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Member postings for michael potts

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

Thread: Adept Hand Shaper
05/04/2022 15:46:15

I have a hand Perfecto shaper, but there is a motorised one on ebay at the moment at £350. I also have a Swan made near Norwich, also hand operated. The Adept at least looks as if it has been looked after, and all the parts seem to be there. As it does not have a reversible sideways feed it could be a pain to use. Another source of information on these machines are the Kay Fisher shaper columns on the internet.

Regards. Mike Potts

Thread: Cowells 90ME 14x1.5 backplate question
03/02/2022 11:23:29

I also have an early Cowells lathe with the 14 X 1.5 mm mandrel purchased about ten years ago. It came without very many accessories, until someone decided to sell many accessories with this spec of mandrel. Having collected them, I decided to check the lathe over as the mandrel bearings had been remade after one of the bearing caps had been fractured. This was the first time I had ever done this, and the results were not good. The dowell pins in the headstock had been filed - not a good sign. Then the alignment was not correct, the mandrel was pointing up and to the rear. So I checked it again and then again the following day. No changes could be seen, so I took the head stock off the bed. On inspection I found two pieces of brass swarf under the head stock. I cleaned everything, obtained new dowell pins and reassembled the lathe. Realignment took well over an hour to complete, but at the end everything lined up to within about half a thou. I decided that this was adequate, if not perfect, sat back, wiped my brow and had a cup of tea.

I fitted the lathe on an old sewing machine stand, and it worked very nicely. The only problems are slipping belts.

The ins and outs of the Perris lathe, its variants, and the Cowells lathe seem to be complicated to put it mildly. The article ' Evolution of the Perris Lathe ' on the website is worth reading. How much is fact and what is opinion is difficult to work out. Brian Perris seems to have been killed in a car accident at the end of 1976. Within a year the PL90 lathe was back in production as the Cowells lathe. It says something that it is still with us.

The design was metricated very quickly, if only partially. Perris lathe dimensions are still used, notably on the mandrel, and there is one BA threaded hole on the cross slide. Care is needed when the smaller and less used screws have to be dealt with, or replaced.

Mike Potts.

Thread: Lathe Identifier
21/12/2021 09:43:32

There is an Invicta IXL lathe on ebay at the moment, quite well equipped. 3 bids £79, at the moment. It seems to be more or less identical to yours. The gear cover has the name details on it..

Regards. Mike Potts.

Thread: A nice find
05/12/2021 16:56:40

A few months ago, I purchased a Shardlow automatic adjustable spanner, a few inches in length. It is a well made and a very solid tool. A quick wash to loosen everything, a brush with a brass bristle brush, and some oil, and it then was completely free and working. The handle is about the same length as my Bahco 6" adjustable. It will open to take nuts from about 5/16" to 1" across the flats. It does appear to be a capable tool, but is just a bit too big to deal with the smaller nuts. It is turned over to tighten or loosen nuts.

Mike Potts

Thread: Gamage's Steam Engine
23/06/2021 21:26:13

The strap and rod are broken and a solder repair has been attempted in the past. It seems to have just melted more of the rod away though.


23/06/2021 21:06:10





This is a rather poorly NDC belonging to my son, the eccentric sheave is part of the crank disc.


Regards. Mike.

Edited By michael potts on 23/06/2021 21:07:14

Thread: Whatever must IKB be thinking ?!
08/05/2021 19:53:47

E s Cox wrote many years ago that hardening equipment for railway service was not easy. He was writing about diesel engines at the time, but it took time to get the English Electric engines that became widely used up to a reliable condition. The Brush Sulzers had to be derated after crank case cracking occurred.

This latest problem appears to be cracking of aluminium by prolonged minor vibration. Aluminium and its alloys are susceptible to this problem. Steel components can be stressed, but as long as the stress is below a limit their life can be long or very long. Aluminium has no such lower limit, even minor stressing leads to failure in the long term.

Mike Potts

Thread: Was this embrittlement, or what?
14/04/2021 20:05:50

I think that you will find that what has happened is zinc embrittlement of the steel. Have you heard of Flixborough, a nylon making plant on the lower river Trent, which was destroyed in an explosion some fifty years ago. The explanation was embrittlement of hot pipes by the galvanised netting holding the insulation in place. Zinc migrated into the steel where the netting touched it.

Early nuclear reactors with mild steel pressure vessels had to be kept above about 100 degrees C to avoid the danger of embrttlement cracks in the irradiated steel.

High temperatures are not needed for embrittlement, but brazing temperatures are high enough to act fairly rapidly..

Google Flixborough, and you may find out more.

Regards. Mike Potts.

Thread: This looks an interesting small milling machine
16/02/2020 19:24:46

It is either a Westbury or a Dore Westbury.

Thread: Threaded Norman Toolpost
10/08/2019 09:55:09

Hello BW.

I have two of these toolposts. I bought one for the Myford Speed 10, and made another to for my Cowells lathe. They are very much better than the standard toolpost, and well worth having in my opinion. They are also a lot cheaper to either buy or make than QCTP s. There was a Myford sized one on ebay a few weeks ago.

The body block will be split so that it grips on the threaded upright when the bolt is tightened. I assume that the upright has a 40 tpi thread about 3/4" diameter. It appears to be a useful design variation.

Regards. Mike.

Thread: Another "what is it lathe"
23/07/2019 14:51:53

One model of the Randa lathe, also sold by Grayson seems to have an infill in the bed slot. The first photograph seems to show parallel lines along the bed which could mark the slot infill piece.

Regards. Mike Potts.

Thread: Yesterdays Car Boot Haul! Odd items
03/09/2018 09:20:20

`Hello Martin.

The Boxford item is a dial indicator as Clive says. It is for checking variations from a zero position ( In the centre of the dial ) such as centring in a lathe chuck, or on a rotary table.

Mike Potts.

Thread: Stuart D10 very early model.... nuts and bolts
09/08/2018 16:12:03

Hello John.

Stuart Turner used a 3/16" X 36 TPI thread, usually for small pipe connections pre WW 2. They had a number of standard threads of various sizes, and sold the taps and dies for these threads. They were in their catalogues. My son has these catalogues at the moment, but when he comes in I will get one and put the list in a post.

Tracy Tools stock these taps and dies, Whitworth form.

Regards. Mike Potts.

Thread: Todays Mystery Object?
19/07/2018 10:42:58

The equation E = mc^2 is the first term in an infinite series giving the energy of an object. The second term is

1/2 mv^2 which is the kinetic energy of the object. The other terms are miniscule as all are divided by c^2 and higher powers of c^2. The series derives from the calculation of the kinetic energy of an object. The mass of the object changes as it moves and is calculated by the equation M = M0 / ( 1 - v^2/c^2 )^0.5. M0 is the rest mass of the object, M is the mass of the object moving at a velocity of v, so if the object is moving, its' mass is M0 divided by something that is less than 1 making it more massive, and the moving mass gets larger as the velocity increases. If the velocity of the object reaches the speed of light then the mass is then infinite. In practice if the velocity of the object is less than 10% of the speed of light then normal Newtonian mechanics can be applied with little error.

The mathematics of relativity become very complex very quickly, making an already difficult subject even more impenetrable. Infinite series of terms do not help either.

Radioactive fusion or fission is another issue. Both processes work because the mass of the resultant particle is less than the mass of the starting particle (s). This loss of mass appears as energy, heat,light or kinetic energy of the particles. The amount of energy can be calculated knowing the loss of mass. All the work of measuring the mass of atomic nuclei was carried out after work began to develop atomic weapons during WW 2.

Mike Potts.

Thread: Change Wheels for Myford ML10
27/04/2018 17:29:58


Start with the gears for fine feed. You will need 65, 70, 75, 20 and 20 tooth gears for this.With these you will be able to traverse the saddle slowly under power. That suffices for me most of the time. If you need to screwcut then buy as needed. As Mike Poole said, you may find a set on ebay. What ever you buy, the next one that you need will not be in your collection - its called Sods Law.

Regards. Mike Potts.

Thread: JWST: Hubble successor faces new delay
31/03/2018 16:17:31

Every time a new type of telescope or detector comes into use we learn something more about one aspect or another of the universe. These instruments are a far cry from optical telescopes. When the gravitational wave detecting instruments were first got going, they found something within a day, and have since seen another type of event that would appear to explain how the heavy elements were formed in nature. Before this observation the physics did not really work, but the idea was published in 1957 in a paper that described how all the chemical elements had been made in various places and times. The neutrino detectors around the world have seen one event, the 1987a supernova, when around forty neutrinos were detected. One instrument saw a group about five hours before the other instruments saw another burst. That was over thirty years ago, and I am not sure that anyone has ever worked out what happened.

Last week a paper described a type of galaxy known as an ultra diffuse galaxy. A number are known, but how they formed and evolved has got a lot of head scratching going on. I first saw this on Phlil Plait's blog, Bad Astronomy, the next day it had reached the Outside Source on the BBC news channel where an astrophysicist was trying to explain it . That blog is worth reading if you are interested in astronomy, cloud formations or anything else in the sky.

Mike Potts.

Thread: Unidentified Rule
25/02/2018 21:06:51

Hello James.

There are currently seven sector rules on ebay at a variety of prices, all fairly high, all similar to yours.

Wikipedia has a long explanation detailing the various scales on the rule. Further editing seems to be needed on most of the scales. The origin of the rule appears to have been Italy in the early seventeenth century. It allowed the user to perform a number of calculations, some stated, and others described as 'complex'.

Put 'sector scale' into google or whatever, and be prepared spend some time looking at the various items that come up, because it does not take long to become complicated and complex.

Regards. Mike.

Thread: Malware bytes anti virus
29/01/2018 10:36:17

I have the free Malwarebytes on both of our computers. From somewhere Immunet installed itself on one computer and some other anti virus program on the other. That started doing all sorts of unpredictable things, and the other computer started to run slowly. I asked our daughter to uninstall both programs, Hey Presto. Everything started to run correctly and quite a bit faster. Malwarebytes had an upgrade and it became a lot easier and quicker to use. Now it tells you when there is an update, and runs a scan very quickly.


Thread: Unknown Engine
25/12/2017 20:01:21

Hello Sam. The following has been written by my son, Edward, who recognised this engine inside a few seconds.

"You have the engine unit from a German toy steam engine, made between the late twenties and late thirties by Doll. Originally it would have sat on a tin base with a horizontal boiler. The reference number underneath is correct: model 365, size 1. They ranged from size 1 to size 4, which had a 6" flywheel and sat on a base 23" by 18".

There were two versions of the engine, one had a single piston valve and both cranks going round together like a Triumph parallel twin; the other (like yours) has two piston valves and quartered cranks. The Walschaerts valve gear isn't original, its unusually complicated for a modification to a toy."

Mike Potts.

Thread: Why Column gear shift
28/11/2017 09:34:41

Or ! Once on my Austin Metropolitan I managed to select two gears at once. Luckily I noticed and managed to deselect the original gear and start again.

Mike Potts

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