my 6040 experience (yeah, and problems) so far

I'm taking some weird perverse pleasure from detailing all my problems, that everyone predicted, in this thread :)

Soooo... I love what I can do to delrin with my litle 6040, but today I had some problems caused by spindle runout (think that's the term, spindle shaft wobbles in the bearings).

It might be getting worse, or maybe it's just the grease getting pushed out. Unfortunately I don't have the means to measure it.

I'm in eBay conflict resolution with the seller. I don't really want to send it all back but it's trying my patience now. I've given him the option to replace the spindle, with a warning that if he sends another duff one he's gettting the whole lot back. Or if he hasn't got any good ones he can refund me money to replace it.

So anyone got a reliable source for a 800W spindle?

Or should I be thinking about stripping it down and replacing the bearings with quality items?

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Originally Posted by jimbowley

Or should I be thinking about stripping it down and replacing the bearings with quality items?

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No you should be sending the whole bag of shite back.!! . . . You didn't just get a Friday afternoon spindle.!! That's has good as it gets so you'll still end up with a dead spindle sooner or later and even if you replaced the bearing chances are the whole Body and shaft are built to the same rubbish standard so runout will still be a problem.!!

Time to cut your losses and bail out while you can without blowing any money IMO.!!

I'm sure I've read threads somwhere where some people got really nice spindles with their chinese machines.

Anyway, pointers to better spindles ?

Quote:

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Originally Posted by JAZZCNC

Time to cut your losses and bail out while you can without blowing any money IMO.!!

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I'm undecided, I'm doing interesting things with it and I don't want to be without a machine for 4 or 5 weeks.

I'm tempted by the stepmores machines, the 6040 with supported X and Y sounds good, but then I don't think flexibilty is a problem for me. But maybe that will be the next thing to surface when I get rid of spindle run out.

Your spindle will probably be different to this one but it might be useful to look at.
http://www.mycncuk.com/threads/7065-...3902#post53902

I took the spindle off the machine and put it in a vice to feel the runout properly. It's weird, it seems to be there at one angle and not another, then it disappears, then it comes back.

I could resist taking it apart, and it was easy. At the collet end a cap is held by four screws. The cap has 6 springs acting on a plate, then some steel shim washers, then a plastic washer and onto the outer housing of a single bearing. The shaft pulls out easily and there is a smaller bearing pushed onto the other end of the shaft.

I don't know about high speed spindles, or any other rotating machinery for that matter, but it seems like a reasonable design.

I'm wondering now if the play I feel is actually play at the other end of the shaft, the other bearing might be a loose fit in it's bore. It certainly didn't give me any trouble sliding the assembly back together but it could be designed with a taper to do that. The play does feel somewhat 'remote' and there are only 2 places it can be.

When the spindle was out I started looking at some play in the Z direction.

One major contributor was the Z ballscrew end fixing wasn't done up, so it was only weight and a bit of friction stopping the spindle moving up and down.

There is still a slight bit of play, which appears to be at just one of the crosswise linear bearings (round 25mm unsupported). There is a miniscule grub screw that is already quite tight. This transforms to both vertical and longwise play at the tool so is more of a problem for my 2.5D work.

Don't get me wrong here Jim but this is what I'm meaning with these machines you'll be constantly chasing this sort of thing and with every hour of cut time it will just get worse due to wear and with more to chase until eventually you'll get sick of it.

I see this time and time again, at the minute your fresh to it and enjoying what your getting off the machine but this will change as your imagination runs riot and Cam/Cad abilty's increase.! This is when the machine will drive you up the frigging wall as it will hold you back and frustrate the hell out of you.
IMO . . . IF you have the option to bail out now and get most of your money back then I'd grab it and put it down to learning and be thankful it didn't cost anything but lost time.!! . . . . . . If not it will cost you and will frustrate you sooner rather than later.

Oh god, don't say that. I'm just trying to get it working properly and now you're saying it will wear out :) I believe you. The problem is I don't want to be without a machine for any length of time. I could handle a week maybe but no more.

More info that might be useful to other 6040 owners.

Investigating the play in the crosswise bearings I thought I spotted the support rails out of parallel, quick check with builders level confirmed it. I loosened off the holding screws, got some mulgrips on there and twisted the top one, couldn't feel any movement at either end. About to give up but tried the lower rail, twist... what was that? was that dirt or did the rail move, yup it looks like an eccentric end connection. Check with the level, now looks true. Do it up tight and yank on the spindle holder ...play in the crosswise bearings has gone.

Very pleased with myself as I didn't know they had eccentric ends.

So now all I can feel is flexibilty, and I can't complain about that because I knew the construction I was buying. And some bearing run-out which might get fixed by a new spindle.

I repeated a run that I did earlier. It was quieter, and got a better result. But still some problem, on tangent lead in and the tabs the tool goes inside the profile