight dent in your spoil board or a piece of scrap. Then zero the x and y axis. Move the router/spindle until the cross hairs are directly over the dent. Write down the x and y values. This is the offset between the router/spindle and the crosshairs. Use these offsets when zeroing x,y using the crosshair laser.

A better approach would be to use two line lasers. They are mounted the carriage on an angle so they shine right under the bit. One line will be adjusted to be parallel to the X axis and the other to the Y axis. This takes some time but the result is a "dead on" crosshair that doesn't require an offset.

In either case, add a variable resistor in series with the laser(s). The dot from a good laser pointer is perceived to be much larger than it really is. This is due to saturation of the cones in the retina of your eye. You can reduce/eliminate the saturation effect by reducing the intensity of the beam.

I have used both of these methods and have reverted to using my edge finder from SDA Manufacturing the few times that I need an accurate zero. (The crosshair is a big wow factor if you have visitors.)

Paul Z