[lesthegringo]

Gents, I am not quite ready for a CNC conversion yet, but having modified my mill to have all three axes with digital readouts (and porting them to PC is in progress) I can now see just how much backlash there is.

I believe that Fignoggle do some ACME threaded leadscrews with delrin anti backlash nuts. As I am in the UAE, and would have to either pay pretty horrendous shipping charges or get them sent to someone who is visiting, whenever that is, I need to be certain that it is the right decision to buy them. Have any of you used these? If so can you tell me how well it worked and whether it really was a simple installation. I have not found any competing products, is there any other manufacturer or method that I can look at?

The other question is with regard to the gibs; aside from lapping them is there some way of improving them? This applies equally to my Clarke 7 X 10 lathe, any improvements would be gratefully received.

Thanks

Les

[Mad Welder]

Hi there Les :wave: welcome to cnczone...

Unfortunately I’m not familiar with the X2 setup but is your stock nut long enough and that you could make a cut (a blade in thickness) on the stock nut to a depth of half of the ID dimension and then drill and tap the nut so as to have the ability to compress this newly cut thickness and so as consequence what you’re doing is to have the capability to tighten the stock nut on the stock lead screw and so to reduce the “slop” and also reduce the backlash…..and this temporary setup will suffice until you’re ready to make your final order for your CNC hardware components….and hopefully I haven’t confused you more either here…… but the mill that I myself have converted to cnc is the Optimum BF20L model and this machine had stock lead screw nuts similarly presented/machined as I mentioned above… and I also used the stock trapezoid lead screw and nut originally in my build…so as to use my machine to build itself “so to speak” and there after I fitted the ballscrew and ballnut…… but used the stock leadscrew under cnc control initially…

Edit: also I would suggest a thread lock adhesive of a medium strength applied to the threads of the bolts that you fit to compress the leadscrew nut....and the reason for this suggestion is the vibration when under machining load may (or may not) loosen or tighten the new bolts you fit which would result in either locking/binding the nut on the lead screw threads or loosening the bolt which will defeat the purpose of the mod completely...

[gort]

What I did on my DIY CNC was to put 2 drive nuts on the lead screw.
They have acme thread on inside, and much finer std thread on outside that screws
into the mounts. By unscrewing one, can force more separation between
the two drive nuts and eliminated backlash. Not too much or binds.
Then lock down the nut, or put a easy access worm adjustment on the nut.

[brianbonedoc]

I have struggled with this too - my solution to fix .035" of backlash to .0025 was to wrap the rubber spider of each Lovejoy connector with teflon tape. And check to make sure the bearing nuts on the right side of the X-axis are tight. Apparently the rubber had dried out a bit - now my x and y backlash are <0.003 which i can live with and use backlash comp in Mach 3 to take to zero.

My Z axis still has about .008 that I am struggling with.

[mduckett]

If you want to give a try at making your own zero backlash ACME nuts, this site has an interesting approach: http://bbs.homeshopmachinist.net/thr...s-the-easy-way

I plan to use this idea someday for my minilathe cross and compound screws but haven't tried it yet.

-md

[Dano523]

Your fighting a loosen battle on the back lash. Yes, slit nut will get you down to around .003, but is not gong to last long since you will have re-tighten the slit nuts up way too often. Another place that will help some is install set screws in the handles to lock them down on the shaft over then just the crush nuts (remove the lash between the key and handle slot on the shaft.

Gib/table lapping is a must, since the tighter you can adjust them and still move the table, the less chatter your going to have in moving cuts. Same goes with a column brace as well, especially if you replace the motor control to put all the power the motor offers down to the work piece (remember to replace the plastic gears with a belt drive since the motor de-crippled from 90V to 120v is going to chew through plastic gears like they where candy.

So step one, lap, install a column back brace, changer out the gears to a belt drive, then replace the motor controller to hobble the motor.

As for backlash, your never going to get it all out, so forgo using the wheel dials, and just DRO the machine instead.

Value budget, you can pick up I gauging scales for around $100 for all three, and be done with it for causal use for around $130 in the end. And when you go to CNC the machine, easily get the money back out of what you spent on just selling the pre-built DRO kit.