Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!

**JAZZCNC** · 09-01-2014

Originally Posted by ba99297

What about self levelling floor resigns ?

The problem comes from the type of resin.? I think Car paints and self leveing Floor paints which are manily polyester resins contain high solvent levels which evaporate and can cause sinking etc.

**Wejjmeister** · 09-01-2014

Originally Posted by JAZZCNC

The problem comes from the type of resin.? I think Car paints and self leveing Floor paints which are manily polyester resins contain high solvent levels which evaporate and can cause sinking etc.

They wont shrink or sink but they do not harden to the same levels as paints are meant to be somewhat flexible to resist cracking etc, so it wouldn't be suitable for this particular job as it would 'give' unlike the epoxy resins used in these forums before which cure fully.

**JAZZCNC** · 09-01-2014

Originally Posted by Wejjmeister

They wont shrink or sink but they do not harden to the same levels as paints are meant to be somewhat flexible to resist cracking etc, so it wouldn't be suitable for this particular job as it would 'give' unlike the epoxy resins used in these forums before which cure fully.

I belive it does shrink and it's why Only Solvent free Epoxy resin is used for Epoxy Granite to avoid voids, sinking and cracks appearing when solvent evaporates.!!

Regards the steel and bracing then yes you could reduce quite a bit of that steel.

**Wejjmeister** · 10-01-2014

Next round guys Mk3!

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Removed steel form sides and changed bed supports. Any better? Saves a lot of excess steel.

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Started on ideas for rails etc... let me know your thoughts please.

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Think this should provide a strong setup, also thinking about using BK blocks to mount Ball screws? Will these be suitable?

Thanks!!

**Jonathan** · 10-01-2014

The covers round your ballscrews will fill up with swarf and cause the ballnut to fail prematurely.

Originally Posted by Wejjmeister

Think this should provide a strong setup, also thinking about using BK blocks to mount Ball screws? Will these be suitable?

Best way is to use a rotating nut. If not, then at this length you'll want two angular contact bearings at both ends to get a respectable speed. Search on Google 'ballscrew critical speed' for more information.