I have printed threaded containers without problems other than the first
item I printed with my own thread library came out with a left hand thread,
doh! East to fix.

I have also printed this https://www.thingiverse.com/thing:23030, which has
quite small threads, without problems.

On Fri, 15 May 2020 at 14:16, Alex Gibson alex@alexgibson.net wrote:

I froze a flexible part and managed to tap it, but attempts to use a die
on a rod have failed, even when frozen.

nop head: do you believe that print orientation is important when
printing threads?  That is, better with the rod horizontal or vertical? 
The vertical attempt failed, even on my Prusa MK3s

Jon

On 5/15/2020 12:31 PM, nop head wrote:

I printed 1/4-20 threading on a Prusa MK3 in PLA without any problems.  They
worked great with each other and with matching metal hardware.  Printed
them with bolts pointing up into the air and nuts in the same direction,
lying flat.

How did your print attempt fail?  If you try to print threads horizontally
you're going to have a bunch of support problems.  It might work with
interrupted threads, I guess.

jon_bondy wrote

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On 2020-05-15 15:08, jon wrote:

I have no idea what 5/16" means, but I have once designed and printed
(PLA) a M16 bolt and matching nut as a test for printing threads. It was
printed with a 0.3 mm nozzle.

https://www.thingiverse.com/thing:1445033

Carsten Arnholm

5/16" in the diameter of the bolt in inches and the 18 is the threads per
inch.  So roughly speaking it's about an M8-1.4 bolt.

cacb wrote

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The first time I tried to print the rod vertically, using PLA and
without threads, it just snapped off.  This time, with threads, and with
flexible filament, it printed to completion (although the top of the rod
was wobbling all over the place towards the end of the print).  The
threads are recognizable, but there are enough small anomalies that it
is very difficult to screw into a nut.  I tried to clean it up with a
die, but there was too much resistance.

On 5/15/2020 4:18 PM, adrianv wrote:

My bolts are short, 20 mm including the head.  But the threads are clean, no
need to do anything to get it to engage with other threaded parts other than
getting the tolerance right.  Seems like if you need a really tall rod you
might have to support it from the side with some support structure, maybe?
I don't know.  If you can't print a perfect 20mm long bolt then you need to
figure out what's wrong with your printer or filament.  (I use Prusament
for my prints.  Don't know how much difference that makes, but I have heard
that people experience more failures and problems with cheaper filament, and
I don't feel like messing around with that.)

There is the problem that a long tall rod will tend to be weak.  I can't
snap my 20mm bolts by hand, but I wouldn't expect them to be particularly
strong, so if strength is critical, you need to do something different.

jon_bondy wrote

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Why do you want a flexible bolt?

I often have problems with flexible prints wobbling. I think it needs a
dual filament machine so it can print a solid core that could be dissolved
out if the result needs to be flexible.

On Fri, 15 May 2020, 22:29 adrianv, avm4@cornell.edu wrote: