3 axis cnc/router bed

**Jonathan** · 04-12-2012

Originally Posted by dudz

What sort of clamps are there for that sort of set up ?

http://www.ebay.co.uk/sch/i.html?_fr...milling+clamps

But you can use just about anything really...

Originally Posted by dudz

or do you make your own ?. I suppose 10mm T slots ?

There are quite a few examples of homemade ones on forums. 10mm should be fine.

Originally Posted by dudz

I try to buy everything on ebay for ease. What grade of Alu should I get for the bed ?

6082 is generally the best value. Aluminium is really expensive on eBay. www.aluminiumwarehouse.com will be much cheaper, or I use Metal Stockists: ASC Metals Lincoln Ltd. - Metal stockholders for East Midlands/North of England as they're even cheaper...

**dudz** · 05-12-2012

Seeing all my rails are 25mm round (unsupported) do I really need to replace them with supported rails ? I see that most machines of this size only have 16 or 20mm supported rails.

**Jonathan** · 06-12-2012

Originally Posted by dudz

Seeing all my rails are 25mm round (unsupported) do I really need to replace them with supported rails ?

Yes, if you are not satisfied with the current rigidity of the machine. Even 12mm supported is likely to be stronger than 25mm unsupported over a reasonable distance, but that doesn't meant you should use 12mm:
http://www.mycncuk.com/forums/faqs-p...ted-rails.html

Originally Posted by dudz

I see that most machines of this size only have 16 or 20mm supported rails.

For much of history most people believed the earth was flat, but that didn't make it flat!

**dudz** · 21-12-2012

Ok... I have the 25mm Aluminium for the bed. I unbolted the original vacuum bed, and noticed straight away that it is bent down on each end where there are no bearing blocks supporting it. 4mm to nothing, from each end to the center !
I took out the 25mm unsupported rails and rolled them on a sheet of glass to check for bend. Seems all ok. The vacuum bed is pretty flimsy. 2 out of the 4 bearing blocks seem to have had their day ( roll a bit rough ). So I suppose I might aswell replace the 25mm rails for supported ones with new open bearings ; SBR20X900 Precision Supported Rail kit 900mm long CNC | eBay

The rail length I need for the X axis is 850mm. Is 20mm rails (as in the link) going to suffice ?
Also the ballscrew seems fine. But as I am replacing the rails, will the height from the 45mm profile (frame) to the bottom of the new Bed be the same for the new rails and the original ball screw bearing ? The new rails are certainly within 2mm (see pdf on ebay link )

**Jonathan** · 21-12-2012

If you're planning on getting the rails from that seller then you can get 25mm for the same price here, or maybe less here if you send the seller a message. I'd go for 25mm since they have one more row of balls than the 20mm rails, so are correspondingly stronger. Having said that either will be a huge improvement on what you have now.

**dudz** · 21-12-2012

Wow, China again. After shipping plus import tax, do you think the prices would still be better ?

**Jonathan** · 21-12-2012

Originally Posted by dudz

Wow, China again. After shipping plus import tax, do you think the prices would still be better ?

To England I'm certain they would be, so unless where you live the taxes are even more extortionate, it should be cheaper.

**wilfy** · 21-12-2012

Originally Posted by dudz

Wow, China again. After shipping plus import tax, do you think the prices would still be better ?

just for the record i've had to pay £21.50 to fedex a week after i got my deliveries from china, i'm not sure if it's that much due to the fact it come in 2 parcels

**dudz** · 21-12-2012

hmmmm..... I just payed 37 euros taxes for an item from the US which cost 85 dollars.

**dudz** · 21-12-2012

I have 45mmx45mm profiles with 10mm T slots. Please could someone point me towards an ebay link that sells the correct T Nuts and bolts for these rails for 45mm profiles. I think the rail bolts need to be M6.

FOUND THEM....thanks