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Old 10-18-2009, 03:02 AM
Titaniumboy Titaniumboy is offline
 
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Question on using stock leadscrews with CNC

Hello,

My first post here. I just found this forum a week ago, and I'm amazed at the level of skill here. Many, many impressive projects ranging from CNC conversions to custom-built bench mills and lathes. I can't believe how many hours I've already spent looking over some of the threads here.

I have never owned a mill or lathe (other than the small Sears lathe that I bought off of a buddy for $100 about 10 years ago, but have never used). I did take some machining classes through the local community college in another state about 12-15 years ago, but that was a long time ago, and it was very hard to build any skills with only touching the machines once every week.

I am currently trying to decide between an X2, X3, or RF45 clone. The prices for the first two would be $391 and $800, respectively (after the 20% Harbor Freight coupon). The RF45 clone looks like it can be delivered for $1550 from Lathemasters, but they appear to be out of stock at this moment. So the X3 is about double the price of the X2, and the RF45 is about double the price of the X3 (and quadruple the price of the X2). Currently leaning toward the X3, but that could change. I realize that these machines have serious limitations, and that each would need a complete rebuild as shown here: http://www.arceurotrade.co.uk/projec...on%20Guide.pdf

My current plan is to take some more machining classes at one of the local community college (by the way, it was very difficult finding any community colleges that even had a machining technology department anymore in this area), and get a solid background in manual machining. I think it would be useful to know how to run a mill manually before attempting a CNC conversion. I would think that a CNC conversion would not begin before next fall.

My use of the mill would be entirely for home hobby use. Home repairs, interesting projects found in Home Shop Machinist, boat and motorcycle upgrades, etc. Eventually it would be nice to be able to mill an AR lower from an 80% forging or 0% aluminum forging, or even mill an AR lower directly from aluminum billet. I envision milling materials such as aluminum, steel, SS, titanium, and plastic.

Anyway, back to question in the title of this post. I see an incredible amount of effort on mill CNC conversions revolve around reducing the backlash of the existing stock leadscrews, with most people apparently going for ballscrew upgrades, with some people settling for ACME screw upgrades. I tried searching for an answer to this, but didn't have much success:

1. Has anyone had very much success doing a mill CNC conversion using the stock leadscrews on the 3 chinese mills mentioned above?

2. Also, I'm confused about all of the attention focused on backlash reduction. Has anyone had any success using table positioning (from DRO encoders or something else?) to enable tighter tolerances from the stock leadscrews?

3. How well does the backlash adjustment feature in Mach3 work with stock leadscrews? ACME screws? Ballscrews?

Thanks for any comments.

Last edited by Titaniumboy; 10-18-2009 at 04:31 AM.
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