Glad it's not just me. They've been around for absolutely yonks. Preferred dissection needle material by the looks. Anything from dissecting (down to cell level), counting and sorting (e.g. spores!!), probing ICs, the list is endless. And I only spotted 'em a month or so ago...rjlittlefield wrote: ...I am clueless about tungsten needles. Do you know a reference that can teach me about them?
I started with fed-up-ness. Glass needle making drives me nuts and I looked for an alternative (again). This time, I stumbled on the IC probes - and it all went from there. Quick summary on how to get/make 'em to start with...
You can buy 'em
https://surgicaltools.co.uk/fst-product ... ders/pins/
https://www.lambdaphoto.co.uk/everbeing ... -tips.html
I bought the second type - pack of ten each of 1 micron and 0.3 micron tips. Totally rigid - tip eventually bends if pressed continually into glass (diatom arranging), but the end can be lapped steeper for an indestructible, but still dead-sharp point.
Or make 'em with tungsten wire. 0.25mm sweet spot for manipulating and small dissecting IMO. I certainly won't be buying any more. Pennies vs pounds per needle cost by making - and I can customise each one as needed.
1. Grind and lap a point on it with a Dremel or two. Eats lapping paper and grinding wheels/disks like crazy. Expensive and slow for thick wire. Fiddly (and therefore slow) for thin wire too. Good for finishing a point to strengthen it or or for starting the tip shape in rubbish wire though.
2. NaNO2 - Spall tungsten off red hot wire on near-melted stick of sodium nitrite. https://www.youtube.com/watch?v=WvepYAwiKU8
Takes a bit of practice and really good for thick, low-grade wire. Bullies the shape onto it. Not good for thin wire (for me). Better than grinding for starting a thick wire point.
3. Electrolysis - the best. Loads and loads of nuances, but principle is super straightforward. I use this now. Less than 30 seconds from cutting wire off the spool to having a finished and polished, fine point. This is a good starting point, there are other similar articles.
http://www.mccroneinstitute.org/uploads ... 996273.pdf
Pic here is one of my first "working" needles done by electrolysis, but I hadn't learnt (any) nuances then. Bit rough, but makes a prettier picture