Opinion about the structure of the router ...

[John S]

I think using 10mm pitch screws is more versatile since you always have the option for higher feedrates than you could get with 5mm pitch should you need it, at the expense of worse resolution of course.

Why does everyone assume you have to travel at warp speed, is it a dick slapping contest ?
Anyway when you are cutting unless you are doing simple carcase routing where all moves are straight and long the home stepper driven machine can never accelerate to these insane speeds everyone is bandying about.

Program a part to run at 2000 mm/min then watch the screen and read the actual feed-rates. No way does it get anywhere near this figure because it never get to speed before it has to perform the next line of code.

Now I could understand 10mm pitch screws if you were on servo's and production work but personally I'd much prefer working more slowly and accurately and get the job done whist the machine is under control, not be boreline running away, especially for a beginner, after all this IS a hobby forum isn't it ?

[Jonathan]

I tend to mention 10mm pitch on this size machine as the machines I've seen in person with 5mm pitch screws don't seem to run as smoothly as mine or get as high acceleration.

Anyway when you are cutting unless you are doing simple carcase routing where all moves are straight and long the home stepper driven machine can never accelerate to these insane speeds everyone is bandying about.

Program a part to run at 2000 mm/min then watch the screen and read the actual feed-rates. No way does it get anywhere near this figure because it never get to speed before it has to perform the next line of code.

With the 3nm steppers on 70V and 10mm pitch my machine on the vast majority of jobs would get to 2000mm/min. I have the acceleration set to 1000mm/s^2 on X and more on Y. So to get from zero to 2000mm/min from zero takes:
v^2=u^2+2as
s=(v^2-u^2)/2a
s=((2/60)^2)-0)/(2*1)
s=0.000555...

So for any linear move over 0.55mm it will get to 2m/min speed, or similarly it will maintain 2m/min for any arc above 1.1mm radius. When I cut woods I generally go at around 6m/min, been known to use 8m/min when roughing. High feedrates are especially good with MDF as you can maintain a big enough chipload to make chips, not dust which is bad for you, without lowering the spindle speed to the point where there is not enough power.

I made the right size pulleys to run my machine on 2:1 for better resolution, but I've never needed to use them.