Luthier CNC

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Originally Posted by A_Camera

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.

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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?

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Originally Posted by bluesking

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?

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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.

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Originally Posted by bluesking

I do have a table saw and maybe if I buy the right blade I may have to take the plate cutting into my own hands - but I'm a little concerned about cutting it square enough - its not a precision table saw by any means! I'm scared enough of the table saw when cutting hardwood - don't know what to expect with aluminium!

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Cutting aluminium on a table saw is no big deal. I have a Bosch GTS 10 J and with the Bosch blade made for cutting aluminium, it cuts aluminium like butter. Squaring the saw took some effort, but now it is square enough for this type of work. It is though messy to cut aluminium, so a shop vac is a must.

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Originally Posted by A_Camera

The link is not working.

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Here is a link to an eBay listing of the spindle I'm looking at:
https://www.ebay.co.uk/itm/EU-3KW-Ai...g/254196400436

I quite like the mounting plates on these square ones - seems easier to relocate the spindle up and down. Obviously still not as easy as a round spindle!

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Originally Posted by A_Camera

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.

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I have read that a constant speed fan is quieter as you suggest, but I don't think I have actually seen that mentioned on any of the listings I've seen on eBay/Aliexpress. I haven't planned a 24V supply either, so maybe it will be easiest if the fan is spindle driven, but I'm obviously still concerned about the noise.

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Originally Posted by A_Camera

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

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

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.

Attachment 25720

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.

Attachment 25721

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!)

Hi Bluesking,

I don't know if you are aware of Nottingham Hackspace, but there is a Bridgeport there. I am a member, but haven't been there for a long time as they were located principally up stairs and I can't negotiate stairs and carry anything. They were in the process of opening up a downstairs workshop for the heavy machines.

https://hms.nottinghack.org.uk

Cheers,

Rob-T

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Originally Posted by bluesking

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!)

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If you can't get access don't worry. You'd be suprised at how accurately you can place holes "the old fashioned way" using a surface plate, height gauge and optical centre punch.

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Originally Posted by cropwell

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

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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... ;)

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Originally Posted by A_Camera

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... ;)

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My point was that a Kress spindle is just a BRUSHED motor and it is noisy. As noisy as any other BRUSHED hand held routers that I have in my workshop. Kress call it a spindle as it has better front bearings than a hand held router, giving it less run-out and more suitability for long switch-on periods as in CNC routing.