Hi, yeah makes sense if one needs to fudge it up and down from the true offset.
Kerf adjustment is odd, if you think about it. Most of the plans I’ve worked off of show the object as drawn with no ‘clearance’ in the measurement.
So if you put the kerf at 1/2 of it’s offset the parts would be exactly on the tool path, pretty much ensure they will not fit. Everything that ‘fits’ together needs some kind of clearance and you can use the kerf adjustment to do that. Exactly what we are using it for.
If 1/2 the kerf is 0.1mm and you want to make more clearance between parts, say an increase of 0.01mm, you may need to go with 0.09mm… Do you want to have to multiply this by 2 to get the 0.18 setting to enter it just so the software can divide it by two…?
If you cut a board with a table saw, you use 1/2 the saw kerf to ensure the parts come out measured correctly. Instead of cutting down the line, you adjust the edge of the blade to the line. This is 1/2 the saws kerf.
Keep in mind that if you set a kerf for all parts, there could be fitting issues. Especially when you have a box top and sides…
Get used to using it, it’s a great and powerful option.
Much like the great and powerful Oz.
Good luck
Just a thought that has nothing to do with it maybe…
When I write a G-code program for the shop CNC and I want to set the kerf so an object will fit well I put a positive number in the the offset. I guess experience tells me what I need but with the CNC and router bits you have the need to account for a bit that may have been reground. That is when I use a positive number which makes the bit move further from center outward making the cutout larger. Smaller circle for instance would need the offset to be negative.
Laser cuts a narrower path but same situation.
Suppose I have multiple pieces to a file. Some are slots/cutout circles, rectangles, or squares. for instance. If I select all of those in Lightburn I can resize items the same size to other dimensions or apply a percentage to the original increment and change all that I have selected. This makes resizing slots in LB to fit different thicknesses of material easy.
Well, anyway I know what I mean. lol
If I use a tool bit that is 0.5" and I regrind it, is it bigger?
Mine certainly aren’t. So I have to reduce the kerf to move the tool closer to the tool path to get the same cut.
If the kerf goes negative, it would move the from the tool path inward…
I don’t know how to compute this, as it would seem it would seem to me that the tool would have to have a negative diameter.
It is smaller so the offset has to be positive to make the cutout larger. The bit will move from center outward to make the cut the desired size.
If the correct adjustment for the tool path is X amount of kerf to cut the actual design or tool path, then a tool <X has to have a smaller kerf for the same results.
Maybe LB figures the positive/negative opposite to what I learned for the CNC.
Jack I see where you are coming from. I am considering my adjustments according to the tool size.
Now, My original 0.5" bit is ground and is now 0.490"
To cut a circle of the same diameter I will need to adjust the offset of the bit 0.10 positive to make the same size circle.
Since you have to have a ‘closed’ object to apply a kerf, Lightburn knows what is inside and outside…
The problem with kerf really shows up when you do something like a box. If the kerf is good from base/top to side, then where the both sides meet they have the same kerf… I’ve found it better to split the kerf equally under these conditions…
There are other issue on how Lightburn has implemented this.
I have a ‘cover’ for my stereo that is simply a piece of flat mdf… each corner has two short sides to keep the cats from sliding it off the top of the stereo…
It’s too large to get into the machine, so I have to do each corner separately…
This is a corner and the rectangular slots are ‘feet’ or standoffs to allow air movement out the top of the stereo. You can’t apply a kerf to the open segment or line that is the edge of the cover…
Another problem is if you don’t have the same kerf on top and sides, where the sides meet each other, they won’t fit…
In LB I probably done my “fix” all wrong but…
I used the Edit Nodes to set exactly where I wanted to change the dimensions of tabs then applied the value/values.
Time consuming but it works for me.
One of the things I found with Lightburn, was I could use all my experience from cad work and get things to work in Lightburn with some effort…
As I got better with Lightburn, I found that I rarely have to go outside of the application and that with the right ‘open mind’ it was very simply done in Lightburn.
The only two pieces of software I use outside of lightburn are gimp for photograph manipulation such as dodge and burn areas and Freecad where I can set it up a parametric drawing so I can adjust the parts relative to each other. I then export via svg or dxf.
I run Ubuntu, so it needs to operate on a Linux based platform.
No matter what, I can’t argue with success 
…the same here.
Jack, what distro are you using and does your camera work with LightBurn?
| Distributor ID: | Ubuntu |
|---|---|
| Description: | Ubuntu 22.04.1 LTS |
| Release: | 22.04 |
| Codename: | jammy |
| LightBurn 1.4.00 | Wed 2022-12-14 @ 15:00 |
I followed this thread to install it on the PI… it worked great and I did a proper alignment via lightburn setup…
It continuously sends frames and that ‘loads’ the machines cpu(s)… not to mention the local network.
The lids ‘gas lift supports’ have passed their gas and it’s propped (not 
) open with a random stick …
Around the same time my hv meter failed, so I had to build another ‘big’ resistor to get it back in operation… didn’t think I’d actually miss it.
Thanks for the answer. I’m on Mint and very happy except camera support. But it’s probably more me who is not good enough at Linux. When I give it another shot I will probably ask nicely for help.
Are you trying to run it over the wifi local network?
The camera is usb so you’d need anther computer at the laser end to capture the cameras output and get it on the network.
Then something at your end… I used obs.
https://obsproject.com/download
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No no, same computer with camera connected via usb and LightBurn via LAN. LB always crashes when I want to use the camera. It has been going on right from the start. However, it must be said that it is not an original LightBurn camera and the fault can easily lie with this camera. Customs and taxes make it too expensive for me to buy an original camera.
Does the camera work with other apps?
Yes, tests with my camera in “Cheese” / Linux Mint work fine.
The last time we discussed this issue in the forum here, the conclusion was that I should switch to Ubuntu. But, I’m kind of the type who never touches a running system 
, so I’m still on Mint and actually also happy that everything else has run completely problem-free since I started the machine (laser and PC).
You could try obs. It’s supposed to create a virtual camera… Lightburn had no trouble using it…
Thanks for the tip, I’ll figure out how to try it.
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