Member postings for Swarf, Mostly!

Regarding ball handles and form tools:

There's a video on the web somewhere showing the use of a form tool to shave a ball handle. I've linked on this forum to that video a few times but, owing to a 'Reset Windows 10' catastrophe, I can no longer find the reference. It was stated that the shaving technique is often used in industry. From memory, the shaving form tool doesn't cut all at the same time but engages the workpiece progressively as the feed advances. It's quite fascinating to watch. Calculating the profile of the form tool must be quite complicated because the angle of presentation is non-intuitive.

Best regards,

Swarf, Mostly!

This may be slightly off-topic:

I happened to look at the rating plate on one of my Hi-Fi loudspeakers the other day. It claimed that the speaker was rated at 120 Watts of 'music power'.

Are 'music power' Watts metric or Imperial?????

Best regards,

Swarf, Mostly!

Hi there, Nick,

Yes, that's the one.

Best regards,

Swarf, Mostly!

Hi there, Steve,

I contributed to a thread on this subject on this forum a few years ago. I just searched for the thread but couldn't find it.

I bought a vial from Level Developments, not cheap but then such a vial is a precision component. I seem to remember Level Developments saying that they only make batches of such vials for engineers' levels occasionally, those vials aren't a stock item.

In my contribution to that thread, I did include some photos of 're-plastering' the vial into the metal tube. They're probably still in one of my albums. I regret not absorbing all Clive's advice at the time, I didn't take enough care with ensuring that the background to the vial is sufficiently white and uniform! (White paint and/or appropriately folded paper. )

I've so far not summoned the courage to reassemble my level. (I do have other engineers' levels. )  The end caps are a tight push-fit and need to be carefully aligned so that their flat extensions are in the same plane and will sit properly on their positions on the cast iron body of the level.

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 17/03/2022 09:27:47

Hi there, Ivy,

I can't answer your query directly. However, if you go on the Myford web-site, they have the illustrated parts lists (aka 'exploded diagrams' ) for all the major assemblies of both the ML7 and the Super 7. They are (last time I looked ) down-loadable.

Best regards,

Swarf, Mostly!

Hi there, all,

Back in the 1960s one of our diving club members was a young woman who had moved down from the Midlands to a London suburb. She happened to have the same surname as the local diary and both she and the dairy had accounts at the same bank (NOT the Midland). This was in the days when banking depended upon manual ledger entries.

The first time the bank debited her account with the dairy's payroll was a bit of a shock, not really compensated for by a later credit to her account of the dairy's entire week's takings. These were not one-off errors!

Eventually they both learned to live with it!!

Best regards,

Swarf, Mostly!

Several months ago, it became obvious that our central heating system had stopped working. It was freezing weather and my first thought was that an excess of ice had built up in the condensate drain. We are Housing Association tenants so I phoned and reported a fault. It was 'after hours'.

The duty repair guy called us back and asked what error codes the boiler was displaying. He then suggested that I wind the wireless thermostat control knob up and down vigorously several times and he would call again later to learn whether this had been successful. I was able to report that this had fixed the problem.

He and I diagnosed that I had had occasion to switch off the mains electrical supply earlier that afternoon - this had caused the wireless thermostat on the hall wall to 'forget' its link to the receiver unit in the airing cupboard.

I was inpressed with this remote problem solving that avoided his coming out so he was meanwhile able to respond to calls from other tenants.

Best regards,

Swarf, Mostly!

Hi there, pgrbff,

On this forum, ALWAYS type a space before typing a right-hand bracket - that prevents the smiley gremlin from waking up!!

Also, always press right arrow before typing a follow-up to a quote - that avoids the quote marker line from also extending over your part of the post.

Best regards,

Swarf, Mostly!

Hi there, Noel,

I don't want to 'rain on your parade' but with all that brass and copper your rotor would have quite a high moment of inertia. That might make it sluggish in responding to gusts.

Still, it's YOUR project so make it anyway and tell us how it works.

Best regards,

Swarf, Mostly!

When I researched EITB some years ago, the only trace of the organisation still extant was the EITB Staff Pension Scheme!

My recollection of the EITB in operation was not as an actual training body (though I'm not disputing that such a body existed). As I understood it, EITB was established to counter the problem that the large engineering firms performed, and paid for, virtually all the training, only to have the smaller firms 'poach' all the trainees once they'd completed their training. So the EITB exacted a levy from each engineering firm, according to their head-count. Firms then reclaimed funds from the EITB for each training exercise they performed.

The system was a bit vulnerable to abuse - I remember that, as a young electronics engineer, I was for a while encouraged by my employer's training manager to attend the IEA exhibition, the Physical Society's Exhibition and to attend various semiconductor maufacturers' seminars on microprocessors. 'Well, it's all training, innit!'.

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 02/02/2022 10:24:55

Hi there, all,

I've posted on this topic before but my basic question has never been answered.

This post has been prompted by reading in today's news about the Henry III gold penny found by a UK metal detectorist.

Before proceeding, I must emphasise that I have no ambitions to embark on a career of counterfeiting - the beds in HM prisons are too hard for my poor old bones and their breakfast times to early!!!

Here's a picture of the coin concerned (cribbed from the Mail Online) :

According to the news article, 52,000 of these coins were minted in or around 1257 AD. This particular coin is the eighth example still existing - the gold content was worth more than the coin's negotiable value so most were soon melted down.

Now, here's my question: you surely don't strike 52,000 coins like these from only one pair of dies, so what technology did mints in 13th century Britain have that would allow/enable them to sink several sets of dies, each striking a common pair of impressions? Even for a soft metal like gold, the dies must surely have been hard???

Best regards,

Swarf, Mostly!

I thought the recommended method for making holes in spring steel was to use a punch and die??

Best regards,

Swarf, Mostly!

Sounds to me like a job for 'rent-a-mog'!!!

Best regards,

Swarf, Mostly!

Hi there, all,

Here's a minor item from the first photo:

I believe that the gizmo with the black drum is called a 'Kymograph'. It's used by botanists or botany students to measure the growth of plants. That would fit in with the RHS connection. I'm no botanist but, to the best of my recollection, you wrap a sheet of smoked paper around the drum and position the gizmo next to the plant under test. There's a clockwork motor inside the drum that rotates it at a known rate. A stylus attached to the plant bears on the drum and leaves a trace on the soot coating from which the rate of growth of the plant can be deduced. (In high CO2 levels, they grow higher and faster.)

The smaller clear object in the bottom right-hand corner of my photo is a spirit lamp. It wouldn't have been used (on its own, at least) to smoke the kymograph chart since a spirit lamp gives a smoke-free flame. In my early days of at-home chemistry experiment (in my bedroom) I used one in lieu of a Bunsen burner.

My grammar school chemistry master gave me an out-of-date catalogue from a scientific supplies firm, Townson & Mercer Ltd. of Croydon. It was even bigger than the last hard-bound Buck & Hickman catalogue, not quite a fork-lift job but pretty weighty. Browsing through it raised lots of questions like 'Please sir, what is a Kjeldahl's apparatus used for?'. An extra-curricular educational supplement!

On the subject of mirror galvanometers, with ribbon suspensions, my Senior Engineer in my first job preferred H. Tinsleys of Werndee Hall in South London. (I can't remember their full address.) I once had a guided tour of the Tinsley factory. They did some quite clever stuff with 'galvos' with multiple coils and connecting ligaments to measure power et. al..

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 29/12/2021 17:12:08

Hi there, Bob,

I wasgoing to suggest that it might be for sharpening the sort of mortice chisel that mounts in a pillar drill and has a twist drill down the middle. But then I noticed the shank, more likely for a prace and bit so more likely for woodwork than actuall metalwork.

Best regards,

Swarf, Mostly!

Hi there, Ralph,

I was taught that if you see thirteen thou. of rust, the item has only lost one thou. of metal. So rust often looks worse than it really is.

It is important to get rid of rust because it is abrasive. However, you need to employ a removal process that avoids making the situation worse by removing metal as well!

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 12/12/2021 14:17:23

Edited By Swarf, Mostly! on 12/12/2021 14:18:00

Hi there, Peter,

Anything cast-in to a casting is usually going to be the same characters for each example (unless the maufacturers have expensive habits!!). So cast-in numbers are usually to identify the casting at an early stage of the manufacturing process or maybe even a pattern identity number for use by the foundry.

Serial numbers are usually stampred in to a seldom-used zone of a larger machine surface or sometimes into a small machined 'island' in an out-of-the-way area of the casting. For instance, the serial number of my ML7 is stamped in to the tailstock end of the rear shear of the lathe bed.

Part number systems for any manufactured item have to be sufficiently comprehensive to guide or direct each stage of the manufacturing process. Each component has to have an identity, i.e. a part number and usually a drawing, and it is necessary to be able to identify each part through the process, either before or after its own machining (and/or electroplating or painting), and including the addition of smaller components or its being incorporated into some larger assembly. This doesn't just apply to machanical products For instance, a discretely-wired electronic device could have both a wiring schedule AND a wiring layout to define the interconnections and routing of that wiring and an items list listing each size and colour of wire, wiring clips, grommets etc. Sometimes, small nuts and bolts and washers were 'bulk issue items', i.e. too minor to be specified individually. (I guess I'm revealing my age here!!!)

I anticpate that some of our draughtsman or ex-draughtsman members may have lots to add to my very summary depiction of a drawing-number system!

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 12/12/2021 14:07:09

Hi there, all,

Why is my first thought to start all my posts with 'many years ago ... '??? Oh, well:

Many years ago, I bought, second-hand, an internal micrometer. Its maker was/is a well-known UK firm (I'd name them if I could remember but the instrument is currently stored away).

On examining my purchase, I discovered that the 0·500" spacer was mssing. I wrote to the makers (it was long before the internet and email!) asking for a quotation for a spare 0·500" spacer to complete my set. Much to my delight, they sent me one, free, gratis and for nothing!! I didn't even have to pay for the postage!!!!

Maybe they deserve recognition for their generosity even after all these years. Maybe I'll dig out the instrument and remind myself and tell you all of its maker!!

Best regards,

Swarf, Mostly!

Gentlemen,

ALWAYS type a space before a right-hand bracket. This avoids waking up the smiley gremlin.

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 27/11/2021 09:29:42

Hi there,

Your photo looks a bit, I emphasise 'a bit', like a Ross-Courtney termination.

I use them in the terminal chamber of the motor on my ML7. They have the advantage of not having a tail like the modern crimps but they also have the disadvantage of being, apparently, extinct!!!!

If you locate a source, fill your own requirements before blowing the gaff!!!!!!!!

Best regards,

Swarf, Mostly!