Before You Buy A CNC Router
There is really not much comparison between the two. Both tools are similar only in that fact they both hold a router bit and can rotate it to cut material at high speeds. A router is a 110V consumer grade tool that is rated for intermittent use while a spindle is an industrial motor that has been manufactured to run all day long, day in and day out for exactly the purpose you want to purchase it for – CNC cutting. Spindles are more powerful (note that hp ratings between routers and spindles are not comparable) and will maintain their full torque down to much lower RPMs than a router. Spindles have precision bearings, which means less run-out and thus smoother and more accurate cutting. The bearings on a spindle also stand up to continuous use better than those of a router. Bearings in a heavily used router will need to be replaced every three-four months, while a similarly used spindle should be good for a few years between bearing replacements. A spindle is also much quieter in operation than a router.
That been said, if you don’t need a heavy cut and noise is not an issue, then a router is a safe choice. In production situations, we highly recommend a spindle. In addition, the full performance capabilities of our machines are fully realized with a spindle because a router will bog down in heavy cutting at higher cutting speeds.
In making a decision, the real dividing line between the two is on how you make your money. If your paycheck comes from someplace outside your shop, then buy whichever you feel you can afford. If your paycheck is generated inside your shop, and your living and reputation is on the line, you need the security and substantially higher cut quality that comes from a spindle.
What is the total usable Z height on the D-Series CNC?
The D-Series 420, 600 and 840 all have a max Z height of 140mm (5.51″). However this does not represent the maximum height of material you can process. From this height you need to subtract the spindle collet nut stick out as well as the length of the cutting tool you are using.
The following represents the spindle and spindle nut stick out you get on a D-Series machine with the HF-500 and MM-1000 spindles
HF-500: 31mm (1.22″)
MM-1000: 38.6mm (1.52″)
MM-1000 (with single spacer): 32.56mm (1.28″)
MM-1000 (with dual spacers): 26.34mm (1.04″)
- NOTE: This is the case with just about every CNC machine on the market, not just STEPCRAFT CNC. Most all CNC machines will have spindle and spindle nut/tool holder stick out that takes away from the usable Z height.
So if you take into consideration the MM-1000 with dual spacers, you would have a total Z height of 140mm (5.51″) minus 26.34mm (1.04″) leaving you with a new max Z height of 113.66mm (4.47″).
Now depending on what you intend to do, you can use this new value to plan your project. If you want to cut all the way through material, you would need to have a tool that is long enough, which you would further subtract from the new Z height value.
Example 1: New Z Value is 113.66mm (4.47″), if you divide that number in half, that would mean you can use a piece of material that is 56.83mm (2.23″) thick and the tool would have to stick out 56.83mm (2.23″) as well.
- NOTE: This would also mean that the cutting height of the tool would have to be a min of 56.83mm (2.23″) or you run the risk of rubbing the shank of the tool on the material.
Example 2: If you intend to only engrave on top of a piece of material, then your tool stick out can be much less. If you use an engraving blank that sticks out say 12mm from the bottom of the collet nut, then that means you can have a max material height of 101.66mm (4″).
- NOTE: please keep in mind you should also allow for a couple 2-3mm of Z height clearance for rapid, non-cutting moves on the CNC as well. So you would subtract another 2-3mm from the above numbers in a practical application.
TWO SIDED MACHINING – For thicker material
One way that you can increase your max material thickness that you can cut through is using double sided machining.
Example: You can take your new Z value of 113.66mm (4.47″) and divide that into thirds. This would mean you can have a material thickness of 75.33mm (2.96″), or two-thirds and using a cutter with a length of 38mm (1.49″) you can cut one side of the project and then flip it over and cut the other side – so you are using a shorter cutter to cut through a thicker material by cutting each side.