X axis drive

[petesos]

Hi All
Does anyone know where or the best place i can get a complete replacement ball screw for my 3040t cnc , tried contacting the company i purchased it from but like a lot of these people on flee bay as soon as they get your money they don't want to know you
Pete

[Sterob]

Is it removed from the machine?
Whats wrong with it?

Probably easiest thing to do would be to take some measurements and do a search online.
If your lucky it will be a standard size.

[Doddy]

Just to re-iterate Sterob's recommendation - the 3040's and similar out of China are not a single design - so there's no easy answer to your question than to measure and search for a suitable replacement.

If you've not played with a ball screw before, be aware that you're probably better to getting the nut as well - and that removing the nut must be done with care if you're not going to lose any bearings in the process (e.g. if you need to swap the orientation of the nut) - google that for more info. Also, when you say "complete replacement" - just what do you mean by "complete"?, screw?, screw+nut?, screw+nut+bearing-blocks? etc. I guess the screw+nut, but it's unclear from your post.

If you post a good picture of your screw we might be able to identify it. Common size for a ball screw would be 1605 (16mm diameter, 5mm pitch) then you just need to specify the lengths of the machined ends. But many of the cheaper 3040s are on trapezoidal/acme threads, rather than ball screws.

[Sterob]

Nicely put Doddy. :encouragement:

[JAZZCNC]

But many of the cheaper 3040s are on trapezoidal/acme threads, rather than ball screws.

Many with ball screws also don't have end bearings as in BK type or angular contact. They are often just standard cheap n nasty deep grove bearings machined into the end plate with a very sloppy fit.!! so the end machining will be custom rather than a standard BK12, 15, etc type machined screw.

Contact Fred at BST and give him the sizes and accurate dimensions of the machined end and he will make one for you.!

[petesos]

HI Guys
Thanks for the replys, have attached a few photos so you can see the type it is , i would rather buy the complete unit threaded bar bearing nuts the whole lot as the hands are not steady enough now to put together but i could manage to put the whole lot in together already built.
The instructions say it is 1404 double thread trapezoidal screws and about 420 mm long .
There is a bit of backlash on the x axis just now and thats what i want to get rid of as its about 1mm 286982869928700

[Doddy]

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]

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]

. 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]

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]

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]

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.:encouragement::encouragement::encouragement :.

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
:beer:

[John11668]

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-RM1204-250mm-1500mm-Rolled-Ball-Screw-End-Machined-Ballnut-For-CNC/183803546169?hash=item2acb8b8a39:g:dsMAAOSw399c0ta S

[johngoodrich]

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-steel-c15-trapezoidal-lead-screws#id_elasticsearch_category=788&orderby=ranking&orderway=asc

[JAZZCNC]

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-RM1204-250mm-1500mm-Rolled-Ball-Screw-End-Machined-Ballnut-For-CNC/183803546169?hash=item2acb8b8a39:g:dsMAAOSw399c0ta S

Yes, I do that's why I posted what I did but you obviously don't otherwise you wouldn't have linked to a ball screw which has end machining for a BK bearing when this machine doesn't have any.!

How difficult is like saying how longs a piece of string.? For me, it would be a simple thing because I'm kitted up and have experience but I suspect from the OP's post he isn't and doesn't so maybe not so easy.? But in either case, it's still a PIG and no amount of lipstick is going to change that.!

Use it to learn on, sell it, and move on is the best thing to do with these machines IME.!

[John11668]

While I bow to your experience Jazz, and I do know that my knowledge of this machine is limited to what I see on those pics . Never seen one in the flesh, Never used one.
But having replaced leadscrews with ballscrews in a different application, I found it no big deal , and it looks to me as if a BF on the outer end of the leadscrew/ballscrew would at least eliminate any end float in that screw without being a challenge to mount.
I dont see enough detail in the crosshead pics to know what is in there but it is hard to believe that an adaptor for a ballnut could not be accommodated. and £ 30 or so is not a massive outlay to keep the machine running reasonably while Petesos (like me ) continues his learning process.
Lets face it , once he replaces this machine it is consigned to the scrap heap.
I am only offering an economic solution to his immediate problem.
If he has the funds to splash out on a superior machine then all well and good ,
I was only suggesting this as an interim solution , which reading between the lines Petesos may be seeking

[mekanik]

Try the guys @ igus
https://www.igus.com/info/lead-screw-systems
I have had a couple of freebie leadscrews with nuts,
They could probably do the machining to a new leadscrew also.(ideally need to replace as a matched set) but just the nut might get you up and running.
Regards
Mike

[JAZZCNC]

While I bow to your experience Jazz, and I do know that my knowledge of this machine is limited to what I see on those pics . Never seen one in the flesh, Never used one.
But having replaced leadscrews with ballscrews in a different application, I found it no big deal , and it looks to me as if a BF on the outer end of the leadscrew/ballscrew would at least eliminate any end float in that screw without being a challenge to mount.
I dont see enough detail in the crosshead pics to know what is in there but it is hard to believe that an adaptor for a ballnut could not be accommodated. and £ 30 or so is not a massive outlay to keep the machine running reasonably while Petesos (like me ) continues his learning process.

No need to bow to me and all suggestions are good but that doesn't mean they are correct. This machine won't accept a BK type bearing easily and would severely limit the travels etc and the price is going to be much more than £30.!
As I see it without the tools to modify the end bearings to accept a ball screw designed for a BK setup the only sensible solution is to replace the screw with one that as been machined to the same end fittings, which is why I said contact Fred at BST. He will machine to any drawing you provide and at hardly any extra cost but it will still be much more than £30.
Other option is to do like been suggested and stick with lead screw and try to source one local.!

End of the day you have to decide how much backlash is acceptable. I would also question where the backlash is coming from because I'm sure I've seen +1mm mentioned and I'd be very surprised if all that is coming just from the screw/nut.? in which case replacing with ball screw won't get rid of that and that is my point about these machines. When you step down this upgrade path you open a can of worms with the only result being wasted time and money. It will always be a PIG with Lip stick on.!

[John11668]

I get all that you are saying jazz, and i agree that petesos would be better placed if he had a better machine , but it seems to me that in his current circumstances it could be not too hard a job to fit ball screw and BK nut. From what I see the BK bearing could be bolted to the outer face of the cheek, with a ball screw fitted through it and secured with the preload nut outside that. The motor end would need shortened and maybe reduced depending on the coupling size , and while there would be no easy place to fit a BF Bearing the fitup would be no worse than it is now with no support.
Yes he needs to ensure that the backlash is not occurring due to a slack fit at the coupling but that should be easily visible and remedied
What we would need to establish is whether the bore retaining the existing crosshead nut would accommodate a 12-04 ball nut, https://www.bing.com/search?q=1204+ball+nut+dimensions&cvid=24a413e73fd04185bf572583f237f892&FORM=ANNTA1&PC=U531
and dismantling to check this should not be a hard job .

[JAZZCNC]

I get all that you are saying jazz, and i agree that petesos would be better placed if he had a better machine , but it seems to me that in his current circumstances it could be not too hard a job to fit ball screw and BK nut.

Well first off it's a BK bearing block, not a nut and I'm not sure what cheek you are referring to.? But anyway it doesn't need to be that difficult if he gets a ball screw machined to the same dimensions as the old screw.

My point was the screw you linked won't just bolt straight into place so it will need more components meaning more cash, it will need some modifications to the machine and if the OP doesn't have the equipment or the experience to do these mods himself then it's not worth paying someone else to do them or having new parts made so it can be upgraded because the machine is what it is and throwing money at it won't make it change from a PIG into STALLION.! . . .It will always be a PIG with lipstick.!

Anyway, I've said my piece on why I think it's a bad route to take based on my experience with these machines and seeing other users make the same mistakes and we obviously won't agree so let us leave it at that and let the OP get on with which route he thinks suits him best.!