I was told today by an engineer who is making replica knurled wheels for the front standard rise/fall mechanism on my 1/4 plate Lancaster Instantograph 1890 patent that the thread size is No 8 Unified fine with 36 threads per inch. Might come in useful for someone in the future? The wheels in question are 1/2 inch diameter and there are 4 on the standard.

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  • Belay that me hearties! Turns out it's 4BA.
    Sorry about that!
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