Dangerous Practices

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Dangerous Practices

This topic has 53 replies, 30 voices, and was last updated 20 September 2010 at 01:22 by Chris Trice.

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12 September 2010 at 12:51 #55501
Crewmech
Participant
@crewmech
Sirs

Upon opening the latest copy of ME (#4386) I was appalled by 3 photos in Harold Halls “The Beginners Guide to Building a SteamEngine”

Where oh! where is this great magazine of ours going when it can allow such a dangerous practice of workholding like this shown in photos #30-31-32 of Halls “Guide to “eginners. Publishing a “Top Tip” does not mitigate such a dangerous piece of advice.

In my apprenticeship days if this method of workholding had ever been attempted, I would have been awarded with an immediate “Kick up the pants” followed by an equally quick visit to the Chief Engineers sanctum.

If ME is going to continue publishing advice and help to new entrants into the hobby surely it DEMANDS that SAFE and only SAFE practices are photographed and shown.

Shame on Harold Hall for his advise, and Shame on the Editor for publishing such a dangerous method

Regards

Crewmech
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12 September 2010 at 12:51 #15481
Crewmech
Participant
@crewmech
4Jaw Chuck workholding
12 September 2010 at 14:25 #55507
Ian S C
Participant
@iansc
Crew mech, please explain, my copy will arrive later in the week (hope), and some get MEW and wont see it. Ian S C
12 September 2010 at 14:57 #55508
KWIL
Participant
@kwil
Ranting does not help, as Ian asks, explain why you consider this to be unsafe.
12 September 2010 at 16:15 #55510
MichaelR
Participant
@michaelr
“Crewmech” please keep us all safe and show and explain the method of work holding which you would use for the operation in pictures 30,31 and 32.
12 September 2010 at 16:44 #55512
Sub Mandrel
Participant
@submandrel
I noticed this myself.

Two of Harold’s drawings imply holding a long workpiece in just the tips of the jaws of the chuck, and does not show any tailstock support.The text makes it clear tailstock support is needed.

I imagine this is oversight not deliberate, but yes I can see it leadinga beginner astray.

Neil
12 September 2010 at 16:52 #55514
JasonB
Moderator
@jasonb
Stick the work would have fitted into that 4 jaw with a jaw square to each face so don’t see why he held it diagonally, could understand if it were too larege for the chuck.

I’ve certaily used this method in the past and even the likes of Sparey shows it in his book

Ian if you are a subscriber then its in the digital issues

Jason

Edited By JasonB on 12/09/2010 16:55:57
12 September 2010 at 20:36 #55527
David Clark 13
Participant
@davidclark13
Hi There

I don’t see a problem with this method.

It has been used and photographed many times over the years.

Like any machining operation, you use common sense and make sure the component can’t move no matter how it is machined.

I have even seen this method photographed in a three jaw chuck.

I think it was holding a flycutter.

regards david
12 September 2010 at 21:20 #55530
AndyB
Participant
@andyb47186
Good evening,

If you look closely, there are round shapes at each end of the casting towards one edge.

Photo 29 shows the 4 jaw used as Crewmech would no doubt advise. The problem comes when reversing the casting for machining of the opposite face.

I, a novice to all this, using common sense, would never mount a casting with a hemisperical face to a chuck jaw! I would certainly copy Mr. Hall’s method.

Like our esteemed Editor, I have also seen the same principle used on a 3 jaw and have used it myself, fly-cutting my home-made angle plates. It worked well, except for the fact that I was using too high a speed so chipped my first effort with an carbide tip.

I am using my great grandfather’s Drummond, and from what my father remembers, all sorts of weird contrivances were used to carry out work; necessity is the mother of invention.

This is the sort of thing the old boys used to do; from the Drummond book of work carried out on treadle Round Bed lathes;

Andy
12 September 2010 at 23:04 #55537
Nicholas Farr
Participant
@nicholasfarr14254
Hi, If the method of workholding in the said photos is dangerous, then explanation should be made as to why. I myself have used this method many times during my fitting in industry when sizeing keys for shafts. I have never had a problem with this method, as has been said caution, vigalence and common sense when chucking anything before swinging the piece to be turned.

Regards Nick.
13 September 2010 at 22:21 #55592
Anonymous
I agree with many of the previous posters; if the technique is dangerous then take the trouble to explain why. Otherwise we don’t have the opportunity to learn. If the OP can’t, or won’t, explain and suggest a better way, then there was little point in the original post.

Looks to me like a case of ‘rant today, gone tomorrow’.

Regards,

Andrew
14 September 2010 at 10:00 #55605
Axel Bentell
Participant
@axelbentell
Gawd people are trained to be so safe these days! C´mon let ppl be responsible for themselfs, If one thinks its unsafe, do it another way, don´t insult other peoples inteligence by telling everyone this or that is unsafe. Common sense, you´ve got it or you don´t, and if they dont they probably won´t learn from instructions!
14 September 2010 at 10:46 #55610
Bogstandard
Participant
@bogstandard
Axel,

I’m with you all the way, but just one thing, common sense seems to be sadly lacking nowadays. You only have to look about when going down the street.

I am a great believer in using old tried and tested methods, and if I come across a mounting problem, I refer back to my collection of old engineering hardbacks for inspriration.

Those were the days when they didn’t have all the modern gizmos, and you just got stuck in and got the job done.

Some people nowadays seem to want the job to jump up on the machine and mount themselves, using hundreds of clamps and bolts. In the real world, it just isn’t like that. You have to make your own decisions if what you are doing is safe or not. If you are incapable of doing that, there are plenty of knitting patterns knocking about on the web.

Bogs
14 September 2010 at 10:51 #55612
David Clark 13
Participant
@davidclark13
Oh, I say.

Don’t recomend they take up knitting.

The needles are quite sharp.

How do I know?

My first wife sat on some.

Oh painful.

regards David
14 September 2010 at 10:58 #55613
Nicholas Farr
Participant
@nicholasfarr14254
Wel David, at least they may get the point.

Regards Nick.
14 September 2010 at 11:47 #55621
chris stephens
Participant
@chrisstephens63393
Gentlemen, I agree wholeheartedly about the problems of a cotton wool culture and common sense should rule. The “but” is that common sense must come from experience and knowledge and I ask ‘where today are newbies to get that experience and knowledge’? It seems as though cotton wool is self defeating, without risk how are you to know when there is a risk?

chriStephens
14 September 2010 at 14:15 #55627
Ian S C
Participant
@iansc
Again Crewmech, tell us why, and how etc. Ian S C
14 September 2010 at 15:20 #55629
Richard Parsons
Participant
@richardparsons61721
It would have been nice to read my subscription copies of MEWS No 168 and ME No 4386. But they just have not arrived. I suppose that there was a shortage on the print run so the weird (minimal) foreign subscribers were forgotten. Or my subscription has run out and no one has sent me a reminder. But I pay by direct debit so how can that be? Mr Editor there may be another reason which I will E-mail you about. This is not the place for it.

As to the problems of safety, a ‘Gnome from the local city’s Elfin Safety’ forbad me to use a hand held graver on my lathe –it was a 6mm Lorch- my reply was “how the h*** did you get in here?” It replied (I could not be sure of its gender) I saw your light in this shed so I came to see what you were doing. Oh it added “You will have to re-hang your gate I took it off its hinges as it was locked. I have the right to go anywhere”. My reply was in Russian well it ended with ‘off’ followed by a call for ‘Ole Alligator chops’ –an old large black mongrel with a set of snappers that would turn a crocodile green with envy. I duly received a visit next day from the rozzers and cautioned about the matter. The idea of trespass went un heeded..

The problem is the idea for the need for absolute safety. Our local Managers (whose job it is to manage the people) must NEVER allow the word ‘Blame’ to appear on their CVs. and they will ignore the rules and laws to to make certain it never happens

When we were children if we hurt ourselves we got a clip from our dads and soon learned to use a longer ‘pokey stick’.

Mr Crewmech we are not running at ‘production speeds’. What is wrong?

Edited By Richard Parsons on 14/09/2010 15:32:33
14 September 2010 at 16:57 #55636
IanT
Participant
@iant
I’ve just received my ME – and what suprised me – was not the photos mentioned at the start of this post – but photo 24 – clearly showing parting-off using tailstock support.

I was always told NEVER to use any tailstock support when parting off and I have never done so – so I cannot tell you what kind of trouble it might cause you but I am very sure that the old guy who told me this knew what he was doing!

Anyone want to enlighten me?
14 September 2010 at 17:15 #55637
KWIL
Participant
@kwil
Just before it parts off it can tilt inwards jamming on the parting tool, instead of just dropping off, it flies off?
14 September 2010 at 17:35 #55639
JasonB
Moderator
@jasonb
But lets look at what he’s actually doing

Its a small lathe with a small chuck hence the jaws have been reversed to enable the 1 3/8″ bar to be held. This dia is also likey to be the max that the machine will be able to part off.

There is probably a greater risk of the tool jamming in the cut and pulling the work out of the jaws than there is of the parted disc getting caught up so maybe Mr Hall did his risk assesment and decided using tailstock support was the lesser of the two evils?

Jason

No who’s going to be first to comment on using double sided tape to hold work or showing a filing machine being used in a series aimed at beginners
14 September 2010 at 17:45 #55640
David Clark 13
Participant
@davidclark13
Hi There

Just back the centre of slightly before breaking through.

Again, I have never done it on turning but have on milling and grinding and double sided tape has a much stronger grip than you would think.

regards David
14 September 2010 at 20:36 #55646
Tony Pratt 1
Participant
@tonypratt1
Can’t comment on the dangerous practice as no photos have been forth coming and I don’t subscribe to ME. As to parting with a centre support I have done this a number of times, as David says just back off before it breaks through and you should have no problem. I have also used double sided tape for surface grinding Stainless Steel with great success, just keep it cool as otherwise you could have a “flyer” on your hands as the adhesive softens!

Regards,

Tony
14 September 2010 at 22:46 #55651
Baz
Participant
@baz89810
I feel that I must agree entirely with Crewmech, this article is aimed at beginners, correct practices should be followed. In years to come people will look back at these articles for instruction and this bad practice, because that is exactly what it is, will be perpetuated. I was fortunate to do a proper engineering apprenticeship and if I held work in a similar fashion I would have been sacked. I also went on to run my own business for many years and if I had seen an employee carrying out this dangerous practice I would have sacked him on the spot. I do not care what any of you get up to in your sheds or garages, it is when you commit your dodgy practices to paper and publish it as beginners articles that it matters. Regarding the double sided tape, the steamchest cover should have been gripped in the 4 jaw and faced, then reversed in the chuck to face the other side. Shame on Mr Hall for his bad article and bigger shame on the editor for allowing publication.

Baz
15 September 2010 at 06:30 #55656
John Olsen
Participant
@johnolsen79199
Well here in faraway NZ I am still waiting to see the pictures to find out what the fuss is about. I did think that the original post read very much like a windup…I was surprised that it was not signed “Mother of three” or some such.

Not that I want to condone bad practices either, but hey, these articles are generally written by amateurs, working with limited equipment, and often with limited experience and limited photographic skills too. It is pretty certain that from time to time one of us is going to do something a way that seems OK, and someone else is going to know, possible from bitter experience or even the school of hard knocks that this is not the way to do it. “A soft answer turneth away wrath” and gentle correction will get better results than ranting. The other thing is that as amateurs with limited machines, we sometimes have to do things in way that would not be acceptable in a production environment That can be OK, so long as you have figured out the risks and how to mitigate them. For example if there is a risk of the job coming out of the chuck or other fixture, the operator should make certain that s/he is not in the line of fire, and nobody else should be present. Turning crankshafts between centres, especially with clamped on offset pieces, is a job like this.

Speaking of which, a while back now Anthony Mount described turning on a delicate little crankshaft between centres with no support between the webs….It surprised me, and I wondered if I should comment, because one thing that crankshafts love to do is wrench themselves out from between the centres and hurl themselves at your forehead. Pretty well every lathe book…Sparey and so on… will tell you how to support the webs to reduce the chance of this happening. But even with the best of care there is still some risk.

I must have had the need to part off without centre support well ingrained into me, I find it difficult to use a parting tool to make grooves when I have the centre in. Something keeps saying “Don’t do that!!!” even though I know I am only going to go in a limited amount. (eg making ball handles.)

But often the really big risks are not so obvious…even when someone tells you, it does not seem as if a piece of shaft turning around and a loose sleeve could be such a big danger does it? Some things need to be demonstrated. Grinders are probably one of the biggest potential hazards in the workshop. It always gives me the willies when I see used wheels come up at club auction time.

On the double sided tape thing, I have just recently read the Quorn articles, and Professor Chaddock was roundly taken to task for this in an article that was also extremely critical of the whole design a month or so after the series finished. It does require care, but I beleive that the tape can give as much grip as a magnetic chuck.

regards

John
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