Workshop Mistakes (True Confessions)

[Tony Pratt 1Participant @tonypratt1]

I often wished in my later days that I had transferred from making 'things' into Quality control, no chance of scrapping £££'s worth of parts, no real time pressure and so much higher paid, I was truly amazed how much money some of them were paid for shuffling paper. I'm sure some will disagree

Tony

[BazParticipant @baz89810]

Totally agree with you Tony, most places I have worked the inspection departments were made up of failed machinists, those that were too slow or made too much scrap, and they strutted around in their pure white coats telling the “ handle turners” how it should be done, and getting paid a fortune for shuffling a few bits of paper. A case of Those who can, do. Those who can’t, inspect. I shall now collect tin hat and go hide in shelter.

[duncan webster 1Participant @duncanwebster1]

You don't want to be in QC, you can still make a mistake and pass off something that's wrong causing problems down the line, or fail something that's right, wasting money. QA is the place to be, truly an exercise in taking what's basically a good idea and strangling it in paperwork

[Martin KyteParticipant @martinkyte99762]

I think there are some huge assumptions going on here, not least that left to their own devices production always do a perfect job. So let’s split things up a little. China makes a lot of stuff commissioned from the west otherwise known as offshoring. They can make rubbish or they can produce the highest quality you want. All down to the quality control department of the commissioners.
Do you still say they are an irrelevance.?

regards Martin

QC is really no different to any other department, when it works well it’s brilliant it can also be a waste of space.

H and S is the same, we love our HS dept. They save us from no end of work.

Edited By Martin Kyte on 15/03/2023 14:58:48

[Howard LewisParticipant @howardlewis46836]

Probaly my epic failure was very much self inflicted.

having made and fitted a 80T gear, in nplace of the standardn 40T, for the input tom the Nortonn box, had mto remebr to mentally adjust the chart settings.

WANted to cut a 1.5 mm pitchn thread for ER collets.

So need to llok at the settings for a 3 mm pitch.

Became obsessed with the 3, and ste B-3. The nut would not screw on.

After a lot of further work, reality struck B-3 wad NOT the correct setting, so had cut a thread that was out by about 16%.

Once the cirrect gearbox setting had been made, the clamp nut screwed on quite happily.

Fortunately had decided to cut thenthread as first operation, so minimal loss of work.

If all fails, read the instructions!

Howardd

[SillyOldDufferModerator @sillyoldduffer]

Posted by Howard Lewis on 16/03/2023 09:31:47:…

If all fails, read the instructions!

Howardd

Skipping over the instructions, or not bothering to read them at all, might be the most common human mistake of all!

Admittedly instructions often feel like a perverse intelligence test, but admitting defeat far too quickly and then trusting to luck seems a universal fault!

Faced with the irksome job of reading a 300 page manual, I apparently believe I'm clever enough to pick up a full understanding by randomly pressing buttons until something sensible happens…

Dave

[RobinParticipant @robin]

Noticed the little wire brush that cleared the teeth on the bandsaw had stopped turning. Reached out to give it an encouraging flick…

[Martin KyteParticipant @martinkyte99762]

Posted by SillyOldDuffer on 16/03/2023 10:03:51:

Posted by Howard Lewis on 16/03/2023 09:31:47:…

If all fails, read the instructions!

Howardd

Skipping over the instructions, or not bothering to read them at all, might be the most common human mistake of all!

Admittedly instructions often feel like a perverse intelligence test, but admitting defeat far too quickly and then trusting to luck seems a universal fault!

Faced with the irksome job of reading a 300 page manual, I apparently believe I'm clever enough to pick up a full understanding by randomly pressing buttons until something sensible happens…

Dave

Fortunately many things these days are processor controlled and set up tends to be menu driven often displayed on small screens and are usually quite self explanatory. I find that once setting new stuff up becomes a frequent task you tend to acquire a kind of generic familiarity with the way things are designed as far as user interfaces are concerned. Icons tend to be standardised such as the little cog wheel for settings or parameters. Having a reasonable knowledge of how stuff operates helps, as you realise what the device needs to know in order to function as you wish. I am not saying I never need to read the manual but happily I do find that generally I know what I’m looking for when I open it and I can say I never read manuals from cover to cover. I find it enlightening to see my wife try and set some of her gadgets up, she really does not know where to start, why should she, so ropes me in.

There are obviously some things that defy logic in setting up but generally things are more and more user friendly.

Think of it this way, if you were faced with a lathe you had never used before I suspect you could drive it after a short while of familiarisation as you know what you want it to do and that you expect there to be levers to engage feeds, reverse motors, turn on coolant etc.

Half of the battle is confidence and knowing what to expect which is what I have and my wife doesn’t.

But do read the manual if it doesn’t become obvious.

regards Martin

[SamsarandaParticipant @samsaranda]

Many years ago, it would have been in the mid 70’s, I was working on my car, a large Cortina 2000 estate, I had it jacked up to carry out a repair on the rear near side wheel area, can’t remember what repair it was, I was in a dream not focussed on what I was doing, I undid one bolt and the consequence of which was that the rear axle was disconnected and it then swung down to the ground, unfortunately for me my hand was directly underneath it. The edge of the brake drum came down heavily across the back of my hand, after I lifted it off I could see that there was serious damage to my hand, there was a large cut right across the back of my hand in which I could see bones, non broken fortunately, and tendons and blood vessels. I got taken to hospital by a friend, nearest A&E was about 45 miles away, and x-rays showed no serious issues so it was stitched up, healed relatively quickly but I still have the scar to remind me what a lack of concentration could result in.

Another instance of lack of concentration occurred when I was in the machine shop at Tech College, we had a long row of lathes against one wall and I was doing some machining with one and had just inserted my workpiece in the chuck and tightened it up, started the lathe and simultaneously there was a loud clang from the wall at the end of the machine shop, yes I had left the chuck key in place and it had been propelled with some velocity across the machine shop. The instructor let go with some very choice language and really laid into me, so much so that even now I remember how humiliated I was every time I tighten a chuck on my lathe. It was very fortunate that my flying chuck key missed hitting anyone otherwise the consequences would have been serious, they say we learn by the mistakes we make, I certainly learned from that one. Dave W

[simondavies3Participant @simondavies3]

My long running clock project includes a 59 1/2 tooth wheel.
cut with CNC showing that CNC executes errors in a more efficient way than by hand.

[Martin KyteParticipant @martinkyte99762]

You cannot have or cut a 59 and1/2 tooth wheel.

You can however have and cut a 59 and 1/2 gap wheel.

🥴

[simondavies3Participant @simondavies3]

Posted by Martin Kyte on 16/03/2023 12:52:10:

You cannot have or cut a 59 and1/2 tooth wheel.

You can however have and cut a 59 and 1/2 gap wheel.

🥴

Strictly I have a wheel with 58 teeth and an uncut part of the wheel that is less than the width required. If I had made that last cut I would have had 59 fully formed teeth and a 60th one that had been part machined on one side.

For the purposes of this thread, I suggest that constitutes 59 1/2, others may differ, as is their prerogative…

[duncan webster 1Participant @duncanwebster1]

Posted by SillyOldDuffer on 16/03/2023 10:03:51:

Posted by Howard Lewis on 16/03/2023 09:31:47:…

If all fails, read the instructions!

Howardd

Skipping over the instructions, or not bothering to read them at all, might be the most common human mistake of all!

Admittedly instructions often feel like a perverse intelligence test, but admitting defeat far too quickly and then trusting to luck seems a universal fault!

Faced with the irksome job of reading a 300 page manual, I apparently believe I'm clever enough to pick up a full understanding by randomly pressing buttons until something sensible happens…

Dave

Universal instruction book for use by women: press all the buttons at random, if that doesn't work ask a man. 😜

[Martin KyteParticipant @martinkyte99762]

Posted by Simon0362 on 16/03/2023 15:00:16:

Posted by Martin Kyte on 16/03/2023 12:52:10:

You cannot have or cut a 59 and1/2 tooth wheel.

You can however have and cut a 59 and 1/2 gap wheel.

🥴

Strictly I have a wheel with 58 teeth and an uncut part of the wheel that is less than the width required. If I had made that last cut I would have had 59 fully formed teeth and a 60th one that had been part machined on one side.

For the purposes of this thread, I suggest that constitutes 59 1/2, others may differ, as is their prerogative…

‘‘Twas only a tongue in cheek comment that we only cut gaps.

😵‍💫

[simondavies3Participant @simondavies3]

‘‘Twas only a tongue in cheek comment that we only cut gaps.

😵‍💫

Sorry, been a long day at the money generating site! Comment reviewed and appreciated – this time!

[Martin KyteParticipant @martinkyte99762]

Posted by Simon0362 on 16/03/2023 16:43:16:

‘‘Twas only a tongue in cheek comment that we only cut gaps.

😵‍💫

Sorry, been a long day at the money generating site! Comment reviewed and appreciated – this time!

We have all done it. That was my reason for building a digital dividing head.

regards Martin

[davebParticipant @daveb17630]

I very carefully screwcut a replacement part for for my dividing attachment. A superb job, I was pleased with it. Until I found it was out by 1 TPI. This was how I discovered that the selector on my gearbox doesn't quite line up with the label. Well yes, of course I blamed the tool, miles out innit!

[ZanParticipant @zan]

When making my dividing head. I was so so proud of the worm, first I had made , many many cuts and a lot of time, Because for me the thread was deep and the tool was wide. The shaft was spot on  giving a precision running fit on the housing It was perfect. Smooth flanks polished crests. I was so proud, that is,  until I fitted it and found it was the wrong hand….. That was in 1988 never throw things out. It’s now built into my loco building ( made 30 years later) stand and nicely rotates my small 7 1/4 loco

Edited By Zan on 16/03/2023 18:59:24

[HopperParticipant @hopper]

In 1975, at the extremely knowledgeable age of about 18, I bought a brand new Triumph Trident 750cc three-cylinder motorbike. Being a typically smart 18 year old and now a third year apprentice I decided to do my own service after the first two free services by the dealer. This including adjusting the tappet clearances via the usual threaded adjusters on the ends of the rocker arms. These were located under a long narrow flat alloy cast rocker box cover secured by a small bolt at each end and two larger bolts in the middle.

Started the bike up to hear a loud clattering noise. OH OH! Must have set a tappet wrong. Took the rocker covers off and checked. All good. Nothing wrong. Put the covers back on. Started it up. Same result. OH DEAR. Must have stuffed something up. So, off with the rocker boxes. Nothing to see here. So off with the head. Nothing to see here. Off to the dealer to buy new gaskets and then I put it all back together a day or two later. Managed to snap one of the small rocker box studs by tightening it up to the same torque setting as the main head studs. Got it out, off to the dealer for a new stud. Reassembled a few more days later. Started it up. Same result. Clatter clatter clatter. WHAT THE ???

Good old Dad comes down the shed after hearing days of swearing emanating thence. I pull the rocker covers off. He takes one look at them and says "What's that mark there?", on the inside of the long flat rocker cover, right above the centre exhaust tapped adjuster screw.

I had only over-tightened the centre bolt in the cover, bowing the whole thing down far enough to contact the tappet adjuster on the end of the rocker arm. Hence loud clattering every time the tappet adjuster hit it. A five minute job to lay the cover on the concrete floor and belt it out flat with a soft hammer and restore the required bee's whisker of clearance. Reinstalled and hey presto! Clatter all gone. Doh!

But once I had broken the factory seal on those rocker box bases, cylinder head gasket and pushrod tube seals, I never ever could get them oil-tight for any length of time again.

[John Doe 2Participant @johndoe2]

My central heating is working at last !!

Faults were:

Boiler overheating and tripping the overheat cut-out.

Air leak in the positive pressure sensing system in the boiler, preventing it from firing up.

Blockage in another part of the air pressure sensing system, ditto.

Damaged flue gasket.

Main board failure – re soldered all connections, but that did not fix it. No circuit diagrams or even schematics available and did not have the time to trace the circuit out myself. New main board.

No restrictor fitted to the hot water loop, so if HW was selected on as well as the CH, the HW would steal the hot water from the boiler and the radiators would stay cold.

Magnetite detected, (with a magnet), in some pipe junctions. This caused blockages which were preventing fill water from the expansion tank in the loft getting into the system, and restricting the flow of water through the system.

Cut out the affected pipework and fitted new pipe, including fitting a restrictor valve in the hot water loop.

All back together, with cleaner fluid circulating and radiators all balanced.

A warm house after 2 weeks of very low temperatures in the house – down to 8°C at one point.

Total cost, about £100 for a new control board and cleaning solution.

BUT………on clearing up, the sheet I had carefully put down on the carpet by the airing cupboard before starting work turned out to be porous and the light coloured carpet is stained. So another £100 to have the carpet cleaned.

Those dust sheets are absolutely useless – they do not prevent contamination getting through.

[DMBParticipant @dmb]

I recently ordered small black plastic balls for a project and upon receipt, were found to be too small, so put on one side and ordered bigger balls! Unfortunately forgot to put a note in plastic bag of the small ones, of thread size. Another small project recently, called for a small ball. Raked out the tiddlers (about 25mm dia.) and quick measure suggested 1/4" BSF or 6mm thread. Gently tried taps in the brass thread but neither seemed OK. Next, short scrap of 1/4"dia. steel was threaded differently each end and one fitted quite well but I thought not perfect. Used the best fitting thread on the project and screwed knob on tight. Success! A balls – up turned good!

John

Edited By DMB on 17/03/2023 11:29:12

[Tim HammondParticipant @timhammond72264]

Loved your account of your Triumph Trident travails, Hopper, as I bought a brand new one in 1976 from a London dealer at a cut price. It was difficult to return the machine to the dealer for servicing, so after the first (free ) service, I did them myself. Nothing particularly difficult and all went well until I rode the thing to Woodham's loco. scrapyard in South Wales (I was involved with the restoration of Urie S15 506 at the time, since you ask ); a few miles from my destination the engine started making horrendous clattering noises and was well down on power. Quick investigation at the yard showed that the noise was coming from the rocker cover, so I checked the rocker arm clearances and bingo! one of the gaps was way out. If you remember, there was a steel ball fitted to the tip of the rocker arm with a flat ground on it, this flat contacted the valve tip, and somehow, when I adjusted the clearance on that one valve I'd managed to rotate the ball in the socket, so that the clearance was between the spherical surface of the ball and the valve stem tip. This was OK until the ball self-rotated to its correct position after the engine had run for some time, with the resulting increase in clearance. Doh! Readjusted and all was well.

I had all sorts of problems with that bike and finished up with a holed centre piston after fitting a Lucas RITA electronic ignition system. Found out 20 years later from a Trident enthusiast that they were noted for this. The clue was in the name "Lucas" – I should have known. Gave up after that, sold the bike and bought a BMW R60/6.

[HopperParticipant @hopper]

Posted by Tim Hammond on 17/03/2023 11:39:41:

Loved your account of your Triumph Trident travails, Hopper, as I bought a brand new one in 1976 from a London dealer at a cut price. … etc

Tim, it was the T150's same "elephant foot" tappet adjuster holding the ball bearing with flat ground on it that flummoxed me. I was convinced I had done exactly what you had done and rotated one of the balls inadvertently and that was coming around and rattling. But no sign of it on checking so concluded something terrible was amiss.

So I learned at a tender age to always check the simple stuff first when troubleshooting. Could have saved days of anguish and permanent oil leaks if I had looked at that tappet cover the way the old man did — instantly.

Had a good run out of that Trident otherwise. Other than wearing out top ends in about 15,000 miles. But it only had one speed in the hands of an 18 year old, including wheelstands off the stop lights regularly and being revved out to 8500rpm every Friday night trying to keep up with the Kawa 900s at the front of the pack. So it may not have been the bike's fault! Traded it in on a Harley Sportster in 1977 and still have that bike today. Agricultural enough to be resilient in the hands of the ham-fisted.

Edited By Hopper on 17/03/2023 12:20:39

[Mike PooleParticipant @mikepoole82104]

The rocker covers on the Trident are barely adequate, the web’s supposed to reinforce the holes for the sleeve nuts crack at the slightest hint of over tightening. Norman Hyde used to supply a much heavier replacement cover as this problem was common. A top end rebuild for gasket replacement was a regular event but even though I would say I have mechanical sympathy the threads in the soft aluminium give up with repeated assembly so I just helicoiled all the 1/4” threads before they gave up. I must find the enthusiasm to get it back on the road, I have now owned it for 45 years.

Mike

[Mike PooleParticipant @mikepoole82104]

One of my memorable machining mistakes was during a turning phase test when I was an apprentice. I was cutting a thread when the instructor informed me that it will never fit the other part. A quick check around and I realised I had set the screwcutting gearbox incorrecty, to give me a chance at completing the test I had to remake the part for which he gave me a one hour extension to the test. As the rest of the group finished their test they were setting up other lathes to save me having to do chuck changes, thanks again lads. Despite having to hurry I got 10/10 for my test, the instructor John Hopkin didn’t mark me down for the mistake.

Mike

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