Thread sizes for tonears and soundboxes.

[flying500]

Is there a previous thread or does anyone have any ideas of common threads/sizes used on Gramophones.
Obviously They vary between British, European and U.S. manufacturers.
I have for example seen to many soundbox needle screw threads wrecked with self tappers and other wrong uns rather than a correctly threaded item.

[Curt A]

Screw sizes and thread pitch are not necessarily standard in all phonograph applications. Screws come in a variety of types (flat head, round head, oval head, etc. and uses - wood screws or machine screws). Wood screws are coarse threaded with pointy ends and no specific pitch (or at least none that matters), machine screws are particular in that they will only work for the thread pitch/count of the hole they were tapped for - example: a #10/24 is a #10 screw with 24 threads per inch.

You need to specify "which" screw you are talking about - motor screws, mounting screws, needle bar screws, etc. since they all vary and they vary between manufacturers. Some screws used on machines that were common sizes in the early 1900s are obsolete now and hard to find and that is the reason people substituted wrong size screws when repairing or replacing missing screws. Someone on the forum can probably identify the size and pitch of any particular screw based on the manufacturer or the application.

I am attaching two PDF guides that explain the various screw sizes that are normally used today, however they may not include the necessary sizes for phonographs...

[flying500]

Screw sizes and thread pitch are not necessarily standard in all phonograph applications. Screws come in a variety of types (flat head, round head, oval head, etc. and uses - wood screws or machine screws). Wood screws are coarse threaded with pointy ends and no specific pitch (or at least none that matters), machine screws are particular in that they will only work for the thread pitch/count of the hole they were tapped for - example: a #10/24 is a #10 screw with 24 threads per inch.

You need to specify "which" screw you are talking about - motor screws, mounting screws, needle bar screws, etc. since they all vary and they vary between manufacturers. Some screws used on machines that were common sizes in the early 1900s are obsolete now and hard to find and that is the reason people substituted wrong size screws when repairing or replacing missing screws. Someone on the forum can probably identify the size and pitch of any particular screw based on the manufacturer or the application.

I am attaching two PDF guides that explain the various screw sizes that are normally used today, however they may not include the necessary sizes for phonographs...

Thank you Curt. Primarily it's Needle screws on the HMV 4 & 5's. I have a small assortment but none fit. I did wonder if they are BA as used frequently before the war!
I remember most of the threads on my old motorcycles were BSC and Whitworth later BSF, I wondered if the gramophone industry followed suite ie BA and BSB?
All the Best
Jerry

[soundgen]

US companies used UNF and UNC threads UK , companies used BA or BSF or BSW perversely HMV threads are all UNF or UNC ( as far as the ones I have knowledge of )presumably carried over from importing Berliner / Victor products and importing the taps and dies to continue use , Columbia UK needle screws were BA threads ( so I assume Garrard were as well ) until the EMI merger where they seem to revert to UNF

[flying500]

US companies used UNF and UNC threads UK , companies used BA or BSF or BSW perversely HMV threads are all UNF or UNC ( as far as the ones I have knowledge of )presumably carried over from importing Berliner / Victor products and importing the taps and dies to continue use , Columbia UK needle screws were BA threads ( so I assume Garrard were as well ) until the EMI merger where they seem to revert to UNF

Thank you Mike, how odd about HMV but it does make perfect sense re the imported Berlinner /Victor items.
I guess that a similar scenario occurred with the automotive industry which in Britain always measured Bore and Stroke of an engine in Millimeters not inches!
All the Best
Jerry

[JerryVan]

I can't speak for HMV 4's & 5's, but Victor Exhibitions use a 1-56 thread and I believe the Victrola #2 reproducer uses 1-72. Wouldn't be surprised if one of those 2 threads are what you've got. The 1-56 is somewhat uncommon, even in the USA.