Shenhui SH-G690 and Red Dot Mirror

[Jimmy Phillips]

All,

I fried my red dot combiner mirror, i.e. the first one that the laser beam hits, and I have no replacement.

Any ideas where to get one and I suppose I can just run the laser for now with it removed, i.e. I just will not have a red dot.

It appears contamination built up on it, and then the laser beam heated it up and it cracked. Guess I should have cleaned that one....damn!

Thanks,

Jimmy

[Rodne Gold]

Just remove it , it's trouble. If you really want and need a red dot , you can hang the diode off the end of the nozzle , however the red dot is somewhat useless , it cant be used for precise positioning and the hole in the nozzle will tell you where it fires.

[Jimmy Phillips]

Rodne,

Thanks bud! That is exactly what I was wondering.

I remembered you stating before something about removing it, but couldn't find it in the search engine.

Thanks again,

Jimmy

[Rich Harman]

I disagree about the red dot not being useful for positioning. My nozzle is 30mm off the surface and the red dot laser is mounted on the side of the nozzle. Under normal use the red dot lands within a couple mm of the the focus point. When I need it to be exact I simply fire the laser to make a mark then tweak the red dot to match.

[Paul Minichbauer]

All,

I fried my red dot combiner mirror...


How did it happen? What do you do to prevent that?

Paul

[Jimmy Phillips]

How did it happen? What do you do to prevent that?

Paul

I suspect from my poor maintenance of not cleaning that lens. To prevent it I would make it part of your cleaning routine.

BTW.....I just removed it as Rodne suggested and have been fine since then.

l8r,

Jimmy

[Bert Kemp]

I agree with Rich, my red dot hangs on the side and is pretty close to where my laser fires and is close enough for 99% of what I do. I think I've read here somewhere that with the combiner you loose a little power, think I read that some place.

[Brian Leavitt]

I guess it depends on the type of work you do. I need my red dot laser to be extremely accurate for the way I do things. The diode hanging off the side of the carriage doesn't cut it for me. I'm sure if you use a super cheap combiner mirror, it'll rob you of some power, but I still doubt it would be noticeable.

[Bill George]

I guess it depends on the type of work you do. I need my red dot laser to be extremely accurate for the way I do things. The diode hanging off the side of the carriage doesn't cut it for me. I'm sure if you use a super cheap combiner mirror, it'll rob you of some power, but I still doubt it would be noticeable.

LightObject.com had in stock at one time, not sure now?

[Kev Williams]

I guess it depends on the type of work you do. I need my red dot laser to be extremely accurate for the way I do things..
Yup. I live & die by the red dot. My machine's dots aren't dead to rights, but I have correction factors for them. For critical stuff I even go so far as to put a 3x loupe in my eye and shine a hi-intensity flashlight at the red dot to wash out the 'flare', what visibly remains is a very tiny red pinpoint. I can usually hit what I'm aiming for within .001". A hanging diode would be fine, as long as it's consistent in where it points, I can correct for it.

I need to get one for the Triumph, it didn't come with one. What I use works for me: I have laser pointer, and cut out a round piece of 1/8" plex just the right size to fit in the 'mirror hole' over the lens, and cut a hole in that so that it fits snug around the end of the pointer barrel. The whole thing fits nicely in the mirror hole. Because the beam was too fat, I took some .010" brass shim stock and drilled a tiny hole in it with the smallest drill I could find around here, cut it to fit over the end of the pointer and taped it on best I could... that helped immensely... For 'basic' alignments I just push the thing into the mirror hole and square the laser barrel to the gantry by eye, this is almost always good to within .03". For critical needs, before installing the barrel, I'll fire the laser at a piece of black brass. Then I insert the red laser and adjust it until it hits the gold dot the laser made. Very easy since the red dot goes from hardly there to very bright. From then on, I can find edges or corners of holes or whatever else I need to locate to, very precisely.

But-- it would be nice to have a separate pointer! :D

[John Noell]

I do a lot of very uneven surfaces and need accuracy. After seeing what Travis used, I went with two pointers off the lens tube at 90 degrees to each other. One is a red dot, the other is a red line. At the beginning of the day I make sure they coincide, and show were the laser will fire, when in focus. When I do a job, I 'frame' where it will engrave and watch the dot for the y axis dimension, and the line for the x axis. Works quite well for what I do.