Saturday, August 23, 2008
Even More feed rollers.
I have also had an idea for making teeny weeny nozzle holes. Rather than drilling them in metal nuts etc (and the latest aluminium one from Bitsfrombytes.com is rather nice) how about this :
I purchased some brass tube - 2mm OD, 1.4mm bore - from B&Q. I snipped off a short section, inserted the leg of a resistor and squashed the end with my wirecutters. Pull out the resistor leg leaving an almost perfect 0.5mm hole. Its not clear in the photo but the hole passes through the nearest part. The result is almost round with a small slot. I will experiment further.
Mounting it will not be simple, I have considered flairing the top end and simply dropping it into a bigger (2mm) hole, or using silver solder (melts well above 250 C).
Copper would be better as it is more malleable, but B&Q didn't have any small enough. I will check to see what capillary tubing I can get from my local laboratory supplier.
STOP PRESS : I just had another thought - we used to get tiny carburettor jets, made by a company called AMAL - for use in gas engine conversions (Calor gas, not gasoline gas). These are weeny nozzles - I just dug out some and the hole is 0.35mm in a brass body with a 1BA thread. The 1BA male thread just about works with an M6 nut. From what what I remember they were cheap AND available from our local Calor gas depot. Why re-invent the wheel?
Now if you go into a IV drug support center in a major metro area they will give you clean needles even though doing so is a felony and using recreational IV drugs is, too.
Veterinary suppliers, however, stock them and the worst I've ever seen them ask is that you sign a register pledging that you won't be using them to give yourself injections of illegal drugs.
Anyhow, they come in all gauges down to very fine holes. File the needle off of one of those up near where it goes onto the syringe and you've got your extruder. :-)
I got acquainted with 'em trying to blow bubbles into molten HDPE a few years ago.
If this is cut off too then we may be able to use the bit of fine tube somehow.
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