Hi!
Quick question: Which settings defines how far below the model it should cut?
Example:
The model and material is 15mm thick and I add some holding tabs that are 3x3mm. I want to make sure that the Lowrider cuts through everywhere, so I want to add an extra 0.5mm to that cut depth.
Which is the best way of achieving this?
/ Oskar
This will depend on what software you are using to author your job. I’m guessing you are using EstlCAM since that is most used tool on this forum. In that case you are looking for Toolpath Depth. You can just set it to 0.5mm larger than your stock. Alternately, you could set Start Level 0.5mm higher than 0.0. Note this potentially will reduce the height of your tabs, so you may want to compensate.
If your problem is uneven stock, not an uneven spoil board, then consider using the spoil board not the top of your stock as your reference . Author your depth of cut bigger than the maximum thickness of your stock. Say you measure the edge of your stock, and it varies in height between 11.8 and 12.1 mm. You might author your Tool Depth in EstlCAM to 12.5mm. Next zero your bit against the spoil board then raise it up 12.5mm (or 12.3mm if you want a bit compensation for your spoil board) and zero Z again.
Okey, I understand the idea behind it. Thanks!
I am using Fusion360. I posted this in the Fusion360 forum and didn’t specify it in my post what I am using. Should have done that 
Do you know if Fusion360 has any special settings for this?
I use Fusion 360 also. I don’t know of any special settings. In Fusion 360 you can specify a reference point for the job origin that is on the spoil board rather than the top of the stock. If you use this method, be careful of any G92 g-codes that are resetting theo origin.
If it’s a 2d path(I think it has to be if you can place tabs) and that the contour you are cutting is at the bottom of the stock, then it’s dealers choice. On the heights tab, set the bottom depth to however deep you want it (say, selected contour and offset - 0.5mm). Or on the passes tab check ‘stock to leave’ and set axial to -0.5mm.
Bingo bango, and bobs your uncle.
If the contour is offset from the bottom of the stock, you’ll have to do some figuring, but it should be pretty easy from here, and you can run the simulator to verify that you’ve got it.