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Member postings for Nick Clarke 3

Here is a list of all the postings Nick Clarke 3 has made in our forums. Click on a thread name to jump to the thread.

Thread: Coke for brazing purposes
23/10/2019 09:26:08

In older copies of the magazines it was always mentioned to pack work being brazed well with coke before brazing with paraffin blowlamps. Even as recent as the earlier Don Young and Tubal Cain articles.

Is there any reason why this is not used today? (or is it?) as coke or breeze is still available and as a way to generally heat a workpiece together with more localised heating it seems like it could still be useful.

Thread: Internet searching
17/10/2019 13:54:57

And I do know the actual answer!! smiley

17/10/2019 13:54:21

Michael -

I wonder what would happen if you typed 'Michael Gilligan internet search' in as an internet search?

Would it never stop incrementing itself?? dont know

Thread: What are these pliers for
15/10/2019 11:40:57

Looking at the slits in the jaws I think they would also work to insert a connector on the end of a wire into a receptacle, the wire passing through the jaws - I used these in this manner for car bullet connectors a long time ago.0-004-00.jpg

 

Edited By Nick Clarke 3 on 15/10/2019 11:42:49

Thread: Cheap ER collet advice please
14/10/2019 09:54:24
Posted by Baz on 14/10/2019 09:35:18:

I am sure that it’s been said before but I feel it needs repeating, you get what you pay for, pay next to nowt and you will get rubbish, pay a good price and you will get good stuff, pay top dollar and you get top quality.

I think the other posts here suggest a slight modification to this sweeping statement - With items at the lower end of the market you cannot assume you are going to get an accurate quality product while with a branded one you ought to be able to.

Unfortunately in today's world you don't know where any product is manufactured and you may get an adequate or good item for little money, CNC makes it as easy to make something accurately as not, but at this point in the market quality control may pass out some that are not acceptable.

However by paying more the name on the box does not always guarantee quality. Trade names and brands are bought and sold and applied to items manufactured elsewhere. You can usually get an improved product from a branded supplier or manufacturer should you have an item you are not satisfied with, but it appears that some bargain brands are also doing this now.

 

Edited By Nick Clarke 3 on 14/10/2019 10:00:49

Thread: Resistance Soldering question
13/10/2019 12:15:03

Are the tips on your soldering plier removable or replaceable?

If so could you make two fine pointed tips to be applied applied to the larger piece, on one side of the joint? This would need to be held in contact with the smaller one of course.

Single sided spotwelding is sometime done in car repair, but at far higher temperatures of course.

Thread: Changing internet providers
11/10/2019 17:48:48
Posted by Brian Sweeting on 11/10/2019 16:18:41:

I have found that some manufacturers technical websites that I used would not allow me to register with the Gmail account because they like a "real" address as against a web based service .

And this is also useful if you are looking for sample electronic components - many manufacturers will go out of their way to support designers.

Thread: Increasing depth of field on a lens
09/10/2019 11:21:19
Posted by not done it yet on 09/10/2019 10:25:10:

C’mon, boys ‘n’ girls, you cannot change the focal length of any given lens. It is fixed. You can alter the focal length by adding other lenses in the system but the focal length of any single lens is reliant on its curvature.

True, but the OP's question was "Is it possible in theory to add a lens or lens combo to increase the depth of field to the existing lens?"

09/10/2019 09:54:10
Posted by Michael Gilligan on 09/10/2019 08:56:10:
dont know
To the best of my knowledge, Nick ... an additional positive lens will reduce the focal length of the prime lens.

If I am missing your point, then would you kindly explain.

MichaelG.

Apologies Michael - got my positives and negatives the wrong way round - but my post was about the practicalities of changing focal length so this is the corrected version:-

In theory it is possible to change the focal length of a lens, but only at the expense of changing all of the optical properties of the device.

The (approximate) depth of field of a lens is inversely proportional to the focal length squared, so by adding a second lens the DOF will be changed as the focal length changes. Adding a negative lens will increase the focal length and so decrease the DOF. If you add a second positive lens you will decrease the focal length and hence increase the DOF, but the magnification and the whole geometry of the setup will change. Almost certainly not worth it.

The classic work I use in a photographic context is Photographic Optics by Cox

The formula concerned is 1/Focal length 1 + 1/Focal length 2 = 1/Focal length 1+2

I hate inverse formulae!!

Take care, Nick

09/10/2019 07:54:27

In theory it is possible to change the focal length of a lens, but only at the expense of changing all of the optical properties of the device.

The (approximate) depth of field of a lens is inversely proportional to the focal length squared, so by adding a second lens the DOF will be changed as the focal length changes. Adding a second positive lens will increase the focal length and so decrease the DOF. If you add a negative lens you will increase the DOF, but the magnification and the whole geometry of the setup will change. Almost certainly not worth it.

The classic work I use in a photographic context is Photographic Optics by Cox

Thread: Triangular Screws
07/10/2019 21:28:08
Posted by Neil Wyatt on 07/10/2019 20:51:09:

Well, all new to me, but interesting stuff.

If I get lobulation, I shall probably visit the doctor for advice.

Neil

I can recommend a good ointment!

Thread: Question from a customer
06/10/2019 14:23:52

Jason's video -

"Pressure on the outside of the can is over 3000 lb" - a bit high and by quoting the force on the can as a whole as pressure misleading to say the least!!

06/10/2019 13:55:35
Posted by JasonB on 06/10/2019 13:45:26:

Can I ask why the differential will only be 14-15psi. If the heat were removed when there was say 100psi in the boiler would there not be a drop of 85psi on the volume of steam?

If a valve were fitted to the feed line and the boiler allowed to cool completely then there would be low pressure in the boiler. The minimum this could ever be would be an absolute vacuum - and in real life it won't be that low.

if the valve is now opened the pressure of the atmosphere in would be 14.7 lb/sq in hence this would be the biggest differential pressure. The 85psi pressure would be pushing out, not sucking in.

Thread: Metrication of models
06/10/2019 13:42:11

The need for exact standard sections becomes less of an issue if the design process is thought through. Where size is not needed to be exact many designers appear to have said 'chuck a piece of 5/32" bronze bar etc when what they needed was a piece of metal large enough to finish to the desired size, more or less. Also with older designs I suspect designers did not want to inflict unnecessary machining down to size on hobbyists with limited machining facilities. To the end of his life LBSC wrote about 'those lucky enough to have a milling machine' when today far more people either possess one or have access to one through a club.

What I am trying to envisage is the designer thinking of 1.2" but making it 1 1/8" for simplicity and today needing to use 30mm for convenience. Neither of the two alternatives are accurate to the original idea, but both work and if you want accurate - today you can mill it!.

One interesting thought about measurements is regarding copper sheet. It used to be thought that 10g, for example, was a replacement for 1/8" being a few thou thicker. 3mm is about 10 thou thinner than 10swg But US 10g (B&S) is thinner again. If we are buying copper sheet or tube with our import streams focused more across the Atlantic than into Europe which will we be getting in the future??

All will probably be within any reasonable safety factor, but several published boilers with 'grandfather rights' as established designs have been questioned in today's world and I don't think this will help.

Thread: windoze 10
03/10/2019 12:33:21
Posted by Peter G. Shaw on 03/10/2019 11:51:36:

I actually completely agree that there is no necessity to upgrade just for upgrading's sake, and this why my equipment is many years old, as my software, and yet it does everything I want quite satisfactorily …..

I also agree - I use XP, Win7 and Win10 here along with different types of *nix and Mac OS - however being a computer nerd I get often asked questions along the lines of 'I use XP and my new printer won't work' or 'I have a new PC that came with Windows *** and now my old software won't work'.

Keeping old systems running depends upon you being able to freeze them in their entirety - as soon as you need to replace one part you can start to get issues.

But this isn't just a Windows issue. Apple upgrade as often and while their systems may seem to stay more stable they don't have to deal with the huge number of independent third party hardware and software suppliers that Microsoft do. To go onto the App store compatibility is checked - it is not at all like that on a PC! - and it doesn't last forever - I have a Mac Mini that is PPC based and won't run OSX 10.5 or later and a Classic Mac SE30 that is restricted to MacOS 7. Both still work fine with their own software and hardware many years after they were superseded.

Thread: Ring Mount
02/10/2019 10:00:20

By the look of it the front section of the lens does not rotate so a ring there connected to the tripod screw on the camera by a bar with a tripod screw at the centre of gravity may be the only way to go.

Thread: nutcracker
02/10/2019 08:40:28

LBSC in December 1956 published a design 'For the kiddies' of a steam hammer to crack nuts.

Don't find the need myself but …….

hammer.jpg

Thread: Surely it's not just me
26/09/2019 19:23:22
Posted by Meunier on 25/09/2019 21:53:03:

Can't resist, bearing in mind your other post Ron --- what thread should you have posted in , BSP/UNF ???
DaveD

If it is a wrong thread perhaps something left hand used in obscure Eastern European machine tools for a short period only in the 1920s??

Thread: Worried
26/09/2019 19:17:59
Posted by MichaelR on 26/09/2019 19:09:32:

What bothered me when we went decimal I lost a 140 pence from my pound sterling, or did I ?, !!

Mike.

On decimal day morning, just after opening time I went into a pub (not quite legally, I have to admit) bought a bottle of Guinness for the sake of spending my first decimal money. After a lot of '2.4 pence is a penny' and 'a shilling is 5p' and 'there are a hundred p in a pound' sort of discussions between the two bar staff I was given my change from a pound note.

Counting it up a bit later for the novelty value of seeing the decimal coins I found I had more than a pound in change ………..!

Thread: 0.300" & 0.400" 28TPI Tap
26/09/2019 18:28:37
Posted by Michael Gilligan on 26/09/2019 18:23:14:
Posted by Nick Clarke 3 on 26/09/2019 18:13:26:

Just been reminded of a weird thread - Leica Screw Mount lenses (LSM) were 39mm dia x 26tpi whitform - now theres an odd mix if ever there was one.

The USSR simplified it to 39mm dia x 1mm pitch - 23 thou of a mm larger pitch which presumably takes account of any minor threadform variations.

Leica lenses will screw into Russian cameras and Russian lenses into a Leica - I have both here - but there can be other differences as well.

.

There has been some quite robust discussion about this, recently, Nick

MichaelG.

Michael

Can't find it using LTM or Leica as search terms on this site - have you a reference?

Edited By Nick Clarke 3 on 26/09/2019 18:28:48

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