Inexpensive Cross-Hair Laser Setup

[nailzscott]

I just setup a cross-hair laser and thought I'd share some pictures. Total cost was around $13. Once complete and mounted, I set the cross hair at the point I want x and y to zero, then enter one of the custom C codes that I have setup to move x and y the distance to where the cross hairs were pointing. I can provide more details if anyone is interested. The picture of the cross-hairs does not do it justice - the laser was adjustable and looks pretty good with fairly tight lines.

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[ghostcreek]

Yes, very interested. Could you post or email me info? Looks good. Thanks for the tip.
Michael
mick@ghostcreek.com (mailto:mick@ghostcreek.com)

[phd1658]

Ditto!

munroe1@verizon.net (mailto:munroe1@verizon.net)

[nailzscott]

I posted 4 pictures - and they showed in the preview, but somehow are missing here - so I'll ad them now. Then another post with the details.
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[nailzscott]

Here are the details.

Parts: Scrap piece of angle iron, some pvc fittings and pipe, Radio shack on/off push button and AA battery holder, spring, battery, and cross hair laser.

I got the laser here: http://www.dealextreme.com/details.dx/sku.5942 for $4. For the laser mounting, I drilled a hole the size of the laser in the 1/2" pipe plug (which is a tight fit to screw into one end of the 3/4" x 5 1/4” Schedule 40 pvc). I wrapped electrical tap around the back end of the laser to make it tight as I pushed it into the pipe plug (pic 2) from the open end of the plug.

I drilled a hole the size of the push button switch into a 3/4" sch40 pvc cap and attached the switch to it. I drilled 2 holes in the 5 ¼” pvc so that, when the battery assembly was installed in the pipe, one screw would be positioned above and one below it.

I transferred these pvc holes to the angle iron and drilled and taped the angle iron, so that I could later screw the pvc pipe to the angle iron with the ¼” screws. I drilled a hole in the angle iron so that I could mount it tight to the router’s clamping bolt. I did do a little grinding on the back edge of the angle iron to make it fit tight against the router bracket.

The battery holder was for a AA battery, so the CR123A 3 volt battery snaps in, but does not fit right; so I had to use a spring I had laying around to make up the difference in length. Since the battery holder with the battery installed is a tight squeeze into the pipe, I did end up filing down the sharp edges of the battery holder to get it to fit inside.

I screwed in the laser/pipe plug assembly into the pvc pipe, which left enough of the wire for soldering. Next, I soldered a battery holder wire to one of the laser wires, soldered the other battery holder wire to one terminal of the switch, and soldered the other laser wire to the other switch terminal. I then slid the battery assembly into the pipe (careful not to pinch the wires, pushed the bolts through the pvc so I could make sure to miss the wires, then slipped the push button cap onto the pvc.

I painted the angle iron and bolted it onto the router bracket and then mounted the laser assembly to the angle iron using the ¼” screws.

The last step was to point a v-bit to a place on a piece of material clamped to the Shopbot table and touch the bit .020 into the material. Then I turned on the laser, used the move commands to move the Shopbot router to a point where the laser cross-hair was positioned at the point I had made on the table. Writing down the x and y coordinates that at that point, I came up with x=.980 & y=3.480. I then setup my the custom C6 with this:
SR
M2 -.980,-3.48
SA

That moves my router point directly over where the laser was pointing.

I think I’ve covered it all, but let me know if you see something missing.

[nailzscott]

I am not sure why the posts are so ugly, but if you have trouble reading it, leave me an email and I can send it.

[phd1658]

Thanks, Scott. I'm going to give it a try....as soon as I move my bot into it's new home Just got through constructing a sound proof(I hope)room for it in the basement.

[ghostcreek]

Thanks Scott, I too will be trying this out. Great work. Thank You very much for Sharing.

[gundog]

Have you checked to see if it stays accurate throughout your z travel?

I bought some of those lasers about a year ago and I have just never gotten around to using them. Nice job.

Mike

[nailzscott]

Your are welcome guys.

Michael, I have used it for 1/2" to 3" thick and it's been fine so far.

I forgot to mention, the laser took about a week and a half since it came from Hong Kong but shipping was free and I used paypal, so it did not seem like much of a risk. I think I may order another one just to have an extra.

I did get another pen type red dot laser for a couple of bucks from them that runs on 2 AAA batteries, but it has a push button you have to hold and I just liked the cross hair laser better anyway.