Ball Screw for CnC Router??

[amas]

Need Advice, i buliding a mini cnc router table about 18" x 24".
is anyone can advice me what size or pitch ball screw i can use.

Thanks & Thanks
amas

[jdwoods]

Depending on the accuracy you are trying to achive. There ae several options. If you are going for inexpensive you can just use std 1/2 - 10 treaded rod and nuts. If you want a bit more accuracy and more robust try 1/2 - 10 Acme rod. the nuts for those can be a bit pricey. An alterative to thoes are power nuts for trash compactors they are around 5-10 dollars each. Then you can get Thompson Rod very accurate and very pricey. Look at Mcmastercarr.com that will get you a good price range and you can order from them as well. I hope this helps

[amas]

Hi John Wayne, Great Thanks about the info, I am very new about Ball screw rod, & also my country all ball screw are selling in mm size.

i can get it close to 1/2in to mm size, if i go for mm size, always the supplier ask me what is the Pitch. like 5 / 10 /15 /?.

So mean is : 1 turn =lenght of travel in mm.

1/2 rod, i can get it close like 12mm rod, John. can you advice me what is the pitch size? i mean 1 turn per travel.

BTW can i use 3no of 200oz stepper motor?, for this size of router table 18" x 24". i also intend to purchase the driver board from HobbyCnC, isit OK.

Very Thanks
amas

[GaryCorlew]

The 200oz motors will be fine, Also the lower the pitch number the faster your machine will travel(ex 5 pitch will travel twice as fast as 10 pitch)

[jdwoods]

Gary is correct. Think of a screw as an incline wrapped around a shaft. The lower the pitch number the greater the angle. As you travel the quicker you get to the top and the more effort it takes for you to get there. As to the size of the shaft the larger dia. the less shaft whip you will encounter.

[amas]

Thanks Guy, this is a Great Forum. hmm i always think the lower pitch, travel less, i am loss now.. let say. now i get a (12mm rod pitch 5) is mean
1 turn=travel 5mm right? so 5 turn=travel 25mm.

Now compare (12mm rod pitch 10), 1 turn=travel 10mm, So 5 turn=travel 50mm......isit...?? so the pitch:10 is travel more that pitch:5. this what the supplier say, sorry guy i just know base. iam very new in this, but i need to learn from your to build my first mini router. Your are Professional

[jdwoods]

May be this site will help http://www.velmex.com/manual_lead_screws.html

[acondit]

amas,

We are used to dealing with TPI (threads per inch or turns per inch) and we often refer to it as pitch which technically speaking it is not. 10 tpi is 0.1 pitch and 5 tpi is 0.2 pitch. So the smaller the pitch the higher the tpi and the larger the pitch the smaller the tpi (they have an inverse relationship).

[amas]

Hi Guy,so if build a 24" x 48" router, can i using same 1/2 rod pitch 5 ball screw? Please Any one can advice me which the correct size of ball screw & stepper motor size, that i can use, if i build 24" x 48" or bigger size 4FT x 8FT router machine. cutting Material like plastic & aluminum.

Advice help thank.