Hello all,
What is the maximum depth the MPCNC can hollow out of a piece of wood? Basically, how thick of a piece can I route out a section before the router interferes with the top of the piece.
John
You design your machine the size you want, but taller machines place more leverage on the bit leading to deflection. To some extent, you can compensate for deflection using a slower feedrate, and/or shallower depths of cut, and/or finishing passes. You can play with your Z height numbers numbers in the calculator. The default size in the calculator for Z is 81mm. In that space you must fit your stock, any clamps, any clearance, and your bit. If you held down your stock with double-sided tape, had 3mm of clearance, had exactly 39mm of bit exposed, you might be able to mill 39mm of stock. If you add in clamps and typical clearances, your max stock thickness drops to around 32mm. Increase the Z height of your machine, and you can fit larger stock.
Note that the leverage issue is primarily associated with the the distance the tip of the bit is below the core. For example, you could build a machine designed to engrave the surface of thick items. As long as the bit does not extend far below the core, you can build the machine for arbitrary thickness of material.
There are also “flexable” solutions to address the leverage issue. Some people have a drop table, allowing them to lower the bed of their machine for thicker stock, but have a shorter machine for thin stock. Personally, I wanted to be able to do 2" foam for cosplay props, but wanted the machine to perform well with thinner stock, so I made the legs adjustble using 3D printed spacers.
Note you are posting in the MPCNC part of the forum which is the Primo. If you are looking to build the Lowrider, the analysis is a bit different.
The collet from the standard makita type routers extends below the core so it depends on the length of your bit.
The bed and the sides need to be in the same plane as each other but they don’t need to be at the same level so you could use a drop bed for really thick stock.