Member postings for Richard Parsons

Hi there

Back to freeing the chuck. Try this it is an old trick and may work. Turn up a short-ish punch so that it is a nice sliding fit into the drawbar hole then fill the drawbar hole with grease or thick oil. Insert the punch and administer a sharp ratta-pan with a good copper mallet. Trying to knock the thing out with w steel bar can swell theens of the MT and cause more problems.

Hope it works

Hi there

What are the threads? On UK gear they would have been Whitworth, British Standard Fine and some BAs in the motor.

If it is British it could be a Perfecto. I have a copy of ME from 1947 showing an advert for something very similar.

Hi Keith

Thanks for the prompt reply.  Yes I am ‘next door’.  I live on the Southern great planes in ‘Mesopotamia’ the land between the rivers (Duna –Danube- and lace w:st="on">Tiszalace>).  There is some sort of a problem with copying the word ‘lace w:st="on">Hungarylace>’ so I will call the place Magyarország instead and see if that works.  3 years ago some gents from ‘somewhere East of Suez’ turned up with suitcases full of cash. If there is something no Hungarian can resist is a suitcases full of cash.  The cleared out all the stockholders, autosbonotok, junk yards and swept the place clean.  Now all you can get is ‘structural steel’.  Copper is impossible because the ‘local didcoys’ keep, ‘liberating’ the overhead conductors from the railways (and from unfinished power lines).  It seems to be a little habit of theirs.

As for Phosphor bronze I have some kilos of it –I brought some 780 kg of mixed metals from the lace w:st="on">U.K.lace> including 50 odd kg of assorted silver steel.

How to tell PB from brass or Gunmetal.  Brass always turns with a fine swaff, it stays yellow.  Gunmetal turns –with a sharp tool- giving fine spirals and PB in little lunate shape chips.  I am going to try put up some photos if I can.

PB is or was usually cast as a bar and has a rough irregular surface.  After a day or so freshly turned PB takes on a reddish tinge (or my bits do).  By the way does the stuff feel greasy and have a tendency to go green? If so it might be ‘Glacier Metal’ and is wizard stuff for bearings.  PB can also feel slightly slippery and is generally harder than brass.  Hope this helps.

JasonB

Many thanks I do not think I will get galvanic action.  The boiler will have to be stainless steel if the local manufacturer is still in business.  I have not been over there since last winter and he may have ‘gone’.  I am also investigating something I saw when I opened a tin of tomatoes yesterday.

Best regards

Dick Parsons

Aluminium Cylinders.

Can any one help, point out problems I will have or offer useful comments?

I want to build a ME Minnie Traction Engine.  Because of chronic shortage of material over here in lace w:st="on">Hungarylace>, I will have to use aluminium, probably hard Dural as I have got a lump of it, for the cylinder block unit.  The cost of the bronze castings is quadrupled by postage etc.  All too often stuff does not arrive or take months.  I think this due to a shortage of ‘cleft sticks’.

I think this will work if I use solid PTFE pistons reinforced with alloy which will not touch the cylinder walls.

According to Corning Dow, PTFE softens at about 250 ºC and melts about 280ºC.

The cylinder on the Minnie is design with a steam jacket around the cylinder.  The cylinder block also acts as the steam collector from the boiler.  So the maximum temperature of the cylinder will be that of wet steam in the boiler.  Superheating with this sort of design is a non-starter.  According to my steam tables these temperatures will be: -

• At 50 PSI this is about 138 ºC,
• At 80 PSI it is 155 ºC,
• At 100 PSI it is about 164 ºC.

I expect to run the boiler at the design pressure of 50 PSI which has a temperature well under the softening point of PTFE.

The valve system will probably be PTFE piston valves again running in a Dural sleeve. 

The major problem is the sealing of the alloy cylinder and valve sleeve into the alloy block.  With bronze cylinder castings they are sweated in with soft solder.  The cylinder and valve guides will be bronze inserts etc.

I ride a little 50cc moped whose cylinders are some form of hard chromed ‘monkey metal’.  It has done well over 5,000 miles.

By the way Thanks to the editor I do not have to unpack and search some 40 black sack containing my copies of ME dating back to the mid-60s.

The original article was interesting in that it describes the experiences of an apprentice at BSA.  The basic production gun-drill consists of a drill face (usually a diamond shape) which has one or two small holes in it.  This is set into a hollow ‘V’ shaped tube.  The hollow part contains oil (under pressure – between 200 to over 1000 psi-).  The oil squirts out of the small holes and drives the swaff up the ‘V’ grove.  The rest of the system is an oil pump a ‘catcher’ which gathers up oil and swaff mixture, a separator to separate oil and swaff and recycles the oil. Nuff said.  You can do the job by using progressively longer series of drills and Peck drilling.  I use ‘pecks’ of the same length as the diameter of the drill.  Try drilling a 4” long 0.075” diameter hole down the barrel of a 1/10 scale musket. –Eek!

Your best bet is to do what Myford probably do, search the internet for a thick walled tube.  It is much easier and will cause you much less perspiration and cost.  The cost of a very long series drill is astronomic.  You can make them but that is another tale.

Hi Steve

You say “A mate suggested that the machine was not running fast enough but it is at the highest rpm that the belt system will allow”.  Therein lays the rub.  Long ago I learned a sort of rule which allows you to approximate the speed of a lathe/milling machine.  For mild steel it is speed = 288/D where D is the diameter in inches (or speed = 7315/D if your in millimetres).  If you are machining a bit of 1inch mild steel you should run at about 300 RPM or the nearest and perhaps lower speed your pulleys will give you.  For harder metals choose a slower speed.  If your tool is ‘singing or chattering’ then slow the spindle down.>>

Choose your tool shape with care. Much has been written about this almost any My Hobby store booklet on lathe work will tell you.  Make sure that your tool edge is sharp.  I ‘rub mine up on a cheapo diamond or an lace w:st="on">Indialace> stone.  I polish it on a bit of an old razor hone I scrounged from an old (h)air chopper who took off more for 1/3d than the others did for 2/-.  Set the tip of the tool at the correct centre height for the lathe.  Use a good gutting fluid and you should get a coconut every time if and over here it is a BIG IF your metal is truly homologous.  If you have to use some of the ‘Old Red Mans’ rubbish then good finishes are rare.  I always (when I can) leave the work piece over night to allow the surface stresses to come out.

Hope this helps.  If it is any comfort two weeks a co I was machining a chunk of 40mm (probably Bulgarian) steel down to make a 27mm pin for an old Hungarian tractor.  I had taken 15mm off and the work piece literally fell in half. Oink!

Good luck

Ian SC Many thanks I will try it.  If it works I will get a big iron, my 60 watt died years ago.

KWIL The problem is that Magnesium oxidises very quickly so it is never -to my knowledge- used as alone.  It can be only used when it is alloyed with something which prevents this -like zinc and aluminium-.

When you use Lumiweld you seem to create a lower melting point alloy than the mother metal.  You heat things up, dab on a bit of the filler rod and stir the molten blob with a stainless steel rod -heating all the time- gradually the melt pool spreads into the mother metal forming a union.  You add more filler as required.

An easy to make a counter bore is: ->>

1.     Turn a short piece of silver steel down a pin to the required clearing size (about 0.75” – 20mm long).  Round the ends to make it easier to insert>>

2.     Turn a length of silver steel –Drill rod- about 3” – 75mm down to a nice fit on the head of the screw.  Centre and drill the bar with the clearing size of the screw so that it fits the item you made in 1 above.>>

3.     Saw off the item and put in the vice in the vertical mill with hole end on your right.  This is important.>>

4.     Use a small end mill and set it so that the edge of the end mill will just graze the edge of the hole and set a stop or adjust the setting ring to Zero.  Make certain that the work piece is on your (front) side of the end mill.  You can either feed in to about 1/3^rd of the mills diameter.>>

5.     Loosen the vice, turn the bar ¼ turn – do it by eye and cut again.  Repeat the process to cut all 4 faces.>>

6.     With a small fine file (or stone) clean up and back off the faces and clean out the central hole,>>

7.     Harden and temper the new cutter.  Clean up with a fine stone.>>

8.   

No but I have a contact over here (in lace w:st="on">Hungarylace>) who can but that is no help.  I also have the remains of some rods I bought in the 70s at the M.E. exhibition at Wembley which allow you to ‘weld’ with a butane torch any thing which has a reasonably large aluminium content.  It is called ’Lumiweld’ (usual disclaimer) and I think you can still get it (try Google).  It works on MAZAK and die cast/pot metal.  It leaves a bit of a mess (I am not very good with it) so you have quite a lot of work to do cleaning up after.  The bloke demonstrating it was welding ‘Coke/Pepsi’ cans together.  Hope this helps.

Does any one know how to ‘soft solder’ or sweat Aluminium together.  Everything I have read says that you can do it but is as silent as a fish in water as to how.

The Editor MEWs

Hello there Dave.  Can you arrange that the CNC G-Code published in MEWS be also made available on the website in a form that could be loaded straight on to the MACH3 package.  It is a pain under the tail to try to copy them by hand.

MDF can be a bit ‘doggy’ because the main binder used is Urea Formaldehyde.  There was a lot about sealing things made of both MDF and hardboard from ‘Elfin Safety’.  It was something to do with escaping Formaldehyde vapour.  With the right sort of bugs (found in the soil) urea breaks down into CO2 and Ammonia.

The problem is how fast is this process?  I have a feeling that the ‘Elfin Safety’ bods may have gone ‘OTT’ (again)

I use pine my self it is all I can get over here.

A few years ago I came across a most useful formula to determine the speed to drill mill or turn. 

For mild steel

• If you are using Inches the formula is 288/D where ‘D’ is the diameter in Inches of the stock you are turning or the diameter of the cutter/drill for milling or drilling.
• If you are using metric the formula is 7315/D where ‘D’ is the diameter in Millimetres of the stock you are turning or the diameter of the cutter/drill for milling or drilling

It is useful guide and should be thought of as a base line.  If you are like me and do not have electronic speed control I pick the nearest speed available.  For harder materials I slow the old Myford/mill/drill down a one or available two speeds (pulleys)!

This thread is very interesting as it shows just how sophisticated model engineer’s workshops have become.  I started with a second hand Unimat SL (which I still have and use).  I made things on it like retracts for my lace w:st="on">R.C. Sealace> Fury.  Then the local council banned model aircraft.  I built a Yacht with  home brewed sail winches.  The local council drained the 12” deep boating pool – it was dangerous!.  Later on when it was well overgrown the junkies used to'shoot up' there and dump their old needles there. 

I then bought a Myford ML10.  I started work making a fire engine (plans by old LBSC -I still have the plans if My Hobby Store wants them-).  I did it the job the way he did using fly cutters, angle plates etc to machine flats.  Steam ways were drilled and files out.  The cylinder was bored on the cross slide with a between centres boring bar and so on.  No vertical slides they were too expensive.  It is surprising what you can do with a few cup square bolts a scrap of steel and a lathe tool mounted on the faceplate as a fly cutter.  You just have to think about it.  Then I built (and sold) Sir Morris de Cowley a nice little Pacific (I still have the plans same as above).

I do not what kit old LBSC had when he built Ayesia, I think it was a round bed Drummond and little else.  Actually the making side of Model Engineering is really a question of how can I make it with what I have got?.  Highly sophisticated machines make life easier but they can add complications.  Ask your self how can you machine the cylinder block of an H10 with your ‘mini lathe’ or what ever?  Look at the casting and the lathe and you might be surprised just what you can do.  It is all a question of thinking about it.  Remember if you cannot spin the work piece round you probably can spin the tool and hold the work piece still.  After all a circle/cylinder is only a very large number of ‘flats’

In Mr Diesel’s original engine the fuel was mixed with the air before it entered the cylinder.  These are found amongst the Compression Ignition types used in model aeroplanes.

The engines you are looking at are the ‘solid injection’ type where fuel is injected into the cylinder at or about full compression.  The real problems are the injector, and the injector pump which contains fuel dosing control to get the fuel correct for the load.

Unless you are using a ‘common rail’ engine with electronic control, which is very different and uses a single pump.  The injector has to stay shut until the fuel reaches a certain pressure when it opens squirts in its load and snaps shut.  It has a ‘dribble pipe’ which then opens to overcome the ‘water hammer effect’ and return the surplus oil to the feed side of the pump.

The injector pump which is controlled by the governor has a rotating cylinder liner. This has a triangular hole in one side.  As the governor decides that more oil is needed it rotates the cylinder exposing a larger opening to the output slot and allowing more oil to be injected.  You needed one pump per cylinder.  These could be either on the cylinder head driven by individual cams or as a block of pumps driven by the camshaft and supplying the injectors by pipes.

Greetings,

In winter my old (above ground) workshop had a temperature range when un-heated of -20 to +5 degrees C. A bit nippy! so I built an Omni fuel (burns anything) ‘Kandelo’ from an old 50 gallon oil drum.  A ‘Kandelo’ is a directly heated storage unit.  The important thing with it is a good flue which should never get above 70º C.  If it does it warns me and I close the dampers a little other wise I am wasting fuel!