Cylinder Boring Techniques for Steam Engines

Will,

I’ve dealt with the following and found them all thoroughly respectable & reliable –usual disclaimers. Some of them are “obvious”; some of them may be a surprise. But as above, I’ve had good results with them all.

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Arc Eurotrade (small tools, lubricants, bearings, machines, etc) – when you put a Swiss address into the shopping cart their website automatically knows that Switzerland = nil VAT

**LINK**

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For all the rest of the following it is as well to remind them that Switzerland is NOT in the EU, therefore Nil VAT.

BTW, when the goods arrive home, I’ve found it’s entirely “the luck of the draw&rdquo as to whether or not you get charged Swiss import duty and MWsT (VAT). Sometimes it gets charged, sometimes not, I see no rhyme or reason for it.

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Allcap Ltd (large range of various fasteners)

**LINK**

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AtelierMB (steam castings & bits & pieces + a few small tools – as I’m not into steam I’ve not used them)

**LINK**

(website in D & E)

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Chronos Ltd (tools and general materials)

**LINK**

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GLR Ltd (tools and general materials)

**LINK**

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GW-Werkeuge (Germany, but good English - tools and some materials)

**LINK**

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Simply Bearings Ltd (as the name implies, bearings!)

**LINK**

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Little Machine Shop (USA – 100% tools and lathe & mill spares but website also has a link to a good metals supplier)

**LINK**

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(Clive Hartland has already given you “Marcels Machines” for S/H lathes & other machinery – mainly high-end)

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Model Fixings Ltd (small tools, nuts & bolts –BA, small Metric, etc, - small bearings, drills, taps & dies, etc)

**LINK**

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Noggin End Metals (mainly non-ferrous, CI, & eng plastics)

**LINK**

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The Tap & Die Company, London (as the name suggests!)

**LINK**

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and just down the road from me (about 1.5 hrs from Zug) there’s a decent live steam track with regular events. Website:

**LINK**

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The above should keep you going for a while. You’ll have to wait until I get back home (3 or 4 weeks yet, I’m overseas) then I’ll copy some other stuff I have and send it to you (your home address by post or E-mail).

I also have a few tips on getting metals locally – there’s a lot of industry in Zug and you shouldn’t have too many problems once you can "work the system".

Hope there’s something for you in the above.

All the best

AES

Neil, (Stub Mandrel)

Thanks for your comments, I realise this is a HUGE subject but your comments are very helpful, thanks. I'll have to wait a few weeks toget home to the shop before I can try anything but you can be sure I'll be back to you.

Cheers

AES

Hi Clive,

Did you bore the cylinders of your engine using an HSS boring bar or a boring bar with an indexable carbide or fixed carbide tip? Am I right in guessing that a normal boring bar would be fine for cylinders of this sise and that a between centres boring bar only becomes necessary for longer cylinders?

Will

Hello Will, I turned the cylinder up from bronze bar and as its a built up part with five parts I drilled through as a start and then fine bored the cylinder nearly to size..

I then made all the other parts to fit and then brazed up the assembly, I then made an expanding jig to fit in the lathe chuck and mounted the made up cylinder onto it so that I could machine the top and bottom of the cylinder assembly true.

Then I lapped out the bore with an adjustable lap made from a bar of PTFE, it all seems fine and the pistons fit well,

Further maching was then carried out for steam passages etc.

My boring tools are the insertable type and the holder is like a square split collet that fits in the tool post. These are available from Brutsch Reugger in Zurich. Perhaps you can get a catalogue from them. The boring tools are also available for internal screw cutting in 60 and 55 degree.

It is a versatile series of tools and are Cobalt grade.

Today I looked at a 3 bee hives and they are doing well, I found boxes with sealed combs of honey and the bees are flying well despite the rain and wind. I was thinking that the weather would stop the bees gathering any honey but they semed to have had a good week with the sunny weather last week.

Clive

Hi Clive,

Thank you very much again - am I right in understanding that you're very particular in choosing the best quality boring tools?

I had a look at the Brütsch Rüegger catalogue - are your tools from the Coromant series (sorry - I didn't see tools marked as Cobalt - maybe I'm misunderstanding)?

Very good to heat that you finished the bore with an indexable carbide tipped tool -

Have you ever built a Stirling engine? I remember the cryogenics engineer at Sheffield a Stirling Engine he had made at the end of his training and I was always in awe of how a gas-tight seal could be made with such low friction.

Great that the bees are doing well despite the volatile weather.

Will

Hello Will, I can take a photo of my Boring tool collection and post it for you to see. At the moment the draw they are in is hidden behind a pile of frames for the bees.

One thing I havent got is space ! These boring tyools have a round body and the toolholder is a square section with a sawn slit that is used to clamp the tool in the body and then in the tool post.

The tools themselves have different heads, straight, angled and screwcutting and come in different sizes from about 4mm to 12mm diameter. When you see the picture you will see what i mean.

Just had to remake 8 flanges as I had drilled the holes in the wrong place and they would not mate up and match the holes for bolting up, luckily in brass so it was quick.

Getting tales of woe from beekeeping friends as their hives founder due to the weather. Its all down to the weather really as the Queens cannot fly and mate, when they do they are of poor quality and the bees know this and want to supersede her but again because of the weather it all repeats itself. It never was like this years ago as the summers were summers and the bees never needed attention like they do now.

Re the Stirling engine, no, I never have made one though I think that they require a lot of careful work and dedication.

I much prefer the more solid engines like Steam and Locos, also IC engines.

Clive

Hi Clive,

That would be interresting to see a photo of your boring tool collection. I've seen the toolholders before but it would be very interresting to see the boring tools you use - there are a lot out there so knowing which are good would be a big help in chosing one.

Sorry to hear about the flanges. It gives the rest of us encouragement though knowing that even experts get things wrong sometimes so we're not alone when things don't go according to plan.

The same climatic changes seem to have messed things up for ice climbers and beekeepers alike.

I'd never understood that the mechanisms for supercedeing a queen were so sensitive.

Will

Hello again Will, I have uploaded some photos of my Boring Tools selection.

The trade name Is Ifanger.

They have an extensive expensive tool catalogue ! I have just looked through it and found the tools I have.

If you now look through your Brutsch Ruegger catalogue you will also find them in there.

Clive

Edited By Clive Hartland on 04/08/2012 22:41:43

Edited By Clive Hartland on 04/08/2012 22:41:57

Wow. I have to admit that I've never seen such a large collection of boring tools. I'd thougth that most folk just had a handful or two to cover different sises.

For the detachable head boring tools, what are the different heads for? I'm guessing there are heads for screw cutting, finishing, roughing and internal shoulders but I'm not sure.

I've found Ifanger - I think I missed them because they're "internal machining" not "boring". They list Internal machining ASB, ECS, DK, GWS, TRG, etc. but I'm not sure how to work out what those codes mean (some are clearly specialised but I'm not sure which are just simple boring and bore finishing).

Are they easy enough to sharpen?

Will

Hi Will, The Ifanger Boring tool system is in a size system from about 3mm upwards to a quite large set suitable for boring very large cylinders.

Sharpening is easy, touch up with a diamond stick or a light touch on a white wheel, they are very tough and are Cobalt tooling and last a long time .

The head shapes are specific for 60Deg and 55Deg, with angle heavy duty and corner types. There is a set for cutting internal Cannelures.

i bought the cutters as certain types of work came up and the smaller ones were for a job doing Fibre Optic receptacles, a long complicated job that was.

The bigger ones I used on the Mill for boring bigger internal diameters rather than use the lathe as the job could stay on the rotary table.

Clive

Hi Clive,

It's good that Cobalt actually refers to the composition of the steel in this case.

Thanks for your advice about sharpening - am I right in thinking that tools like this should never be allowed anywhere near the dark grey carborundum grinding wheels used to shape HSS tools? Are white grinding wheels always a finer grain?

When you say 'diamond stick' what should I look for in buying one? I've a set of diamond stones but the manufacturer didn't specify the grain and they don't seem to hone to a very fine finish.

The fiberoptic job sounds difficult - small and fine alignment!

I was having a look at some of the suppliers AES had mentioned and trying to work out where to get materials to make the piston and valve spools. Looking through the 40 page catalogue of one at the moment - wish they'd state composition as well as code numbers for the steels.

Will

Will, Arc Eurotrade do diamond stones, a set of 4 at £12.60 . these are what I use. They are on a plastic handle and weigh nothing, so post will be cheap.

I use both types of grinding wheel, it all depends where I am at the time I need to sharpen tools as I work in two different places.

materiel, I would ask for S/steel in 304 grade for the spool and a bit of bronze for the piston if its used in a Cast iron cylinder. If its a Bronze cylinder then a bit of S/steel will do. As long as they are different no problem. You only need small quantities, unless you want to hold stock for other jobs. Remember to order enough to hold in the lathe so that you can get the job out of it !

Aluminium bronze is much harder than ordinary bronze so avoid it. Leaded bronze is good.

The bees were flying well today and I have another sale for a Nucleus as the chaps hives have all lost their Queens. I may visit to have a look myself to make sure. This chap is always in the hives and I think it upsets the bees.

I may take some honey next week, i hope the weather holds out, it was 23C at 3pm today.

Clive

Hi Clive,

Good to hear that the bees are doing well with the better weather.

We have wonderful creatures in France and Switzerland that oscillate their wings like a bees but look more like a giant moth. They don't land on flowers but hover in front of them to suck the nectar out - like a miniature humming bird. Probably very different from bees in their lifecycle but amazingly beautiful so I thought they merited a mention. Wish they lived in Scotland.

I hate paperwork so I'll try to get enough stock that I don't have to order again soon. I'm also expecting to have to make two or three attempts at many of the components (more for some) as I refine design and technique. Then there's the next engine to think about...

The diamond stones will go on my first order to Arc Eurotrade

One odd question came into my mind. How close should the piston come to the end of the cylinder? Trying to work it out from first principles I reckoned that the piston should come as close as possible to the ends of the cylinder but many designs seem to leave a fairly large clearance.

How should I work out the sise of flywheel to use? I vaguely remember the calculus to work out the moment of inertia of a a flywheel but I've no idea how to relate this to a steam engine so I thought I'd guess the sise of flywheel based on roughly the the relative sises of flywheels and cylinders used in horizontal mill engines.

Will

Hello Will, Your hovering Moth is a 'Hawk Moth' which mimics a humming bird, we get them here as well.

This evening I transferred the bees into a travel box for delivery on Sun. morning. I will go down tomorrow night at dusk and close the entrance and bring the up home and they go first thing in the morning.

I think most flywheels I have seen on models seem to be relatively heavy, they must add inertia to the motion. Working out what size and weight I have no idea. If it looks right it will work !

As most steam engines have the cylinder head flush with the head of the bore some relief is needed to clear the steam inlet ports. On the little 2 Cyl. model the cylinder head goes into the bore about 1mm as the inlet port is machined in the cyl. head, but on the Evening Star the piston stops about 3 or 4mm short of the end of the cylinder. This to keep the steam inlets clear which are drilled through the sides of the cylinder at an angle. It all depends on the design and method of steam transfer used.

I suggest that you draw it up and use cardboard shapes of the components in the flat with fulcrums pinned down and see what happens as you turn the parts. It will give you a good idea if your design is feasable.

Clive

Edited By Clive Hartland on 10/08/2012 22:08:03

Sorry - nothing to do with cylinders but, seeing your discourse on the Humming Bird Hawk Moth, I thought you might like this pic of an Elephant Hawk Moth which visited the other day.

Norman

Edited By NJH on 10/08/2012 23:01:53

Hi Clive and NJH,

Thanks for the information about and photo of the hawk Moth - it must be too cold for them in the Northern half of Scotland. Did some background reading and interesting that some types of hawk moth pollinate orchids - interesting that such a beautiful pollinator works with such beautiful plants. (I've a collection of less specialised orchids - just simple Phalenopsis but still beautiful.)

Hope the Bees' move goes well.

I was thinking about bringing the steam in via the cylinder heads so that clearance coul.d be minimised - I was trying to work out how it would affect performance - theoretically I think it should give an improvement.

Cardboard prototype is probably a good idea to make sure that everything fits together.

Will

Michael, Thanks for clarifyng some of the 'Dark details' of the steam engine. As you say a lot of designs just follow successful previous designs and whether they work well is another thing altogether.

Normal saturated steam and super heated steam, does cladding help in the first instance? I would assume that the less thermal transfer the better.

The reason I ask is that the boiler on my Evening Star is shown as bare and with no cladding, which is the best way to deal with this?

Clive

Hi Michael and Clive,

Thank you very much for such a detailed explanation. I think Corliss would definitely have agreed with you - he tried to keep the volume between valve and cylinder to a minimum. (He also had separate passageways for incoming and outgoing steam to minimise heat transfer from hot incoming to cooler outgoing steam). I think André Chapelon also put emphasis on the design of the steam passages.

Lentz certainly seemed to feel that cladding the cylinder was important - photographs of Lentz Paxman engines show thick insulation round the cylinder

**LINK**

Will

Hi Clive (any anyone else who's watching this thread),

Here's my first attempt to specify what metals to use for the bore, piston, etc. I'm probably wrong in several places so please correct me:

Metals bought locally from www.ateliermb.com to avoid high shipping costs from the UK.

First I need to rebuild the mangled-remains-of-a-Suart-S50 I bought on Ebay - a new piston will be needed so I'll try this brass

Messingrundstangen Ms 58 Bohr- und Drehqualität, Festigkeit: F45 - 50, sehr gut zerpanbar
Which I think means:
Brass Ms 58 Drilling and machining quality, strength: F45 - 50, very good machining properties

(I'm guessing that it's right to use brass rather than bronze in a cast iron bore? The oroginal Stuart parts list said brass.)

I'll make a new eccentric strap from the same stock (going to have to hunt for a tap for the BA threads Stewart use).

All the gaskets and gland packing mentioned in the Stuart parts list are missing - I'll phone Stuart and ask for replacements. (The poor engine is in a terrible mess - it looks like an encyclopaedia of bad machine technique.)

The eccentric like it may have to be re-made - for this and for the valve spools of my own engine a steel with good machining properties - I think I've 3 choices:

Edelstahlrundstangen 1.4305 Blankgezogen, Automatenqualität, Festigkeit: 60, gut zerspanbar
1.4305 stainless steel round bars Drawn Blank, machine quality, strength: 60, good machinability

Stahlrundstangen 9SMn 28 K Blankgezogen, Automatenstahl, (teilweise auch 9SMnPb 28K), sehr gut zerspanbar
Steel rods 9SMn 28 K Drawn Blank, mild steel, (partially 9SMnPb 28K), very good machining properties

Stahlrundstangen St 37k Blankgezogen, Festigkeit: F40 - 45, gut zerspanbar, gut schweißbar
Steel rods St 37k Drawn Blank, strength: F40 - 45, good machinability, good weldability

Which one should I go for? The second one would maybe make my life easiest (a nice free-cutting leaded steel) but first might give best corrosion resistance.

Now for my own engine:

For the piston:

Graugußrundstangen GG 25 Gußeisen mit Lamellengraphit, geschält
Cast iron rods GG 25 cast iron with lamellar graphite, peeled

Sphärogußrundstangen GGG 60 Stranggegosen, Gußeisen mit Kugelgraphit
GGG 60 ductile iron rods contunuously case, ductile iron

Not sure which of the above I should use.

Cylinder: Random lump of scrap brass supplied by a friend.

For the base plate a cast iron cooking plate from scrap catering equipment - hacked into shape with a circular saw then milling machine to tidy the edges.

Flywheel: bought as casting.

All other parts from the metals listed above if precision is required, otherwise from random scrap.

Can you suggest flexible piping that's safe for use with steam while I experiment with different valve designs, etc.?
(I want to experiment a little with rotating valves (similar to Corliss valves) and piston valves before deciding what type of valve to use.)

Will

Hi Clive and Michael,

I rattled through some equations and the result came out that the smaller a boiler is, the more important it is to insulate it. I'll try to post them on here so that you can check for errors in my working (not sure the best way to typeset equations in HTML). Lentz put a lot of insulation round the cylinders of his engines but I know nothing about boilers so I'm only guessing that they would have been well insulated as well. The heat loss from an uninsulated metal vessel filled with water is substantial - great for domestic central heating systems but a problem when trying to keep metal vessels filled with water or steam hot (I found this out the hard way on dairy equipment but a little insulation made an enormous difference).

What did you think of the choices I had to make re. what stock to buy to repair the Stuart S50 and build my own engine? I'm particularly confused by the different sorts of cast iron.