Member postings for Nealeb

My motorbike with a wet clutch clunks badly when going into first after a cold start. Starting in gear with the clutch disengaged frees the clutch plates and, I feel, saves wear and tear on gear teeth. I give it a couple of seconds for oil to start flowing and ride off gently. However, this is generally starting at the top of my drive so the engine is barely doing more than idling for a short while before it has to do any real work. I wonder if the car drivers with their "start in gear then drop the clutch" habit were brought up in a similar school - free the clutch on starting?

My particular hate are those bikers who insist on starting bike, then spending 5 mins putting their gear on "while the bike warms up". Always feels to me like "while the bike is wearing out" - I much prefer to warm the engine with gentle riding until warm, after those initial few seconds to let oil circulate.

Edited By Nealeb on 14/07/2023 10:45:03

Back in my student apprentice days, the safety briefing before we were allowed in the mechanical workshop included the instruction to wash before and after. After, obviously, but also before because "oil can cause cancer of the scrotum. You know what cancer of the scrotum means? Bits drop off!" Might not have been accurate but certainly memorable.

Caught on as a catch phrase among us apprentices. Whatever someone was doing, "Wouldn't do that if I were you." "Why not?" "Bits drop off!"

If a man can use a hammer at a rate of, say, one blow every 5 sec, i.e. 12 blows per minute, and each blow (see a previous post) is around one-half of a single breaker blow, then we are looking at something of the order of 2000 times more energy dissipated at the chisel tip. No wonder the concrete just gives up.

No idea of the equivalent figure for bloke with lump hammer but personal experience based on trying to break up a concrete path with chisel and 7lb club hammer, then going out and hiring an electric breaker of, probably, similar spec to that of the OP, is that the breaker was around 1000 times better than me with hammer. At least. And by a very considerable margin. 10mins with hammer and chisel left a few gouges in the concrete. 10 mins with the breaker left a considerable length of broken concrete fragments. Heaviest bit of the job was carrying the breaker and its bits out of the car, round the house, and up the steps to my back garden and back again an hour or two later. Would have been less but I stopped for coffee...

Auditor, eh? Fancy a job piloting a deep-sea submersible?

All in all, it does sound like a bit of a shoe-string operation.

Cheap bedside clock/radio from a car boot sale? Mains-driven so unless the workshop mains frequency is also subject to your local time warp, that should stay accurate! Not a lot of good if you turn off all power to the workshop when not in use, though...

Sounds like a lever indicator rather than plunger type, so it is not recommended for accurate measurements anyway. The accuracy of readings depends on a number of things like angle of probe to work, length of probe (some DTIs come with several different length probes) and so on. Generally they are used for comparative rather than absolute measurements. So as long as the thing works smoothly over its range, I wouldn't worry about accuracy per se.

I wouldn't worry about it. The new Online Safety Bill currently being proposed by the Government will allow them via unaccountable large technology companies to legitimately plant spyware on your phone and, presumably, other Internet-connected devices, in order to send selected snippets back to an anonymous Government department without your knowledge. What could possibly go wrong? After all, I'm sure that there is a law which forbids the bad guys from exploiting any back doors installed on a phone, so that's OK.

But let's look on the bright side. If the scammers can read your phone directly, then you won't need to be bothered with all these scamming calls. That has to be a good thing, doesn't it?

That looks like an Autolock-style collet chuck designed to hold only the appropriate screwed-shank cutters - it won't hold a plain shank cutter.

May be wrong - just trying to interpret the images! The body looks as if it has a centre point at the back which is a key part of the holding mechanism.

On the other hand, with the right cutters, these are probably the most secure collet chucks you can get! There is a correct way to install cutters into these chucks, but let's make sure we know what we are looking at first.

Back in my youth - in the days of party lines, for those who remember such things - we would always answer a call with our number. These days, like others, it's just a simple "Hello" to avoid giving out any information. But, not all slightly odd calls are scammers.

Yesterday, I took a call on my landline from a woman asking to speak to Mrs X (names changed to protect...). Never having heard of Mrs X, I suggested that the caller had a wrong number. She asked what my number was. I said that if she told me the number she had dialled, I would say if it were correct. She would not tell me but after a bit of to and fro she said that she was a nurse from a local hospital department. I said that I had been speaking to that department very recently and perhaps there had been a clerical error. Turns out that she was the person I spoke to a couple of weeks ago, and it seems that there must have been an error in records at their end. Maybe I shall be meeting Mrs X when I go to the seminar under discussion in a couple of weeks!

It does raise an interesting question, though, of how you reliably authenticate two people who do not know each other over a phone without revealing any information that could be of use to a scammer. Back in my day job in IT security this was always a significant issue between computer systems - and still is - but in the real world it's one that doesn't seem to have a well-identified solution. I did once have a call where I rang them, and to help them identify me they asked me to name a road close to where I lived. That seems like quite a good one. But when you get a call from, supposedly, your "mobile phone provider" who asks security questions - no way!

In the early days of the London Underground, wasn't there an experimental 2-5-2 intended for use on the Circle line?

My concern would be a relatively fine thread in cast iron - it's ok for a coarse backplate thread, for example, but closing nut threads take a fair load.

That article references a long blog post by someone well-respected in the mathematical community, Stephen Wolfram, who gives an explanation of what is going on under the covers. It explains quite a lot about some of these big AI systems and why they give odd results sometimes.

What I had not realised (and I am grossly simplifying what I have read) is that these systems do not really have any understanding of what they are saying. In essence, they might start with a sentence that begins "an AI system is useful because..." and then continue the sentence based on a probabilistic estimate of what words might follow, where the probabilities are derived from "stuff" that they have previously seen in their training material (essentially, "the internet" plus anything else their builders throw at them). There is no intelligence or understanding beyond that, plus some nod towards the rules of sentence construction.

It's a bit like someone who knows nothing from their personal experience who reads this forum, and then parrots back what they think they have seen in answer to someone else without any proper understanding of what they are saying. Maybe like what I am doing here?

Anyway, it was a good read at a more-or-less intelligible level - worth a look if that kind of thing interests you.

How long is the parallel portion? It would need to be getting on for the length of the collet to guarantee that the piece being held is not twisted very slightly off-axis. And is it guaranteed to be accurately aligned with the tapers anyway? In the taper adaptor's normal role, I'm not sure that accuracy is needed there.

Personally, I would use a 2MT centre between a centre-drilled hole in a short stub held in a chuck/collet/whatever and a tailstock centre (assuming that the tailstock is accurately aligned). I'm pretty sure that that is how I did it, last time I machined a 2MT taper - I think I had a centre to use as a gauge like this with a centre hole in the "blunt" end.

One of the fun things about model engineering - techniques can differ so much depending on what we have available!

While that is technically correct, I suggest that you consider buying the "exact" size collets, both imperial and metric, as it is generally easier to put a cutter into a close-fitting collet. It will usually grip initially with just a nip up on the closing nut; a looser fit means that you often need three hands and it's just a bit more fiddly. Admittedly my experience has been with my mill and CNC router so cutters held vertically and I realise that a cutter grinder has different geometry but it might be worth a thought.

But is that not correct? "Practise Putting Green" sounds to me like an instruction to employ ecologically-sound techniques when putting.

Not that unusual - I have found that eBay prices often include postage so that if you order multiple items you multiply the postage charges built in to the prices. Where I can, having found something on eBay, I often look for the company's web site to see if there is an alternative.

First time I bought steel from my local stockholder, I ordered via their web site. Prices weren't bad. When I went to collect, I was told that I shouldn't order that way. "Ring in your order, or just come in and buy over the counter." About 30% cheaper! Very helpful bunch for model engineers as well - happy to cut short lengths of the chunkier sections.

Along with nostalgia, irony is not what it used to be - recognised...

I like the idea of thread milling but put off by the cost of cutters! The idea of a modified tap sounds interesting but how is it modified? My understanding of a thread mill is that it is "flat", and even a multi-tooth cutter (to get proper thread crest rounding) looks like a set of circular cutters stacked. A tap, of course, has a helical thread. Do you grind off almost everything to leave the equivalent of a single-tooth cutter?

Itching to have a go now...

(Shouldn't say multi-tooth, I realise, but I mean a cutter which cuts several adjacent threads at the same time. I see these listed in the catalogues)

Edited By Nealeb on 13/05/2023 08:53:06

Some of the recent posts allude to a principle that I usually apply, but which is not just foreign but counter-intuitive to those brought with more traditional drawing-board-and pencil days.

Sketches are called sketches for several reasons, not least of which is that the lines and shapes you create in your sketch do not have to be the correct size or position initially. In fact, I will often draw, say, a circle roughly but not exactly the right size, and in roughly but not exactly the right place. This avoids being misled into thinking that it is aligned with a point when it is not quite there. I then add a dimension to get the circle to the correct size and use a constraint to lock the circle's centre to the point required. That way, I have forcibly defined everything I need and not relied on anything that looks about right but which cannot be trusted to be precise. This is also why I never use snap to grid or similar, or even bother unduly about making lines horizontal or vertical when I sketch them - there are constraints which will do this more accurately than I can draw! Note - I do not drag sketch objects into position. I use constraints to both move and fix reference points together.

I'm sure that someone must have mentioned this already, but it is a technique that is not obvious but becomes second nature after a while. While I do this in F360 and Solid Edge, I'm sure that an equivalent must exist in the Alibre suite.