I've recently started trying to mill my own PCBs. Basically copper-clad FR4 boards (wish I could find FR1s for cost reasons) with a cheap 3018 Pro CNC router (typically sold under the SainSmart brand). I'm not expecting miracles, since it's not what I would call a high-grade piece of kit (nor am I able to operate the software to a high grade) but it will hopefully beat perf boards out in time - especially if I'm repeating the same board over and over (such as A/V boosters for retro consoles, of which my brother has many). I'm having trouble, though, getting what I would consider reliable cuts. Mainly it's the traces themselves. I'm currently using a 0.2mm 30° V-bit to cut them. But because the blanks (as is probably expected) aren't perfectly flat, I'm finding I have to make the cuts fairly deep (in the order of 0.3mm-0.4mm, instead of the 0.1mm I want) in order to reliably do the whole board, even with something as small as 2cm x 4cm. This doesn't make a massive increase, but it does mean some cuts are up to 50% wider, which is a problem when I'm still trying to make sure the traces are not completely cut through (cheap bits, so I don't expect them to be exactly 0.2mm, and I doubt the spindle is 100% true either). To that end, what kind of bit should I be looking at? 0.2mm bits are going to be extremely fragile (I've already broken three 0.8mm flat bits dialing in feed rates for cutting the board free), and I've heard similar of narrower Vs (like 10°), but I really feel like I need something with a more consistent width so I can simply cut deeper. I'm also wondering if anyone has some tips to offer for starting out - particularly in the case of making sure enough copper is left to connect everything but it's not close enough to easily bridge solder. I'm using KiCAD with the traces set to 0.4mm and flood gap set to 0.4mm. FlatCAM creates the GCode with the assumption that the mill is using a 0.3mm bit just to get a bit more material left behind. I'm thinking I need to go up to a higher flood gap, however (0.5mm? 0.6mm?), but that will naturally change if I start using larger bits for cutting. Cheers. PS This is my latest run. As you can see (particularly at the bottom left) it just isn't leaving some traces behind and a few pads are a little thin, but it's giving some very nice results (IMO) so I feel like a little more persistence and tweaking should be all it takes.