ebay J Head hot end

Hi,

I am assembling my first 3D printer currently (Prusa i3 rework)
I have a J Head hot end from ebay
[www.ebay.com]

When I threaded on the aluminum heater block assembly onto
the M6 threaded nozzle throat, the heater block threads until
it contacts the aluminum heat fins, but in the pictures I've seen
there is a gap there, apparently for preventing heat conduction.

Has anyone noticed this and found a solution? If the M6 nozzle
throat was longer it would not be a problem.

cheers,
Jamie

what you have there is actually a counterfeit E3D hotend sold as a Jhead, I would suggest that you contact the seller as almost all of these e3d/jhead counterfeits are not built very close to the released drawings if at all.

for genuine resellers of Jhead hotends :jhead wiki page

and for genuine resellers of E3d hotends : E3D

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Quote
thejollygrimreaper
what you have there is actually a counterfeit E3D hotend sold as a Jhead

While definitely not being a real jhead, no where does it say that it's a E3D hotend. It's a hot end, and it's similar, but it doesn't claim to be what it's not so I don't think you can call it a counterfeit. Maybe a knock off...and a cheap one at that. Caveat emptor...you get what you pay for...etc...

With a real E3D hotend you should be able to screw the nozzle into the heater block so that there is a slight gap between the nozzle and the bottom of the block, then screw in the heat break until it makes contact with the nozzle. Then screw the heat sink onto the break. If it spins all the way down without tightening, then it was either threaded too far or the break is two short. But there definitely should be a break there. Having the heater block contact the heat sink defeats the whole purpose of having the narrow break.

Quote
cdru

Quote
thejollygrimreaper
what you have there is actually a counterfeit E3D hotend sold as a Jhead

While definitely not being a real jhead, no where does it say that it's a E3D hotend. It's a hot end, and it's similar, but it doesn't claim to be what it's not so I don't think you can call it a counterfeit. Maybe a knock off...and a cheap one at that. Caveat emptor...you get what you pay for...etc...

With a real E3D hotend you should be able to screw the nozzle into the heater block so that there is a slight gap between the nozzle and the bottom of the block, then screw in the heat break until it makes contact with the nozzle. Then screw the heat sink onto the break. If it spins all the way down without tightening, then it was either threaded too far or the break is two short. But there definitely should be a break there. Having the heater block contact the heat sink defeats the whole purpose of having the narrow break.

it makes the claim to be a jhead in 3 separate places in the ebay ad, it is claiming to be something it is not, hence why i call it a counterfeit, to call it a knock-off or clone is to also imply that some part of it may be the same as the genuine article

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Just toss it and accept your losses and get a real Jhead or E3D. I have been down that road with one of those and they are complete junk, save yourself some time and buy a real E3D. The company that sells these a lot is GeeTech and their "specs" are way off, and PLA will not work with it.

Edited 1 time(s). Last edit at 11/18/2014 05:26PM by zerodameaon.

I agree with Jolly, counterfeit. It seems like just some 'dood' creating something with a lathe without having any real knowledge of hotends. I see this a lot, E3D clones being advertised as J-heads.. It's a good warning sign that you should not buy anything from these kind of shops!

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http://www.marinusdebeer.nl/

Irregardless of whether it's some dude with a lathe or the real McCoy, it's a poor artist that blames his paint brush. I'd suggest getting a hold on some ceramic (mineral wool) srtip material and placing it between the heater and the heat sink. A PTFE washer would work too.

PLA does suck on stainless steal "throats" (chinese for barrels I guess), but If you soak a cotton ball in vegtable oil and feed the filament through it, you should be OK.

Quote
DisruptiveTech
It's a poor artist that blames his paint brush.

That saying does not really apply here unless you mean it in the sense that a artist buys a brush without any bristles and paints a horrible picture then tries to blame it on the brush. He would be to blame for trying to use something broken from the start.

Even vegetable oil is not enough to get these working right, I tried all the stuff that is suggested for the E3D V5 and PLA. None of it worked for more then a few prints, even polishing the barrel did not work for long.

Quote
zerodamaeon
That saying does not really apply here unless you mean it in the sense that a artist buys a brush without any bristles and paints a horrible picture then tries to blame it on the brush.

Well, you can always scalp a horse and duct tape it's mane to your brush. Then again, I can fix anything...

Hi,

I have a couple unrelated questions if anyone wants to help a noob more, but first I will
say I just took some 1/16" wood dowel and stuck two pieces of it between the aluminum
heater block and the heat fin section.

Ok the questions! I have seen pictures of the Prusa i3 rework printer with the
heated bed stage stepper motor mounted at the front of the printer and also
at the back of the printer. Using the Reprap build instructions I put the
stepper at the front of the printer, I saw it at the back of the printer on another
site later, and switched it as I thought I'd made a mistake in the assembly lol,
but anyway does it matter if it is front or back? Also the mechanical endstop
I am using seems to be hitting the heated bed instead of the aluminum
heated bed support, this is quite strange as I could have sworn it was hitting
the aluminum bed support before I rotated the stepper motor to the back of the
printer. Any recommendation on what could be wrong with this mechanical
endstop? I thought it was a standard size part so would just work

This is the mechanical endstop I used:

[www.ebay.com]

cheers,
Jamie

Make sure you didn't open up a gap in the filament path when you added the dowell. That would allow hot PLA to swell into the gap and cause jams. Also, the E3D needs a fan, and that clone doesn't seem to come with one.

As for the motor, it should work either way, you might need to reverse y-axis and set the y endstop as max rather than min, but ultimately all that matters is that the bed moves in the right direction. That said, I'm not familiar with the i3, and your problem with the endstop suggests its not symmetric. You might have to improvise a mount to get it working.

Quote
jmorken
I thought it was a standard size part so would just work

This is the mechanical endstop I used:

[www.ebay.com]

RepRap has only first steps towards standardisation: [reprap.org]

As you can see, a 4-wire endstop doesn't match even this preliminary standard.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

I have tried that style of hot end. TBH my particular version is spot on acurate. It has a good head on it and has teflon lining in the barrel. It does not require cooling for ABS. and has given me good resolution. It does not leak either. I must have gotten lucky. I also spent 15 bux on my version so the chance I took paid back huge.

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Modicum V1 sold on e-bay user jaguarking11

Teflon lining and an advertised limit of 300C?

Quote
Andrew Smith
Teflon lining and an advertised limit of 300C?

I guess the teflon doesn't go all the way into the heater block

The E3D v6 also uses a Teflon liner!

[e3d-online.com] says:

Quote

With no PEEK or PTFE in hot regions of our HotEnd we can reach 300C with the supplied thermistor. By swapping a thermistor for a thermocouple (may require additional electronics) you can reach over 400C.

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http://www.marinusdebeer.nl/

Teflon lining in the heat brake eliminates problems with pla. As for advertised max temp? I have no idea. I run mine around 230-250c.

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Modicum V1 sold on e-bay user jaguarking11