Correct, EEPROM setting for Z steps is 800

my friend dropped all the metal balls inside the ballscrew nut and we had to put all of them back in and there was 1 extra
anyway it took a while but we did it.
It is working fine

Then there are a couple of other problems:

Mounting it upside down would have cut the vertical travel by quite a bit, because I'm using a coupling flex nut at the motor side which already reduced the travel down by about 30mm, this would have reduced it another 30mm.

The there's the issue of actually removing the ball screw nut from the screw itself.  They already warn against doing it, because you can never get it back on correctly (all the recirculating balls are preloaded, so they'd fall out.

So it works great the way it is, and the solution to move the axis forward a couple of mm was more than adequate.

Edit:  I had the wrong dimensions in there, because my calipers were offset when I turned them on.  anyway, I fixed the flange and plate dimensions.

Has anyone else done this with the metal table support? You seem to have different table, likes its been laser cut out of wood?

I can now answer this question.  Check out my other post on the print bed bed upgrade. 

http://www.soliforum.com/topic/4650/upg … print-bed/

While I was doing a heaterpad replacement I upgraded to the aluminum platform as well, and moved the ball screw to that platform.

The problem I encountered was the same as before, the ball nut is very tall and large in diameter.  When you bring the platform up to the top, the back edge of the nut hits the horizontal rod ("Y" motion transfer rod).  Not by much, only about 1mm.  So I offset the centerline of the ballscrew forward by about 2mm. This means that the screw and the vertical rods are no longer aligned, rather the screw sits 2mm forward.

To accommodate this, I also had to move the "Z" motor forward 2mm, so I elongated the 4 holes at the bottom of the case.  So now everything works OK, and the platform can move all they way up, with the nut clearing the horizontal rod by 1mm.

Let me know if you need any additional information.  It's not a very tough mod.  Actually this is a lot easier than the mods I had to do for the original wood platform.

thanks! with the SFU1204 did you have to do anything to the Al platform to make it fit(other than taking out the orriginal nut) ? does the new ball nut screw screw right in or will i have to drill new holes?   

thanks again!

Read the first post.  I had to make an adapter plate.  First of all, I don't have an aluminum build platform, I have the original wood version.  The surface where the original nut is, was too narrow to fit the ball nut, additionally, the ball nut is so tall, that when homes, the top of the nut would hit the cross rod at the top (the rod that transfers motion for the "Y" axis).

So in my case, I had to lower the nut, which is where the adapter came in place.  If you have the aluminum platform, you'll have to find out for yourself what you need.

For those that have the wood build platform, here are the STLs

thanks again!

Additionally, you are looking at imperial/SAE sizes.  The problem with that is that you'll have to deal with weird round-off  errors which occur in the translation from inches to millimeter.  In fact the is the reason why many change the "Z" rod from a 5/16 to a M6.  This way, the stepping values become whole numbers.  You'll no longer have to use values like 0.1058 for your layer height, just input .1000 or .3000.

Anyway, buying a ball screw at McMaster, even though I'm sure the quality would be very good, is prohibitively expensive, so I would go on eBay and buy one of the ones made on China.  You'll spend less than 1/3. 

The Ball screw I bought is a SFU1204.  That means it's 12mm diameter and has a 4mm pitch.  The 4mm pitch translates into a microstep value of 800 for the printer, and produces nice even layers without the round-off effects.

Here is the link to the ball screw I bought:
http://www.ebay.com/itm/SFU1204-Ball-Sc … 19d2677b00

The same guys sell pre-configured ball screws, but they are configured for CNC machines so they have a very long area that is turned down with special keyways, and you don't need that.  Technically, you need only about 5/8" (16mm) at each end machined down to 8mm so it fits the 5mm/8mm coupler.  The other end would fit nicely in a 608ZZ bearing (top bearing support block).

If you can find a coupler that supports 5mmx12mm, then you probably not need to do any machining other than cutting the rod to length.

Another thing you can try, is to contact the vendor before buying, tell them you want to buy the item, but want them to cut it to length and machine the ends to your spec before shipping.  Many of these guys will do it for and additional $20-30.

Whatever you decide though, get a metric ball screw, not SAE.  You'll also find that the SFU1605 is the most common, but that is simply HUGE, and the ball nut is also proportionally huge.  In this particular case, bigger is not better.  The 1204 is just right.  If you can find a reasonably priced 1005, that would be nice too, as the smaller screw also has a smaller nut.

BTW, assuming you want the same setup as what I have, the total length of screw you need is 11" (about 278mm).  On that, you machine each end 5/8" so you have a total of 9.75" threaded length on the 11" rod. 

Let me know if I can help with anything else.  If you need the adapters I made, I can post the STL.

Good luck.

http://www.mcmaster.com/#ball-screws/=nwruyy

what size screw am I looking for? if its not on there please be kind enough to link me to the one I need so I can order it

On this model the hair was impossible to fix, because it literally has not volume/thickness, and many of the strands intersect each other.  Of this reason, the slicer has a very hard time dealing with it, and it comes out really crappy.  I tried Netfabb Studio, MeshLab, but none of these can do much about the hair.  They fixed 95% of the main model, but none of the hair... 

Perhaps some of us here that are well versed on this subject should start a thread on how to clean up models especially those that are familiar with Meshlab and its various filters.  I was able to figure some out, but I haven't scratched the surface yet, so I'd really like to see a good tutorial.

I also have started to add my own home made supports, since neither Slic3r nor Kisslicer can do the type of support I want.  The way this model was cut, it only needed support for the chin, hands, tips of the shoes, and back of the hair.  Slic3r would have wrapped the model in scaffolding all around, which would have been a bear to remove.  Kisslicer can't even handle the model, so it's useless for this type of work.

So my approach is to add my own strategically placed supports.  I start with a model of a very thin (.25mm) bar which I load along with the main model, then I rotate, stretch (or shorten) and then place it where it's needed, then duplicate it and add it in other places.  Yes, it intersects the model, but it provides the needed support, and since it's very thin, it's easy to remove and only leaves very small marks behind.  Here is a picture of the unsliced model on the Repetier platform.  Notice the supports under the hands, the back of the hair and the tip of the shoes.

Last but not least, this is a thread about the ball screw, so in terms of improvement, I think it helped quite a bit, and it really provided much needed rigidity.

The overall build height has been reduced down to just a little over 170mm. 

Originally the Solidoodle screw was press fitted down the motor shaft, which allowed the print bed to go all the way down to where it nearly touched the bottom of the frame.

Between the extra height imposed by the flex coupler, and the fact that I had to lower the ball nut mount by nearly 11mm so it can clear the "Y" cross axle, I now have 173mm of total travel, which doesn't really matter to me as I prefer to cut my models before I print them anyway.

On the positive side, the ball screw is 12mm thick compared to 8mm before, and is completely rigid.  I'm not exactly sure what kind of steel it's made of, but my buddy that machined the end told me this was one of the toughest pieces of metal he ever had to cut.

The end result is a VERY STRONG and RIGID platform.  On the standard Solidoodle you can see the print bed move, especially when the printer is doing very fast moves like infill, or when it sometimes hits the edge or some bump in the model.  That's all but gone.  This is ONE SOLID BUILD PLATFORM.