Ball Screws or Belts

[1druid1]

Hi All

Just starting to think about building my homemade CNC Router, got a few different plans and trying to come up with a design that suits me. What I know for sure is it will be a flying gantry build and it will have a cutting area of about 800mm x 600mm and may cut depths up to 60 - 70mm in pine and mahogonny, possibly a bit larger. So the question is how to move the different axis, I know nearly 80% use a ballscrews, but has anyone used steppers and belts to completly drive there system. What are the advantages and disadvantages of both, what is the best for acuracy, I know you can get precision ballscrews but for the size of the machine, these would leave me broke :-)

Cheers

Dougie

[jdell42]

I know nearly 80% use a ballscrews

Most of the DIY machines use ACME screws which are significantly cheaper than ball screws and ball nuts. All the ACME screws for a 2x4 machine would be less than $100 USD.

[1druid1]

Thanks for the reply, for a length of 39" what diameter screw would be best suited, how many starts and turns per inch?

Cheers

Dougie

[EL34]

I got all my screws, bearing blocks and a motor mount from these guys.

They are cheap and will cut the screws to any length you need.
They cut a 1/4" motor coupler end and two areas that ride in the bearing blocks that they sell.

http://www.precisiontechmachining.com/

[jdell42]

Thanks for the reply, for a length of 39" what diameter screw would be best suited, how many starts and turns per inch?

1/2" should be more than plenty. The number of starts and TPI is up to you but common sizes are 10TPI single start and 8TPI 2 start.