Drilling razor blade with pencil sparks? - Page 1
Forum section: electronics / beginners

author: superUnknown
author_rank: Regular Contributor
timestamp: January 20, 2014, 03:42:52 pm
content: Is this even possible? BS?

author: robrenz
author_rank: Super Contributor
timestamp: January 20, 2014, 03:45:05 pm
content: Bad link, but yes using the pencil as a graphite electrode in an edm machine will easily drill thru the razor blade.

author: superUnknown
author_rank: Regular Contributor
timestamp: January 20, 2014, 03:46:09 pm
content: sorry. BBcodes. working now.

author: deth502
author_rank: Frequent Contributor
timestamp: January 20, 2014, 06:51:04 pm
content: not only can you, but it is much, much, much easier than what you saw in the video. i made a small homemede one to burn out a broken tap with 2 light bulbs as a ballast, 2 large caps, and very little else. i used a brass tube as the electrode.

author: deth502
author_rank: Frequent Contributor
timestamp: January 20, 2014, 06:57:31 pm
content: something like this:only iirc, i had 2 100w bulbs in there, no resistors, no meters. you can estimate the current draw by the light from one of the bulbs and used that as you "meter" and no variac. amof, i dont recall using a transformer. went right from the wall to the rectifier.

author: Fraser
author_rank: Super Contributor
timestamp: January 20, 2014, 07:17:38 pm
content: If this is like 'spark erosion', I recall my Father showing me how the internal cooling channels were cut into titanium gas turbine engine blades at Rolls Royce (Aero Engines) in Bristol. The tubes extend up through the blade from the root to tip AND from these channels through the blade to its leading and trailing trailing edges. I was amazed that the process was capable of accurately cutting the cooling tubes within a curved surface, following the centre line of the blade. Clever stuff.I attach pictures of one of my Gas Turbine Engine blades given to me by my Father when I was a youngster. Its an HP Compressor blade from an RB199, Olympus or Pegasus Engine..... I can't recall which. I always loved the Pegasus that is used in the BAe Harrier so it may well be from that Engine. I also have the LP blades from such engines. They are much larger and do not need the cooling channels. The HP compressor blades would melt without such cooling. How the tubes were cut used to be an Industrial Secret.

author: superUnknown
author_rank: Regular Contributor
timestamp: January 20, 2014, 07:42:14 pm
content: Those blades are incredible! No doubt done with a No2 pencil?

author: Fraser
author_rank: Super Contributor
timestamp: January 20, 2014, 07:52:46 pm
content: I didn't provide a scale indicator in my picturesThe holes are truly tiny diameter. The blade is only approx. 2 inches (50mm) long !

author: superUnknown
author_rank: Regular Contributor
timestamp: January 21, 2014, 01:02:18 am
content: Quote from: deth502 on January 20, 2014, 06:57:31 pmSo would that spark at mains frequency (60Hz) or much faster because of large caps? How fast?

author: deth502
author_rank: Frequent Contributor
timestamp: January 21, 2014, 03:41:14 am
content: it had a "bacon sizzling" sound to it. so, yeah, probably about 60 hz.im surprised no one mentioned it, and yes, i will agree that it was as unsafe as shit, but it was a quick and dirty solution to get a hardened tap out of a piece of aluminum that already had too much machining time into it to scrap, and safety precautions were taken.another thing is its usually done using a dielectric fluid of some sort. i just used water for mine, which will create hydrogen, which is explosive. again, not the safest, but follow a few safety precautions, like only using in a well ventilated area, chances of things going awry can be greatly reduced.

author: deth502
author_rank: Frequent Contributor
timestamp: January 21, 2014, 04:19:33 am
content: ok, i give up. spent at least an hr looking for the article. i thought it was a popular mechanics article, but it turns out it was more likely a popular science article. they have a "complete archive" online, i found some reference to it in the march 1968 issue on page 149, but their "complete" archive jumps from page 148 to 155.

author: macboy
author_rank: Super Contributor
timestamp: January 22, 2014, 05:33:28 pm
content: Quote from: deth502 on January 21, 2014, 04:19:33 amThat's probably because the article on page 149 is extremely dangerous!