Member postings for Richard Parsons

Edited By Richard Parsons on 06/01/2012 06:02:02

Lard oil You can still get it. Basically it is the lighter fraction of pig fat. The ‘oil’ can be extracted by part melting and filtering. There is a sort of discussion about it here.

Happy New Year to all

Rdgs

Dick

Kevin … It all depends on what cutters you want to grind and how much you wish to grind off. For ordinary work like touching up lathe tools, drills, cold chisels etc. One of the first tools I bought was a small 6” offhand grinder. I still have it 65 years later. I now seldom use it. At one ME exhibition at Wimberley I bought two diamond coated files to do a job. They were a large flat file and a large rat tailed file. They were to straighten op some glass wear my mother in law had. I started to use these to ‘touch up’ lathe tools. I now have several diamond files and plates.

Drills I seldom break, but when I do I use the offhand grinder and true them up and finish them with a hone on a coarse diamond stone cutting plate. In the UK I could buy them for £2-£3. I run them in a small angle grinder (which someone had had binned) with a backing plate to stop the stone cutting plates from flexing.

In the late 1970s I bought my first vertical milling machine and then I made my tool grinder around 1980. Now I seldom use it. With a packet of Chinese diamond files and a bit of thought I can touch up an end mill by hand. I now use a trick written up by our good editor (David). This to touch the surface you are going to file with a felt tipped pen. It helps guide your filing. I know it is not as accurate as setting up a tool grinder but it is far quicker. Many of these tricks I learned at the SMAEE stand from Prof Chaddok.

Most of the complex equipment we have for sharpening things was designed for de-skilling and speeding the job up. If we have to do a ‘one off’ it is often better to do it by a bit of thought and by hand.

Oh by the way it is illegal to change a grinding wheel unless you have a certificate issued by your local authority.

Hi Peter Did your lathe come with any switch gear. As I remember it 3 phase motor usually had a ‘Memota’ (a trade name) switch. You pressed the green button and the rest was automatic.

Billy you are right the Antikythera was a mechanism to replicate planetary motion and to provide corrections to sundials used to set the public water clocks. It is not the only example of such an apparatus in existence. There is Richard of Wallingford’s celestial clock, which he never finished, but has been made as a modern replica. There is also the great clock in Prague and hordes of others. None of these are computers in the true modern sense of the word but are mechanical simulations of the situation as we understand it. It of course is incomplete in the same way that when you think that float glass is flat. It is not as I learned when I used a piece as an optical flat in an 8” Newtonian telescope. Float glass is actually a spherical whose radius is that of the earth where it was made.

I had fun once with the corrections to a form of gyroscope. This thing was mounted on a large steel tube which went down into the bed rock. It used to display movement and seemed to be slowly moving in one direction. They had taken the earth’s movements around the sun but had forgotten earth’s precession or the earth orbit round the sun and the wobble of the earth’s axis. My programmer had the vapours over that one. The corrections were added to the program but it still showed drift. Not acceptable to the customer. I had to do a lot of digging into astronomy and found that the sun its self was moving through space. New corrections were added and the thing settled down to be within the experimental error. The customer bought the system but not the program. We can write that ourselves they said. Result -2 years later the sued us for the program specification and lost the day. The bought at a huge cost both the program, its specification and support from the Executive in Electronic Information Organisation. Yes assistant analyst was the EIEIO!

Billy I will agree with you about the wheels on the Home Pointing Chariot. The Chinese were very good craftsmen. They knew about both the Compass plane and the lathe so there was no problem over wheel sizes. The main cause of errors with the chariot was bumps in the road, but these generally averaged themselves out. The chariots would be deployed in ‘foreign’ or ‘enemy’ territory.

They used lodestones yes but they did not understand the problems of Magnetic Variation. which is something the Hungarians do not know either.

Have a look at the Beijing Ancient Observatory. Although this place is quite late on, the mid 1400s, it was very accurate. It had one of the world’s first seismographs for providing the authorities with information about earthquakes (for disaster relief). Its main use was for providing accurate information for astrological.

Stub Here is a very nice example of Heron’s Aeolipile. What I want to find out about is the levitating chariot. Or was it a trick?

Heron was employed to make worshipers in the various temples go Oh-Ah! and incidentally put coins in the collection boxes.

The Greeks knew about static electricity and the Babylonians built batteries. Even the word Electron is the Greek name for Amber.

If you want to talk about computers how about the Antikythera here

Dick

Ah Terry

Heron of Alexandria was employed in the Department of Applied Miracles by the Association of Local Temples. His Aeolipile was interesting but of low power. I have seen an example of it made from a beer can using a nail to punch the holes and as bearings

A form of it was used to turn a set of dancers which may have been very similar to the Zoetrope a very early machine which creates the illusion of movements. He was made the famous Automatic Bird Garden.

Some of his work was based on a ‘Wash and Brush’ up machine for use in temples. It was inventedby Philo of ByzantiumYou poped a coin into it and a hand gave you a lump of soap/pumice. After a little delay it filled a bowl with water so you could wash your hands.

I will not go into old Leonardo’s Lion. Nor the home pointing chariot invented by the Chinese which was basically just a differential gear

I think that Heron’s use of string, rollers and pegs really takes the biscuit. I might make something as I can get wood, nails and string.

James

The copy you want is in the MEW Online Archive (if you have a subscription)

Have a look at this – Not bad for 50 AD. Think what old Heron could have done with a better power unit!

Rdgs

Dick

Automata were all the rage in Roman Egypt. Have a look at Heron of Alexander (10-70AD). He built a fully automated Greek Theatre (including thunder storms etc). It used cams rollers and cables. It was driven by weights and was pre-programmable. He also made a weight driven truck which could be pre-programmed to change direction. It could also be re-programmed.

Ok it was not digitally controlled, but the basic elements of automation were present

Rgds

Dick

A twin Cylinder Marine engine … Why not. All you will need to do then is build a Yarrow or Scott Marine boiler and a suitable boat. Or how about making a horizontal mill engine, with its Lancashire boiler and a cotton mill for it to drive. Or you could build a Rob Roy

One other suggestion why not sell them and buy something you realy want/need

Rgds

Dick