Calipers at Maplins

Tim Leech · 2005-11-19T19:22:37+00:00

I don't really like Maplins, a bit too much like Dixons , butthey have their uses.They've got a 150mm digi caliper on offer at 15 quid as part of theirChrimble promotions. There are probably cheaper ways of buying themnow, but there's no postage, VAT, or any other extras if you have ashop nearby. I got one today, haven't checked it yet against any sortof standard but it all seems to work OK, even has a thumbwheel whichthe cheaper Mitutoyos don't.CheersTimDutton Dry-DockTraditional & Modern canal craft repairsVintage diesel engine service

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John Stevenson 20 years ago

The guy across the road from me used to work for Co-op optical services on contact lenses. As I had done him a favour once on his trailer he told me that next time I wanted some glasses to see him, so I did. He pulled a big box of frames out and got me to choose a pair, all modern but had probably been on display in a window and discarded. I gave him my prescription and he took them to one of the branches for some lenses to be cut/rolled/ground/ stamped on [ delete as necessary ]

He told me the frames were free and I'd have to pay the interdepartmental charge for the lenses.

Two lenses, cut/rolled/ground/ stamped on [ delete as necessary ] to the same post code as Jodderell Bank, with Reactolite [ non welding variety ] -- £7.50

So that's the mark up.

That was four years ago, last set of driving glasses I had done out in Cyprus two years ago, £42 with eye test and frames all in. The laugh was they all come here to learn the job.

I'm buggering off again over Christmas so I'll get my close work glasses done then.

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

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Cliff Coggin 20 years ago

Economics lesson two.

Become an optician and you will never be poor. D&H wanted over £200 to fit varifocal lenses to my existing frames. Needless to say I walked out.

Cliff Coggin.

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Peter Parry 20 years ago

SWMBO has quite a complex prescription and over a few years has saved a lathes worth of pennies by using

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than benefitting from the savings I have no connection with them).

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Jonathan Barnes 20 years ago

I have astigmatic eyes... Correction is a cylindrical element to the geometry, varifocal requires a sperical grind with variable radious ...

Whatever they use to grind lenses must be a prity special bit of kit.

While I bet the machine is some sort of varient on a CNC mill my curiosity has been aroused by this thread... Anyone have any information / pictures of lens grinding machines ?

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Dave Baker 20 years ago

I once fixed the computer for a company that made the lenses for spectacles for local opticians. When I needed new glasses I got an eye test, took the prescription, popped back to this place and reminded them of my previous service to them. The guy showed me how lenses are made and how much it costs while he did mine for free.

The lenses are bought pre ground to each possible optical specification as a round blank about 60mm in diameter so they'll fit the biggest possible frames. They cost maybe a quid each. Clearly you need to have hundreds of those in stock because there are so many possible prescriptions. You then pop them in a CNC cutting machine which scans the shape of the frame and cuts the lense to suit. Takes a couple of minutes per lense. What most people think actually happens is that a blank flat piece of glass or plastic is ground to a particular curvature for every set of specs ever made. Doesn't work like that at all.

The mark up at the retailer end is a fricking joke. My chap had a right old whinge about it when he did mine. His few quid per lense turns into as much as £100 per lense by the time the poor sap at the receiving end gets the specs perched on his nose.

So here's the deal. Go to

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or your Yellow Pages and lookup optical goods mfrs in your area. Them's the chaps wot make the lenses. They'll be well happy to charge you a few quid direct rather than some poncy optician charge you ten times as much for their work. My local one is Fairplay Optical Ltd in Watford. Tell em the bloke who fixed their pc sent you. I'm sure they'll post lenses out regardless of where you live.

-- Dave Baker

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Tony Jeffree 20 years ago

You have to realize it isn't the cost of the lens blanks & machinery that is the major factor in setting the price of specs, it is the cost of Mercs ;-)

Regards, Tony

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cerberus 20 years ago

Can't help with pictures but if you pass a Vision Express have a look inside. My local one has the machinery in a glass cubicle so you can watch your lenses being made.

--=20 cerberus

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Nick Müller 20 years ago

Quite a late answer, but still interesting (maybe): I have built a DRO around those calipers (and digital scales).

I have documented the digital protocol, built a interface (including PCB) and written software to run on an old laptop that serves as a display:

If you have questions, feel free to ask.

Nick

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Geo 20 years ago

Fascinating piece of reverse engineering and well documented.

Have a good holiday.

Geo

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Nick Müller 20 years ago

That's what I whish all around here, too.

Nick

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winanskeith 17 years ago

Nick, are you still supporting the Yadro with tech help? Can't seem to get a hold of you very easily. That is why I am contacting you on this forum. I want to know if you can write a macro or subroutine to allow me to choose which batch file (m.bat or l.bat) to run at start up and to also automatically answer "yes" to the start up questions. Also how do I shut down Yadro after I am done, other than with Ctrl-Alt-Del? Is there an easier way to contact you? Thanks, Keith

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Nick Mueller 17 years ago

Yes! But I was (I posted that here) unreachable for several months while I moved. Was a bit of an disaster with the phone. And I won't tell you why I do have DSL now. ;-)

eMail works and they are being answered. When did you last try?

Hmmm ... doesn't work right now. But what is the difference wether you type "l" or "m" to start YADRO or type "l" or "m" when YADRO is running? Sorry, I don't understand your motivation.

Those dialog-questions can be easily removed. You can either try it yourself when you look at the sources and look for the question asked, or mail me (what file, what "yes", etc.).

It is Alt-E.

eMail? :-)

Nick

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Nick Mueller 17 years ago

Oh, and there is a new protocol. I'll get one of those scales in a few days from USA and will implement it (will take some time). Also new are scales with 3V supply. They do work with the interface (requires changing an resistor), but you can't mix 1,5V (the common ones) and 3V scales as long as you supply them from the interface.

HTH, Nick

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