Router build

[Blackrat]

to clear the work piece ... the bit will foul if it doesnt retract far enough

dont really wanna lower the bed (or raise the gantry) as this will induce more flex , vibration , resonance and the list goes on

[Clive S]

to clear the work piece ... the bit will foul if it doesnt retract far enough

dont really wanna lower the bed (or raise the gantry) as this will induce more flex , vibration , resonance and the list goes on

Well how about moving the z bearing blocks higher up the plate. ..Clive

[Boyan Silyavski]

Its a part of my designs also to be able to move the spindle up to clear for a large work piece. But in real life that would mean realigning vertically the spindle, and its time consuming process. The only proper way to do this without fiddling is to make a custom mount and machine the spindle so they fit perfectly, as i make now on my machine now. But its expensive.

having in mind at which stage are you and the prices of ball screws and rails for Z, if simply you made the error and bought them short, spend now 100 quid and buy new ball screw and rails, instead of compromising the whole investment. If don't have them, all the better. The Z should be made properly, not to speak that you want a high performance Z.

[Blackrat]

+1 clive ... i hear ya ... but then you go down the whole road of tuning fork ... and defeat the whole purpose of having the rails move

im going with bearings moving , like i drew on the original concept, its much easier and i doubt there will be any loss by going with this

silyavski ... i have enough travel on the rails and screws ... its just the design now. I have about 230mm between gantry beam and table top. but only having 230mm of movement isnt enough , i need another 120mm minimum to pull out a long series bit

for example - if i were to machine a block of foam for a plug that is 160mm thick .... and lets say i needed to machine right to the bottom of the foam , so i would need a bit of 120mm long ( the router clears the piece for arguments sake)

then the travel required would be the piece 160mm + 120mm bit + clearance 50mm = 320mm right ? if the move the block up like Clive suggested by 90mm then i would have sufficient clearance

going to redraw bearings the other way and have a scrutinize

[JAZZCNC]

+1 clive ... i hear ya ... but then you go down the whole road of tuning fork ... and defeat the whole purpose of having the rails move

im going with bearings moving , like i drew on the original concept, its much easier and i doubt there will be any loss by going with this

This is ok if your only ever going to use long tools that reach the bed or material base but what happens if you want to use short stubby cutter.?

In this case if you have to drop the spindle in the clamp this then gives you a long fixed length lever that is a long tuning fork.!! That never changes it pitch no matter if you raise the Z axis.
This does make a differance and in some materials you will clearly see it compared to having rails moving. You can certainly forget cutting aluminium and expect any kind of decent finish.!!