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Member postings for duncan webster

Here is a list of all the postings duncan webster has made in our forums. Click on a thread name to jump to the thread.

Thread: New Chuck won’t screw on
28/07/2021 18:34:47

If one buys something and it's not fit for purpose, send it back. Any attempt at rectifying it, buying a tap for instance, will void any warranty, and anyway why should you be put to the expense of a tap.

one advantage of ebay/paypal is the no quibble return

Edited By duncan webster on 28/07/2021 18:36:04

Thread: Stainless Watch case
28/07/2021 13:52:52

I'm not seeing any photos

Thread: Help with surface plates in Derby
27/07/2021 18:22:54

Best of luck finding a planer nowadays, and if I had £300 spare I wouldn't blow it on a surface plate

Thread: Centec 2B - New arrival and Q&A
27/07/2021 18:20:41

Don't you have captive drawbars?

Thread: Running needle roller bearings
27/07/2021 18:17:26

You can get hardened rods, meant for running linear bearings on. These are surface hard and I'll bet you could at least face them with carbide, perhaps even turn shoulders.

Thread: Reflex Gauge Glass Material
27/07/2021 10:36:32

Drawn bronze can be a right pig to drill and tap

Thread: Metallurgical coal
25/07/2021 23:24:05

More on Michael's link rubber steel Seems you still need coke, but a lot less, and you need a lot of electricity

25/07/2021 17:37:33

Carbon is not a catalyst in the iron making process, it is part of the chemical reaction. It combines with the oxygen from the iron ore leaving behind the molten iron, which can then be made into steel. This means that even if we could find enough coffee grounds, we'd still be producing CO2.

The neat trick would be to find a way to use plastics (hydrocarbons) instead of coal. Use the stuff which cannot be recycled, saves digging up coal, and gives the plastic waste a value so it won't be dumped into the rivers/seas

24/07/2021 16:32:24

I got on to my MP about this. As expected he didn't understand the difference between using coal to make iron and burning it in power stations. I think the main reason for the government calling in this application, which had been approved previously, is the COP26 meeting, but as I said to the MP, if the delegates to that can't understand the difference, perhaps the should find some better delegates. In the meantime we will continue to ship coal across the oceans producing more CO2 than we would if we dug it up in the UK, increasing imports when we could be exporting it to Europe.

There may well be a better way, but if it exists it isn't proven at industrial scale, so it won't be available for a long time . What I would question is why we import coal and iron ore to make iron which is then turned into steel, and export vast quantities of scrap steel, some of which which we presumably re-import. Why not just recycle it ourselves?

Thread: Centre Drill Leaves a “Pip” - Sometimes
23/07/2021 19:53:29

So why are spotting drills so expensive, best I can find for one off 3mm is ~£5 whereas I can buy a set of 5 different centre drills for that price.

Thread: Hydrogen
23/07/2021 01:22:25

Despite being called a rare earth, lithium is quite common. It is the 25th most abundant element. There is even talk of mining it in Cornwall, but then they keep on talking about cornish mining and nothing ever happens. Can you imagine the greens allowing it even for zero emmision technology

Thread: Bench grinder
21/07/2021 22:31:51

My el cheapo grinder vibrated quite badly, so I bought a new wheel with 1.25" hole and made new washers, the one nearest the motor has a boss to fit the in the wheel, just a bit shorter than the wheel so the other washer clamps up. this new thick boss/washer has 2 grub screws to hold it to the shaft. All unbalance problems gone away. I cribbed the idea off a RJH Ferret grinder

Thread: New Chuck won’t screw on
21/07/2021 22:23:29
Posted by Richard Jarvis on 21/07/2021 16:50:43:

........., told supplier only to be told that they are machined on a myford and then checked on two other spindles to check fit. .........

Thanks Richard

If I were making backplates for a living I'd use something more 'industrial' than a Myford. Don't get me wrong I'm on my second, but only as a hobby

Not that this helps, but the backplate I bought from RDG/Myford fits lovely. If you divulge your approximate location there might be another Myford owner near you and you could try it on their machine. With a bit of care you can do this Covid secure

Edited By duncan webster on 21/07/2021 22:23:50

Edited By duncan webster on 21/07/2021 22:24:25

Thread: Setting up rear parting tool properly
21/07/2021 17:59:22

The face of the tool holder shown in the top picture should be facing the chuck, so it looks as if it is set up for the lathe going in 'forward'. This confirmed by the second photo. No chance of the chuck unscrewing, but the tool is canted the wrong way, hence the need for the notch. I think this is simply the wrong tool holder for the job. Boat tool holders have a very poor reputation anyway

Thread: E10 Petrol
21/07/2021 12:20:06

No one remember Cleveland Discol? If Harry Ricardo reckoned it was OK that will do for me

Thread: I think I'm in love... with a metal bender :-)
20/07/2021 17:17:27
Posted by Bikepete on 17/03/2016 20:37:11:

Watch this and tell me you don't want one:.........

OK, I don't want one. Haven't got space

Thread: Vehicle reversing sensors
20/07/2021 17:04:22
Posted by SillyOldDuffer on 20/07/2021 11:31:21:
Posted by Nigel Graham 2 on 20/07/2021 00:50:54:


Reversing, last week, at the pumps it was my delight to see a caravan driver make a complete Horlicks reversing up to the air pump. It's on a curve... Is it just me, or are caravans the most irritating vehicles on the road?



The weekly commute to my last paid job involved about 70 miles across single carriageway roads in North Wales. At least tractors are not usually going that far, but Shed Draggers holding queues of 20+ cars for mile after mile were not uncommon. Gaily driving past laybys and then pedal to the metal when they got to the occasional wide straight bit, no thought of letting anyone past. Tin Snails are nearly as bad. I've been told that in some states of the USA there is a legal requirement to pull over if you're holding up more than 6 cars

Edited By duncan webster on 20/07/2021 17:11:50

Thread: CNC Lathe Scratch Build
19/07/2021 12:17:37

Been having a think, always dangerous. Your post of 14/11 shows the tool-post at the far side of the spindle, so gravity will try to move the tool down the slope into the job. Cutting forces will try to move it away. I know that ball-screws don't have a lot of backlash but it's not zero. If this is thought to be a problem you could either clamp the cross slide to prevent it moving, or over-do the counter-balancer so that the tool-post is always up hill if you see what I mean. Perhaps I'm overthinking it, not unusual.

On to some sums. The tool-post/slide assembly weighs 9kg on a slope of 45 degrees so the force due to gravity along the slope is 9*9.81*cos(45) = 62 Newtons. If I assume your air tank is at 80 psi, that is 5.5 bar so you need a cylinder sqrt((68*4)/(5.5e5*pi)) = 12.5 mm diameter. To allow for the tank pressure dropping before the switch kicks in re-do the sums at whatever that pressure is, which will make the cylinder a bit bigger, and then add another bit to make sure it's always uphill, or if you decide to undercompensate make it a bit smaller

Edited By duncan webster on 19/07/2021 12:23:10

18/07/2021 12:55:33
Posted by Joseph Noci 1 on 18/07/2021 10:23:55:

Going to read all about air tank.cylinder pressure based counterweights - new to me, and seems that it will be complicated..

Ady1, I fear you have lost me..not sure what you referring to..


Think gas strut but with an air cylinder instead of the strut. If you find a cylinder which gives the right load with your compressor tank pressure, that's all you need. The force will change a bit depending on actual tank pressure but I doubt that would matter. If you need a pressure regulator to drop the pressure then when the cylinder is compressed the pressure will build up, but the volume of the pipework will limit that. What do the moving bits weigh?

Thread: The last Gravity Ropeway
17/07/2021 23:46:30

This is very interesting LowTech. Has details of aerial runways many miles long

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