Printable View
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. !Quote:
Originally Posted by petesos
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.Quote:
Originally Posted by 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:
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
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 themQuote:
Originally Posted by petesos
https://www.accu.co.uk/en/788-carbon...g&orderway=asc
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.!Quote:
Originally Posted by John11668
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.!
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
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
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.!Quote:
Originally Posted by John11668
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.!
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+b...ANNTA1&PC=U531
and dismantling to check this should not be a hard job .
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.Quote:
Originally Posted by John11668
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.!