Member postings for SillyOldDuffer

Hi JA,

I've used Python on a Raspberry Pi 2 and it all works fine. You're probably tripping over something simple like trying to execute Python3 code with the Python2.7 interpreter. What was the error message?

Cheers,

Dave

Chaps,

I'm afraid this thread contains some dubious advice. You are taking a significant risk if you ignore this particular security warning because it is reporting a problem with the digital certificate that proves that a website really is who it claims to be.

There are a number of 'legitimate' faults that can cause the warning, most likely being that the certificate has time expired. But the purpose of the certificate, which is part of the electronic security system and not just a bit of paper, is to protect you and the site from spoofing. The warning may well mean that the website's address has been hijacked and that you have been misdirected to something only pretending to be trustworthy. Such as criminals masquerading as your bank or a favourite shop.

Under no circumstances whatever should you spend money on a website with a certificate problem; nor should you use it for downloads or give it any personal information. Wait for the site owner to restore trust by fixing the underlying problem before you do any business with it. It's safe when you don't get that warning message.

Ignoring this type of security warning is analogous to weighing down a safety valve because it is "leaking". You'll probably feel very foolish if you get blown up because the real problem was a stuck pressure gauge...

Cheers,

Dave

One big advantage of a cheap digital caliper is that you do not have to treat it with respect. The brave little warrior below cost £4.99 from Lidl and is about 5 years old.

I sometimes use the tips to mark out work. Last year I dropped it on a concrete floor and then stood on it. It went through a spell of losing zero which turned out to be due to a pack of bad batteries, possibly fakes. Later it became unreliable because the innards had collected oily swarf and needed a good clean.

I wouldn't claim much accuracy but measurements are in close agreement with my other (not quite so cheap) digital calipers and a micrometer. It's certainly 'good enough' for most of my purposes. And despite a hard life it's still going strong.

My point is that it's sometimes useful to have disposable tools that can be abused and broken without the owner feeling bad about it. I need counselling and alcohol whenever I spoil a quality tool!

Hi Grant,

Many thanks for the offer of a pdf but I think I can make one using the info you've already published. My version will be much more utilitarian than your nicely finished prototype. I might publish a photo if it's not too horrible!

Cheers,

Dave

Gosh thanks Grant! I was thinking about exactly this problem today and your solution is better than the "spanner" I was going to wastefully bodge from a bit of rusty 3/8" plate tomorrow.

Ta,

Dave

Thanks for satisfying my curiosity Sean.

I bought the switches for the mercury at a Radio Rally during the 90's. But I decided to keep them intact when I realised how beautifully they'd been made. If they're historic I might ask the Antiques Road Show what they're worth!

Not quite so much sparky fun as a power rectifier, but I wanted to use the mercury to make a replica of an "Italian Navy Coherer". This was an early type of wireless detector consisting of a spinning disc with a sharp edge rotating in a thin layer of oil floating on mercury. The oil insulated the disc from the mercury unless a radio signal was present. I never made one!

Cheers,

Dave

Hi Sean, welcome to the forum. It's nice to have another expert to quiz!

I wonder if you recognise the pictures of this mercury timer switch as being the work of a scientific glass blower?

It's about 80mm long, the pip end tube is 21.25mm diameter and the other, lower, end is about 19.75mm diameter. The lower end is flat, but the whole assembly tilts 10 degrees towards the electrodes.

Inverting the assembly causes the mercury to pass into the other chamber through a large inner tube (about 8mm i/d). When the switch is returned to the normal position, mercury drips into the lower chamber through a pinch tube, taking about 25 seconds to drain back. During that 25 seconds the mercury makes the switch by shorting two electrodes in the top chamber.

I have 3 of them and have often wondered if they were hand made and what they were used for. Something that rotates and waits for 25 seconds before repeating I guess.

The design and construction are ingenious. If this is what you do, I'm impressed!

Regards,

Dave

Good point Tim! And if poor old Dobbin did have the misfortune to fall into a scaled down mine-shaft, he wouldn't go splash at the bottom. I'll need to experiment if my model coal mine is to be realistic. I wonder if anyone would lend me a horse...

Cheers,

Dave

You might try moving the radio around to see if you can find a good spot for it. This works because internal reflections inside the room will be either reinforcing or cancelling each other out. It's very unpredictable because the indoor RF environment is very complicated: people are mobile reflectors and there are wires, pipes and lumps of metal all over the place.

Your radio might be a bit deaf, especially if it's an older model. The £20 radio I recently got from Tesco for my workshop is much more sensitive than my somewhat expensive brand-name bedroom clock-radio.

An outside antenna in the clear will always out-perform an indoor antenna. The simple rule is to get the antenna as high and as far away from the house as you can. Indoor antennas only work if the local signal strength happens to be high.

DAB is a VHF system (170 - 220MHz vertically polarised) so a home-made dipole would consist of two rods (or wires) each about 0.65m long, arranged up and down. Or you could buy a folded dipole like this.

The placement of your TV antenna is a good guide to where a DAB antenna should go, but lower down will probably be OK.

The hard part looks to be that weird connector. I've never seen anything like that on a radio before but it might be one of these.

Ideally the antenna and radio should be impedance matched to each other and the transmission line (Coax or ribbon) This can get quite complicated if you are rolling your own, but I wouldn't worry too much about it unless the radio still doesn't work after you've tried it - a crude outdoor lash-up might well be "good enough".

It's slack terminology, but a "digital" antenna is simply one optimised to receive the frequencies digital TV signals are transmitted on. It might be necessary to install one if your old antenna happened not to work well enough after switch-over. Analogue and digital signals were introduced on different frequencies in the same band so that they wouldn't interfere with each other. Unlucky people sometimes found the digital signal was just outside their old antenna's bandwidth, or that reception was marginal anyway.

Regards,

Dave

Edited By SillyOldDuffer on 09/01/2016 23:02:34

I enjoyed a Radio 4 Extra DAB programme the other day about LTC Rolt whilst adjusting my lathe. It's available for 25 days on the web.

If you haven't come across him before, LTC Rolt was an Engineer who wrote several good historical books on Engineering and Engineers. "Red for Danger" is about railway accidents.

Although tiny the Somerset Coalfield is more interesting than most. Bell Pits, early engines and tramways, a canal said to be once the most profitable in England, the father of geology and of course the world famous Radstock Giant Dragonfly

I thought I saw one over Bath once, but it turned out to be a Hercules.

Another example of "you can't scale nature" is contained in some black humour from the coalfield. It relates to mammals when they accidentally fall down a mine shaft. Apparently mice walk away unharmed, dogs break their legs, men break all their bones, but horses splash. (F = mv²)

If I was a betting man I would have put money on heat-treating, but 10 minutes of red-heat didn't soften the weld all that much. (It was noticeably easier on the threading tool though. )

Grinding the weld off with the Dremel worked rather better, which suggests to me that it's only the visible weld ridge on this bit of pipe that's particularly hard.

Gordon W's suggestion would have been overkill in my case but I can well believe that his 'belts and braces' approach might be essential on other pipes. I'm learning that, when it comes to machining it, there are often huge differences between similar looking metals even when they have the same name.

Hopper and Martin both make very good points about seamless. Next time that's what I'll ask for. Another disadvantage of heat-treatment is that restoring the finish later is even more work. And weakening the seam of a pipe that's also been undermined by cutting a thread could well be problematic even if I'm not working for NASA!

Thanks again,

Dave

Thanks guys! Good ideas AND an excuse to buy a bigger boring bar. I'll try the Dremel approach first as I'm slightly less likely to burn the house down with it.

I'm pretty sure it's mild steel because I bought it from a proper metal supplier - it's not an odd bit of scrap. I didn't know it was called "ERW" though: I'm in danger of becoming educated!

Ta,

Dave

My Windows 7 Pro workstation was updated to Windows 10 Home a few months ago. I've just spent 90 minutes this afternoon watching it doing another major upgrade to Windows 10 Pro version 1511. I think I did 5 reboots.

I guess that the upgrade from the Professional version of Windows 7 has only just become available with the result that this particular machine has had to do a full upgrade twice. The good news is that it all worked!

Apart from the time taken, the only negative so far is that Microsoft re-offered Cortana again. (I'd disabled it for privacy reasons.) I nearly went into rant mode after jumping to the conclusion that all my other privacy settings had been unset too. Fortunately this turned out to be paranoia - the latest upgrade respected my privacy settings. Hurrah!

I also took an anti-virus upgrade from Avast that tried to convert me to Chrome, tried to get me to reject my choice of search engine (DuckDuckGo) and then tried to load an Adware plug-in into Firefox. You have to be careful what you load - even reputable providers need to make money somehow. Whilst I don't have a problem with advertising as such, I am very concerned about the way that tracking and other technologies are misused.

Dave

I'm trying to cut a thread inside a length of 3/4" i/d mild steel pipe with a mini-lathe. The pipe is exactly the right size for my application but it has been made with a welded seam that's left a ridge running inside the tube.

The weld is very hard and it defeats my threading tool:

I've tried skimming the ridge off with a carbide boring tool but it also bounces over the weld without much effect.

Can anyone tell me how I might overcome the weld line please?

Many thanks,

Dave

"Easier and quicker to have used the vice and a hand drill. " - now he tells me!

I wish I had a good reason for using a power tool but truth is I did it thoughtlessly. Very likely my thinking head was skiving-off, again.

Thanks Andrew.

I tried stoning a drill once and just spoiled the drill. Thanks to Roger's video link I now know what I was doing wrong!

Cheers,

Dave

Well I've read about it and even had a few mild grabs before, but the real thing was still a shock. A shim being made from a bit of surplus electrical brass needed two 4mm holes in it. First hole no problem, but then the drill snatched violently in the second. In a less than blink the brass strip wrapped itself around the drill, the machine vice leapt into the air, and the bench-drill stalled, clunk.

Then I had to use pliers to get my twist drill out of the tightly wound brass strip's death grip.

My bench-drill is only 1/3 HP.

I've learned a bit more about metal-working and confirm that no Model Engineers were injured during the making of these pictures.

Regards,

Dave

Whilst I don't believe the European Union to the best of all possible institutions, dare I suggest that the EWF probably isn't to blame for recent flooding or for the suffering of flood victims. I read the directive and didn't see anything obviously unreasonable in it. For instance it says:

"(13) There are diverse conditions and needs in the Community which require different specific solutions. This diversity should be taken into account in the planning and execution of measures to ensure protection and sustainable use of water in the framework of the river basin. Decisions should be taken as close as possible to the locations where water is affected or used. Priority should be given to action within the responsibility of Member States through the drawing up of programmes of measures adjusted to regional and local conditions." This is hardly a challenge to the British way of life.

What might be a problem to certain vested interests is, with my emboldening:

"(11) As set out in Article 174 of the Treaty, the Community policy on the environment is to contribute to pursuit of the objectives of preserving, protecting and improving the quality of the environment, in prudent and rational utilisation of natural resources, and to be based on the precautionary principle and on the principles that preventive action should be taken, environmental damage should, as a priority, be rectified at source and that the polluter should pay. "

"Dredging" isn't mentioned by the directive at all. Am I missing something?

I upgraded two machines to Windows 10, one from 8.1 and the other from Win 7 Pro. Both upgrades went smoothly and I like the look and feel. As others have noted there are problems with "clutter", not all applications are guaranteed to run after the upgrade, there might be hardware and driver compatibility issues, and there are a few bugs.

But it is the privacy issues introduced by the upgrade that that caused me the most grief. Sorry Neil but I found the amount of information being leaked by Windows 10 to Microsoft and their partners to be unacceptable, and I also disliked various strong nudges during the install that encouraged me to adopt new applications like Cordova that "share" even more of my information. The problem is that the customer has to hunt down the offending features and turn them off manually. And it turns out that the only way to completely stop your computer reporting back to Microsoft is to buy the professional version.

My advice is to proceed with due caution. Don't just accept "recommended" settings, don't set up a Microsoft account unless you need one, and don't adopt the likes of Cordova and Edge unless you specifically want them. (They're not evil, but...) Make sure that features you don't use are disabled: for example do you really want applications to be allowed to access your microphone or webcam?

Most of the internet is a good thing but never forget it has a dark side. There's spam, malware, spoofing, hijacks, phishing, bots, trojans and people who collect and sell details of your interests, contacts, and spending patterns. Some of data collection and misuse is criminal. I think it wise to manage the risks and wasn't pleased to find that Windows 10 opened me up by default.

Cheers,

Dave

Hi Rik,

I had the same symptoms and assumed it was an electrical problem. It was actually mechanical.

My display was mounted on top of the control unit. Switching off causes the contactor inside the box to drop out with a healthy thump. The vibration shook the usb cables sufficient to cause an intermittent connection. I found my plugs & sockets to be slightly loose at the display end, but not obviously so.

Your set-up looks to be less vulnerable to vibration than mine but it might be worth adding some form of strain relief to the cables to ensure that the plugs can't wobble.

Hope it's as easy as that!

Regards,

Dave