It's begun....

[Washout]

Yeah I figured the single x axis ballscrew was causing weakness - I'll get a mail over to Chai for a new ballscrew with appropriate machine end and go the pulley/belt route (seems less prone to error than two steppers). I'm looking at Zapp/Gary for the belt and pulleys if I can decipher what length belt to order (whether the length is for the whole belt or the loop if folded in half - if that makes sense).

As always thanks for the sage advice and assesment of the machine once its been upgraded (I like the sound of "beast" :-) ).

Chris

[JAZZCNC]

I'm looking at Zapp/Gary for the belt and pulleys if I can decipher what length belt to order (whether the length is for the whole belt or the loop if folded in half - if that makes sense).

Determine the screw centre distance and pulley pitch/number teeth then use a belt calculator (see attached) to find the number of teeth. (Or looped belt length) But if you order by number of teeth there's no room for error.!

The machine will be a beast at this size and strength. To give some idea my machine Y axis travel is 1100mm, so technically more likely to be weaker or more flexy than yours.
Smack bang in the centre at 3/4 Z extension so possible 120-130mm extension below Z axis. I've just cut a oval pocket 70mm x 30mm length single pass at 8mm Doc 45% step over @800mm/min 12Krpm in 6082 T6 Aluminium just using blown air no misting or coolant(quick initial squirt of WD40).
In doing this, it first spiralled down to depth, it then had to cut full slot for about 40mm and while it moaned slightly more than the when cutting 45% stepover it still handled it no problem and the actual 45% stepover was a doddle and I'm sure I could have easily pocketed at 45% step the full 10mm depth of material.

While bit extreme on DOC and not something I do often at full slot width. I Can't see why your machine couldn't do this kind of cutting and like mine will most certainly easily handle half this DOC at higher feeds.