Member postings for SillyOldDuffer

Meaningful title.

Stay on topic.

Avoid hobby-horses, politics, racism, sexism, religion, stereotypes, bad-language, propaganda, provocations and jargon.

Think about your message. Make sure what you typed makes sense and actually says what you meant it to say.

Try to be polite and in good humour..

Check your facts.

Use the spell-checker.

Treat everyone with respect and don't demean people even if you are a world-class smarty pants.,

Tolerate mistakes, misunderstandings, ignorance and the other guy's circumstances and objectives.

Apologise when you get it wrong.

Provide evidence and references if you can.

Say thank you and recognise good work.

Don't be put off by criticism. Nobody is perfect.

You're all wonderful!

Cheers,

Dave

The bigger the better is good advice, but don't forget whatever you get has to fit in your workshop and you have to have the wherewithal to cope with the extra weight.

Like Martin King 2 I have a WM18 that came with an erratic Z DRO. In my case the problem was due to a small misalignment of the fixed and moving parts of the DRO caused by a rough casting that interfered with the fit. The washer fitted to overcome this wasn't quite good enough and the DRO tended to bind and jump. Removed from the mill the DRO worked fine.

Once I'd worked out what the problem was it was easily fixed in a few minutes by filing the casting until the DRO ran straight.

I've owned the mill for a year and haven't had any other problems with it.

Regards,

Dave

Edited By SillyOldDuffer on 19/12/2015 23:39:28

Martin Connelly's comment that "The laptops effectively had zero cost because I already had them." reminded me of an unpleasant encounter I once had with a Finance Manager when he laid into identical logic in one of my carefully crafted Business Cases.

It's a dodgy argument because not everyone has an old laptop and because old laptops become unreliable and have to be replaced. Putting it another way, someone telling us "my Hurco Machine Center is effectively zero cost because I already have one" definitely wouldn't help the debate much.

That said trying to drivie a real CNC machine with Arduinos would also be a false economy.

Douglas Johnston shouldn't be discouraged about his programming skills. Many professionals also "make programs that work regardless of how clunky and inelegant they are".

Cheers,

Dave

Bob's use of a single crystal to drive two oscillators was new to me, but hey it worked!

Using two Arduinos rather than one is apparently easier because of a limitation in the standard Arduino library, which is that the tone() function can only be used on one output at a time. Bob's project needs two outputs.

There are alternatives that don't require board surgery.

It is possible to synchronise two Arduinos using the code below, but they drift apart over time. I tested the code using a Duemilanove and a Mega2560. An oscilloscope shows that the Arduino's start exactly in step but drift apart thereafter. For a nominal 400Hz the Mega2560 outputs 400.7Hz whilst the Duemilanove outputs 400.64Hz. Their 16000kHz crystals are oscillating at slightly different frequencies (16000.30kHz and 16000.48kHz). For Bob's application I doubt this would matter, but his solution fixes that problem.

const int input_sync_pin = 6;
const int output_sync_pin = 7;
const int tone_out_pin = 8;
const int led_pin = 13;

void setup() {
// put your setup code here, to run once:
pinMode( input_sync_pin, INPUT_PULLUP );
pinMode( output_sync_pin, OUTPUT );
digitalWrite( output_sync_pin, LOW );
while ( digitalRead( input_sync_pin ) == HIGH )
{
; // Waiting
}
// Synchronised now
pinMode( led_pin, OUTPUT );
digitalWrite( led_pin, HIGH );
}

void loop() {
// put your main code here, to run repeatedly:
tone( tone_out_pin, 400 );
}

Connect GND to GND, and pin 7 on one to pin 6 on the other, twice.

Another way is to use one Arduino to produce two tones at the same time. This is possible by installing the third-party library at *LINK*. The library needs a small fix before it will work. After installing the library, find the file "Tone.cpp" and edit it. Change the line reading "#include <wiring.h>" to "#include <Arduino.h>" Don't forget to tell the Arduino IDE to use this library.

The tones produced by this example program are based on the same clock and are closely synchronised.

#include <Tone.h>

Tone t1;
Tone t2;

int f1 = 500; // Hz
int f2 = 1000; // Hz

void setup() {
// put your setup code here, to run once:
t1.begin(6); // Tone1 Output on pin 6
t2.begin(7); // Tone2 Output on pin 7

t1.play(f1);
t2.play(f2);
}

void loop() {
// put your main code here, to run repeatedly:
// Example increases Tone2 by 1000Hz after a second. Resets to 1000Hz when the output is higher than 65kHz
// Tone1 stays at 500Hz. The two tones are output on different pins at the same time.

delay(1000); //mS

f2 = f2 + 1000;
if ( f2 > 65000 )
f2=1000;
t2.play(f2);

}

Microcontrollers like the Arduino offer lots of opportunity to model makers. It's probably heresy but I think a well-built steam engine using an Arduino with sensors to control valve events and boiler pressure etc would be rather more efficient than a mechanical equivalent. I wish my workshop skills were up to it!

Kudos to Bob for having a go.

Regards,

Dave

For 2D drawings my vote is for QCad too. Although the free version is sufficient for most purposes I paid for the Pro version because it has extras that simplify some common drawing functions. QCad is relatively straightforward to use.

A disadvantage of full featured packages like Autocad is the learning curve. They include functionality you may not ever need.

I use FreeCAD to experiment with parametric modelling. It's a development project and a bit prone to crashing. Nonetheless I've found it very useful for learning about 3D design and, in the real world, for visualising complex objects. There are some good tutorials on the web.

Edited By SillyOldDuffer on 12/12/2015 21:12:58

Hi Alan,

You asked "Out of all the sites I have visited, and like most people I suspect that is hundreds, why is it only the ME site that is a problem?"

Well, I agree with Clivel who said earlier "So it would seem that the problem is not caused by your choice of OS and browser, but is instead caused by something else on your system, Until we can establish what that is, it is extremely unlikely that Katy will be able to duplicate the problem so as to create a fix."

I think you have a combination problem in the sense that "your system" includes everything between you and the ME Site. I suspect that the ME Site is sending instructions to your browser that are touched by something else such that your browser misplaces the black bar. It is likely that when other sites malfunction you don't notice.

The services behind apparently simple web browsing are complicated and fluid. For example the ME Site's login page calls 9 different web sites all of which are capable of asking your browser to do things that might not work properly. ( The sites are www.model-engineer.co.uk, www.gstatic.com, www.google.com, www.google_analytics.com, www.facebook.com, static.ak.facebook.com, s-static.ak.facebook.com, connect.facebook.net, and ads.myhobbystore.co.uk )

Software and human errors are common on the various systems that comprise the Internet. As a result your browser may be asked to do stupid things and the way these are handled (or not!) might well cause the kind of problem you've got.

You might like to try right clicking the offending page and selecting "Inspect Element". This opens up the detail that Firefox is working with. You might see an error that relates to the black bar, though decoding this stuff isn't for the faint hearted.

My example doesn't explain what you're getting but Firefox reported the following errors and anomalies on my view of the ME login page:

Net Errors

GET http://ads.myhobbystore.co.uk/adserve/;ID=154425;size=728x90;setID=162072;type=iframe [HTTP/1.1 200 OK 338ms]
carouFredSel: No element found for "#CarouselMain". jquery.carouFredSel-6.0.4.js:4261:4
GET http://www.model-engineer.co.uk/sites/7/images/website_images/Header980x222.jpg [HTTP/1.1 404 Not Found 34ms]
Password fields present on an insecure (http://) page. This is a security risk that allows user login credentials to be stolen.[Learn More] <unknown>
Password fields present in a form with an insecure (http://) form action. This is a security risk that allows user login credentials to be stolen.[Learn More]

Console

Error in parsing value for 'background'. Declaration dropped. default.css:2387:13
Error in parsing value for 'background-image'. Declaration dropped. default.css:2389:22
Expected colour but found 'top'. Error in parsing value for 'background-image'. Declaration dropped. default.css:2390:38
Expected ',' or '{' but found ';'. Ruleset ignored due to bad selector. default.css:2493:69
Expected 'none', URL, or filter function but found 'alpha('. Error in parsing value for 'filter'. Declaration dropped. cropper.css:23:8
Expected 'none', URL, or filter function but found 'alpha('. Error in parsing value for 'filter'. Declaration dropped. cropper.css:48:8
Expected 'none', URL, or filter function but found 'alpha('. Error in parsing value for 'filter'. Declaration dropped. cropper.css:97:8
Expected declaration but found '*'. Skipped to next declaration. jquery.bxslider.css:21:1
Unknown property '-moz-box-shadow'. Declaration dropped.

I see that you've eliminated the business account as a possible cause. Can you think of anything else in your configuration that's has been in place for a long time? It's a very odd bug in that "This problem is not new. It was in evidence when I experimented with Debian, OpenSuse, Centos, and Ubuntu all of which was several years ago." Also "One of the three machines (not working at the moment) has had a fresh, default install of LM and the first site I visited was the ME one." As your configuration is respectable, whatever is causing this bug might be very difficult to pin down. I've run out of ideas, at least for the moment.

Please try a different Browser - I think the site is worth it.

For those who prefer news of hands-on engineering I confess wasting yesterday afternoon making a complete horlicks of a simple brass screw. Mistakes included: misaligning and over-tightening a knurling tool so that it twisted off the tool-post; carefully turning the rod down to 2.75mm ready for an M3 thread, mangling the finished knurling on an otherwise perfect second attempt during parting off; and then breaking a digital caliper by dropping it. The root cause throughout the fiasco was operator error. I gave up in disgust and a barrage of bad language.

Cheers,

Dave

Hi Alan,

I too prefer Firefox but I'm quite prepared to use something else when I hit the odd problem. I wasn't suggesting that you dump Firefox, rather that you use a different browser to try and eliminate Firefox as the cause. If using A N Other browser lets you login and use the ME site properly you've learned something about your problem.

The one thing you said in last night's post that's distinctly non-standard compared with most of the users of this site is:

"My internet connection is via a business as opposed to a private account and my ISP does not block any traffic."

As far as I know all ISPs block certain categories of naughtiness behind the scenes, and they are very coy about their internal security measures. This is not least because ISPs have to protect themselves as well as their customers. But more significantly in your case a business account might well include better protection than a domestic account : there will certainly be several service differences.

It would be good to eliminate the business account as a possible cause because it is exactly the sort of common feature in your configuration that could be causing a number of different machines to misbehave in the same odd way. Is there any way you can test this by connecting one of your boxes to the internet using an ordinary domestic account, perhaps by asking a neighbour to help?

The set-up you describe should work - I suspect you're looking for a small glitch involving the ME site, Firefox and some other factor. Given that lots of people are successfully using linux and Firefox to browse this site all you have to do is pin down that "other factor". Unfortunately doing so seems to be quite a challenge. Sometimes I hate computers!

Cheers,

Dave

Hi BigAl, you have an interesting problem. I notice your comment:

So you have a situation that's extremely common in your environment but rare elsewhere. I have access to a number of different machines running El Capitan (MAC), Ubuntu 15.10 and Windows 10. The ME site works with all operating systems and with all the browsers I had time to try (Firefox, Chrome, IE and Dooble). On most of these I use two ad-blockers.

The only similar problem I had was with Firefox on Windows 10 where the black bar was briefly misplaced before reappearing in the correct place. This only happened once but it does hint that there's something odd about the way the bar is rendered.

For security and privacy reasons most of my browsing is done from Ubuntu, mostly using Firefox. I have a good look at the ME site most days and haven't noticed any problems with it.

You might just be unlucky, but I suggest your issue may be due to something in your environment: something that is common to 3 different computers. For example:

• Your ISP may be applying some form of blocking. I think this is unlikely, but...
• Your gateway/router may be applying some form of security. It is worth checking the settings and perhaps trying a factory reset.
• Have you installed an additional firewall or other network devices?
• Is your hardware similar on all three boxes? In particular do the machines have the same graphics card? Not all cards are well supported by linux; some need to be tweaked or have special software loaded.
• Are you using the same video screen on all three machines? Sometimes these are fussy.
• The common factor may be you! Did you install anything in the way of software or browser plugins that might be interfering? Did you use the same installation media? - perhaps it was corrupt. You seem to be computer literate - did you change anything on all three boxes?

Apologies if I missed it but I don't think you've tried a browser other than Firefox yet. They are easy to download and install - Ubuntu software centre lists at least 10. You only need one to work!

Cheers

Dave

When all else fails, read the manual It includes a circuit diagram and identification of parts. The maker's policy is that they won't supply spares unless you know what you're doing. For the rest of us they have a customer support service, which would be my first port of call unless the thing is so old that you decide to replace it.

In the absence of obvious water damage, the most likely cause is a dodgy heating element - as others have suggested. The fix for that is to replace the whole "Tank Assembly"

The best way forward if you don't want to be accused on this site of having a "holier than thou" attitude to H&S is to disconnect the RCD. It may make your "Power Shower" experience a whole lot more electric, but don't forget, “That which does not kill us, makes us stronger.”

Cheers,

Dave

Coin crushing is an interesting application of this technology.

Going back to Joe's original question: if his pressure pulse is completely contained then the container will have to immensely strong. And even if the container doesn't break it's possible that a shock wave will travel through the wall and cause it to spall.

For personal safety it would be prudent to box the inner container leaving an air-gap of several cm between the two containers. The outer box is a screen rather than a pressure vessel and it doesn't have to be strong because the energy level is relatively low. But I have no idea how hefty the inner container would need to be.

An ordinary glass bottle will resist enormous pressures provided the pressure is applied slowly. But it is easily shattered by an impact. The elasticity of the material must be important but the analysis is well beyond me. It feels like a job for an expert.

I suggest the best way forward is to experiment. I would start with the biggest container I could make on my lathe. Cast iron is too brittle. Aluminium, brass and copper are too soft. I guess high tensile steel would be better than mild.

Good luck,

Dave

Shoot me down in flames if I've got it wrong but I think the maths shows there isn't much to worry about here.

Joe's very impressive capacitor stores 8KJ of energy. In comparison a kg of hard coal stores about 30MJ. His capacitor contains the energy equivalent of less than 0.5 grams of coal.

What makes the capacitor fun is that the energy can be released very quickly. Whilst spectacular, the effects of the discharge will be short range because the amount of energy in the system is relatively small.

I shall sleep easy in my bed tonight!

Regards,

Dave

Colin: good idea especially as I have some nice new plugs that don't fit my current car.

Francis IOM: It's a fair cop guv! My design rationale for building the key is far from logical. I like retro technology and making mechanisms. Brass and steel are sexy. In my twisted mind an interrupted beam would be the thin edge of a wedge leading to a fully electronic or computerised solution. I enjoy that kind of project too, but we ME types have to justify all that expensive metal bashing kit in our workshops somehow!

Cheers,

Dave

Lots of good ideas here thanks. Now I'm spoilt for choice!

I'm going to experiment. I'll start with a relay contact and a pin stolen from a D-connector. Then I'll try some silver wire from a bangle. If that doesn't work I have plenty of cupro-nickel in the shape of old florins and dud nicads.

I've gone off tungsten because further research indicates it's more suitable for high-voltage / high-current applications.

I have always believed that silver oxide is a good conductor. Now I'm not so sure. I couldn't find much on the internet.

Thanks again everyone.

Cheers,

Dave

Chaps,

I'm making an experimental semi-automatic morse key (like a Vibroplex) and need some advice about how to make reliable electrical contacts for it.

The key has two contacts. One hits a vibrating arm to make dots. The other is a simple on-off used to make a dash. When contact is made a 5V control voltage is earthed to key a telegraph relay or radio transmitter. The switching current is of the order of a few milliamperes.

At the moment the contacts are made between an adjustable M3 screw and a strip brass spring.

The arrangement works but brass on brass is far from ideal, especially given that my wetting current is low.

I own an ex-military morse key with tungsten contacts. Tungsten appears to be readily available as 2.4mm diameter welding rod. Has anyone had any success machining this? My Mini-lathe and I are intimidated!

Alternatively, has anyone tried silver plating brass at home. Is it possible without using Silver Nitrate and Potassium Cyanide? I doubt either is available 'over the counter'!

I see 2mm diameter silver rod can be bought on ebay. This looks like something I could work with but none of my practical books cover silver and I have no experience with it. Am I cruising for a bruising?

Finally, does anyone have any other suggestions? The cheaper the better!

Thanks,

Dave

Peter might consider that his vision of quality might not satisfy an enthusiast with rigorous views about publishing standards. She would require all posts to be evidence based together with references and mathematical proofs etc. All authors would be required to be accredited and their submissions would be put through a strict peer review process. This Stalinist version of the forum wouldn't allow mere artisans to publish Build Threads!

"Model Engineering" has always covered a wide-range of interests. Technologies and methods are strongly inter-related and I like the cross-fertilisation of ideas I get from ME, MEW and this website. The most important thing for me is that a good percentage of the content should be interesting and/or informative, which it usually is. I'm happy with the forum as it is, warts and all.

If it ain't bust don't fix it.

Steve,

This NOAA page has Excel and Open Office spreadsheets that calculate solar positions. I was able to convert the formulae they use into Python fairly easily: unfortunately the resulting program is rather too big to post here.

By the way I can recommend Python. It's much more capable than BBC-BASIC!

Another particularly useful language is 'C. It's used by the various Arduino microcontrollers and one of them might be well suited to your requirement. They are cheaper and easier to interface than the sort of computer that's man enough to run Python. There's nothing in the solar position calculations that couldn't be done on an Arduino in C.

On the other hand you may have better things to do than learning another computer language!

Good luck with your project and apologies if I've been teaching granny to suck eggs.

Dave

This is a link to an application note that explains how better efficiency can be got from a LED.

But I think your real problem is not how to make the battery last longer, it is how to remind people that it needs recharging. How about fitting a low battery alarm ? They aren't difficult to make if you can't buy a ready made module.

Cheers,

Dave

Linux users may be pleased to hear that at least 3 of Richard's programs run 'out-of-the-box' under wine. I've not fully tested the programs but everything I have tried works OK. My platform is an Acer laptop running 64bit Ubuntu 15.04 and wine 1.6.2.

Linux and wine might be a good way of continuing to run Richard's 32 bit software in the event that a future Microsoft O/S no longer supports his discontinued development environment.

I would have a good look at the contents of that water-butt! Last month I replaced one and although the water at the tap looked OK the inside of the old butt was unpleasant. Much more like drowned snail soup than Evian.

Rainwater is acidic due to Carbon Dioxide and pollution. Just how acidic your rainwater is depends on where you live and how polluted your air happens to be when it rains.

My water-butt is fed from a tiled garage roof. There is plenty of opportunity for minerals and other nastiness such as bird poo to be dissolved by the acidic water as it drains into the butt. Once inside the mixture can go to work on the snails. Given enough time the result will be hard water because snail shells are made of Calcium Carbonate. And there will be lots of microscopic rotting vegetable matter and bacteria in the water as well.

Rainwater is a good idea for boilers but you have to be careful to keep it clean during collection and storage. I doubt that a filter on an ordinary water-butt is good enough, especially if the water has had time to develop an eco-system!

My experiences with Warco have all been positive. I have a Warco mini-lathe and WM18 mill. Both arrived in good alignment and worked straight 'out of the box'. Although both benefited from some minor fettling I encountered nothing like the horror stories told on the web about Chinese lathes . I also have a small Warco bandsaw. Although rather rough it is fit for my purpose. I'm very satisfied with my purchases which are are a good match to my skills, interests and requirements.

Your expectations of the lathe are worth thinking through before spending your money:~ they may not be the same as mine! The class of equipment we're talking about here is competitively priced for hobby or other light use. It is not meant to provide tool-room precision or support continuous production work. If that's what you want you will either need a much bigger budget or a bit of luck and/or good advice buying a surplus industrial or educational machine.

I've found Warco to be responsive and helpful when dealing with after sales issues and also with a lost-in-transit problem.

Good luck