Here we go again . . . MK4

**routercnc** · 02-12-2018

Originally Posted by Zeeflyboy

re tightening the retaining nuts, you can also dremel a little flat head screwdriver slot into the end of the ballscrew shaft and use that to hold the shaft still while tightening the nut.

Well I say "you can", I've never seen anyone else do it but it soother's probably a really great reason why not to, but it works for me! No more worries about damaging the important part of the screw vs not tightening it well enough.

Nice idea. I was thinking of flats machined on the end or on the last part of the ballscrew behind the housing but a slot looks good as it still supports all of the pulley. My other thought was that with the right equipment you can wobble broach a hex pocket into the end.

Paulus, rail is about 700 long and travel is currently 360. I could go a bit more but when the spindle is quite low nearer the bed it would hit the sides so have limited it to that.

**routercnc** · 22-12-2018

Episode 23 is now ready . . . . . finishing off ready for first real chips !

**Chaz** · 22-12-2018

Well done mate, certainly one of the best DIY builds I have ever seen. The attention to detail is immense.

In the cutting videos, the spindle bogs down. What power is it? Are you running full speed?

**routercnc** · 22-12-2018

Hi Chaz,

Thank you. I can't tell you how relieved I am to have finally 'finished' the machine (they are never truly finished are they?) and I can spend some time with the family again. I hope it gives some ideas and inspiration to others.

Yes, the spindle is a 1.5 kW Chinese spindle and I knew it would be the next limiting factor. I have other designs in CAD for various spindle options but they will have to wait for now. It works, and I can certainly make a few hobby parts with it.

It was running at around 12,000 rpm in the film (full speed is 24,000 rpm), with a 6 mm 2 flute 45 deg cutter for aluminium, with the approximate WOC and DOC shown on screen. Feed rate varied - the heavy cuts were around 700 mm/min and the finish cuts were around 1400 mm/min. I finished the tram and final build yesterday morning, and I basically had about 20 minutes yesterday afternoon to get some cutting footage before my 'time was up' so basically went for it. Although I didn't have much time to experiment I soon found the limits. I actually broke the tips off both flutes by being so aggressive.

Much to think about and reflect on over Christmas, but first a break !

**Chaz** · 22-12-2018

Originally Posted by routercnc

Hi Chaz,

Thank you. I can't tell you how relieved I am to have finally 'finished' the machine (they are never truly finished are they?) and I can spend some time with the family again. I hope it gives some ideas and inspiration to others.

Yes, the spindle is a 1.5 kW Chinese spindle and I knew it would be the next limiting factor. I have other designs in CAD for various spindle options but they will have to wait for now. It works, and I can certainly make a few hobby parts with it.

It was running at around 12,000 rpm in the film (full speed is 24,000 rpm), with a 6 mm 2 flute 45 deg cutter for aluminium, with the approximate WOC and DOC shown on screen. Feed rate varied - the heavy cuts were around 700 mm/min and the finish cuts were around 1400 mm/min. I finished the tram and final build yesterday morning, and I basically had about 20 minutes yesterday afternoon to get some cutting footage before my 'time was up' so basically went for it. Although I didn't have much time to experiment I soon found the limits. I actually broke the tips off both flutes by being so aggressive.

Much to think about and reflect on over Christmas, but first a break !

Ok, that makes sense. Go 24K, anything less has even less torque. I'd fit the largest spindle that you can in there, clearly limiting the machine. Congrats once again.