Low cost 0 backlash transmission - Ball bearing + trapezoidal screw

[M250cnc]

True, you're not going to be able to put anywhere near as much force on it - and the pressure is much greater due to the tiny contact area. Probably only a couple of mm, not 20, since it's only contacting at two lines (in theory). Could improve this with more bearings.

I was being generous, so its even worse than i thought it was.

Yes it does. Except one thing - the sort of machines we're making are generally not used for heavy cutting (like commercial machines). I think this method excels when you're only cutting woods/plastics so the forces are low. ACME rod would certainly be better, but I just used stainless rod as I know that eventually I will probably buy a ballscrew.

It could be good for a PCB machine where low backlash is going to help with accuracy and the cutting forces are tiny.

To drive a small PCB machine a belt drive like they use on the RepRap machines would do the job better, be easier to implement, would last longer and be far stronger. You also do not need angular contact bearings for the fixed end of the screw either. That is the HD 10mm pitch belts BTW.

Phil

[Jonathan]

To drive a small PCB machine a belt drive like they use on the RepRap machines would do the job better, be easier to implement, would last longer and be far stronger. You also do not need angular contact bearings for the fixed end of the screw either. That is the HD 10mm pitch belts BTW.

Belt would certainly be a lot easier, not to mention faster. The 'Rapman' machine at school was pretty poor to be honest, mainly due to not being put together very well though I think! It only used 5mm belts and the pulleys were laser cut from acrylic.

[M250cnc]

Belt would certainly be a lot easier, not to mention faster. The 'Rapman' machine at school was pretty poor to be honest, mainly due to not being put together very well though I think! It only used 5mm belts and the pulleys were laser cut from acrylic.

Your not agreeing with me are you.

I use these belts on my lathe the Z is about 300mm BC

I was cutting some tool steel and a bit too hard it pushed the bar in the lathe chuck but the pulleys are about £30/40 each, built it has awesome power. Backlash is 0.05mm

Phil

[Jonathan]

Your not agreeing with me are you.

I use these belts on my lathe the Z is about 300mm BC

I was cutting some tool steel and a bit too hard it pushed the bar in the lathe chuck but the pulleys are about £30/40 each, built it has awesome power. Backlash is 0.05mm

Phil

Sorry maybe I came across wrong there - I meant to agree with you!
I meant to say that the laser cut pulleys and only 5mm wide belts were not good.

I've used XL pulleys and 1/2" (some bigger) belts on my machines. HD belts would be nice...

...better than the X-axis nuns.

Just noticed that typo I made - oops!