metric vs. imperial acme screws?

[carsonau]

I live in australia and I plan to mill things that have been designed with a metric system in mind.

For my CNC router...would getting metric acme screws be preferable over imperial ones? What are the disadvantages of using imperial acme screws if every part i plan to mill is in metric?

I say this because i am able to source imperial acme screws quite cheaply, but metric ones are almost 2x more.

[Degrom]

Originally Posted by carsonau I live in australia and I plan to mill things that have been designed with a metric system in mind. For my CNC router...would getting metric acme screws be preferable over imperial ones? What are the disadvantages of using imperial acme screws if every part i plan to mill is in metric? I say this because i am able to source imperial acme screws quite cheaply, but metric ones are almost 2x more.

Hi, Welcome to the site.

Regarding your question, I am also in the same situation. What I have found is that finding components for metric acme screws is going to be a problem. (Most of the anti-backlash units are made for imperial acme screws)

Hope this helps a bit.

[anoel]

It doesn't really matter a whole lot when your leadscrews are imperial and your parts are metric. We make metric parts in the states on imperial machines all the time... A 1/2 Dia screw with a 10 turn per inch lead, it's in metric terms a 12.7mm 10 turn per 25.4mm screw. If one turn of the lead screw moves the axis .1 inch then the same screw moves the axis 2.54 mm. It's not nice round numbers in Metric terms but once you have your machine set up to use metric units you don't have to think about whether or not you have imperial lead screws or not.

[Greolt]

G'day Carsonau and welcome to the forum.

What Anoel says is correct. Don't be concerned about it. Use the imperial screws.

I have a small mill with metric screws and steps per mm are 400. On my router steps per mm are 106.482364.

Not a nice round number but in use it makes no practical difference at all.

Where are you up to with your design and build?

Keep us posted and make good use of the wealth of knowledge and experience to be found on this forum.

Where in Aus. are you?

Greg

[carsonau]

I am in brisbane! I am just in the planning stages of my "build". I have already ordered a 3-axis kit from hobbycnc.com

I am thinking of a design similar to a Joes cnc. For the next two weeks I have access to a Roland CNC Router (450mm x 720mm), so i plan to route my MDF (from bunnings) in the next two weeks. Getting everything together after that could take much longer... :P

[Degrom]

Originally Posted by carsonau I live in australia and I plan to mill things that have been designed with a metric system in mind. For my CNC router...would getting metric acme screws be preferable over imperial ones? What are the disadvantages of using imperial acme screws if every part i plan to mill is in metric? I say this because i am able to source imperial acme screws quite cheaply, but metric ones are almost 2x more.

Hi Carsonau,

Do you mind sharing you source for Acme screws. I live a few degrees south of you and can't get a proper supplier of acme screws.

thanks.

[Dingo745]

Have a look at this site. I got some metric leadscrews from them.
http://www.tea.net.au/
T.E.A. Transmissions Pty Ltd Australia

Phone: (07) 4129 2533

Fax: (07) 4129 2437

Email: sales@tea.net.au

Save yourself the hassle and go straight to a proper ballscrew like these http://www.homeshopcnc.com/page3.html
Money well spent I.M.O.

[Degrom]

Originally Posted by Dingo745 Have a look at this site. I got some metric leadscrews from them. http://www.tea.net.au/ T.E.A. Transmissions Pty Ltd Australia Phone: (07) 4129 2533 Fax: (07) 4129 2437 Email: sales@tea.net.au Save yourself the hassle and go straight to a proper ballscrew like these http://www.homeshopcnc.com/page3.html Money well spent I.M.O.

Thanks, I will give them a ring.

I am busy with a plasma table so ball screws is not a good option with all the microscopic dust the cutting process produces.