Luthier CNC

[bluesking]

Don't worry about the noise generated by air cooled spindles. It only makes a difference if you will be cutting air. ...and you'll be surprised how quiet an air cooled brushless spindle is compared to the Kress or a router...

I have been using air cooled spindle for some years now, though it is only 1.5kW, but it is that noisy before cutting starts. If it must be replaced I'll buy another air cooled spindle, that's for sure.

Thanks, it would certainly make things easier to go with air-cooled. I have a small room set aside for the CNC to go in anyway, so that will probably be the best way to deal with overall noise.

You mention that you have a brushless spindle? The one I'm looking at has brushes as far as I know:
https://www.aliexpress.com/store/pro...56c041d6TtIpdJ

I can't find brushless spindles above 1kw. Where did you get yours?

[A_Camera]

Thanks, it would certainly make things easier to go with air-cooled. I have a small room set aside for the CNC to go in anyway, so that will probably be the best way to deal with overall noise.

You mention that you have a brushless spindle? The one I'm looking at has brushes as far as I know:
https://www.aliexpress.com/store/pro...56c041d6TtIpdJ

I can't find brushless spindles above 1kw. Where did you get yours?

The link is not working.
Anyway, all three phase spindles are brushless, for example this one:

https://www.ebay.com/itm/From-EU-3-P...8AAOSwBydbh178

Note that this is just one I picked from ebay, though I bought mine from a different seller. Anyway, the only thing I'd do differently today is that I'd probably by a spindle with square housing today, and if possible, I'd buy one with active cooling fan, which is driven with a separate 24V, so the fan has a constant speed. I think those are better than the round ones with the fan mounted on the motor axis.

[cropwell]

you'll be surprised how quiet an air cooled brushless spindle is compared to the Kress or a router....

I wouldn't. I've got a Kress, they are just as noisy as any other brushed motor router.

[bluesking]

Made a few minor updates based on the useful comments to date:

Upped the side plates from 15mm to 20mm (I've changed my mind about using reinforcement ribs here - seems like these might increase the risk of snagging on something or someone whilst the CNC is doing its thing)

Changed the front and back from extrusions to solid 20mm plates. Added 3 foot-like features to these so the base of the machine is basically a tripod to prevent it wobbling on the workbench.



Added some heavy duty steel brackets to the centre of the bed - I can't afford the cost or weight of a solid aluminium bed so this is my compromise. It'll all be connected to an MDF sheet lying on top of the bed structure with a 2nd MDF sheet on top of that as a spoil board.



Most everything else will be achieved using long screws into the extrusion cores, attaching them to the various plates.

Won't be able to machine my big plates on any CNC I can get access to but I am hoping to get access to a Bridgeport mill so I can at least drill all of the holes in precise locations (assuming I can figure out how to use a Bridgeport!)

[A_Camera]

I wouldn't. I've got a Kress, they are just as noisy as any other brushed motor router.

The Kress is MUCH noisier than any brushless motor of the same (or even higher) power. My 1.5kW brushless spindle is definitely much quieter than the 1kW Kress. Perhaps you misunderstood my post... ;)

[Ger21]

- Relies on low-risk mature technologies (parallel port, Mach3)

Mach3 is obsolete, and imo should never even be considered for a new machines. And trying to use parallel ports on PC's these days is far more problematic than it was when Mach3 was created.

Consider UCCNC, which is very similar to Mach3, but far superior in most ways. For the same cost as a Mach3 license, you can get a UCCNC license plus an AXBB motion controller. This will be far superior to Mach3 and a parallel port, with superior performance, and much greater reliability.

[bluesking]

Mach3 is obsolete, and imo should never even be considered for a new machines. And trying to use parallel ports on PC's these days is far more problematic than it was when Mach3 was created.

Consider UCCNC, which is very similar to Mach3, but far superior in most ways. For the same cost as a Mach3 license, you can get a UCCNC license plus an AXBB motion controller. This will be far superior to Mach3 and a parallel port, with superior performance, and much greater reliability.

Thanks Gerry. Clive also pointed this out. When I started planning things out in more details I quickly realised you guys were right.

Since then I've got a UC400ETH. Didn't know about the AXBB at that time but I already have a parallel BoB that brings the VFD and charge pump features so I think it'll work out functionally similar.

I intend to use UCCNC.

[bluesking]

Following on from my plate design work, yesterday I drilled the various holes:



Everything seemed to go well. I have a mixture of M5, M6 and M12 bolts to accommodate. Many of the holes don't need tapping so I created mostly 5.5, 6.5 & 13mm holes to accommodate the screws.

I also have a bunch of M5 holes that needed tapping. Here I made a bit of a mistake. Really didn't think it would make a difference so I just used a 4mm drill bit I had laying around. Drilling went well, but as soon as I started to tap this happened:



My lack of metalworking experience takes it's first casualty! Today I re-drilled all the offending holes and I think I got away with it overall.

Here's what I have learned:
1) If you want to use a M5 tap, you need a 4.2mm hole. No getting around this. Maybe 4.5mm would also work, but I didn't even try this as 4.2 worked perfectly.
2) If you break a tap in a hole there really isn't any way to recover. You try to drill it out, but because aluminium is so much softer than hardened steel, the drill bit wanders around the tap creating a bit of a disaster.
3) Cutting oil is a mixed blessing. Makes all the work super messy but I think improves results. If doing again I'd drill all the holes dry and use cutting oil just to do the tapping work.

The one hole I messed up was meant to attach to one of my z-axis HIWIN carriages. I'm hoping I can get away with using only 3 out of the 4 holes to mount this. I think this will be fine so I'm not going to bother buying/making a whole new plate for now.

[Doddy]

Here's what I have learned:

Been there. I think most of us have.

[mekanik]

Hi Bluesking
Broken drills/taps in non ferous materials can be dissolved using Alum solution.
https://www.google.com/url?sa=t&rct=...9aX0rtzdbxJhZP
Also when tapping go with the recommended size from your Zeus book ie 4.2mm but use a solid(no flute's) spiral tap.
Regards
Mike