judging by the die plates which I have and those in the clock workshop, they were not usually any decided thread so much as what the particular craftsman thought to be ideal or useful etc…….

I have always liked die plates for some reason and have quite a collection!

…..BA threads are relatively recent, ….I think first devised in 1893, or thereabouts (?)..well after most die plates as far as I know. Also, different trades had different ideas about what threads they needed. I have never seen a Whitworth die plate, but who knows?

Many years ago I was told by an old chap in Birmingham’s gunmaking quarter these were purchased as an apprentice and used to make your taps and taps to make dies when needed. Over time they become worn hence the screws (pins in gunmaking) became larger but of course anything made still fitted perfectly. Interchangeability was not a consideration ! Now you often find threads on early 20th century guns that are “nearly” BA or small Whitworth threads but oversize etc.

In all probability the same applies to other craftsman industries of yesteryear.

John

And it probably still applies today in practice John. I have some very small metric dies and taps (<1mm) and the likelihood is that I'll break a tap before I damage a die.

If (when!) I do so, I will most likely try to make replacements using the die rather than trying to purchase a (single) new tap. The small metric set I purchased was not too expensive, so will almost certainly be carbon steel. Any replacements I make will be shorter than the commercial ones, as I'm only tapping a few threads depth (and in non-ferrous materials).

As I can no longer get 16BA screws/nuts (certainly not at a reasonable price), I may well take a similar approach for these too, purchasing just the 16BA die (& probably a 14BA one too). My existing BA screwing tackle only goes down to 12BA and whilst I can still get 14BA screw fittings currently, that might change going forward.

Regards,

IanT

If an old tool is of identified make but not in the normal catalogue, could it have been made for internal use?

High catalogue price might indicate the assumed customers would be companies, not individuals.

' ' '

I certainly agree with Howard Lewis' remark!

I have a trammel with brass holders for the scribers, on a hardwood beam not graduated but giving 20 " maximum radius. No company names, but both holders are neatly stamped 'R J SANDFORD 1920'. From careful examination by magnifying-glass I think they were hand-pierced and filed to their elegant profiles, after their various bosses had been turned, from solid.

A neat touch is the stock scriber-holder's fine-adjustment of over 1/8 " travel, working against the end of the beam.

The pressure-pads under the clamp-screws fit very well indeed. I have just taken one out to examine it, and it shows faint file-marks on the screw contact face.

One oddity is some drilled holes in each face of the holders, neatly set out but of no obvious purpose.

I've not needed to repair it, although I did clean the brass, by cloth and 'Brasso' only.

Perhaps Mr. Sandford made it 100 years ago, as one of his apprentice-pieces, possibly for pattern-making or sheet-metal work. It has clearly been used a fair amount, but shows little wear, so fair use too. If he was the chap I think though, as far as I knew he was a retired cabinet-maker. That was in the 1960s when I were a lad, so the chronology would be about right.

Now looking at this lovely, lightly-patinated old tool with new respect, yes, I have used it a few times. The first, for which it proved ideal, was in setting-out a jig for assembling two hexagonal steel frames, using basic geometry to construct 120º angles on a large steel plate.

If R.J. was watching from the shadows, I hope he approved….