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Don't buy this hotend

Posted: Thu Aug 15, 2013 5:15 pm
by kbot3d
After selling a number of extruder setups and a couple dozen full printers of various styles, some have chosen to purchase a hotends.com hotend clone from ebay. At the request of a local who wanted to cut a few corners, I ordered and installed a $36 clone from ebay. They are similiar in build but do NOT perform the same. I have built enough printers to solidly say that the $30 discount is not worth the headaches.

Enough so that I went out of pocket at a loss of $70 and bought the customer a replacement hotend before even delivering his custom printer. To each his own but I thought it only fair to give this notice. The money you save on a cheap hotend will cost you time , aggravation and filament. Please dont purchase a mk4 or mk5 clone on ebay

Re: Don't buy this hotend

Posted: Thu Aug 15, 2013 7:32 pm
by cvoinescu
I second that. A fraction of them may be good, but hotends.com and the authorized resellers are the way to go. Generally speaking, if it's a new Mk IV on eBay, or if it comes with a 1.75 mm "conversion kit", it's almost certainly bad. If it's touted as a Mk V, check these tell-tale signs.

The original J-Head Mk V and Mk VB:
  • is made of brass (yellow), not aluminum (white);
  • does not have a nipple at the tip of the nozzle;
  • has a fairly shallow shoulder at the base of the nozzle cone;
  • does not have a grub screw;
  • has five grooves on the PEEK part, not four;
  • has nicely, cleanly machined grooves in the PEEK part.
Also, I'm sure the eBay people don't pay Reifsnyder any royalties.

Here's a sample from an eBay seller, claimed to be a J-Head Mk V, which fails on all six counts.
FakeJHeadMkV.jpg
Fake J-Head Mk V
FakeJHeadMkV.jpg (92 KiB) Viewed 2850 times
I've also seen absurdities such as "All in one GENUINE J-HEAD set Original Improved Design", "UK made all-in-one J-HEAD set ! Original Design!", and "All in one GENUINE J-HEAD set for RepRap Made in theUK" [sic].

On the other hand, this one may well be the real thing, although it's hard to tell.

Re: Don't buy this hotend

Posted: Thu Aug 15, 2013 8:46 pm
by kbot3d
The one in the pic is exactly the clone I have. It is a waste of money. To add to the notes listed. The inner hollow setscrew is an oddly larger size which does not allow for a teflon insert so there is an open cavity for the filament to deform causing jams. If using a bowden line like is needed for a rostock, this also means no chance of retraction to change colors as the filament swells in this cavity and will not draw back into the line.

Re: Don't buy this hotend

Posted: Tue Apr 15, 2014 6:48 pm
by phr0ze
The easiest thing to tell is the number of slots in the peek is 4 then its fake. Apparent in most photos. If the hotend is too wrapped up in tape to count the slots then don't buy a hotend from that moron either even if he has the right parts as he has taped over all venting. (http://www.amazon.com/JMT-Printer-0-35m ... ead+hotend)

I get my hotends from Makerfarm.com or 3dmakerworld. Both arrive very quick in the US (2 days).