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Thanks for your research, Jeff. I archived those auction pages since eBay will eventually delete them.
Dave Wise From: [email protected] [mailto:[email protected]] On Behalf Of Jeff Dutky via groups.io Sent: Wednesday, July 21, 2021 4:43 PM To: [email protected] Subject: Re: [TekScopes] Binding Post Thumb/Head Nut Replacements I have added another picture to the album (/g/TekScopes/album?id=266234</g/TekScopes/album?id=266234>) showing all six candidates I have tried for replacing missing thumb nuts on 500-series scopes and plug-ins. The picture shows seven nuts, labeled A-G. The nuts are: A: An original Tek thumb nut, full height, as would be used on a 500-series scope, plug-in, or binding post adapter for a 465 or 475. B: "316 Stainless Steel Knurled Thumb Nut 1/4-28 Thread" from eBay (<> C: "M5 Precision Knurled Thumb Nut" from eBay (<>) D: "M5 Steel Leveling Knurled Thumb Nut" from eBay (<>) E: "OEM by Bosch 50534 1/4-28 Knurled Steel Nuts" from eBay (<>) F: "1/4-28 Internal Wrenching Allen Nut Alloy Steel Black" from eBay (<>) G: "1/4-28x7.5mm(L)x10mm(OD) Metric Threaded Brass Knurl Round Insert Nuts" from eBay (<>) My evaluations are: (A) are, of course, practically perfect in all particulars. I'm still surprised and saddened that I can't find a source for them. Were these custom made for or by Tek? (B) has very pleasant diamond knurling, at least as fine as what Tek used, but is about 1.5X the outer diameter and about 3X as tall. It is only threaded half way through on the flat end, which makes it hard to use the female banana jack with this nut in place. While it is larger in diameter than the Tek part, it looks like it will still leave enough clearance on something like a CA or D plug-in to use the UHF or BNC connectors, but it may be too large for use on some TM500, 5000-series, or 7000-series plug-ins. (C) is the wrong thread, closed at one end, and too short, so it will not properly clamp a wire inserted through the binding post. The knurling is very nice. It's a shame that these are otherwise unsuitable. (D) is the wrong thread, and the outer diameter is much too large for even the relatively roomy 500-series plug-ins. The nut is also about 1.5X the height of the Tek part. The knurling is coarser than the Tek part, and is not diamond knurling, but I think it's still pleasant. They are entirely unsuitable to the task. (E) is the same outer diameter as (B) but only slightly taller than the Tek nut. The knurling is much coarser than either (B) or the Tek part. Like (B) this seems to leave enough room for the probe inputs on 500-series plug-ins, but may be too large for some TM500, 5000-series, or 7000-series plug-ins. (F) is almost perfect; only slightly taller than the Tek part, it does not interfere with the use of banana plugs, and looks very nice on a scope or plug-in. The knurling, while not diamond, is very fine and pleasing. I liked these so much that I ordered several more bags of them in case of future need. (G) is slightly shorter than the Tek part, which means that it leaves a little bit of the threaded shaft/banana jack cylinder exposed to damage. The brass doesn't look nearly as odd on a scope or plug-in as I feared it would, and even though the knurling is very coarse, it still feels nice on the fingers. These have the singular advantage of being very inexpensive (I got 15 pieces for under $9, and could probably have paid even less if I were willing to buy larger quantities). (F) and (G) are my favorites, but (B) and (E) would do in a pinch. -- Jeff Dutky |
