X axis drive

**Doddy** · 10-08-2020

That looks like it's got a few miles on the clock, but - if you'll forgive the impertinent question - do you know that the backlash is because of the screw / nut? Have you checked the mounting of the nut to the bed?, and have you checked the mounting of the screw and the coupling to the stepper motor? if the problem is elsewhere than the nut you could save yourself a lot of hassle.

If you're confident it is the screw/nut - then from what I've read in the last 10 minutes some of the 3040/trapezoidal screws use a delrin (plastic) nut - and that (rather than the screw) is likely to be the cause of the backlash - although 1mm is pretty horrendous - surprised the nut is still holding together with that. I'd expect if it is the nut that it's got progressively worse to the position that you find yourself in today. If it is delrin then it's not hard to re-cut a new nut using a bit of heat, delrin, and the original screw. Otherwise...

Eyeballing the photos you've provided - it looks as though the nut is attached to the carriage with two M4 or M5 bolts - use a hex key/drive to unscrew those and you should be able to persuade the nut from the carriage - then you can properly assess it for backlash. I've spent a short time googling/ebaying/amazoning and the T 14 4mm p2 trapezoidals are not immediately obvious from the "usual" sources. It might be worth looking to see if you can get similar, even if not the same. Maybe the Chinese suppliers (including Jazz's recommendation) may be able to source a nut.

I'm purposely ignoring for now your reluctance to perform a lot of disassembly/reassembly - that might be unavoidable.

**petesos** · 11-08-2020

Thanks guys for the help
And yes i am going to replace it all with better quality fixings as and when they need replacing , going to start removing x axis tonight and will post photos and dimensions so i can source a supplier . Jazz have you got a number for the engineer you mentioned .
And by the way guys i work in the urethane industry so if you need bar or sheet urethane drop me a line

Pete

**routercnc** · 12-08-2020

Originally Posted by petesos

. Jazz have you got a number for the engineer you mentioned
Pete

Fred is at BST automation on Aliexpress over in China. You are dealing directly so would need to be happy with how Aliexpress works, and create an account. Send him an email to make sure he can help with that type of thread first.

**petesos** · 13-08-2020

Right guys
You guys been in this game for a long time so am asking for your recommendations ,
The x axis screw on this cheap chinky machine is 12 mm diameter trapezoidal and am looking for a good replacement ballscrew as i will replace all the ballscrews as they wear .
What would be the best upgrade { ballscrews } from the cheap screws that are on there already, any ideas please

**JAZZCNC** · 13-08-2020

Originally Posted by petesos

Right guys
You guys been in this game for a long time so am asking for your recommendations ,
The x axis screw on this cheap chinky machine is 12 mm diameter trapezoidal and am looking for a good replacement ballscrew as i will replace all the ballscrews as they wear .
What would be the best upgrade { ballscrews } from the cheap screws that are on there already, any ideas please

You are not going to like this reply but it's the honest truth.!! . . . You Can't make a silk purse out of a sow's ear. !

So don't waste your money trying to upgrade this machine. Just use it as it is and save the money to put to another machine which is designed correctly and uses ball screws etc.

**petesos** · 13-08-2020

Originally Posted by JAZZCNC

You are not going to like this reply but it's the honest truth.!! . . . You Can't make a silk purse out of a sow's ear. !

So don't waste your money trying to upgrade this machine. Just use it as it is and save the money to put to another machine which is designed correctly and uses ball screws etc.

Cant beat honesty Jazzcnc.
Yep i know what your saying , I have just had a reply from the sales girl who i bought the machine from in Switzerland that they could send the new replacement part and if i could deposit 280 quid sterling into there account she would send me the part i want.

My wife was so pleased with me that i only used the F word eight times in the return email.

.

So yep that is my course of action make do with it till something better comes up . but need to find a way of taking the backlash out in the meantime so am going to do a strip down

**John11668** · 13-08-2020

I will presume you know the machine type Jazz, and that your silk purse comment is warranted ,
But would it really be so hard to replace with Chinese Ball screws
https://www.ebay.co.uk/itm/SFU1204-R...MAAOSw399c0taS

**johngoodrich** · 13-08-2020

Originally Posted by petesos

Right guys
You guys been in this game for a long time so am asking for your recommendations ,
The x axis screw on this cheap chinky machine is 12 mm diameter trapezoidal and am looking for a good replacement ballscrew as i will replace all the ballscrews as they wear .
What would be the best upgrade { ballscrews } from the cheap screws that are on there already, any ideas please

i would just replace with the same as you have got now. go to somewhere like accu.co.uk they have lots of trapezoidal bar and nuts to go with them
https://www.accu.co.uk/en/788-carbon...g&orderway=asc