Member postings for not done it yet

Referring back to the u-toob by Keith Rucker (machinerydotorg), from where this thread title was plucked, I presume, Dale Derry immediately indicated he had bought his Clausing lathe for $750 and the extras cost him $300.

But where do you draw the line? Are Dale's measuring, cutting, sharpening machines, etc regarded as extra 'tools' or more machines? It would seem that all his 4 lathes and 2 mills were second hand bargains! Hence his comment, on the vid, that 'machines are cheap'.

5 litres per minute of approx 90% purity, using only approx 300W power input will far out-perform electrolysis, I would guess. Electrolysis would make exactly the right amount of hydrogen for the rocket fuel, mind!

Hydrolysis purity would be 100% after drying, but for volume oxygen concentration, the pressure adsorption method will win hands down on running costs.

Edited By not done it yet on 10/10/2016 18:47:30

If only a bare lathe, the bottom of the V could be broached by use of a home made square broach (see clickspring u-toob) after carefully drilling the bottoming hole on a circle marked on the lathe, the rest being roughed out with any method appropriate (manual or mechanical) leaving only the sides to be finished very laboriously or by some mechanical assistance.

Are the indiviual turrets adjustable or does the accuracy of alignment rely on this part?

It looks, to me, to be a turning and milling job. Perhaps not simple for many of us, but more of a setting up problem for the angled cuts, but apart from that no real basic difference than cutting a gear?

The no milling machine is the problem to get over.  Local college course?  Friendly local group?.

Looks heavy for most vertical slides on a lathe, but doable if really wanted.

Edited By not done it yet on 10/10/2016 14:48:34

Edited By not done it yet on 10/10/2016 14:49:43

Oops, duplicate!

Added:  My machines are second hand, so the tooling:machine cost ratio is high!

Edited By not done it yet on 09/10/2016 17:56:04

Vices should not be included

The whole hobby might be a vice, but it should be vise in the list, shirley?

Time of acceleration is the key to the calculations, for Newton's second law to apply. Time of flight being for the projectile exiting the muzzle.

Applying f=ma for this time results in the energy transfer. Using the average acceleration and time one can calculate the average force applied.

Whatever that value (it matters not) because applying that same force, whatever it might be, to a large inertial body (mass of gun) will provide the average acceleration for the given time. Because the gun is so much more massive, the final velocity will be so much smaller than that of the bullet. Because the energy in Joules is proportional to both the mass and velocity squared, the energy of the bullet will be far higher due to the velocity squared part of the calculation.

Firing shotgun cartridges outside the gun normally results in the case splitting. So the burn energy is dissipated sideways through the split. Furthermore, the burn rate is far diminished because there is little pressure build-up. In the case of a steel cased bullet, things are not quite so benign. Pressure build-up rate can result in far higher pressure before the bullet is discharged from the case.

Not anywhere near as high velocities, of course (time of acceleration is short), but there is the possibility of lethality, all the same, at close range. Depends if the bullet and case fly apart in opposite directions or if the case bursts. Not something to try. Years ago, many .303 bullets were fired by the village lads by sticking the bullet in a crevice and firing them off with an airgun touching the primer. They certainly carried a punch! I've fired cartriges stood on the end of an airgun, but never tried to fire a .303 that way.

At junior school in the 1950s we used to make long cordite or gunpowder trails around the playground and light them off at the end of the playtime. There were plenty of live ammo around in those days. It was not until about 1973, when the army disposal teams were enlightened to our local ammo dump (after a WWII practice mortar bomb killed a lad who found it, took it home and was told to take it away), that the area was cordoned off and cleaned up. I also know that a Stirling sub machine gun was thrown in a pond where I lived. The 'easier' days of the black home guard cartriges. Certainly lethal when used to blow carrion crow's nests out of high trees from a good distance. Dad only used his best gun, and the open choke, for those cartridges!

Old oxycons are typically used for surface mixing burners by lamp workers. Ours is a 5l/minute version. They cost around a couple hundred quid from a supplier, or less from a private seller. 10l ones are readily available but rather more expensive. These are all reconditioned ex-medical use, mainly, I would think. They are no longer certified for medical use as the filters are no longer there or compliant.

Oxygen purity can be up to 98%, but performance drops off as the maximum service volume is approached. Down to upper 80s as I recall. Ours is low pressure, so not sure if it would work with an internal mixing torch but I may try it sometime. I'm not too keen on compressing oxygen, but a diapragm compressor might make enough pressure for a short run from a well cleaned compressor tank?

Edited to add that I would not contemplate compressing acetylene on a home scale.  Too dangerous.  Triple carbon-carbon chemical bonds are not very stable!

Edited By not done it yet on 09/10/2016 11:10:19

Danny,

The projectile is up to speed by the time that it exits the barrel

Simply Newton's First Law of Motion in operation for that. No longer any resultant force from the powder burn, so no further acceleration. Now it will be slowing, only due to friction in the air, for a horizontal shot (no effect of gravity on the horizontal velocity).

Recoil of a gun is most easily calculated from the momentum law, as it basically an impulse, where one part of the original body (the projectile) exits the muzzle with a known velocity and mass. Momentum will be mass x velocity and as momentum must be conserved, the recoil of the rest of the original (the gun) will have the same momentum, but in the opposite direction (so if the first value was positive, this will be negative).

Energy can easily be calculated by use of the Kinetic Energy equation E = 1/2mv^2, where, in SI units energy (E) is in Joules, mass(m) is in kg and velocity (v) is in metres/second.

This ignores things like the mass of propellant (that is converted from solid to gas) and any wadding, etc., but is a good approximation for all but the real scientific boffins.

Edited By not done it yet on 09/10/2016 01:32:03

Some of the Physics.

Newton's Second Law of:

Force = Mass x acceleration

a

pplies as soon a 'firing' commences.

For a propulsion system the thrust must be caused by the force of the propellant against the rocket. This will, indeed, invoke Newton's Third Law, so the rocket will move in the opposite direction.

The coke bottle ejects water according to F=ma, but the problem is one of inertia as well as thrust. That bottle is heavy at maximum force (Force = Pressure x Area) and acceleration will be reduced, but as the bottle gets lighter (reduced water content) the force will reduce because the pressure is dropping (not like a space rocket with diminishing mass, but constant force).

It is a balance of pressure and volume of water expelled for our coke bottle and there will be an optimum fill volume for any given pressure. Too little water and the thust will disappear before the rocket has achieved maximum velocity and too much will mean the pressure will be much reduced, thereby expelling water more slowly while still with a high inertia. Added to that, the water being expelled at low pressure will have little increase in velocity in the opposite direction of rocket direction. Of course, the aperture area through which the water is being expelled will have an effect also (ignoring the ever present air friction as the rocket moves faster).

Nothing simple, but while momentum must be conserved, the momentum of the water contained in the bottle and ejected from it will be a very complicated system, with forces of gravity dragging the whole lot towards the centre of the Earth whether inside or outside the bottle! Momentum is easier to sort out when a couple of bodies strike or become a single item.

An alternative is to cast some delrin (m.p. about 170 Celsius) around your lead screw. An apparent easy fix for a full lead screw nut, but might be a bit more of a challenge for a half nut.

Acme threaded rod is available from suppliers, if you wish to make your own tapping tool.

Hope this helps.

Yes, yes, it is a no, no!

If anyone on here wishes to advise a third party to make potentially dangerous alterations to a grinding wheel, then be it on their head should it all turn nasty (even litigation, like!).

Perhaps better to reduce the spindle size on the grinder, but that, too, may be sized for safety. Why not use the rarely used grinder with these cups?

Be safe. Industry insists on abrasive wheels being fitted and tested by a competent, trained operative, I believe.

use pullies to increase the distance the weight travels.

Bungalow? Bore a(deep) hole through the floor? Not sure that the weight will travel any further unless your pulley is in the roof!

Perhaps use some metal parts in your clock to reduce the friction losses? Best solution, if you are that lazy, is to get someone else to 'wind' it for you!

Any well designed vise would fail safe - the handle should bend before destroying the vise by over-tightening.

I would say get an old one, of good quality, and replace the jaws if necessary. There are loads out there at good prices (I know a man who buys most of the decent vises at a regular auction I attend, cleans them up, paints if necessary and sells them on at a good profit).

If you don't like it, or prefer another that you come across, just swap it out and sell it for about the same as it cost you. Shiny new vises are money pit (if you make the wrong choice).

How many 'larger' jobs?

I swap around two change wheels and reverse the lathe for the odd screw cutting job on my (non-mini) lathe. And further, how many times (on a metric item), might an imperial thread make no odds? If you want to be a purist, go ahead and swap out lead screws, half nuts, etc. Of couse, maybe your mini lathe has no provision for swapping gears.

On the other hand, just get the job done. Following experience will tell whether it was the right decision or not and at least it would be easier/quicker swap

ping next

ti

me....

In your position I would stand still, stop turning round in circles, and do it. Make a decision for a ch

ange and get the job done. Then enjoy a lathe with metric lead screw and imperial cross and top slides? I would be changing those lead screws as well, if I were a purist!

On a final note, most threading jobs on a mini lathe might be handled with taps and dies, so even less need for continuous change-overs (and leave the alernative lead scew on view with a label on it denoting metric or imperial, or stick a label on your lathe, or colour your threading dial, or something else, to save having to measure up thread pitches all the time - if you change them regularly).

Whats the easy way to destroy them

Which? The nests or the queens?

Nests need proper annihilation by the experts and if queens have mated and left the nest we are potentially in big trouble!

Queens can look as though they are dead, but wasp queens can survive in a freezer...

Never mind the 'splats'. The night lit up by poor headlights of the period, on a warm summer's evening, would make it appear to be 'snowing' in the 1950s and into the '60s. So many moths, etc. This is no longer a normal occurence, these days.

Ask any ecologist, who records/maps moth numbers etc, and they will tell you that numbers have diminshed rapidly since the introduction of neonicitinoids. Bad news for everyone and particularly for the fauna that would feed on these insects.

one on my inner thigh, i must have squashed him as I squatted

Steady on Clive! You know, as well as I, that drones don't have a sting!

Dustig bees does not work. Yes, it gets rid of a few phoretic mites, but around 85% of the mites will be 

busy reproducing in the cells at most times.

Only useful for colonies with no brood, IMO. One problem is that the sugar, if too much, can damage or kill some of the brood. I have only used it on swarms or splits with no capped brood, by removing all the bees from the hive, rolling them in icing sugar, and then allowing them to crawl back into the hive.

The main problem , for survival of the honey bee, is humans. Who spread the varroa across the planet in double quick time, by transporting bees around the world? Who sprays/seed dresses insidious insecticides around the environmement, affecting all manner of non-target insects? Who lose lots of swarms, to become the next round of feral colonies each swarming season? Who parks bee colonies in close proximity to o

ne another so disease vectors are more easily transmitted between colonies? Who continually treats the bees with medications to remove most, but not all, varroa, thus keeping non-varroa-resistant colonies alive?

Yes, beekeepers, farmers (mainly, but horticuturists and gardeners, as well) and purveyors of nerve agent type poisons are very much to blame for the sorry state of our honey bee population.

Edited By not done it yet on 03/10/2016 23:22:56