[nickjb]

After 6 months of moderate use (and a bit of abuse) my 3040T router has developed a bit a play in all 3 axis. Looks to be between the white (delrin?) nut and the threaded bar. Is this part replaceable/available? Should I be looking to upgrade the lead screws at this stage (or the whole machine )?

The spec says "Leadscrew 1404 double thread Trapezoidal screws" but this doesn't throw up much in Google

[aarggh]

The plastic nuts on trapezoidal thread screws are the worst for wearing and play. What you can do is take the nut off and slit it crosswise in from the end. Then fit a hose clamp around the outside. This will allow you to compress the delrin nut around the thread, but don't make it too tight as you'll wear it quicker. A better longer term solution would be to make a new nut using some long nuts to suit the thread, and fit them inside a tube with a spring between them to put pressure on them, to help remove backlash. Sounds like hard work but it's really not.

cheers, Ian

[procat]

I also have 3040T router... recently having problems with the upper side-to-side axis. It clicks at two-three points on it's travel, only in one direction. I'm thinking something is wrong with the plastic nut. Are replacements known?

[handlewanker]

Hi, OMG......anyone buying a 3040T and not realising that it has Acme screw threads....'COS THAT'S WHY IT'S SO CHEAP......has now got to pay the piper etc.

The very best plan would be to change all screws to ball screws......cost more, but now you have the machine the extra cost will give you a much longer life and backlashless (for a while) motions.

You could make or get made some bronze nuts, two for each screw and have them spring loaded against one another to get some degree of backlash reduction, provided you don't reverse the screws against a heavy load, in which case you will override the spring pressure and get some backlash creeping in.

I've seen the prices of the 3040T at around A$750 as opposed to the ball screw ones that go for approx A$1,300, so the extra cost as a retrofit is not an economical solution, but a necessary one.

A ball screw drive will give it Rolls Royce status to a degree......your steppers will work better and smoother with the frictionless drive anyway.
Ian.

[procat]

My problem with the clicking was a broken shaft coupler. I probably had the feed rate too high. $3.09 for a replacement part including shipping from china. (4 week lead time, of course)

If your livelihood depended on making a product on a CNC table, a cheap chinese table is probably not the way to go. If you just want to explore and learn about everything that is required to make a cut part or engrave line art and are a knowledgeable DIY, the chinese machine I've been very happy with considering the price point. I've learned so much about CAD (drawing programs, typically use LibreCAD), CAM (using the free old version of BAMCAM) and Mach3 the free/old/likely pirated copy that came with the table. This hobby takes serious time to learn, though I did have the cnc setup and moving on the first day I got it.

It's not fast or production quality. Though, depending on the part to be made I could see these possibly being useful in a business setting.

Also some of the latest CNC's out of china seem to be shipping with ball screw threads.

Likely at some point after I've feel I've learned enough about CNC machines to make an informed buying choice, I'll probably buy a higher quality unit. This has been a great sink or swim test unit for me.

[beauman58]

Hi All,
Just took mine apart because it didn't move as easy in X as Y or Z checking with my hand turning the screw. Thought it might be the cheap bearings. No luck in that one, it's the screw itself is bent. Also for those of you with these machines check each axis without the stepper attached and turn them to compare the freedom of travel. If it feels like there is a difference especially in X and Y you probably have the same issue. Good luck on getting a replacement from your Chinese Ebay supplier. Mine has went so far as to get another account with Ebay. Probably not going to get any satisfaction from yours either. Mine went by the name Tool-Zoom and now is called Super-Medical-Shop. Ebay is looking at it but I suspect I am on my own with both the controller being defective (missing steps) and the lead screw being bent slightly. The screw nut can be tightened by the way and can also be shimmed for excessive play/backlash.other problems
The controller can't be fixed without redesign as far as I can tell and I did hundreds of hours of research into it here. Some can be I have heard and some can be improved with wire replacement and noise reduction caps but overall the damn things suck. Ordered a Gecko 540 yesterday so I know will be fixed shortly. LOL
Another important thing to do with your machines is tram them so that you know for a fact it moves the one inch you told it to. If not you may have to adjust the settings in Mach 3. I have heard that the steps per inch is wrong in the manual I am using but haven't checked it yet. Hope this helps.

[handlewanker]

Hi, you need to define "bent" as opposed to "kinked".

Bent mainly means the shaft has a gentle curve to it, whereas kinked has a definite bend point in one area.

If the screw is bent you can straighten it with care and lots of time, but a kink is usually a no go.

With the bent shaft supported on two centres or two vee blocks or whatever you use for vee blocks like two pieces of angle iron welded together etc, you can find the high point and progressively bend it back to almost perfect straightness by gripping it in the vice with wood packers and apply pressure to one side progressively a bit at a time, checking as you go etc.

A kink is a different story and highly unlikely to be present unless the screw had a sharp object impact somewhere on it, which makes successful re-bending back a doubtfull exercise.

The screw is a case hardened shaft and only the outer layer is glass hard, so that makes the inner core fairly pliable to careful re-working, but if the case develops cracks during the re-bending process the balls will probably impact on the cracks and make the shaft eventually unusable.

Otherwise the screw is a write off so you have nothing to lose by attempting careful re-working.
Ian.