Member postings for JohnF

Hi Gary, I have not read all the posts so apologies if I repeat etc, I too have worn varifocals for many years and no real issues however I would say make sure you get a top of the range lens -- not "mum's own" brand - there is a big difference in user performance at least that's been my experience [Wife's experience also] I have had Seiko, Zeiss, Nikon and all have been excellent. The first pair I had were an unknown brand and pretty much put me off varifocals but was persuaded to try a "better" brand by the optician -- as different as night & day !

As with all spectacles they are great but not so good as mother nature's originals !

John

edit -spelling

Edited By JohnF on 31/08/2020 19:38:08

Mark -- photos and your location may help !

See this link for adding photos --- **LINK**

John

Some form of indexing device off a Tool & Cutter grinder ?

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

One of the main reasons for adding at the very least your country in your profile ! Better if you are more specific, county, town but just country would be most helpful

John

Jon, see your messages

On Ebay now from Rotagrip 12: imperial resolution 0.001"

 Chronos also have them but more expensive        John

**LINK**

Edited By JohnF on 15/08/2020 20:18:00

Peter, its a long, long time since I had mine apart but if you PM me with your email I do have a pdf & jpg copy of the manual which may be some help. Its just sectioned diagrams/drawings of the machine sections with all the part numbers on -- no explanations but it will assist in what is where.

John

I would use a different material ! EN19T would be better, easy to obtain and machines well.

John

Edit! Standard practise really but forgot to say turn all diameters in one operation, support it with a centre in the tailstock and don't forget to leave a service end to remove the centre. If there are threads [most likely] I would screw cut them.

Edited By JohnF on 06/08/2020 22:06:38

Chris, I had the same problem on two fronts when I started with hearing aids, mine are the behind the ear type with a tube into the ear canal. I had considerable discomfort with the top of my ear caused by the tube and the ear canal due to the size of the cushion/plug on the end. Both were resolved easily with different components.

Well worth asking the ENT specialist what they can do IMO.

John

Captain, most things have been said already however the first thing I would make is plug gauge to test the internal thread you are cutting. Measure the mandrel thread using the 3-wire method then replicate the thread on a piece of steel bar so you can be sure the thread in any attachments you care to make will fit the mandrel on the wood lathe.

Also remember you cannot disengage the half nuts when cutting a metric thread on an imperial lathe, you must travers the carriage back between each cut. However if you do have a chasing dial there is method of using it but not in the normal way, I do have a written explanation if you want it but have a look at this link for a pretty good video of the method **LINK**

Lastly you asked the bore size for the thread and Brian is correct at 29.5mm but I would recommend you truncate the thread by 0.1 - 0.2 mm so make the bore 29.6 - 29.7 thus ensuring clearance on the root of the mandrel. Also remember to take this into account when cutting the thread to depth.

John

MichaelG thanks that a much better link ! There are some interesting things pop up now and then on the Facebook pages relating to machining etc -- the rest of it -- well !!!!!

John

Clive for the material I would suggest M-machine metals **LINK** no connection other than a happy customer. If you want to buy a "standard" full length of material they will cut it into say 3ft lengths and send it to you.

As for EN19 [4140] this is not a case hardening steel, you can harden and temper it but to achieve reliable results on a batch of components you really need a muffle furnace. The same applies to case hardening. The process you describe above will not produce a case hardened surface on EN19.

It all depends on the standard you need to achieve and the final purpose of the components ?

John

PS As you may be aware you can purchase steels already heat treated in the T condition EN19T  EN24T one of these may be OK for your project ? Both can be machined as supplied.

Edited By JohnF on 28/07/2020 10:18:39

Hi everyone there has been several discussions about universal machines, machines of the future etc etc. I came upon this by chance and thought it would be interesting to members

John

**LINK**

Nicholas it’s the Pilgrim Fathers fault —- took the wrong bucket for the gallon ! Can’t spell proper either 😇

Trouble is what is a TRUE Billion ?

It was when I went to school a Billion = bi - million i.e. 1 million million 1,000.000.000.000 but it was I believe Mr Wilson who in the 1970's ? decided to devalue it to 1.000,000,000 i.e. one thousand million !

The same logic applied to 1 trillion = 1 million, million million !!

Guess we are stuck with the new order !

Brian as Clive suggested dump the carbide and grind your own HSS tool, stone or hone it to ensure a fine finished edge then use plenty of lube, try different lubricants, I find a mix of cutting oil and Rocol works well on this type of material or many other steels. The material you have chosen will not be easy to attain a high grade finish but it can be done.

Good luck

John

This item is part of Sir Henry Wellcome’s museum collection. It contains six cartridge-like cylinders made of steel in a leatherette case. It is probably English, made between 1840 and 1890

These may be "position finders" if they have numbers 1-6 stamped on them, used to pick your peg when shooting and offered with a small tipple, Sloe Gin, the number being on the base. However being made of steel and they appear to be nickel plated would be strange? Normally a plated none ferrous metal or silver / silver gilt.

John

Hi if you have the two keys/spanners for adjustment or fitting the extension piece then you can remove the head with the probes and from memory part of the spindle can be removed then the thimble screws out -- from memory only ! I have a similar set branded with another name and many years ago dismantled them for cleaning -- mine were ex industry and not been loved !

However if yours are as you say new old stock I would first lubricate them with clock oil -- I use this because it has less tenancy to congeal. I acquired a small set [275-500] at the ME exhibition that were in superb condition but a little gritty all I did was lube them and they were fine

Hope this helps

John

Dreadnought or Millenicut, have never used a horse rasp but I think the tooth form would not work well ? Dreadnought are capable of removing material very efficiently, Millenicut give a finer finish.

Regards John