My apologies for the confusion Jack. For the last year and a half I’ve been running an OMTECH MF1220-50. The focus tool on the 50w was about 18mm thick. A few weeks ago I bought a ZF2028-60E (and sold the 50w), so I’m getting used to the differences between the two machines. The nozzle/lens tube on the 50w was rock solid. Not so much on the 60w. As I mentioned, there’s a big difference between them in the distance from the nozzle to the workpiece. The focus tool that OMTECH provided for the 60w is 5 to 6mm thick, and I get a nice focused dot when I pulse the beam. I’m just not happy with the amount of play in the tube.
This is why many people change out that head assembly to something more functional…
The hole on the side of my factory head wasn’t even in the center of the lens/tube path… not to mention it was pretty heavy.
I went with the head design of Russ Sadler with the C series lens tubes.
The focus distance is how far the material is from the lens… For a 2" lens… so the nozzle matters…
Need to take a photo of the engraving on the tube… I do have one for the 4"… I engrave what lens/focus distance… Don’t remember 
Good luck
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Thank you for the information Jack. I don’t know how much of a problem this is going to be down the road, whether I should look into getting a lens/tube assy., or if I should contact OMTECH about it. In a nutshell the lens tube is slightly too small and it rocks back and forth ever so slightly when touched. Please excuse the poor drawing but it might explain it better.
The red circle is the lens tube and it pivots at the set screw, along the X axis, enough for it to bug me but I don’t know if it’s enough to be detrimental when cutting or engraving. After resting the nozzle on a 3-2-1 block to set nozzle height I removed the lens tube from the head. There was about 15mm of tube above the screw mark. I pushed it in another 15mm or so but it had no real effect on the wobble. I suppose I could put a layer or two of Teflon tape around it to take out some of the play. Or I could be overthinking this and I should just let it be. It just bugs me. Here is a picture of the tube and nozzle.
If I was going to replace it, what should I be looking for? I do about 60/40 engraving to cutting.
What lens holder/head you purchase is up to you… There are plenty out there. I like the simplicity of the Russ Sadler designed head myself. Not to mention I’ve removed about 2/3 of the X axes mass. My acceleration value is around 45000mm/s^2.
As you can see it holds the tube square to the head. This is for vertical alignment… A 3mm acrylic attachment that works very well… another part from Sadler.
If you wish to pursue one of his designs, let me know…
Good luck
Which will certainly affect the spot position on the platform, so it’s best fixed.
Rather than squishy tape, use brass shimstock to get a rigid assembly.
Measure the allegedly matching ID and OD, divide the difference by two, then cut a rectangle 30 mm tall by (3 × the OD) from that thickness of shimstock.
Roll the rectangle around the bottom tube (with the gap away from the screw), assemble, and screw it tight.
The lens tube in my laser wasn’t as loose as yours, but the clamp holding the focus “pen” was sloppier, so it now has a similar brass shim. You can see one edge below the red pen clamp:
For sure, they made all the tubes the same OD, so whatever they send will be exactly the same.
Great idea Ed, thank you. Now to hunt down some brass shim stock. Maybe Amazon. I also see you made a collar for your led pointer. I did the same thing for my 50w and now I’ll have to print one for the 60w.
Anybody with a 123 block is required to have a shimstock assortment on the shelf! 
I’ve been whittling away at a big K&S pack for decades and it’s nowhere near gone …
It puts the pointer just slightly off-axis so you can fine-tune the position by rotating the collar. The whole affair is too sloppy for words, but it was a nice thought.
“Anybody with a 123 block”
You’re absolutely right (hangs head in shame as he shuffles off to find some shim stock).
Looks like a lifetime supply to me!
Ed, I went to the link you provided in the hope that there might be a link to the STL file you used. Is it available somewhere or is it a product of your fevered imagination? If it’s the latter is there a chance that you might share it? It would be something I’d like to Tinker(CAD) with. If you’re amenable to the idea.
The geometry comes from the OpenSCAD program at the bottom of that blog post, which then spits out the STL file, so you could ahem tinker the source.
The STL file is in binary format, so I can’t add it to the Gist along with its source.
Maybe this will work after you strip off the TXT extension:
Pointer fine adjuster.stl.txt (20.8 KB)
Definitely not a miracle pointer mount, but it works better than having the pointer jammed into an oversized ring with a screw.
Thanks Ed, I’ll be printing it tomorrow first thing.
That’s something I’d like to pursue down the road. In the meantime, I was looking at this offering from Amazon, https://www.amazon.com/Cloudray-Dia-20mm-FL-50-8-Replacement-Engraver/dp/B07BGV7RWM
If I understand what the product info is telling me, the 1.5" FL lens is 18mm in diameter and all the rest are 20mm in diameter. Am I reading that correctly? I can try to shim up the lens tube I have, for the time being, but I think replacing it with something more versatile would serve me better in the long run. I bought an 18mm 2" FL lens to play with, but if I get the Cloudray head it appears I’ll need to get 20mm lenses instead. If that’s the case, I should probably return the 18mm lens and get the 20mm. Does that sound about right?
Good idea to move this to a new thread?
This is already solved…
About the head, how does yours mount to the X bearing?
Notice, it wouldn’t work on mine…
The metal part with green stripes is the bearing… So I don’t think it would work with this kind of head…
You are correct. The pulse issue is solved, and I’ll open a new thread for replacing the lens tube/laser head. Standing over my laser I can see that the mounts are different enough that the Cloudray wouldn’t work. Hopefully the new thread will provide a permanent solution that doesn’t involve brass shims.
My mount
Cloudray mount
To well and truly wrap up and close out this thread I wanted to let you know that some .003 shim stock has got the lens tube rock solid in the mount. Thank you for the suggestion. I also printed the red dot pointer collar, and it works quite well.
I love a happy ending!
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