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Registered Member #72
Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659
Gradually reclaiming space in my garage, shrunk all the coins and crushed all the cans I need to, so ... 2 off 50uF 5kv pulse caps by CSI, metal case 100x120x280, porcelain insulated terminals 1 off 2uF 10kv pulse cap by Plastic Capacitors Inc, metal case 100x120x180, porcelain insulated terminals
And for the Marx generator ... 6 off 1.3nF 40kv doorknobs by CeraMite, 38x45dia, internal thread is coarser than M4, so guess 5/32" x UNx
Mains frequency (so not pulse, but launch disks nicely) ... Many 1uF MOTs (can be abused to 5kV happily), Lucas terminals Many motor run 440v types in the 1-40uF range, Lucas terminals, for mains PFC
To charge them ... an assortment of ferrite transformers, cores, whole flybacks
Not really looking to make money from these, more interested in rehoming them to an interested taker rather than putting them in the skip. Offers/discussions by PM please. Location, UK, just North of London
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1714
Dr. Slack wrote ... 6 off 1.3nF 40kv doorknobs by CeraMite, 38x45dia, internal thread is coarser than M4, so guess 5/32" x UNx
Ooh! But fractional inch threads smaller than 1/4 inch are practically unheard of, at least in the USA. From your dimensions I would guess the threads are #6-32 or #8-32 (M3.51 or M4.17 x 0.79, vs. standard M4 x 0.70).
I thought it would be easier to find and check some doorknob capacitors in _my_ garage than to look up datasheets, but I was wrong. Found some datasheets for Vishay Cera-Mite brand capacitors and it looks like #8-32 is indeed standard. Here's one series:
Who would have guessed you were a shrinker of coins? Ever talk about it here?
Registered Member #72
Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659
I don't think I have, the shrinking was well prior to joining this forum. I've crushed a couple of cans more recently, I might have posted a pic or two of those, but whether here is another matter.
Registered Member #3272
Joined: Mon Oct 04 2010, 11:40PM
Location: Beaverton, OR
Posts: 101
if it is about 4mm but coarser would probably be 10-24. 10-32 is almost the same as 4mm, so close that they will usually interchange unless the thread depth is more than about 4-5 threads.
There are a lot of threads under 1/4 that are still fractional, 1/8", 3/16", 7/32", though you see them mostly in firearms now.
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1714
Thanks, Jerry, I learned something new. Still, I have never seen a 5/32 or 3/16 or 7/32 machine screw or nut. Just found their thread pitches in British Standard Whitworth tables, but have not found parts for sale in USA. 3/16-32 and 3/16-24 threaded rods are in hardware stores and fastener catalogs, but I always figured they are re-labeled 10-32 and 10-24's.
I think you meant M5 x 0.80, not M4 x 0.70, as nearly mating with 10-32 (D=4.83mm, P=0.79 mm).
My favorite almost-match is 5/32" and 4mm, such as in a set of Allen wrenches.
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HV capacitors
Found some datasheets for Vishay Cera-Mite brand capacitors and it looks like #8-32 is indeed standard. Here's one series: 
