|Howard Lewis||26/02/2021 14:23:23|
|4683 forum posts|
I beg to differ, most strongly.
To me it is very important that newcomers to the hobby learn the correct way to do things. Without this they will have problems, and possibly become disillusioned and give it up as a bad job and waste of time and money.
If what Industry does does not apply to us, are you saying that there is no need to mount cutting tools at centre height, or to keep them sharp?
We may not have the equipment to work to the levels of precision that Industry can. Comparatively few Model Engineers have access to Slip Gauges, and some of the more exotic measuring equipment, but the same basic principles underlie our home workshop activities.
My shop is most certainly not to Standards Room or Calibration Room levels of temperature or humidity control. It does not need to be, but holding a micrometer in a hot hand for a long time is not the path to any sort of accuracy., any more than measuring a component, fresh off the lathe and too hot to hold.
What we, each, do in our workshop may not equate to industrial practice, we are unlikely to be under the same time and cost pressures, but the basic principles still apply. A machine that is out of adjustment will not produce accurately whether in your shop or in the Toolroom at Derby..
There will be differences in detail from shop to shop (In one company the foundry on one side of the road cast the same cylinder block upside down compared to the one on the other side of the road! ) But the same physical laws have to be obeyed.
As a died in the wool GWR enthusiast, I hold Doncaster in less awe than Swindon. Cook improved the middle big end on V2s by changing to the Swindon design, eliminating what had always been a weak point, dating from LNER days.
Running gears with excess backlash will not provide accuracy, and running without backlash, aka interference, will result in noise, and wear of both the gears and the bearings and shafts. That cannot be good practice.
I hope that I have made my point adequately
|Chris Crew||26/02/2021 15:02:02|
43 forum posts
Howard, With the greatest respect we can take this no further, it has run its course as I am obviously incapable of explaining my opinion in a form of words that acceptably encompasses both the practicality and essence of the points I was trying to make on the 'modus operandi' that can be adopted in home workshops, in mine at least. I rather think you may be confusing industrial standards with amateur workshop techniques and practicalities but lets not go there!
Sadly, not being a railway 'anorak' myself, it was a monumental irrelevance to me what the workshop practices were of two railway companies that both disappeared in 1948 and were then integrated within the then BREL. I just got on with the practical education being offered to me at the time which stood me in good stead for most of my life even though I didn't eventually make a career in the railway industry.
Each to their own, as they say, and I am certain that we both succeed to our own individual satisfactions in what we do by whatever means.
457 forum posts
I'll stick to engineering products, otherwise it's not relevant to this forum, compare Vertex products to Chinese products, there's a clear difference in quality control.
|Tim Stevens||26/02/2021 17:45:38|
1411 forum posts
Howard Lewis writes:
To me it is very important that newcomers to the hobby learn the correct way to do things.
Whatever you need to do, whether engineering or anything else, there cannot be one 'correct' way only to do the job. If this was accepted universally, progress would not be possible. It wouldn't just be back to carbon steel tools and treadle lathes, it would be back to walking everywhere and flaking flints.
Certainly there are some methods which are better than others, because they are simpler, or more accurate, or quicker, or cheaper, or quieter, etc. Any of these might count as better, but none is ever best - it depends on so many factors.
And while the same physical laws do indeed apply, without progress and trying new things we would never have found out what they were.
And now a comment on quality control. It is not possible to judge the quality of an item without seeing the original instructions, drawings etc. A part make to slack tolerances may look careless and may not work well, but if it matches what the spec says, it is not a QC problem.
457 forum posts
That's a good point about quality control, you often find Chinese engineering tools don't have tolerance specs listed anywhere, so it's literally a lottery whether you get something you're happy with.
|Ketan Swali||26/02/2021 17:54:54|
|1354 forum posts|
Please... let’s all calm down and keep our views moderated and polite.
Vertex is a Taiwan brand. A very high percentage of their products are generic - made in mainland China by sub-contract manufacturing . They just have good Q.C., stock holding and marketing.
Ketan at ARC
457 forum posts
That's specifically why I mentioned Vertex, to make the point that they can make acceptable products, but a culture of allowing items that have left factories without QC tarnishes that.
|An Other||26/02/2021 18:33:52|
|195 forum posts|
For what its worth, I'll sit on the side of Chris Crew. I took this hobby up as a change from (or perhaps an extension) to my work as an electronics engineer - and I want to stress the hobby aspect. It became clear that I would never have all the money to spend on it that some people clearly have, so I had no choice but to do the best I could with what I had, but then I never had the intention of producing anything to 'Rolls' standard: just to keep myself interested and entertained.
Many years back, when Chinese stuff began to appear on the market, this was great as far as I was concerned, I could afford some of it, and it helped me take my interests further. I concede that some of it was not of the best quality, and I spent many happy hours modifying and improving my chinese lathe and mill - and I would never have been able to afford a lathe from any other source.
I have no problem with people wanting to produce the best work they can - but surely that is the point? - if you do it as a hobby, then what is wrong with simply doing the best you can within the limits of your funds and abilities? I would surely not have given it all up just because I could not afford the 'best' kit on the market - I did it for pleasure, not fame or profit.
457 forum posts
An Other, in all honesty, as long as the buyer is happy, that's all that matters, I often think peoples expectations far outweigh their financial investment, when people buy a £25 set of collets off ebay, then come here and start a thread about their disappointment, I can't help but think what did you expect.
What rubbed me up the wrong way was the name calling.
|Martin Kyte||26/02/2021 20:10:48|
2313 forum posts
Taking a few steps back, the correct way of setting up change wheels is such that they do not rub but also don't have excessive backlash. One good way of achieving this is to use paper strip. It's not the only way.
|Tom Sheppard||27/02/2021 07:37:37|
|27 forum posts|
The correct way to do sometthing varies between engineers and bogmatism doesn' t help. Nor does the blanket condemnation of products from China. The work produced on them gives the lie to that. A Myford is a thousand pounds and fifteen hundred with a new coat of paint but it might be knackered and how is a beginner to know? The Chinese equivalent needs work, all of which is explained in many tutorial videos, freely available. It is new and half the price. Accessories are readily and cheaply available and their availability brings many people into the hobby, most of whom don't have the space, money nor skills to get the best out of a ton and a half of toolroom lathe.
|Nigel Smith 4||27/02/2021 08:33:33|
|20 forum posts|
Slightly off tangent to the original post, concerning Chinese lathes. I have a Harrison L6 lathe built in the UK in 1965, and a Chinese Sealey SM27 mini lathe built in 2020.
The finish of the Sealey is what I would describe as 'agricultural', for example bits of filler have fallen off and the castings are quite rough, the bearings are of an unknown quality. BUT... the finish and accuracy of anything I make on the Sealey lathe is just as good as anything I make on my 56 year old British Harrison lathe.
The Sealey is a cheap Chinese lathe (I paid around £2k with some accessories and a stand), the Harrison would have cost thousands in 1965. I admit I was sceptical buying 'Chinese crap' (as described earlier) but for the price I cannot complain, indeed if it were not for 'Chinese crap' many of us here would not be owners of lathes and enjoy the pleasures of turning.
For what it's worth, I did work for Rolls Royce!
|John Hinkley||27/02/2021 09:25:24|
1065 forum posts
Can I drag this thread back to the original question .....
If I understand Julian's enquiry, he is merely asking what gear selection will provide a "reasonable" feed rate for turning. I don't think it matters overly much. For example, I have selected the lowest ratio of gears I can in the train to give a minute (as in small - not time) travel per revolution of the spindle. I haven't worked out what that is and it doesn't really matter to me. It just gives a very fine feed, which is what I was after. Yes, it takes forever to make a long cut, but, hey, I'm not in a hurry and I'm happy with the finish I get. Just try a few set-ups and see what happens.
The only time Julian will need to pay attention to gear selection will be when he graduates to screw cutting and needs a specific thread pitch. But that's a whole new can of worms, worthy of a new thread. Or better still, a search of the forum for the myriad of threads that have already beaten that subject to death.
Now I'll let you get back to your off-topic debate!
(No wonder Julian hasn't replied to this thread and his post count remains stubornly at 1.)
Edited By John Hinkley on 27/02/2021 09:25:43
|Mick B1||27/02/2021 09:37:57|
|1862 forum posts|
Another vote for Chris Crew and his backers. Engineering is an attitude of mind - it's making what you want with what you've got, or have the ability or patience to make for yourself.
Back in the mid '70s I bought a Mitutoyo mic and Vernier set. People used to sneer at 'Jap-crap' at the time, but those gauges are still working now - and where are the Sinclair Black Watches and Cambridge self-assembly scientific calculators now, that others were spending their hard-earned on in those days?
Teaching established methods as holy writ is pointless. Many of us have lived and worked long enough to know the world changes, and what's a sparkling new way of doing things at one time can become a restrictive, hide-bound orthodoxy a couple of decades down the line.
Edited By Mick B1 on 27/02/2021 09:40:09
|john halfpenny||27/02/2021 10:06:49|
|143 forum posts|
I'm with Chris as well. In my apprenticeship I was taught the prejudices of my instructor and the approved methods of my employer (aka prejudices of the chief engineer). Most of these were excellent practices which I espouse to this day, but some held me back until I understood that other good and safe methods were available, even those which I would at one time decry as being dreadful short cuts and bound to lead to poor results.
|not done it yet||27/02/2021 12:02:26|
|5790 forum posts|
but some held me back until I understood that other good and safe methods were available,
Something to do with being ‘able to think for yourself’. Some can, some can’t and some are not allowed to do so.
I’m sure that the ones able to think and reason for themselves would soon compare the backlash obtained with a standard sheet of paper and replicate that amount quite closely (and most certainly close enough) as long as the other precautions are followed (it’s not a recommendation, to check backlash in several positions of the gearing, for no good reason). Sheets of paper are not all the same.
What you don’t do is try to run before you can walk!
|Howard Lewis||27/02/2021 12:53:03|
|4683 forum posts|
At least we agree on something, that this will never be resolved for both of us to agree. You have have your belief, and I have mine based on my experience of engines and fuel injection equipment, where fitness for purpose in paramount in competitive markets.
Never been called an "anorak" before. Based on what i would describe as scant knowledge, and an inability or inclination to count rivets, that has to be a compliment!
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