Member postings for wotsit

I too would like a moderator to delete my account if possible

OK, OMG, you win - you abviously have no sense of humour, nor understand the spirit of a forum. I have long felt this forum is dying, having followed it from inception. I will miss a few of the people who post sensible info,  but I don't need the hassle anymore. Bye to all. URL deleted.

Edited By wotsit on 01/12/2013 12:57:43

More problems with Windoze Pain - Nowadays most versions of Linux are free, better than WIndoze, and no longer 'for Nerds only'. They install easily on almost all computers, and you can even try them out before installing without having to install it - the websites of (for example) Mint and Ubuntu both carry details how to prepare a LIve CD to run from the drive on a computer and try out all the functions, (and incidentally check whether the flavour of LInux can be successfully installed on the computer). The only difference between a Live CD and the installed version is that the CD runs slightly slower, otherwise everything can be checked, including Internet connections. The LInux community is far more hands-on and responsive than WIndoze, so any problems you do have can be quickly resolved. If you are desparate, you can even run Linux alongside WIndows on the same computer (and its easy to setup - see the Linux websites).

Usually, installation of a Linux OS also includes commonly used applications by default (but don't have to be installed, or can be removed easily later), such as LIbreOffice - this will do everything MS Office, Excel, etc will do, but usually better. It can also save documents in WIndoze formats or PDF if you insist, so no problems with compatibility. For users of things like Visual Basic/.Net, LInux has Gambas, which is an excellent basic-like object-oriented programming tool - my homebuilt EPROM programmer is programmed with it. There are alternatives for all WIndoze applications, and they are usually better.

Personally, I moved some years ago to Ubuntu, then to Mint. Ubuntu has now developed its own flavour of desktop - still easy to use, but some traditionalists aren't too happy with it, so Linux MInt caters for them - this is a menu-driven OS (like XP if you must have a comparison, but without the bugs) - this is probably the most popular Linux variant at the moment (= Ubuntu)

Viruses are very few and far between, updates are free and frequent, there is a vast library of easily downloaded applications for all purposes - and its all free.

There is also a very helpful and responsive community of losers, with many blogs and help forums, so any problems can be quickly and easily solved.

This forum displays fine on an 8 year old laptop running LInux MInt 14 - everything looks fine, and always has, from Updates of Linux Mint 10 through 15.

So why do we get these threads about ongoing problems with WIndoze? - take some action fro yourself - change it. You wouldn't buy and keep using a new car with problems like WIndoze - you'd demand your money back and go somewhere else.

Sorry - rant over - just fed up with weekly intrusions of Microsoft.

Plenty of screwcutting calculator for the minilathe in the internet, along with dicusion and theory. e.g.

http://littlemachineshop.com/Reference/change_gears.php

http://www.gizmology.net/changegears.htm

http://www.varmintal.com/alath.htm#Cutting_Odd_Threads

(Scroll down page for this last one - has downloads of WIndoze compatible VB program - much easier to use than messing about with Excel)

.......hundreds of others available.

Not sure if its relevant to what you are doing, Andy, but many years ago we experimented with a digital camera made from a static memory chip at the place I worked then (I think we used a 2114 if memory serves).

The idea was that if the plastic covering the chip die on the integrated circuit was removed, then light could reach the 'cells' making up the memory. This was not too difficult to do, simply by rubbing the IC on 'wet & dry' paper, finishing off with metal polish. (probably skim it off with a miill and fine cuts these days).

The controlling processor wrote a logical '0' into a memory location, then read it back. If light hit the cell, then the charge (logic '0' ) leaked away, and it would read as a 1. Conversely if no light fell on it the charge was retained, and read as '0'. The memory is actually an array of these cells, so multiple 'pixels' were available, all individually addressable using the normal memory addressiing. Light could be focussed on the array with a simple lens, producing a 'digital eye'. We found we could distinguish numerals and letters written on cards - the processor also analysed the returned pattern read from the cells - but the experiment was terminated shortly after, and as far as I know, it just remained an interesting experiment.

Edited By wotsit on 14/05/2013 17:57:25

Once made a set of replacement brushes for a 100v dc motor by cutting down the brushes from a car starter motor. They had a 'coppery' tinge o the colour, so I suspect they were loaded with copper powder(?). Worked fine, without undue wear or dirt. I don't know if this would work for a 230v ac motor in a machine tool - the starter motor brushes were rated at nominal 12v DC, and of course at very high current (can be over 300 amperes instantaneously for a starter motor), so they must be fairly robust, and probably very low resistance, so may be worth a try.

Connections to carbon brushes is not always easy - I drilled a small (~3/16 inch) hole in the brush, and used a tightly fitting spring 'screwed into the hole, and a wire soldered to the other end of the spring.

Interesting video on the Metro - but prepared by BLHeritage, so not really objective (e.g comment about 'huge space inside for its size' - so is a matchbox). However, my point was not about design innovation - Brits have shown they can do that under pressure - the issue seems to lie in the realization of the ideas. As the Metro video shows, the ideas were there, but the car itself (Like many others - Allegro, Marina) was useless - I remember tinfoil on chocalate bars that was thicker than the metal used on most of the BL range of that era.

As per Mike Clarkes comment. many years ago I owned one of the early rare 'flat-floor' E-types - priceless nowadays, but they rusted faster than you could polish them - beautiful design, lousy realization.

I think Tony Jaffee has it right - the chinese stuff is here to stay, and for many people it is the only way to get into their hobby. I know I could not have done it without my chinese lathe and miller, albeit that they are much modified to perform as I want. I simply could not afford the price of European-made machines, whereas I could afford the chinese stuff, and pay for improvements over time. It should also be noted that many companies nowadays don't just push the chinese products onto the market without some preparation, and I know some companies do contract with the chinese to improve the machines. There is also another side - the Chinese need to learn what is acceptable to the market, much as the Japanese and Taiwanese did in years gone by. I believe the time will come when the Chinese stuff is as good as any other.

Perhaps also we should consider has already been done - look at the lack of machines available in the 1950 - yet people like LBSC produced original work. The Gingery machines are another example - what would those early masters have done with a Myford? Is the limiting factor not the machine, but the operator?

Edited By wotsit on 27/02/2013 13:31:18

Not sure I would agree that Britain has the worst managers in the world - after all, it is not uncommon to see claims that Britain has some of the most innovative ideas, but can't put them into practise. It is very hard to believe that only the 'inventors' know what they are doing, but everyone else is dumb.

It seems to me that the difference is that inventors often work alone - responsible to no-one but themselves, whilst ongoing development is invariably due, eventually, to a group of people. Now retired after a lifetime with many reputable companies in Europe, I would say the biggest handicap Britain has is its reliance on commitees - tryng to please everyone all the time, and at the same time complying with idiotic regulations. Trying to complete projects on time successfully and within budget used to be the bane of my life when working with 'project teams', but on the very few occasions it was possible to do the job on ones own initiative, it was easy to reach all the targets (another nonsense modern buzzword).

Its easy to say single managers (dictators) are unaccountable, but in modern business this is also demonstrably untrue - all managers have to account to someone (finance, shareholders, a CEO), and if they don't do their job, they lose it. I have seen some very good managers lose their positions simply because they carried the can for a 'team' which was more concerned with covering their own a**ses and looking good, rather than getting the job done.

Adys comment about Italian cars is interesting, and true. What is remarkable is that the Italian motor industry turned itself around, and now produces decent cars. What did the now non-existant native British car industry do? - got rid of all its famous names, merged several times into an enormous uncontrolable entity, and produced abortions like the Rustin' Metros and Marinas, finally falling apart, and letting the Germans and the Chinese pick up the assets (I believe a Chinese company bought the rights to MG for one pound). How many Chinese assets has Britain bought?

Edited By wotsit on 27/02/2013 10:14:23

I haven't seen one of these caliipers, but I am assuming they have an LCD digital display - LCD displays commonly 'fade out' when they experience high or low temperatures (depends on the LCD, but down to 0C or above about 35C). They should recover when the temperature returns to normal, but some don't. I have a wristwatch which is absolutely useless when I go ski-ing!

I believe Jo and Neil have not only hit the nail on the head - they have driven it through the plank!. Why aren't they employed as editors of a rejuvenated ME? - these sort of things all used to appear in ME in what were surely the 'good old days' , before, as Jo says, they were hived off into specialist magazines.

Sid,

My apologies - you are right about the bi-monthly publishing - its some time now since I cancelled my subscription, and I'm getting on a bit. I realise that different people like different things, so it is hardly fair to complain about articles which others find interesting. That said, I found the same problems with some of the contents of ME. The Darjeeling Himalaya loco springs to mind. It was a wonderful piece of work, but it went on and on and ...... perhaps better published as a separate book. It would be interesting to know how many people were building this loco, because it is hard to believe that a high proportion of readers were. I remember filling in at least two Customer Questionnaires about magazine contents in the last few years, but I cannot remember ever seeing any results, which may have indicated where readers interests lay.

Harold,

I cannot argue with an insiders explanation of the reasons for introducing magazines. Perhaps what I failed to explain clearly is that I believed ME suffered by the introduction of MEW. Looking at past copies of ME, there were always articles covering both modelling and workshop aspects. Like many people, some of these interested me, and others not so much - however, some of the articles, perhaps outside my usual interests, gave me ideas. Since the split, the balance of articles in ME has changed IMO. ALthough there are occasionally workshop related items, I for one find the range of subjects now covered is considerably smaller than it used to be, making ME of little further interest to me.

You say that many readers 'would not have taken ME just to have a few pages devoted to their interests', and again I have to agree, but then why does MEW use material which at one time would surely have appeared in ME? This implies I need to buy both ME and MEW to get the same content as I used to get in one magazine. It seems to me that you have created the opposite case - why should I buy MEW when it has only a few pages devoted to my interests? I would also point out that not everyone can afford the cost of two magazines, both probably with limited appeal.

Unfortunately, and rather sadly after many years, for readers like me ME/MEW have lost their appeal , so like others I look elsewhere.

Surely the view that 'one mag complements the other' is a contradiction of the actual case. For most of its life, ME covered the fields now covered by two magazines. IMO the only obvious reason for the split into two mags was to increase the amount of money that the publishers take off gullible readers, Simply by introducing another high-priced magazine, and spreading the contents of the original mag over two publications, they doubled their income - and apparenlty no-one said a dicky-bird!

Sandy Morton is right - Sad to say, there are other magazines with more interesting content than ME or MEW. Try comparing some of the older MEs with todays offerings.

I think Bazyle has it the wrong way round - ME + MEW may come twice as often, but each copy is (less than) half as interesting. ME used to be published twice monthly earlier in its life, so now you are getting 1/4 of the content per magazine for a considerably greater cost. (I also did not renew subscriptions).

Sorry to bring this subject up again. I have read this thread (and others), and have become a little puzzled at some of the (apparently) conflicting advice. My workshop is single story, brick built, concrete floor, with fibreglass lining behind wood-panelled walls. There is no ceiling, simply wood lining panels nailed under the rafters, and the gap between lining and tiles filled with fibreglass wool. I have no heating of any kind. (not much gets done in winter )

I have several machine tools (lathes, a mill, pillar drill, hacksaw, etc, plus a large selection of handtools. The metal lathes and mill normally have an old curtain thrown over them when not in use - this was not to inhibit moisture, but to reduce the amount of dust collecting on the machines (very dusty here in summer - eastern Europe).

Autumn is usually very wet, followed by a winter of mixed snow (~100cms) and rain, with temperatures down to more than -15 degs C, before it starts to get warmer for summer, which can reach 40 degrees C.

When we first came here, I was worried about tool corrosion, but never really got around to doing anything about it - the machines tools sometimes get oiled during maintenance. Despite this, I have never suffered any corrosion at all on these tools.

At some times, I would appear to have the warm-cold-condensation conditions perfect for corrosion yet none appears, (for which I am duly grateful), but it does make me wonder why some people seem to get it badly, yet others have no problems (but I do have 'rusty hands' - another problem )

Edited By wotsit on 08/01/2013 19:36:44

Robin,

I have a (huge) old tranformer which is nominally rated at 11V, 15 Amps. I have no idea what it was originally used for. I acquired it years ago to strip for the copper wire (another project), but never got around to it. I just used a solid state full-wave rectifier (easy to find), and I have a 5000 uF 40V capacitor to smooth it,. (It works without the cap, but a bit noisy for some reason).

I have to admit the whole thing was not 'designed' - I just needed something to do the job in a hurry, so whacked it all together without much thought. As you can guess from my description, as it stands, it could be a bit lethal. It all sits in a wooden case, and the only protection is a fuse in the power lead. I did have a 25A fuse in the motor lead, but this blew sometimes, so eventually I just removed it. (I know - but its my shed, and I can take my own risks!).

I can't say I have ever had problems with startup current - as you say, rule of thumb says 5 or 6 times running current. I normally switch on with no mechanical load, so the load current / inrush current is probably relatively low, so I guess this is the reason. May be a problem if I startup on-load (ie motor stalled - must try it sometime).

As I noted before, transformers now are pricey - I did run it for a while on a car battery, albeit at reduced voltage, and it still worked Ok for me - a bit down on power (18V motor). (A battery is probably cheaper than a transformer these days! - use the guts of a 12V drill maybe?)

I suspect smps supplies cannot start up under such a heavy load, but I have never investigated it.

I did a similar thing sometime ago, Robin. Usual thing - the batteries died, and new one cost more than the original drill, so I just bought a new one. The old one lay around for ages, then I needed to tap multiple holes in an ally block, so it was just the job. two small (ongoing) problems - The chuck was the usual auto thing, and not particularly good quality. I find it difficult to get it tight enough to stop the taps slipping in the chuck. Its OK up to a point (good safety feature!), but its annoying with anything over about M4, because it slips too much then. Maybe a chuck and key would be better. Other problem is the bearing for the chuck - its really not man enough, and there is quite a lot of side to side play if I pull the chuck around. So far its not a big problem, because the taps are started in a pre-drilled hole, and the pressure is axial, as in the original drill.

I keep thinking about using the gearbox part to build a better machine - proper bearings for the chuck, and a geared or toothed belt drive, because the low speed torque is not so good using a variable power supply (and it draws a lot of current ! - I was lucky to have a suitable transformer, but they are expensive if you have to buy one.).

A little puzzled at the apparent opposition to Linux. I agree that some time ago Linux was 'Nerds' delight. I transferred from Windoze about three years ago - I really miss Windoze like I miss hourly enemas. The days of 'rolling up your sleeves and digging into the guts of Linux' are long gone.

Seriously - I agree there is a short learning curve for ex-Windows users, but there is nothing hard or long-winded about it. There is a huge library of excellent free software, and IMO it is easier to install than most Windows-based stuff. If you need advice, there are excellent online help forums.

I think the advantages of Linux easily outweigh the ludicrous cost of Apples for poseurs, or Windoze. The following link may give you some idea of what is available (and Ubuntu 12.10 has just been released if you are interested - and it can be run from a CD if you want to see what it is like without installing it - see the Ubuntu site.

www.makeuseof.com/pages/best-linux-distributions

www.makeuseof.com/pages/best-linux-software

I have nothing to do with producing Linux, just a very satisfied user.

VC.

Sorry about the belated reply - never enough time to do the necessary.

I hope you don't get troubles with the electronics of your mill. I got involved with mine maybe 10 years ago now, when I bought a Sieg type lathe and mill from a German importer (I lived Germany then). At first I had little work for the miller, but I managed to burn out the lathe control circuit in a matter of days. I eventually replaced the output drivers (I think this may be what you mean when you refer to the devices bolted to a heatsink). However, they went 'phut' sp many times that I became thoroughly sick of it. I also found out that the mill circuit was almost identical (there were differences in speed compensation circuitry, but they were both built on identical PCBs, with some detail changes - identical output stages.

There have been multiple threads on this issue, and the clearest thing which has emerged from them is that there seems to be several different versions of the controller/motor combination. Predominantly there seems to be what I call the 'old' version, which has two parallel output drivers on heatsinks, and a small daughterboard attached to the main PCB. Someone in this forum posted a circuit diagram and photos of this some time time ago, but beware, there are differences between the circuit and actual PCBs. I obtained a later controller from a German source, using a single out put stage - much better design, and built with SMD components. This was very good, but had no adjustments, and I found that it would not start from zero RPM - the (mill) motor ran at quite RPM when the start button was pressed.

I have also seen other controller variants fitted to these machines. I guess Ketan Swali could also supply some info on these controllers - I believe his company supplies replacements, and I know he has commented on this in the past.

I eventually got sick of the whole story - I bought the machines to do work, not to have to spend my time repairing or modifying them, so I built a foldback current-limited controller. This simply monitors the current taken by the motor, and when it begins to rise sharply (if the motor is overloaded or stalled), it immediatelyreduces current supplied to zero. I have never had a controller problem since this was done.

Whilst I agree to some extent with Ketans statement that these are lightweight machines. If you overload them then you can expect problems, but I would point out that the electronics (and sometimes the gears) apparently fail in normal use - look back through old threads in this and other forums. I believe there is a requirement that articles sold for public consumption should be 'fit for purpose', and it would seem that some variants of these machines are not fit for purpose for one reason or another. I think this is demonstrated by the number of posts asking for help to fix a problem, or the number of websites offering 'updates' to workaround the problem. Whether the machine costs 350 pounds or 3500 pounds (and I wish I had money like that to spare for my hobbies!), while I agree that it is impossible to allow for machine abuse, it should still do what it is sold for.

Ketan,

Interesting point about the loading on the bearings of a machine modified for belt drive. I modified my mill about 5 or 6 years ago and replaced the useless plastic gears with a toothed belt drive. Since the toothed belt does not stretch (in theory!) then I would expect the loading on the bearings to be much the same is it is for gears, because there is no need to tension the belt to maintain a (relatively) non-slip drive.

It has been noticeable in the various threads on modifying these mills that the trend has been to poly-v belts or similar, and to reject the toothed belt drive. I guess mine cost me about 20 pounds for the pulleys and belt, and it fits in the same space as the original gear drive with approximately the same ratios. It took me about two hours to modify, and has been working happily on the same belt for about the last five years. Of course, I have lost the alleged 'safety factor' of belt slip or tooth breakage (!!!) to protect the machine in case of jamming, but despite stalling the machine several times (no-one is perfect), I have had no other damage (but see below)

Incidentally, I don't entirely subscribe to the catastrophic failure mode of the gears providing protection on jamming. The gear on my machine cracked radially, but apparently not due to a jam - it seemed to me that the gear was somewhat loose on the shaft, and the key was a poor fit, which I believe caused a shock effect when loaded, until eventually the gear cracked radially through the key slot. There is a suggestion in this thread that the electronics should protect the machine, but this was definitely not the case with the older machines. If the machine was jammed, the output driver of the electronics simply went short-circuit, and yiou lost all speed control - it happened to me several times, until I became sick of repairing the thing, and built my own fold-back current limiting circuit.

Neil (Stub) - I think the requirement for symmetric waveforms will depend on the subsequent electronics - IMO most 'dumb' electronic systems (TTL, CMOS, etc) would probably clock on the edges of the pulses, implying that so long as the waveforms were present with reasonably fast edges, then the symmetry is not so important for a simple system using only leading edge detection.

However, one way to increase the number of pulses per rev is to use both the rising and falling edges of the waveform, and in that case, the quadrature waveforms need to be symmetrical, otherwise the pulses will tend to occur in pairs (two pulses, followed b a longer gap, then two more pulses - hope that makes sense). It is easy electronically to detect the rising and falling edges and combine them to provide quadrature pulse trains, providing two pulses for each slot in the wheel.

This method was used in the original German design for an Electronic Lead Screw (sorry - forget the guys name just now) - there was some discussion about this in this forum. (Tony Jaffee is the expert on this, I think).

An alternative to using a mechanical gearing system to increase resolution would be to use electronic phase-locked loop pulse multiplying system - I assume you want to measure rotational speed rather than absolute shaft position - this (put simply), is just an oscillator which produces the required output pulse. This output is divided by whatever multiplication is desired (e.g. 5), so a train of pulses at 1/5 the output frequency is produced. These pulses are compared with pulses produced from the optical wheel system, and an error signal is generated by the difference between the two pulse rates. This error signal is used to make the oscillator 'track' the mechanically produced pulses, but at (in this example) 5 times the frequency. There are easily available devices to perform this function (E.g CMOS 4046 and variants), or nowadays, PIC microcontrollers and the like can be programmed to do it.

Another possible method is to measure the time between pulses, rather than the number of pulses per revolution. For example, if you have the simplest system with 1 pulse per revolution, then one (shaft) pulse can be used to trigger a counter driven by a high speed pulse generator. The following pulse from the shaft pulse generator indicates the end of the count. The number of pulse generator pulses counted between shaft pulses is a direct indication of shaft rotational speed, and can be many thousands if required. Note that any system using this will have some lag in response times (depends largely on how it is designed), because (in my example) at least one revolution must take place before a count is available. I don't think this is an issue for the requirement of hobbing, if you just want to maintain a definite ratio between the rotation of two components.

Hope some of this is useful.