How to focus jtech 2.8w laser

I need to adjust the focus spot for the 2.8w jtech laser. i have read the instruction on how to but on the 7th step: 7. “Now you can adjust the lens to get the smallest spot at the surface. Adjust the lens one direction and if it gets bigger, then adjust it the other direction until the spot is small. It is fine to pass it a couple of times in each direction until you get a feel for where the minimum will be.” Im a bit confused. Do i adjust the lens while the laser is still on? my common sense tells me i have to switch laser off then adjust then switch laser on and adjust again… please tell me how you guys do it?

You can set the laser to a a really low setting (either by adjusting the pot on the driver board or with a M3 S____ code). Then when the laser is barely visible you can focus the laser without cutting off your finger. OK that might be a bit of an stretch but it does hurt a bit if you put your finger into the beam. Jtech has a blog post where they go into this in great detail. Focusing Your Laser 101

I did what Mike said. I entered S100 and M3 for low power the focused the laser at about 2". I then cut a wood block that I use to set the z-height for the laser.

thanks all for the response. sorry it took me so long to reply back. ive managed to focus my laser. but now im stuck on uploading old setting after uploading 0.9g jtech…

im am stuck in this step.5. Upload your old GRBL settings

Since you just re-flashed your arduino, you will need to put your parameters back on it. Hopefully you saved them from step 3! You will also have to send the command:

$N1 = F4000

To set the default feedrate.

If you don’t have your settings file, here is ours to use: DOWNLOAD Settings File

where do i type in the command and how to upload the settings file. (i only can save it in *.txt

ive found this link. changed the setings and still trying out to see the outcome…