One of my lead screws is bent. Not a lot, but the incessant wobble certainly can't help and it's just annoying as hell to watch. The screws appear to be 8 mm trapezoidal thread 2 mm pitch single start 6 mm root diameter Maybe my search skills are getting weak but I'll be darned if I can find anyone who stocks these.
If you don't dislike the bookseller: http://www.amazon.com/Drillpro-400m..._UL160_SR160,160_&refRID=0Q153T5ZC8XG8HGSRJV9
Yes to both. Definitely not straight. And unfortunately that Amazon one is a fast lead screw. It looks to me to be four separate helices. Our lead screws have a single thread.
Tedious but maybe just ask E3D to send another one? Or they may be kind and give you the spec ! From China you will probably wait much longer than post from UK.
No, it's just the picture. Look under "see more product details". But if they send it the wrong way it will be bent too...
I've learned the hard way not to order things where descriptions and pictures do not agree. However reading the fine print that one says: Lead of thread:8mm Which I think means your nut will travel 8 mm per revolution which jibes with the picture looking like a "four start lead screw" Here's a brief discussion of this sort of thing: https://www.buildyourcnc.com/leadscrews.aspx UPDATE: Answering my own question after an hour or two of searching there is a source in Connecticut, PIC Design. http://pic-designcatalog.com/cgi-bin/lansaweb?srve=PRDLST+F(LW3CATURL)=ACME_STYLE_SCREWS For a 500 mm long, 8 mm diameter, 2 mm pitch, 2 mm lead (single start) trapezoidal lead screw their part number is ARS1X082M-05 Cost for one is $52 plus shipping. Looks like a pretty rare item here in the USA. BONUS UPDATE: I found an ebay listing from a Chinese vendor who actually knows how to describe the item http://www.ebay.com/itm/8mm-T8-Trap...hash=item210cee415a:m:mC5Y2SetJRHJRXEacuJH3fQ Naturally it's much cheaper at $21 each, but of course quality is unknown and shipping takes several weeks.
Afraid not, but I do have a funny story about it. I was curious about the Chinese ebay source so I ordered four of their 2 mm lead (single start) lead screws to compare to the PIC ones. I don't take quality for granted but even so I was bit surprised. When I compared the threads on the PIC lead screw to the Chinese ones, guess what? The threading on three of the rods from ebay were essentially identical to the PIC one (not speaking to surface roughness/tolerances here) but the fourth rod had a noticeably different pitch! Maybe out of phase by a millimeter over the length of the screw. Now given how the four z-guide rod rod BigBox is sensitive to crabbing induced jamming, the last thing you want is the right and left z screws moving the bed at different rates. This story has two morals. You get what you pay for, and, if you need matched parts, you damned well better compare them to make sure they're identical before you install them.
I have an option for quality parts, http://www.zappautomation.co.uk/ Although they are in the UK they will ship to the US and are fast at dispatching. Given that with Royal Mail anything posted internationally is out of the country within 24 hours of posting ( yep, it's true) US purchasers are then only reliant on the speed of either USPS or the UPS courier that Zapp use which can make the whole operation painless. Zapp supply really good quality and stock a whole range of items not just lead screws, oh an no, I'm not affiliated with Zappautomation in any way
No probs Doc. I first found them searching for steppers when I built my first printer in 2011, surprisingly they were cheaper than anyone on eBay at the time, obviously no longer the case, the popularity of 3D printers has worked wonders for us on pricing in virtually all areas.