There i was righting up a nice big explanation on "anti-backlash Nuts" lol, o well ill pop it in the FAQ's for next time anyway.

I think now i understand what it is your talking about, you called it "float" another term used is called "whip", so when the rod is spinning at high speeds or any speed the end that isn't supported has the possibility of movment as its unsupported.

Ok so how can we corroct this? or how can we eliminate this ?

I think the best way i have seen it done in the rockcliff machine is like CheekieMonkies has done on his build, he has simply used 608zz Skate Bearings mounted in the machine giving a supported option to the Threaded Rod. Please see the quoted text below, along with his pics.

Right i'v got a few ideas on things i'm going to change with the default rockcliff plans, you dont have todo what i'm about to show you, but you may as well as it will make for a better machine in the end.

i'v decided to added skate bearings to my threaded rod to support them, as i say the plans dont suggest to do this but when your machine is doing rapid movments you can get whats called "wip" in the threaded rod if its not supported. At first i was only going to support my threaded rod at the opposite end to the motor, but then i thought well why not do it both ends while your there it will only make it better anyway, so thats what i did.

You can see in this first pic i'v cut out a 22mm diameter whole to recive the skate bearing, the skate bearings are 8mm inside diameter by 22mm outside diameter and they are 7mm deep. I'v cut 10mm deep so the bearings sit 3mm deep from the surface. Befor i did this i drilled all the way through with a 14mm bit so the threaded rod and nut can pass through and spin, that would be the smaller hole you can see in the pic.
Click Images To Enlarge !

[img]http://www.mycncuk.com/forums/download/file.php?id=51&t=1[/img]

[img]http://www.mycncuk.com/forums/download/file.php?id=50&t=1[/img]

So the sun was still blazzing and the girls still shoping, so i pushed on and got some more done.

i decided befor i went on to the next stage, i would test fit the rods and rails and the bearings of course, you'll notice that i'v put my bearings on the out side of the machine. This isnt a must but i would like to put some tension on the rods so by putting them on the outside we can do just that.

To test fit the rails i had to make the 50mm x 50mm rail support plates, again i just marked the center and drilled out a 13mm diameter hole to recive the rails. You can see the rails are to long so ill cut them down later on in the build, i may not though as i could just rebuild the machine to a bigger size !
[img]http://www.mycncuk.com/forums/download/file.php?id=69&t=1[/img]

[img]http://www.mycncuk.com/forums/download/file.php?id=66&t=1[/img]

I have seen this done on a few diffrent machine builds and it has given good results, i would recommend you take a look at CheekieMonkies build log CLICK HERE !. He documents his build stage by stage and i hope you find it useful.

i'v got an ebay shop up selling things related to the forums as i stock them. i'v sold quite a few sets of the bearings if your still looking for some please take a look on this link: eBay

The bearings are £3.97 for a pack of 8 and i'v only got 2 sets of 8 left in stock, however i'v just imported the same again but only this time they will be abec7's so that little bit better.

Let me know if i can be of help !

CNCUK