What is the maximum or recommended height for the Z axis of a lowrider2?
Sadly, that’s the answer. How many zeros are you chasing? How critical is precision for you? Are you planning on a lot of fiddly, flat-pack style furniture with snug tolerances on tab in hole connectors? Are you planning on doing a lot of sign carvings? Inlays? Planning on trying your hand at aluminum?
The less z-axis you have, the better. More specifically, the closer you are to z = 0, the more accurate/precise/rigid your machine will be. If you know the maximum thickness of the stock you will be working on, you can base your z-axis on that. Leave yourself enough room to safely make your travel moves and maneuver your stock under the gantry and bit, plus possible bit changes. The nice thing about the LowRider design is that you can actually have a huge z-axis, but leave it all hanging below the table with no impact on performance.
My personal suggestion (and this is from a non-LR user) is to think about the most common thickness stock you’ll likely to be using (flat sign? thick chopping block? furniture stock?), and the longest bit you’re likely to use. Then, build your machine and table accordingly. Remember that if your bit only carves/cuts 1/2" deep, having a 3" z-axis still leaves 2.5" of unusable stock below the bit at the theoretical maximum. But if your table has a removable/drop spoilboard, you could gain that much thickness of stock without impacting rigidity.
Extra Z capacity won’t hurt you, other than carrying around some extra steel.
On the Primo, the Z capacity is all at hte expense of machine rigidity at the deepest cutting depth, which is also the most frequently used for through-cuts. The LowRider is the opposite, where the lower you go, the more rigid the machine, and cutting higher comes at the expense of rigidity. you can have a lot of extra capacity for Z with a LowRIder 2 and have no real consequences for your majority through-cuts.
For the 3, there is a bit of a stability cost, because the extra mass all comes in at the top. I added 50mm of Z to mine, and I don’t think that hurts it at all, but if I were chasing .001" tolerances, it probably makes a difference.
I agree. The LR2 is strongest when the gantry is at the bottom. If you actually try to surface a 5" tall log, you will have problems. But milling foam shouldn’t be an issue. The extra capacity won’t really hurt you much, if your gantry is already at the bottom.
Ok. The materials I would use would be MDF up to 25mm thick, plywood, chipboard, acrylic and maybe aluminum more than that.
Ok. Why are you worried about the max recommended height?
because I hadn’t seen anything about it and I thought it could affect if Z was too high it could affect the accuracy.
Makes sense. There isn’t a maximum, really. But if you are cutting 25mm materials, then you need to find a 25mm bit (not easy) and you need to raise it more than 25mm over the top of the material, so 60mm-70mm, or so total. That is totally fine.