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Member postings for Max Tolerance

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

Thread: Anyone recognise this mains connector ?
29/07/2019 23:07:20

The plugs are still available and used widely in industrial heating applications. Typically on injection moulding machines and plastic blown film lines, but also on any item where things get hot. Try R.S. or google industrial heating element suppliers. They are normally two piece ceramic with the brass or plated socket pins sandwiched between the two halves and with a stainless or aluminium shell. Though some can be found made of a temperature resistant plastic/ fibrous material instead of the ceramic. They are available in male and female forms though the female is most common. I have found old versions of these made with imperial pins 1/4" but your furnace obviously has the metric pins. Normally silicone sheathed heat resistant cable is used with these plugs and in some cases glass coated high temperature wire. The silicone stuff is good for maybe 250 degrees C and the glass covered wire can easily stand 800 / 900 degrees C. Important if you accidentally drop some hot metal on it.

All the plugs I have seen are rated at 250 volts,

Thread: Workshop - indoors or outdoors
25/02/2019 22:19:38

Cellar every time. I have a large one under the entire house so there are a complete suite of rooms. Access from a wooden stair case at the end of the hall but also from outside since the garden is built at a lower level than the front of the house making one wall of the cellar an outside one. There are two external doors and a couple of windows in this wall, so I have been spoiled. I generously allowed my wife to have one room with a window as a wash room wink 2 and she said I could have the rest.face 1 I have a modest !!! workshop with millers,lathes, grinders, drills etc,etc. and three phase power. Benefits are most notable on those filthy winter nights with the rain and wind lashing outside. Just pop down the stairs into the cellar where it is warm (never below 60 F even in the coldest winter) dry, so I have no rust issues, and everything is hidden from the prying eyes of our fellow criminal elements.

How I got all this down there is another story.

Thread: Plastic Balls in Bearings?
24/02/2019 19:39:59

Plastic /acetal / polyamide Bearings have been used in engineering for at least the last thirty years to my knowledge. They are used in all sorts of consumer items including vacuum cleaners. Other users are washing machine manufacturers, computer printers, medical equipment, office machines, the car industry and probably a host of others too.

The advantages are cheapness, lightness and the ability to run without lubrication, they are also non rusting. There are companies who manufacture these in the same range of sizes as conventional bearings. Although they normally only cover the smaller sizes. They do not perform well in very highly stressed applications and of course for high temperature work. They can however run at very high speeds if used correctly.

The ceramic bearings mentioned in earlier postings are intended for extreme applications such as high temperature or where there are problems with lubrication etc. Typical uses are turbo chargers model jet engines etc. They are hideously expensive especially in larger sizes.

Thread: Model engineers - enlisted in war efforts?
02/01/2019 20:59:33

Many model engineers and home mechanics were encouraged to make parts in WW1 particularly shell bases. A local group would be set up usually with some worthy such as the local vicar in charge. He would send off for the blank bases, normally drop forged, and these would then be sent to each individual worker to be finished turned, threaded, etc. Then collected and posted back to the factory to be fitted to the shells.

As can be imagined many of these bases were no use. The problem was that without gauges and factory methods of Q.C. it was just hit and miss if they fitted or not. It should be remembered that the modern tolerances achievable with today's electrically driven lathes and cheap ( relatively) micrometers where not easy to obtain when many home lathes were treadle powered and calipers and a rule where as accurate as it got. Thread gauges in a home workshop were unheard of.

Some groups proudly produced many thousands of these and were congratulated by the dignitaries of the day for their patriotism and contribution to the war effort. But when you look at the countless millions of shells and other ordnance discharged during the war it must have been a drop in the ocean.

The real work was done on Herbert and Ward capstan lathes using "unskilled" female labour.

Thread: Unnecessary waste of paper
30/11/2018 18:53:54

When I bought my first house, an end terrace. It had an access path running past the side of the house to a housing estate situated behind the terrace. At some point probably in the mid twenties the local council had installed a street light on the path. However due to the narrow width they were unable to use a standard lamp post so it was fastened to the exterior of my house wall. They set up a payment as "rent" on the patch of wall at one shilling and sixpence (7.5 pence) per year. In the twenties this would have probably been enough for an evening in the pub but by the time I moved in it was not worth having. However every year I received a first class stamped envelope complete with a typed account letter and a hand written cheque to the value of 7.5 p signed by the borough treasurer, the accounts dept and the official who had raised the cheque in the first place. What this must have cost the local council I don't know but I would have settled for a small one off payment. I had one of the cheques in a frame in the hallway as a talking point for many years. I would have been embarrassed to present it to the bank.

Thread: 3 phase
21/10/2018 17:06:41

I had three phase fitted many years ago by the then Norweb local supplier. It is a long story but I was fortunate to have it done for free. One problem that I have found is that since the de-nationalisation of the supply industry it can be quite difficult to find a supplier who will support a three phase supply to a domestic property. Most of them now require meter readings via a website or app. However they only have a system for a single reading on the afore mentioned sites.

This leads to difficulties especially when contacting them over the phone. When you mention three meters they think your property is divided up into flats or that you have an ordinary meter, an off-peak meter, and can't count properly. Other problems can arise if one meter has a lower reading than the other ( normal on a mixed three phase / single phase supply) they then think you are doing something dodgy. It means for me that I am tied to one company who do seem to be able to cope. It also helps that I can work quite happily on three phase and fit my own wiring etc.

I have never had a problem running the domestic system alongside my three phase. Everything was done to sixteenth edition regs. originally and seventeenth edition later (not much difference in three phase) The main advantage of the three phase is the loading on a higher voltage is less than by using a VFC on a lower one. And it does depend on the number and types of machines you want to run. Some of my machines especially the specialist swiss types would be extremely difficult to convert or run on a VFC because of the integral multi pole motors used. Although I have fitted a three phase 415v Input inverter onto one of them for the speed control.

Thread: Taylor Hobson engraving spindle
17/11/2017 21:00:43

Not sure why you would want to strip one down but they are not really user repairable. The bottom bearing is made as part of the shaft with the inner ring machined as one with the central part and the outer ring as one with the belt pulley. Between the two is a complete compliment of steel balls with no cage. The bearings were greased using a special type. If the spindle is damaged i.e bent it is nearly impossible to do anything with it. If the balls are worn then you will find the inner and outer ring will also be damaged. If there are balls missing then these can be replaced but you will probably find the spindle runs eccentric especially at the higher speeds necessary for fine engraving. Finally the end float adjustment is obtained by careful tightening of the internal screwed parts of which there are a number.

Taylor Hobson used to offer a service repair but obviously this isn't available any more. However Pantograph services employ a number of ex Taylor Hobson people who should be able to help at a price. Unless you can be sure of the provenance of the parts offered on eBay there is a large risk of getting a dodgy unit and I personally would be wary of obtaining one from this route.

I don't think the spindle from a K type machine fits the D machine. But the A,C and D machines all take the same type.

Thread: Is a tool & cutter grinder worth having?
10/11/2017 20:47:02

Depends on whether you know how to use it. Does it have any tooling etc. and what state the bearing etc. are in.

If it is a tool room grinder like a J&S or similar it will be heavy and large. It may have air bearings (good clean air supply needed) or not(bearing wear problems)

With no tooling they are useless. The cost of buying and keeping a decent one will probably be more than you spend on new cutters of the standard type, end mills etc. in a decade.

However if you know how to use one it does give you the ability to make your own special tooling and sharpen pretty much anything. So it is horses for courses can you justify the cost for your workshop. Have you the knowledge, space and time to use one properly. Do you have a need to make or sharpen special tooling.

Only you can answer the above questions but if any are in the negative don't bother.

Thread: BA threads. Why the tpi?
22/10/2017 20:26:25

Before asking why the imperial system is so illogical it should be remembered where it came from. Originally before the nineteenth century standards as we know them did not exist. The English system of weights and measures were conceived to make trade etc. easy for a largely illiterate population. So each trade had its own system and each district or town had a local "standard" that could be used to check any suspicious weights or measures.

From the Roman mile (one thousand steps for soldiers on the march) to the sheep's fleece (7 pounds) the barrel, hogs head etc. all meant something to the people who used them. Some still remain with us even today Carat (used for gem stone measurement) Hand's used for horses height, Timber measures to show how much useful timber can be taken from a round log all these were devised to suit a specific purpose. The Acre used for land measure (the amount of land needed to produce a given quantity of crop) etc. etc.

Then engineers and philosophers started to look for a standard that could be used for their work and that is when things get interesting. In Britain Joseph Whitworth was responsible for the first truly scientific definition of the inch. He applied this to the threads that still bear his name. The thread angle and pitch was carefully chosen to suit the iron or steel materials available in his day. He did not have access to the high tensile steels we are used to.

The French were responsible for the metric system which was devised on a "scientific" principal involving one degree of arc of the earth at the latitude of Paris. This attempt which was somewhat better than previous systems but even this was not perfect. All that remains of this standard are the names. The current metre was defined by the International Standards Organisation and was applied through out the world, even the "metric" countries had to revise their systems to comply since they all had slight variations in their previous standards.

It may be interesting when talking of logic that the French also tried the decimal week consisting of ten days. It was not a success.

Curiously enough even the metric French still cling to their old measures for wine. Think Magnum, demi-john etc.

Thread: Why do we never have great documentaries in the Uk that go into detail
30/09/2017 22:40:11

A die hard refusal to accept any thing new like the metric system? I was taught the metric system whilst at school in the sixties. I have used it all trough my engineering career as have most if not all of my contemporaries. The BA screw system is metric based. I don't remember a single instance of any professional engineer refusing to use it.

Old issues of Model Engineer from before the first world war contain designs using metric dimensions. Many, many, questions have been asked about cutting metric threads with imperial lead screws in books ,magazines and engineering works all through the twentieth century. In locomotive works engines have been executed in metric dimensions. I.C engines, especially motor bikes have always had metric pistons and been expressed as so many c.c. from the very early twentieth century.

Much of this before the ISO standards were put in place. The main obstacle to the adoption of the metric system generally, came from the usual place......... POLITICIANS, not engineers.

30/09/2017 19:31:23

I can remember as a young lad in the late fifties early sixties going down to our local library in the evenings to watch films. I am talking real films here, shown on old fashioned projectors. These featured many old crafts and skills such as clog making, Coopering, Fitting steel tyres on wooden cart wheels etc. One in particular showed a huge stationary engine flywheel being cast. It included footage of the moulders preparing the mould, the molten metal being prepared and poured and finally the removal of the fly wheel from the sand. There was another showing ships propellers and one of a large naval gun being erected and tested.

I don't know where these films came from or who was responsible for their production or even why they were shown but I never missed a one. Looking back I must have had free admission because I certainly didn't have any money for tickets or anything. I often wonder where those films went. Maybe they will surface on the net one day.

Thread: 2040 deadline for Diesel and Petrol cars.
26/07/2017 21:27:03

Just for interest. Electric cars outnumbered I.C. cars at the end of the 19th century. Dime in the slot charging stations where installed in large American cities. The "experts" of the day laughed at the thought of I.C. engines ever being any good. Come the 1st WW Britain and France built thousands of I.C. engine wagons etc. Aircraft engines I.C again, developed at a tremendous rate, in Britain, France, Germany and Italy. Why?

In a Model Engineer editorial it was discussed that oil and coal where running out. Everyone would be driving electric cars within a few years. The power would come from small wind mills and a tidal barrier in the Bristol channel. Sound familiar? The date was December 1920.

The "experts" were wrong. Politicians lie for a living.

The biggest promoters of the electric car are the ones who will make the biggest profit from the tax payer subsidies.

Just a few reasons why I am sceptical.

Edited By Neil Wyatt on 27/07/2017 08:32:53

Thread: Milling machine motor bearing
25/06/2017 22:29:25

You don't state which end bearing you fitted. Normally on a motor the shaft end bearing if fixed and locked in place usually with an end cap, or on some cheaper versions a circlip. The other end of the armature is allowed end clearance to allow expansion in the armature shaft during running and is normally fitted with a wavy type spring washer.

If the front bearing housing has worn then you need to make a better repair than centre punched dots and lock tight especially given that the housing will likely be some type of die cast aluminium / zinc type metal. The best way is to bore out the housing true to the flange and fit a bush to give total support to the bearing outer ring. There are available ready made bearing shims made to suit popular sizes of metric bearings. These are made of steel and are a top hat section complete ring (not split or joined) normally about .25mm thick. maybe one of these would work for you. I don't know where they are sold but your local bearing supplier should be able to point you in the right direction.

Thread: Cutting a fine groove
25/06/2017 22:13:26

All hard hacksaw blades are still available from good tool suppliers. I never use anything else!

The modern bi-metal blades are widely sold and many people seem to think they are the only type in town. Even some sales reps. deny the existence of all hard blades.But if you persist and are willing to pay the extra then you can still get hold of them. As the previous poster mentioned they don't like bending and will shatter if not used correctly (hence the popularity of the bi-metal ones) Unfortunately many users have never been shown the correct way to use a hacksaw and would find it an expensive learning experience.

At work I can leave my hacksaw out on the bench and no-one will use it because they hate the blades snapping. .......BUT I am the only one who can cut a straight line and the younger lads think it is some kind of magic secret that only I know. They will confidently state that it is impossible to do this with a hacksaw even when I demonstrate that it isn't.

Another source of good HSS is machine hacksaw blades, the old fashioned reciprocating donkey type saws.Not the modern band type. These make excellent tools and because they are quite wide there is a lot more strength in them.

Thread: Farm sale
02/06/2017 21:58:39

It is as mentioned Herbert 2D capstan. One of the older models although they didn't change much over the years, mainly detail changes. The lathe would normally take 2047 collets and these are specific to the lathe you cannot use Ward collets or other similar types due to the included angle of the head and also slight differences in the diameter. It is possible to fit these machines with a new collet closer and nut so you can use Burnerd or Crawford multisize collets since the metric versions of the 2047 are quite rare (they do exist but many must have gone to the scrapper years ago) the imperial versions turn up occasionally on certain auction sites.

The main problem for anyone trying to fit one of these lathes in a home workshop is the motor. It is a hefty three phase unit designed for rough industrial use. they are almost indestructible and extremely heavy so the current drain on start up and reversing peaks at high levels. You can go from full speed forward to full speed reverse with a flick of a handle and the motor will do this all day as often as you like without complaint. Whether an inverter would stand the strain is debatable and I would imagine rewiring to delta would be very difficult and very expensive even if it could be done.

How do I know all this? Well I have one in use in my shop. I have a three phase supply which helps and I make numbers of parts on a fairly regular basis. However as per previous posts you need to understand how capstans operate and have the necessary specialist cutter holders, die boxes exc. to make the best use of it. Once set it can be operated by a complete novice and produce massive numbers of identical parts all day every day hence their popularity in the days when Britain made things. Now superseded by CNC these machines are a relic of our industrial past and many thousands of them must have gone to the great scrap yard in the sky since the sixties/seventies

Thread: How many have 3 phase in a DOMESTIC house
19/10/2016 20:05:44

I have a three phase supply fitted for "free" by the old NWEB. My house was built around the turn of the century (1901). In those days electricity was a new thing for houses and if a new house wanted to be connected to the mains as it was called then, they used the tram supply generated by the local authority. The only problem was that this was usually D.C. When the national grid was set up later then of course the supply changed to A.C. and voltages where standardised.

In my street when the national grid was connected they decided to use the original two core D.C. supply cables so one phase went down one side of the street and a different phase went down the other. Later a three phase cable was laid to supply the street lights, however they left the houses as they were. Around twenty years ago the supply cable to my house failed (after all it was approaching 100 years old) it was a lead and paper insulated cable and very light by modern standards. The electric board were very busy at the time so In exchange for me digging the trench across my front lawn they kindly agreed to fit three phase power for "free". Happy days!

I only pay one standing charge and standard tariff, the only down side is finding a supply company who will accept three meter readings instead of one since most of them unbelievably can't cope with it for domestic customers. But if you want to fill your cellar with machinery you can't beat it.

Thread: What would you ban and why? (Definitely tearoom!)
21/08/2016 21:17:25

I would just ban the politicians and dodgy lawyers. Then there would be no-one left to ban anything.......................

Thread: The ID the collet game
03/06/2016 21:08:43

It is a Crawford multisize collet. it is complete as is since these didn't have the "leaves" that Bernard (and others) used.

If the correct collet chuck is with it then no problem it can be used, that particular one will hold between 1/4 and 3/8 as indicated. From the photo it is difficult to say which series of collets it is from since there were five different series, B going through to F the largest went up to 3 1/8 inches but the B series stopped at 1 1/8. All were available in light duty with plain bores (as sample) or heavy duty with serrated bores. They are not interchangeable with Bernard collets since they have a different included angle on the body and various other dimensional differences.

They do turn up occasionally on a certain auction site in round, hexagonal and square bores and I own a full set of all the "B" range however I seldom use them because I find the Bernard type to be superior for my applications and also because my Bernard set has a lever operated chuck rather than the scroll type which I find too slow for repetition work.

Thread: Springs??
30/04/2016 19:09:24

Try Lee springs (no connection) They have an excellent site with downloads that list springs in size order with a separate column showing loads/ length etc. really easy to pick what is wanted. each spring is classed with a group letter as well as a reference number. All springs in the same group cost the same so easy to work out costs as well.

Max

Thread: custom big tap needed
30/04/2016 19:02:28

Hello Douglas,

I should be able to manage this on my big Colchester. It can go as course as 6mm or 4 TPI. If the tap is for wood what sort of thread form is used? also what material would you be looking to make it from? i.e is it just a high grade steel or does it need heat treatment etc.

Regards Max

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