8BA to 1/8 Whitworth

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@JohnF

I agree that it doesn't look very worn

... I was simply comparing the measured OD with 0.126"

MichaelG.

Edited By Michael Gilligan on 26/06/2019 23:31:22

At that age it may well have been cut with a 2 piece die which could have been adjusted over or under a nominal diameter so may not look worn but could be undersize or simply sized to fit whatever the matching pitch tap produced.

It would help to know what the item is and what part of the world it may have come from.

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@ Jason

JohnF seems pretty confident

... hopefully 'Nearly Done' will confirm or refute.

MichaelG.

Edited By Michael Gilligan on 27/06/2019 10:14:40

I missed the reply that it was an English fishing reel.

For the job at hand, this probably comes under the heading "too much information" ... but I will post it anyway, for convenient future reference: **LINK**

https://www.ring-plug-thread-gages.com/PDChart/BA-thread-data.html

MichaelG.

5BA is looking good (dimensions, English made, and John's fishing reel knowledge), but if it's a non-standard thread, or was made off-spec by worn/inaccurate tooling, what's the best way of making a nut to fit?

If it was a bigger diameter screw, I'd make a silver steel tap metric pitch = 0.6 'near enough', and undersized to suit the worn out male. But this, I think, is a tad delicate for my lathe, mill and clumsy paws. How were small taps made in the good old days?

Dave

5BA may look good on paper but not a lot of use to the OP.

He has said that the male thread measures 0.085", don't know about you two but that's smaller than what I drill tapping size for 5BA so any 5BA nut is going to slide straight onto the thread not screw.

Thanks Michael,

All info is appreciated.

Yes John is correct it's from an early hardy perfect. I did do some research before getting the nut made and even ran a brass 8BA nut down it, but that nut was not very thick

I think John could be right about oversize due to old tooling. I think I shall try an 8BA die on the stud and see how it feels.

really appreciate the help given on here.

This shows the brass 8BA nut that I tried first.

.

Which is exactly why I wrote:

"BUT if it started life at 5BA, it must be very worn."

MichaelG.

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First: Measure it [much more accurately than any of us has done thus far]

'Know thine enemy'

MichaelG.

It's certainly not 5BA, whose o.d. is very close to 1/8 inch.

(8BA is actually 0.126 " full diameter, and a lot of model designs specify 1/8 " dia rod for 5BA studs, so within tolerance.).

I still think 7BA but I'm surprised an 8BA nut will fit.

SO

7BA 0.098 " full dia, pitch 0.019" : 2.5 mm 0.48mm respectively.

8BA 0.087 full dia, pitch 0.017 " : 2.2 mm 0.43mm " "

Diameter measured: 0.085" (2.16mm)

Pitch from the photograph, very slightly <0.5mm

Inch values rounded to 3 dec. places from 4-figure tables. The sizes look odd because the full BA range is a metric geometrical series.

If it's none of what anyone's suggested it can only have been some non-standard thread of the maker's own.

Does anyone have a spare 7BA nut they can give, or a 7BA tap they can lend, to Nearly Done? (I might have a tap, but not a nut.)

.

I beg to differ, Nigel ... but presumably that's a typo, and you meant 5BA

MichaelG.

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Edit: What worries me most though is that there seems to be some confusion between metric pitch and tpi

... Back to the gardening now [pull weeds whilst the sun shines]

Edited By Michael Gilligan on 27/06/2019 12:54:22

Thank you Michael.

Yes, my error.

FIVE BA is of 0.126 " diameter.

'

I quoted the Imperial sizes of BA threads to cater for measuring these parts in both, and directly from a text-book giving both scales in one table for the same reason.

BA is metric but so different from the ISO-M range only one or two sizes are vaguely close together, and then only by coincidence, not proper fit.

I wondered as an exercise if they could feasibly be screw-cut on my Imperial lathes. Using a spread-sheet (whose absolute reference function really comes into its own for such things), I managed to produce some fairly close change-wheel combinations for short threads before the cumulative pitch errors become too large. They'd still need finish-profiling by die,

'

I'm not yet gardening fit, and my lawn (using the term loosely) is becoming a hay-meadow with lots and lots of flowering grasses and their seed-heads. Managed to trim the front-garden buddleia yesterday, before its low-growing branches closed the pavement to anyone over three feet tall.

I'd agree with the OP and MG; the pitch is greater than 0.5mm, not less, at around 0.6mm. However, the thread is a mystery to me. Possibly a special by Fred in the toolroom?

Like MG I should be in the garden, but to hell with it; I'm going to knock out the rest of the traction engine frost spikes on the repetition lathe. It's going to take several proper workshop sessions to overcome the frustrations of the last two years at work. And to come to terms with being a member of the great unwashed, aka unemployed.

Andrew

This is insanely ambitious, but I wanted to play with another iOS App

[ the reference object length is, as before, 20mm on the rule ]

As Andrew suggests ... Perhaps it is "Fred's special coarse"

MichaelG.

Nearly done, just go for 8BA and I'm sure you will find it OK , I have made many parts for these reels over the years and never found anything other than BA or Whitworth threads on them. I just made a locking screw over the W/end for one 5/32 Whit LH. see photo.

The reason for the very small anomalies in the sizes is due to wear on the tools - taps and dies - most of these craftsmen as an apprentice purchased a die plate -- you see heaps of them on the auction site, just a flat plate slightly egg shaped with die thread cut in, these were used to make the taps and in time became worn but because the parts fitted together it mattered not.

As a matter of interest Hardy [of Alnwick] vintage reels mostly have the initial or mark of the man who made it stamped inside thus if you needed a spare part or additional spool it would go back to the person who made it.

Just to recap I would make a new one and you may or may not know after the lock nut is fitted the top of the thread was very, very lightly riveted over so it could not be lost.

John

Thanks John.

I hoping you could be right, as the new 8BA nut made for me does go on for Almost two turns.

Im hoping running a 8BA die carefully down will clear it !! One is on its way from eBay.

That is a beautiful locking screw you have made there.

Ive been taking my time getting this reel working nicely and this is the last thing to finish it.

Inside Its stamped RB who I believe was Robert Borthwick who worked at Hardy's 1890 to 1920.

Gents Thanks for the replies.

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... I stand corrected

I must be doing something terribly wrong with my measuring, as there is no way that I can make the pictured thread 59.1 tpi

MichaelG.

[ in the Dunce's Corner ]

Michael, you may well be right from your expanded photo however the proof of the pudding etc, the best way is to hold an 8BA tap against the thread and use only the number of pitches the nut will have - not many they are quite short. Although I have never come across one it is worth noting that its very close to 3/32 x 48 BSF ???

It is most unlikely that the thread would have been anything but a "British standard" -- used advisedly because of the time this reel was made -- which would point to Whitworth, BSF to BA but I appreciate there were a great many threads used in various industries.

ND yes you are as far as I am aware correct about the initials RB

John

[Michael you can take the hat off ! ]