I always say what works for you is the best. I’m just pointing out some types of failures that can occur when using this technique.
Sorry about the phone… I like my large screen… you probably will too when you reach 70.
Wow I’m sure I won’t get use to that expression.
You sound like you’re surrounded by laser equipment. Set a laser pointer up on your machine and let’s go thru it. I know it works on mine, I want to see how well it works on some other machine.
Just… Talk me through it, a thought experiment will suffice.
Assume nothing is aligned.
You stick your perfectly centered, perfectly perpendicular laser pointer up the tube. So it now comes out the top of the head, and vaguely goes in the general direction mirror 2.
Now what?
Ok so now we went form talking about hitting the head or something to a thought experiment?
Didn’t look at your profile but now I’m guessing Canada. 48x96 seems very North American…
Ok you have a beam straight up into mirror 3. Cool. It’s angled somewhere towards mirror 2. Simply adjust mirror 3 to put the beam on mirror 2 center. No tape, you can see exactly where the spot is on the mirror.
Move X axis near to far. How’s it tracking? Need to make a tweak to the frame? Just keep moving it until you stay on the mirror and as center as possible. Have fun if X axis is warped. Keep in mind that if your off center on 2 then the error grows by mirror 1. Especially over the range of motion. I’m only dealing with 14x24. I would recommend doing this with machine off and poor lighting.
Does this make sense? Any problems so far?
You just align it in reverse. Make m3 hit m2 near and far, then make m2 hit m1 near and far.
Same game just the opposite direction. And of course it’s unlikely that the source led is aligned to the actual optical path generated by the tube.
It allows you to see the beam, which you can’t normally.
Some people love them, just like honeycomb, I live fine without either.
Yes Jack. Your aligning mirrors in reverse from lens back to the actual CO2 laser beam.
How to align the two beams is what you’re really asking. And you can’t fire a CO2 laser into a laser pointer. I guess you could but it wouldn’t help. This is were you need to actually test it in your machine.
I like honeycomb but they are a pain to clean.
You get really hung up on this “head” ordeal. What would you rather we call it? The “3rd mirror & lens contraption”?
I said 24x48", or 60x120cm, give or take, in the Netherlands.
Here’s where things start to go wrong already. For most people this isn’t “simple”, but we’ll overlook that one.
The real issue is saying you should center it. There’s absolutely no need to, and your alignment may be drastically off if you do so, if that doesn’t coincidentally happen to be parallel to the axis.
Please do give me a good reason as to why it should be centered? (Hint: there isn’t one. But feel free to try)
So that’s a whole bunch of moving back and forth, exactly like the tape method? No benefit to using the pointer here.
How’s it tracking? Well, if you don’t mark where it hits, you’re just going to have to remember that? That doesn’t feel very accurate.
“Tweak the frame”, what doest that mean?
“Just keep moving it”, moving what, the head, the 3rd mirror, the 2nd one?
As centered as possible, again, why?
Based on what light-bending physics would that be the case? Again, what does having centered have to do with this?
Not quite, and quite a few 
Can’t offer any light bending physics…unless we shot the beam around a planet. Sorry about the size and I’ve always heard cool things about your country.
So most folks are going to purchase a machine that is in decent shape. Few are going to build one like us. However say the axis from 2 to 3 is not parallel to the x axis. You’re going to see drift in the dot on 2 as you move X. Correct? Now your not aligning mirrors, your repositioning one or both mirror holders so the beam path is near parallel. I know your thinking that you can’t just reposition holders as it breaks the beam plane. To that I say yes it does. However you can see that easily as you move the axis without this fire and retape sequence. And mirror 3 is not yet in play. And no unsafe conditions of test firing an open laser. Not clear how that isn’t better?
Not clear why I have to measure anything. I’m looking at position and movement of the dot on 2. The more it’s in center and less movement over X the better. It’s pretty simple. For folks with purchased machines it’s just position. Just a guess as I never worked with a purchased machine.
Does that make sense? Willing to give it a try?
Let’s get some terminology clear first. You’re aligning the beam, to an axis.
So if the beam isn’t parallel to the X axis, you’d hope you so that. However, if that deviation isn’t large, it’s hard to notice if you don’t simply mark them at either end. Your brain is quick to think “good enough”, whereas a sharpie mark on a piece of tape is hard to lie to.
Moving the holders isn’t going to do much for getting the beam parallel to the axis. For that you actually need to play with the screws. The beam position, still parallel to the axis, can be adjusted by moving the holder.
Mirror 3 is the one in the head, the first one you hit with your tool. How can that not be in play?
You shouldn’t test fire with the laser open, and no one is advocating for that either?
You don’t have to measure angrhing either way. You’re always looking at the movement one way or the other. But with the tape you mark it so it’s actually accurate, rather than a guesstimate.
If it is so simple, then please answer the following.
WHY SHOULD IT BE CENTERED ON A MIRROR?
If there’s only one thing you answer, let it be that. Make it make sense. Why bother centering it?
Besides, it shouldn’t be “the less movement”, it should be “absolutely no movement”, regardless where on the mirror.
Mainly because it gives you extra slop in your alignment. If you have 18mm mirrors and the beam is 8mm then the beam doesn’t see a 18x18mm mirror it sees a 12mmx18mm depending on it’s orientation… 12mm - 8mm is 4mm, leaving only 2mm on each side of the beam for misalignment.
The only mirror that doesn’t comply with this is m3 as it needs to go down the center of the lens tube, so you need to be able to move the impact point on the mirror in both the Y direction (I do this with m2) and in the Z direction which I do with sliding the head up and down.
Here is a photo of both head and m2… you can see that I can adjust both m2 for impact in the Y direction and the head can be adjusted in the Z direction.
This was the stock head, as you can see, center of the hole isn’t the center of the mirror or the lens tube.
It’s a convenience thing, not a “must”. I’m not saying it can’t be centered, but AT NO POINT during the “get the beam parallel to the axis phase”, should you give a single hoot as to where the beam hits. I don’t even care it it hits the mirror at all at that point, let alone the center.
You align the beam to the axis by making sure it hits the exact same spot, at the front/back of the axis. Then your mirror is aligned. DO NOT TOUCH THAT MIRROR AGAIN to try and get it centered. Instead, ‘simply’, move the targeted mirror so you ‘catch’ the beam. Preferably, but not necessarily, centered, for reason you mentioned.
The point here is: it doesn’t matter whether you hit it centered or not (so long as it’s fully hitting the mirror, obviously), and at no point during alignment should you care about where the mirrors are hit.
Well, you shoot a basketball into the net with the goal of passing thru the rim. Aim for the center and if it deviates then hopefully it will make it. So I agree with Jack. Try for the center.
I think we are concentrating way too much on some pretty detailed stuff. I can’t imagine that others can follow this. The real goal to explore how to align the two beams. The CO2 beam has to travel thru the same path as laser pointer. For that someone needs to make or get the tool.
You asked why centered in mirror and I replied that it gives you a wider error range.
If you’re at the stage of may not hit the mirror, then it doesn’t matter.
And yes having these and modifying mine, I know how to align it quick and accurate.
This is absolutely false. There is no possible way to align the laser pointer to the actual output of the co2 tube to ensure they are exactly the same. Even splitters built inside the co2 tube by the factory are often incorrect. Including the splitter through the lens pointers are off somewhere as there is no way to guaranty they are following the same path.
In context, as far as a human eyeball goes, they are probably pretty close… as far as a correctly aligned laser, they are likely not the same.
Maybe eyeball measurements are OK for you, that’s OK too.
I think we’ve drifted off in a far too technical way to help the OP @tantrim has requested and suggest we either create a new thread or restrict this to the OP’s query.
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Not only is that a horrible analogy, but it is horrible advice, too. “Hopefully it will make it”, simply means you’ll never get your laser aligned and the thing will cut horribly, and engrave worse. In fact, you may make alignment worse, rather than better.
You align the beam to the axis, not the arbitrary position of an object on the axis (the center of the mirror in this case). You don’t “aim” the beam, you align the beam. TO. THE. AXIS.
For what it’s worth, @jkwilborn did NOT say to aim for the center. He said it was better for the mirror to be hit in the center. That is a CRUCIAL difference. If you don’t notice that, then perhaps this is a bit more complicated than you’re aware of.
Those “details” are the difference between a usable machine, and an expensive paperweight…
Seeing as you can’t come up with a reasonable answer to justify your own recommendations, I’m going to, respectfully, claim it is you who can’t follow, at this point.
Which leads me to the crux of the matter:
This. Is. NOT. True.
You do NOT need that tool.
The way you make your claims makes it sound like that is the only way one can align a machine properly.
Whereas from your explanation one thing has become quite clear: if you don’t know how to align a machine properly, then a hacky laser pointer isn’t going to magically fix that.
So perhaps my plea is this: stop recommending people do things your way (as if it’s the only way), if you yourself can’t substantiate why it would work in the first place. The instructions you’ve given so far will get things more out of alignment than into it, I’m afraid. Respectfully.
Ok clearly i can’t advise some folks to try something new and sorry I hijacked the subject for a while. Let’s all go back to our corners and continue doing what we believe works best based only on theory alone.
If anyone ELSE wants to try this alignment technique then please get a laser alignment tool & start a new thread and we can discuss how well it works.
Good day gentlemen.
It’s not because I’m old fashioned or stubborn. It’s because it’s fundamentally flawed. And I’m not arguing because I’m against “new things”, I’m arguing because you’re making new people believe this new magic bullet is the only way to solve their issue, whilst simultaneously giving instructions that will make it WORSE.
YES. You can use a laser point thingy to help with the last mirror, but NOT with the instructions you’re giving. It’s not because it’s new, but because it’s wrong. As in, objectively wrong, not as in “in my opinion”.
Yes. Sure, make it sound like we don’t know what we’re talking about because we dare question the validity of something based on sound logic, and indeed theory? If the theory doesn’t add up to begin with, then there’s little chance for practical results.
If anything, please try and inform yourself a bit better on the matter, before giving out advice like it’s the sole truth. Especially if you can’t back up your claims with factual evidence, instead of "let’s shoot a hoop and hope we hit something"
?
First get the fundamentals down, of how to align a single mirror, with or without laser pointer. Because if you don’t know how that works, the pointer isn’t going to make a difference anyhow…
I’ve been adjusting mirror 1, far more than 1/16th. It is having no effect on the distance on the burn mark from corners 2 and 4 ( back right, front right). All it appears to be doing is moving where the dots hit, not the distance/relation from each other.
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