1. #1
    Need these, or need pointing in the direction of the cheapest place to get them-

    * Power table feed ( universal type will do ) for my x axis
    * 16mm ball screw + nut 2000mm long with ends machined with supports
    * 12mm ball screw + nut 600mm long with ends machined with supports
    * 2 x universal handles for my x + y axis

    Could do with a decsent engineering supplies for other bits and bobs in the nottinghamshire area.
    Cheers
    Jay

  2. #2
    Quote Originally Posted by chip View Post
    i bought my screws from this fella, end machined with supports, if you look through his shop..., does any size to,although i havent actually used mine yet,ive not come across any complaints from others.
    http://cgi.ebay.co.uk/3-ballscrew-16...item3a5e94115a
    Agree with this. Used him twice for rails and ball-screws and the service has been excellent. Got the ballscrew machined slightly differently to standard, and I think he didn't charge any extra :)

    Make your own handles? Surely a good first project for your new machine!?

    By the way I hope you're not intending to spin that ballscrew, unless it's under lots of tension... 2m screw that diameter will whip a LOT severely limiting your rapids. You want to rotate the nut ideally, not the screw. That's what I did on my build with similar length screws.

  3. #3
    The 2m ballscrew should be fine there isnt going to be any rapids just a steady feed, as for making handles, I have my own cnc machining business but its not worth all the hassle of making them when I can buy them pretty cheap, same goes for most of the other bits I need, unless it needs to be a specific shape.

  4. #4
    Quote Originally Posted by jpcnc View Post
    The 2m ballscrew should be fine there isnt going to be any rapids just a steady feed, as for making handles, I have my own cnc machining business but its not worth all the hassle of making them when I can buy them pretty cheap, same goes for most of the other bits I need, unless it needs to be a specific shape.
    The critical speed for that length of screw is 290 to 650rpm - depending on what bearings you use. That's 1450 to 3250mm/min assuming 5mm pitch screw. I guess 3250 is ok - why are there not going to be any rapids?

    I generally go on the if I can make it cheaper I do philosophy!

  5. #5
    Quote Originally Posted by Jonathan View Post
    The critical speed for that length of screw is 290 to 650rpm - depending on what bearings you use. That's 1450 to 3250mm/min assuming 5mm pitch screw. I guess 3250 is ok - why are there not going to be any rapids?

    I generally go on the if I can make it cheaper I do philosophy!
    I'm gonna agree with Jonathan, you will soon get sick of going at those speeds over a large distance, plus going too slow with a fixed high speed spindle means you will burn cutters/material and wear them out quicker.

    I generally go on the principle that i make it as good as possible, so it will last indefinitely. An example is my lathe in the video on the home page you will see i used telescopic ballscrew covers they are very expensive and i had to wait 6 weeks for them to be made. The inbuilt seals will not keep out contaminants so a few months down the line they would all be ruined.

    Phil

  6. #6
    Its only going to be turning rubber off tyres at around 1000mm/min, and it will only be doing one cut at a time, rapid will only be used to return it to the start point, ive sourced a supplier that is going to be issueing me what I need for beer tokens so I can get what I want, so I may upgrade to 25mm for the extra rigidity

  7. #7
    25mm would get roughly 2500 to 5700mm/min depending on what bearings you are intending to use on the screw?
    I found the formula to be pretty accurate in my case. It suggested that the Y axis screw would whip over 6000mm/min, and it does. I'm running it at 4000 to be safe.

  8. #8
    My y axis is only going to be used to wind out by hand to a position then locked off, ballscrew is overkill really but I want the anti backlash etc
    If im only needing 1000mm/min with a 5mm pitch then its only gona be turning at 200rpm wich I think will be fine

  9. #9
    Quote Originally Posted by jpcnc View Post
    My y axis is only going to be used to wind out by hand to a position then locked off, ballscrew is overkill really but I want the anti backlash etc
    If im only needing 1000mm/min with a 5mm pitch then its only gona be turning at 200rpm wich I think will be fine
    Yes I'm sure 200rpm will be fine, so long as your happy waiting 2 minutes to traverse the whole bed.
    Surely if you're operating the Y axis by hand then you can compensate for the backlash by hand, as one would normally when using a manual machine? I suppose not having backlash helps get a good finish as you can use climb milling...not sure if that's an issue cutting rubber.

    You might want to consider the drive mechanish I used on my Y axis - very very cheap, and very little if any backlash.

    http://www.mycncuk.com/forums/showth...ll=1#post16365

    (post #7)

  10. #10
    Its a lathe set up theres no climb milling, as for the ballscrew if i get it for free i might aswell do it for the optimum set up

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