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Re: Actual Nozzle Diameter

PostPosted: Mon Apr 01, 2013 4:05 pm
by cvoinescu
brnrd wrote:With the 3 j-head mk-v that I'm using, it ends up around 0.34-0.35 mm.


I remember reading that J-heads are drilled slightly below the nominal diameter, to allow for wear in time. Your experience seems consistent with a slightly under-drilled J-Head (say 0.32 mm), with the free-air spaghetti always being quite a bit larger than than the bore (say 0.38 mm), and with the need to stretch it just a little for the bridges (back to 0.35 mm). Please note, I pulled those numbers out my body part closest to the chair.

Re: Actual Nozzle Diameter

PostPosted: Mon Apr 01, 2013 8:03 pm
by brnrd
So, your experience is like you always touch up the nozzle diameter by a slightly higher value, never lower.


I don't know if the parameter I set in slic3r is larger or smaller than the actual nozzle diameter since I didn't measure the actual diameter, but it's usually very close to the specified diameter in my experience. The only exception in the ones that I've used was the Arcol v4 hotend.

I remember reading that J-heads are drilled slightly below the nominal diameter, to allow for wear in time.


I'm not sure if that's why Brian (hotends.com) drills his 0.35 mm nozzle slightly smaller. I thought it was more because that was the closest he can get to 0.35 mm with the bit set that he has.

Re: Actual Nozzle Diameter

PostPosted: Mon Apr 01, 2013 8:11 pm
by cvoinescu
brnrd wrote:
I remember reading that J-heads are drilled slightly below the nominal diameter, to allow for wear in time.


I'm not sure if that's why Brian (hotends.com) drills his 0.35 mm nozzle slightly smaller. I thought it was more because that was the closest he can get to 0.35 mm with the bit set that he has.


http://jheadnozzle.blogspot.co.uk/2012/ ... -bits.html

Re: Actual Nozzle Diameter

PostPosted: Mon Apr 01, 2013 8:52 pm
by orcinus
I just thought of a roundabout way to measure the nozzle diameter without pin gauges.

Take the thinnest sewing needle you can find.
Insert it into the nozzle as gently as you can (so you don't deform the nozzle opening), as far as it goes without any resistance.

Take a sharpie and paint a notch on the needle.

Take a micrometer screw gauge and measure the needle diameter at the sharpie'd point.
(caliper might work too in a pinch)

Re: Actual Nozzle Diameter

PostPosted: Mon Apr 01, 2013 11:18 pm
by Digitalmagic
Measuring a bore of this size is at least lacking of precision. Why not relying on the maker specifications?