Member postings for not done it yet

doing up a Suffolk mower remember?

Nope!

Not replacing the rings with new? What is the ring gap in an unworn part of the bore? Can you see a line in the ring groove to determine where the inside stepped ring fits? The more worn (on thickness) is likely the top ring.

There won't be a ridge dodger if original, so that step is likely bottom side of second ring. You may need a ridge dodger if the bore is worn and you fit new rings.

Are they square or tapered rings (if not appreciably worn)?

You might need a magnifier as well as your reading specs. If there is metal displaced on the outer edge of the ring (sharp edge) it will be the bottom of the top ring.

A pair of horses' arses to determine railway track width. Two ox, needing a rest when pulling a plough, to determine the furlong (furrow long). The Americans losing a spacecraft by mixing two different measurement systems.

All arcane examples of unit determination or what might happen with mixing systems. Even imperial bearings have been metric for decades, apparently.

How often do you see a u-toob where someone converts other fractions of an inchoto the simpler decimal measurememt (thousanths). Drill bits in a box, marked as fractions but used as thousandths of an inch. Not many inch 'micrometers' in 1024ths!

Americans might call their system anything they like; they might claim some units are English, Imperial. American user standards, etc. But the still use the BTU (British Thermal Unit) as a measure of energy. Go figure....

Some, I know, dislike metric because "It is French". How quaint, or peculiar (and luddite)!!! I hear children stating their height and weight in old units, but don't have a clue as to how many pounds in a stone or even feet in a foot! And the only pints you might find are beer volume or blood donoring (actually 400g). Even spirits and wine are dispensed in metric volumes these days.

Even rugby- a real British invention, for sure - went metric decades ago. Cricket pitches may be 22 yards between the stumps but that does not change the fact that those stumps are 20.13 metres apart. Are tennis courts imperial or metric these days? I would guess that most professional golfers are metric users as well?

Metric rules, particularly now as SI units. But the computef industry still uses 1024 as a standard....

Call your tools metric or 'old units', because that is what imperial units are - old units.

If the OP were to state the actual mass of the item to be turned, the real offset from the centre line, dimensions, material, density, and more - he might get a more specific reply.

I would not countenance making a judgement on the information given. Rotating devices are dangerous enough without stretching close to mechanical limits. I note that a 4" item would have a surface speed of around 2000' per minute. Just those two off-centre jaws will have a considerable (non negligible) effect on the balance of the chuck.

But why haven't they made a return visit to the moon ??

A serious question? Why go back to somewhere when the rewards are known to be minimal at most?

Why send humans, with a considerable risk of failure, when robots can accomplsh the same at far less cost? That is why.

A lack of thought, or understanding, by the poster methinks! Or simmply some ulterior motive to unnecessarily arouse the suspicions of the 'don't really have a clue about science' brigade.

Horizons are far distant these days. 350k miles is chicken feed, compared with unmanned probes to asteroids, Pluto and other distant space objects. Satellites are able to collect and transmit data to scientists, who can safely sit in their offices and sift through the important findings.

The moon is simply made of green cheese. Not much benefit in mining green cheese for consumption on Earth, is it? Elvis has copyrighted all the interesting things on the moon, including laying claim to all the best bus routes, so Citybus have lost the desire to join the race ad the profitable routes are all taken. We know that wid turbines won't work too well up there too. Can you really think of any good reason to send more people to land on the moon?

Only a question from a non-thinker, I think!

All your teeth gone blunt, hacksaw? Or has the blade snapped?

The interweb conspiracy mongerers. They are everywhere. Most are complete idiots, but some are clever idiots.

Do you really believe all that you read? Don't you think the ruskies were not watching every move? Get real, if you expect your other posts are not to be treated as fantasy!

I got a distinction rating for that paper, so I reckon my result and reasoning/explanation was more than adequate. Most, I believe, answered 4MW and were probably marked as correct. The problem arose, I think due to the first part of the question being about a described turbine and the later part using the definite article rather than the indefinite article. It was a low mark question anyway. At least it was not a 'multiple guess' question like a lot of the GCSE papers these days!

Perhaps it was just a question to sort out those that apply the definition correctly? Or possib

y an error on the question writer's part. I prefer to use term for gear trains as speed 'reduction' or 'multiplier' - no ambiguity possible then.

I once had a degree level question that asked for the output of a one megawatt turbine if the rotor diameter was doubled. I answered ''One megawatt. Attempting to increase the output of a one megawatt turbine by a factor of four (by quadrupling the swept area) would 'let the smoke out' - ie the turbine would fail." A bit like noon and midnight - they cannot be 12am and 12pm by definition! Midnight is actually both 12am and 12pm! Noon is the meridian.

From this thread, it would appear that his 'behind time' will be somewhat reduced due to his non-replies to paid-up ex-customers.

Peterborough? A large catchment area! There is a small MES in Stamford (there are Peterborough signs on the outskirts of the town) and free membership to newcomers.

They were not overconfident of success? No press or spectators.

Space 'starts' from about a 100,000ft (c.20 miles). So maybe a bit further to go, yet, to get into a sensible orbit?

melts around 1000-1100C. I agree.

Not so. Cement clinker is formed in a kiln at around 1450 degrees Celsius. The kiln charge could easily become molten, probably over 1500 C, but that would be a production disaster - quickly scours away refractory linings, potentially blocks the cooler, is nigh-on impossible to grind into cement powder - and is avoided like the plague. Seen it all, after working in the industry for umpteen years.

Cement loses its strength about 600 degrees Celsius. It is dehydrated.

Plaster of paris is more usual as a binder, but not ideal. Portland cement, I would say, is inappropriate for anything over a few hundred degrees.

Ee bay?

I'd be interested to know what sort of accuracy those that can set their 4-jaw "in a minute" with a bit of chalk, fag paper, end of tool, etc can get.

There you go, you see. I, me and myself am not a trained machinist. I can often set up a piece of material in about a minute, but not with the accuracy you are thinking of. Certainly sufficiently accurate to knock out a part from an over-sized piece of material because I know that it need not be as accurately centred as your lovely SC chuck! As long as I finish the machining before removing it from the chuck (usually parting off) there is not a jot of difference between the two types, as regards accuracy.

I didn't know it when I started, but soon learned that I could not even re-chuck a perfectly round bar in my cheap chinese chuck. Yes, the ones typically sold with most new lathes. It may take me longer than a minute (often does!) to centre a part accurately in the 4 jaw, but at least I can, if I want/need to.

I do use the 3 jaw, but if the 4 jaw is fitted it is about as easy to centre a workpiece as changing the chuck (and it still not be centred to the accuracy you were suggesting).

As I said earlier, it is with hindsight that I would choose a 4 jaw independent over a 3 jaw if I were only to have one chuck. Very hypothetical, now that there are several chucks stashed away in my workshop. And I still would not class myself as a precision machinist, by any means. I make things to suit a purpose.

A 3 jaw is easier for a beginner, just no more accurate and a lot less useful than a 4 jaw independent. But we are not beginners for long (not talking about ability here) and once you get started, you soon realise the need for a different chuck to that 3 jaw. And mostly, people do not go out and buy another 3 jaw chuck of he same size. They get a 4 jaw independent as a first extra purchase.

Both the liquid and the bones could be converted to fertilizer - they are, at least, using KOH rather than NaOH. I would endorse that, whether the liquid was sprayed 'locally' or taken away to a bulk fertiliser processing facility. The bones would clearly be good calcium/phosphate fertiliser, presumably.

Which ever way, I would not want all that Potassium to be lost by draining down to the sea.

Edited By not done it yet on 22/05/2017 16:51:49

where those like Neil and myselW

Put me in that bracket, too. I bought a lathe with a 3 jaw chuck. But in hindsight, I could have done better with the 4 jaw independent from the off. Most certainly able to use a dti, so perhaps ahead of you two at the starting point, but the 4 jaw chuck is far easier than working round not being able to remove the item from the chuck (until all turning is completed). Unbolting and bolting on chucks is a pain (yes, I will put up with not being able to turn with the lathe in reverse).

for size aren't 3-jaw chucks more expensive than 4-jaw chucks?

They may be offering a smaller or larger 4 jaw than 3 jaw - we don't know. There may be a quality difference, as well.

Only one set of jaws needed for the independent chuck is yet another plus for the 4 jaw, too. The first time anyone re-chucks a part they will wish they had a dti! That is if they notice the problem, of course....

It is somewhat a revelation that the lathe is actually being offered with a choice of chuck.

They are made using a very specialized type of material, it's designed to suffer as little expansion/contraction as possible under temperature extremes.

Your point is? Or was that just a passing 'aside' Makes no difference to the method of scratch removal. Needing to remove the scratches, not polish them, may be important.

Cloudiness may have a different connotation.

From the net:

Today, the canopy is a multi-layer structure. In case of the F-16, it consists of three layers:

The innermost layer is 0.5 inch thick polycarbonate and drape-molded into the compound curvature shape.The center layer is 0.05 inch polyurethane to bond the inner to the outer layer.The outer layer is a 0.125 inch layer of acrylic (PMMA).

So not really any different on the surface, which is where it will get scratched/abraded? Poly methyl methacrylate - perspex to many.

Edited By not done it yet on 22/05/2017 11:51:34

A DTI is really for secondary operations or tapers for me

Only because you never re-chuck anything, Ady?

I would suggest that 3 jaw chucks are supplied as standard (generally) because it is convenient for those that don't know the limitations, they are cheap and t

he puchaser will likely need to get a 4 jaw independent fairly soon (extra sale) if they need to do anything other than basic turning.

My advice might be to check the individual chuck prices and go for the most expensive one to buy separately, if the price of lathe and one chuck is the same for either combination!

One might ask the question in a different way. Like... Which would you buy if you were starting again and could only have one chuck? Or ... Which is more useful - a 3 jaw or 4 jaw independent? Or... What did you start with? Or... How soon did you need another chuck? Or ... Does it make a difference whether a quick change chuck or a bolted on variety?

Think here jet fighter canopies? They get scratched; they are repaired by polishing with different grades of suitable abrasive paste - finer and finer until the pilot can see through clearly. Likely some vids on Utoob? No different than polishing glass lenses. Only here it is often more cost effective to replace with a new item.

One can only renovate the surface. If cloudy all the way through, no amount of polishing will resolve the issue!

Think here an extreme. Say you only had five indents on a full turn of your item. It would make a different set of indents the next time around if the 'wrong'diameter, but there are incremental diameters where the knurl would superimpose 5, 6, 7, 8, etc knurls per turn. So ideally the diameters need to match the knurling wheel in use. Often knurling a little deeper will make the small amount of difference imperceptible.

Try it and see.