screws, bolts and fasteners used on vintage TE - Page 1
Forum section: electronics / repair

author: tatel
author_rank: Frequent Contributor
timestamp: September 24, 2024, 05:31:13 pm
content: In my current case, I need to identify this set screw used on F931B knobs.I can undo most of them with a 1.5 mm hex key, but there are some more tight where the key slips.Diameter seems to be 3.5 mm, so perhaps this is a metric set screw and the matter is I need better quality metric hex keys. Long is about 4.78 mm which looks a lot like 3/16 however. Then this would probably be an imperial screw and I would probably need a set of imperial hex keys, particularly a 1/16" one. I'm getting it anyway, but it would be nice to have confirmation about what kind of screw this is.From a more general point of view, it would be nice if a compilation of different screws, etc, used in vintage Fluke, HP, Tektronix, (put your favorite brand here) could be made,with links to providers if possible, and compatible replacements. A little bit like the sticky threads on this section. Alas, I have been unable to find much about this matter in these useful threads.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 24, 2024, 05:42:25 pm
content: imperial allen keys go down to 1/64" increments

author: HalFoster
author_rank: Frequent Contributor
timestamp: September 24, 2024, 06:08:17 pm
content: Google Wiha hex key sets: 35392 Metric, 35393 Imperial. Amazon has them and they are what I use for all set screws.

author: tatel
author_rank: Frequent Contributor
timestamp: September 24, 2024, 06:14:08 pm
content: 1/64" increments? Wow, fine fine tangerine.In looking at this:https://www.amazon.com/Bondhus-16936-Balldriver%C2%AB-L-wrenches-BriteGuard/dp/B000E7ZQ8U/ref=sr_1_15Hoping they will be good enough.

author: George Edmonds
author_rank: Frequent Contributor
timestamp: September 24, 2024, 07:13:47 pm
content: If it is 3.5mm OD it could be 4BA which used Imperial keysGeorge Edmonds

author: TimFox
author_rank: Super Contributor
timestamp: September 24, 2024, 08:33:34 pm
content: A detail about inch-dimension hex keys ("Allen wrenches").Almost all standard sizes are binary-fraction inches, but there is one extra at 0.050" in many sets.0.028" and 0.035" sizes are also found in sets.(e.g.,https://www.mcmaster.com/7158A4/)American turn-counting dials for Helipots often used small spline (or Bristol) wrenches, along with other knobs, with a quite-different hexagonal- or four-fold symmetric cross-section.Seehttps://mgs4u.com/product/ss-508-bristol-spline-l-key-kit/

author: BrokenYugo
author_rank: Super Contributor
timestamp: September 24, 2024, 08:59:31 pm
content: #6-32?https://www.engineersedge.com/screw_threads_chart.htm

author: tatel
author_rank: Frequent Contributor
timestamp: September 25, 2024, 09:39:35 am
content: After looking at the vernier of mi caliper through a printer loupe, I would say diameter is 3.46 mm +/- 0,02 mmFromhttps://en.wikipedia.org/wiki/British_Association_screw_threads4BA has 3.60 mm outside diameter. 6/32 and 6/40 both have 3.5052 mm outside diameter and I'm unable to find anything closer to 3.46 mm so I'm going to try 6/32 set screws.This AliExpress seller seems to be one of the cheapest and one can choose between 304 stainless and 12.9 steel.https://www.aliexpress.com/item/1005007168325606.htmlAnother Ali seller:https://www.aliexpress.com/item/1005006097897350.htmlAnd one from Ebay: :https://www.ebay.com/itm/185383761203Not really sure if 304 stainless would be better than 12.9 steel. I guess, to avoid rounding the hex socket heads, on these little set screws, one should choose a good steel alloy. 12.9 sounds like plenty. When I was into speleology, we used metric 8 machine screws made from 8.8 steel to hold the ropes in pits. Would be 304 stainless tougher than 12.9 steel? Or would it be better because it wouldn't rust? What would you choose?I'm attaching a pdf with some pomona screws that at first glance looked as if they could be used on some Fluke devices to fasten covers, etc, but after a close-up look, that seems to be wrong.If after some repair you happen to know what screws could be used in any vintage device, could you please report about it?

author: Hamelec
author_rank: Regular Contributor
timestamp: September 25, 2024, 02:30:39 pm
content: see table

author: BrokenYugo
author_rank: Super Contributor
timestamp: September 25, 2024, 05:27:09 pm
content: 304 is bubblegum compared to 12.9 or A574, quenched and tempered alloy steel.

author: tatel
author_rank: Frequent Contributor
timestamp: September 25, 2024, 05:45:48 pm
content: Wow, what a difference. 12.9 it will be.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 26, 2024, 11:06:13 am
content: With such small screws it is unlikely to find a high strength version like 12.9. So if offered at Ebay of Ali.., chances are that it is not the claimed strength. Still sometimes excess inventory lots of special parts end up there.Normal such small screws are more 5.6 grade or similar.For 304 stainless, this is only the chemical composition. The actual hardness can vary a lot, depending on the degree of cold working. So it can be rather soft, but also quite hard.

author: BrokenYugo
author_rank: Super Contributor
timestamp: September 26, 2024, 01:35:28 pm
content: While quality is obviously not guaranteed on AliExpress, afaik 12.9 or some similar flavor of hardened chromoly is standard for all those little black oxide socket head screws, at least by US standards.

author: Hamelec
author_rank: Regular Contributor
timestamp: September 26, 2024, 02:53:20 pm
content: Quote from: Kleinstein on September 26, 2024, 11:06:13 amI dont think so, a lot of Set screws are hardened and tempered

author: CatalinaWOW
author_rank: Super Contributor
timestamp: September 26, 2024, 03:21:50 pm
content: Do be sure to buy known high quality tools. Dimensional accuracy on lower grade sets is often uniform across the size range. And what is a negligible error on the larger sizes makes smaller sizes nearly or totally unusable.

author: Overspeed
author_rank: Frequent Contributor
timestamp: September 26, 2024, 03:33:25 pm
content: HelloUnder 1/4 inch of OD the US system change of ''name'' the 8-40 or 6-32 or ...first number is the size ( OD ) 2 other are the pitch ( number of thread per inch )Check Brownell's gun parts that common screws to plug sight hole on gunRegardsOS

author: Hamelec
author_rank: Regular Contributor
timestamp: September 26, 2024, 04:38:28 pm
content: here is a more or less complete overview of threads (sorry, most of it is in German)http://www.mikroskopfreunde-nordhessen.de/dateien/Gewindetabellen-2011-12.pdfhf

author: tatel
author_rank: Frequent Contributor
timestamp: September 27, 2024, 12:23:22 pm
content: Quote from: CatalinaWOW on September 26, 2024, 03:21:50 pmI got Bondhus 16037 from Amazon. Easier than looking for imperial allen keys here, and easily cheaper. I didn't hear that name before. but buyer comments on Amazon look pretty good, and Googling for it, I see it's a US company from Minnesota that produces ball, hex and torx tools. I hope they will be good enough.

author: tatel
author_rank: Frequent Contributor
timestamp: September 27, 2024, 12:29:51 pm
content: Quote from: HalFoster on September 24, 2024, 06:08:17 pmWiha 35393 returns a screwdriver?

author: tatel
author_rank: Frequent Contributor
timestamp: September 27, 2024, 12:56:46 pm
content: Quote from: Kleinstein on September 26, 2024, 11:06:13 amWell, we will see. I ordered from the first Ali seller linked before. 50 pcs, UNC 6-32, "12.9" steel = €2.87, delivered. At that price, one can try and use these set screws.Anyway, as said before, We trusted our lives to 8.8 screws. To use a tougher screw just to fasten a knob in place looks a little bit overkill to me?

author: factory
author_rank: Super Contributor
timestamp: September 27, 2024, 05:13:58 pm
content: From another thread asking a similar question about grub screws from HP TE, this subject is a common topic on many forums, vintage TE from most US makers use the same sizes, some use Bristol spline instead of hex/Allen screws.Quote from: factory on June 10, 2024, 06:40:15 pmDavid