machines which I have made, am making, or intend to make, and some other stuff. If you find this site interesting, please leave a comment.


More Scale Stuff


There is the 1464 Turkish bombard (black), 17 tons, 307kg granite ball;  the 1779 long naval gun off USS Constitution or HMS Victory 24lb balls; and a 24lb carronade.  All 1:10 scale.  Interesting to see them together on my kitchen table?

Model Ottoman Bombard – Painting

I would have preferred that the title of this blog was “Finishing the Ottoman Bombard”, but I am still waiting for the vectors of the barrel mouth decorations and Arabic (?) writing, and the touch hole.

But I have at least painted the bombard, and the pictures follow.  You will notice that I have not attempted to reproduce the bronze or copper colours of the orginal in Fort Nelson.  Partly because I doubted my ability to make painting such variegated patterns realistic, and partly because the cannon would not have looked like that in its heyday of 1464.  It would probably have been either black, like most SBML cannons (smooth bore muzzle loading), or possibly gaudy golds and reds and blues like other medieval items.  So I painted it black.  I like it.  If I get evidence that it should be more colourful I can change it later.


First coat – Primer.  Hmmm… interesting colour.


Next coat – matt black brushed on, to fill the hairline wood cracks.  Incidentally, the (dirty) parquetry floor is also made from the red gum house stumps from which the cannon is made.


final two coats –  matt black, from a spray can. 


So there it is, finished except for the barrel mouth engraving, and the touch hole.  Now what to do with it…   SWMBO says it might be useful as an umbrella stand.


The breech.  25mm diameter explosion chamber.  1:10 scale


The barrel, 63mm bore.


Assembled.  The model is 520mm long.


It does need some decoration


Ottoman Bombard Photo to Vector

Bombard mouth.jpg

This is the low res photo from Fort Nelson.  High res photo on its way.

In the meantime, I have contracted with a US firm to convert the picture to vectors.  More $US.  ($US50 to be exact).

I am not sure that this is going to work.  But I will report to you.

I do wonder what that the Arabic/Turkish writing means.  Does anyone know?  I am pretty sure  that it is not complimentary to Christians/Westerners/Non Muslims.  Maybe it is just an instruction not to look before the touch hole is touched.  Or “do not stand here”.

PS.  Note added 17 Oct 2016.    The translation is   “Help O God the Sultan Mehmet Khan son of Murad.  The work of Munir Ali in the month of Rejeb.  In the year 868.”

868 = 1464 ce.



Does anyone have a decent photograph of the writing on the muzzle?

I have repeatedly hunted through every picture which I can find on the net, but they are either taken at an angle, or too poor quality to be useable.

Does anyone have a photograph which I could beg buy or borrow?

I also need a photo of the touch hole.

I have contacted the Fort Nelson Armoury Museum, but not too surprisingly there was no response.

Is there someone in the Portsmouth UK area who could pop in and take some pics for me?

POSTSCRIPT:  October 5.   I have had 2 excellent and positive responses to my appeal.

First, reader Richard sent me a connection to a Turkish Dr/Professor, who has made a 1:25 model of the bombard using 3D printing.  (at least that is how I think he has done it.  My Turkish is non existent).  I am following this lead.

Secondly I have had a response from Fort Nelson Armoury, with a good photo of the barrel mouth, and a high res photo on the way, after payment of a significant, but not unreasonable fee.  Isn’t the Internet wonderful!!


TURKISH BOMBARD – the real thing

I have found this video to be particularly useful in my modelling of the Ottoman bombard. The subject of this video is the gun that the Turkish sultan gifted to Queen Victoria when the Brits and the Turks were allies.  It might be one of the guns which fired on the British fleet in 1807, when it (the gun) was 343 years old!

Notice the colour.  It is aged bronze.  I am thinking about how to reproduce that colour on my model.


Length of the assembled gun 5.2m (17′)

Bore 635mm

Breech weight 8942kg

Barrel weight 8128kg

Average weight of shot 307kg

the model is at a scale of 1:10.  photos soon.  being painted.


Modelling A Turkish Bombard- The Pins


There are 16 pins at each end of each section of the cannon.

These were certainly used as leverage points, for very strong men with large levers to rotate the 8-9  tonne segments against each other to engage and tighten the screw.

I cannot see how the pins would have been cast with the breech and barrel.  For my model I decided to make separate pins and fit them into the gap between the big rings, then insert a grub screw through both rings and the pin.  The holes are then filled.

I wonder if a similar method was used in 1464.  I would love to have a close look at the original cannon to figure this out.  From the photographs, I can see no evidence of later insertion of pins, but neither can I see how it would have been done any other way.


Drilling the holes for the grub screws


In order to continue with red gum, I made my own pins.  This is the setup.  The blank is held approximately centre in a 4 jaw….


…and the pins are turned, centre drilled, drilled, cut to length,  and tapped M4.  64 altogether.


The M4 x 25mm grubscrew is screwed into the pin.  The wood join is super glued.  Also, I am attempting to patch the worst of the thread tearouts.


Using a battery screwdriver to insert the grub screws.  The pins protrude above the ring surface for a reason..



Sanding the pins flush with the rings.  Check the photo of the original 1464 model.  There is also some wood filler in other splits.  Not surprising after holding up a house for 70 years.

The holes are now filled with wood filler, and will be sanded flush.  They should be invisible after painting.

Next the painting, the stands, and some cannon balls.  How to reproduce that aged copper colour…


Modelling a Turkish Bombard -4 Decoration

The decoration around the barrel is formed by a repeating pattern, which when milled, very cleverly forms 2 identical patterns.  One is excavated and one is the original barrel surface.  You will see what I mean if you look at the pictures in the earlier blog, and the video below.

It took me an evening of experimenting on the computer to work out the system and draw it.


Then I measured the diameters of the 2 gun components, calculated the circumference, (OK it is not rocket science.   3.142 times diameter), then working out the number of identical shapes which would fit around the 2 different diameters, at the same size and spacing.   Amazingly, it took 18 shapes to fit almost exactly around the barrel, and 16 of identical size almost exactly around the breech.  the angular spacing was 20 degrees and 22.5 degrees.

Then the shape was imported into V-Carve Pro, and G codes were generated.

My CNC mill does not have a 4th axis, so I used a dividing head to move the workpiece at the precise angles.  See the setup in the video.  That meant that the pattern was engraved into 16 and 18 flat surfaces, rather than a continuous cylinder as on the original.

It worked very well.  There were minor compromises due to the shapes being milled with a fine end mill but when you look at the pics I hope that you will agree that it is effective.

I calculated that the milling had to be at a maximum depth of 2mm in order to cope with the curvature, but if I do it again,  I would reduce the depth by 25%.

The first part of the video is a shot of CNC drilling.  Then the CNC routing of the repeating patterns.  Each angular setting of the pattern took 4 minutes to complete.  136 minutes altogether.  In reality, it took a whole day, most of which was spent doing the setups.



Bombard Model-3 turning the barrel

Another session or two, and this project is complete.

Now how do I make a cannon ball 62-63 mm diameter?  In wood will be ok?  Does not have to be granite.  I could make a mould and cast it in aluminium or lead, but stone would be authentic…..   thinking.

ps.  Re cannon balls.  I will cast them, in cement!   Now, how to make a mould.

Bombard Model -2. Big Thread

The breech and the barrel are joined with a very large thread.  On my 1:10 scale model it is 60mm diameter, and has a pitch of 6 mm.  These dimensions are measured off Internet photos of the original bombard, so they might not be faithfully accurate to the original bombard.  If anyone has accurate plans of the bombard I would be very interested to hear from them.

I experimented with various spindle speeds, feed rates, depth of cut, and finally decided that red gum wood is not the ideal material to be cutting a thread with sharp points.  However, at 200rpm, and taking 50 cuts to reach the full depth, and using a very sharp tool, the end result was OK.  I will fill the tearouts.

In order to make a functional join in the wooden cannon, I truncated the apex of the thread.  In the gunmetal version I will attempt a more faithful to the original, sharp look.

For some reason, the wood held together better during the internal thread cutting than the external.


The male thread was cut on my newly CNC converted lathe,  between centres, but the fixed steady on that lathe was just too small to hold the barrel, so the internal thread was cut on my bigger Chinese lathe.

Next I will bore the barrel to 63mm, then turn the exterior of the barrel.


Bombard Model. Turning the Breech


So if you watched the video, you can see that I have a problem with the big thread between the breech and the barrel, at least in the wooden prototype.  It might work better in brass or gunmetal.

The thread has a pitch of 6mm and a diameter of 60mm.   It is big.

My plan at this time, is to make a brass male threaded section, and glue or screw it into the breech.  Then to make a steel tap using the same G code, and cut a thread into the wood of the barrel.  (p.s.  note 30 Sep…  I continued to experiment with feeds, speeds, and cutter shapes in the wood.  The final result was OK so I did not make  metal threads.  That will have to wait until I do this project entirely in gunmetal or brass…  maybe never)

Turkish Bombard 1:10 scale

Just for fun I will use my newly converted CNC lathe to make a 1:10 bombard.  The original was cast in 1464 and was thought to be a close copy of the bombards which Mehmet 2 (“the conqueror”) used to breach the walls of Constantinople in 1453.  There are several of these bombards still in existence, including one in UK, which was given to Queen Victoria by the then Turkish Sultan.

These bombards were last used, against the British, in 1807, when a British warship was holed with substantial loss of life.  Pretty amazing for a 340 year old weapon.


5.2 meters long, 1.060 meter diameter. 16.8 tonnes.


The large thread connected the halves.  Easier transportation, and casting.



Is this Turkish or Arabic?


Granite balls are 630mm diameter.



A reconstruction of the walls of Constantinople, with moat.  Almost 1000 years old in 1453  


And as they are today.  Massive.  High.


Huge siege cannon used in the final assault and fall of Constantinople in 1453. Diorama in Askeri Museum, Istanbul, Turkey.  The bombards were probably dug in, to manage the massive recoil, and concentrate the aim at a particular wall section.  There is a wooden structure built around the cannon in the background of this modern picture.  As far as I know there are no surviving  wooden structures like this.  Nor have I come across any old pictures, but if anyone knows of any I would be very interested.  The bombards took about 3 hours to cool, cleanout and reload.  


My model will be about 520mm long.  I would like to make it from bronze, or gunmetal as in the original.  Any mistakes will be costly.

So I have decided to make a prototype in wood.  That will test my drawing, the machining procedure, and the final appearance.  Not to mention how the CNC lathe will handle the task.

I will use a very dense, tight grained Australian hardwood (red gum).  The wood was salvaged when my house stumps were replaced with concrete.  Some was used to make parquetry, and the rest was put aside for possible future use.  Such as this.


About to cut off the below ground section of a 70 year old house stump.


A 5hp metal lathe with a tungsten bit chomps through the hard dry wood.


I turned 6 lengths before I found 2 that were satisfactory.  The rest had sap holes or splits.

I have used Ezilathe to generate the G codes.

to be continued….


CNC Lathe Conversion- final

Before I am hung, drawn and quartered, for operating a lathe without guards, here is the proof that I have been sensible.


Guard over the X axis pulleys.  I like to watch the wheels going round and round, hence the transparent top.   Also note the cover over the exposed ball screw.


Cover over the Z axis pulleys and belt, again transparent.  If I wore a watch it would be transparent.


I also installed an ER40 collet chuck.   I will be using this for all work with diameters under 26mm.

A Matter of Scale

Before I get onto a brief reflection about scale, the photo below shows 2 cannon barrels.

The big one was what impelled me to converting a manual lathe into a CNC lathe.  That time consuming, costly, and ultimately very satisfying project, started because the CNC lathe which I used to turn the big barrel could only handle the job by doing it in two stages…. doing the breech first then the muzzle.  That was due to the big barrel being too long for the lathe, at 300mm (12″).

The small barrel was a test for the CNC converted lathe just finished, being the first complicated shape which I have made.   To save on material, I made it at exactly half the scale of the big one, ie 150mm long (6″).


Comparing the two barrels reminded me, that if an object is twice as big as another, in all 3 dimensions (height, width, depth), it is 8 times as heavy.   And any projectile, and weight of black powder, would also be 8 times the weight.  But the wall thickness of the explosion chamber is only TWICE as thick.

My point is, that if scale is maintained, the smaller the cannon, steam engine, boiler, whatever…..  the less likely it is to explode.

Not that these cannons will ever be fired.  Just hypothetically.

CNC Lathe Conversion – 17

First Test Run

After some test runs without tool or material, I performed some measurements.

500mm movements along the Z axis were reproduced multiple times with a deviation of 0.00mm!  (the Z axis has a ground ball screw)

100mm movements along the X axis deviated 0.02mm.  (the X axis has a rolled ball screw).

I was delighted to note that the lathe is extremely quiet and smooth.  The only noise is some belt slap from the very old belts, and from the stepper motors.

The video below was taken from my iphone, while I was operating the lathe controls, so please excuse the erratic movements.

The steel is 27mm diameter.  750rpm, 50mm/min feeds.

And the guards will be made next step, without fail.

The G code was generated using Mach3 for these very simple shapes.  For more complex items I use Ezilathe.


The lathe is 600mm between centres.  38mm spindle bore.  Swing about 300mm.

Steam Engine Oilers

Knowing that I have an interest in CNC machining, Tom, from the Vintage Machinery Club in Geelong asked me to make a pair of oilers for a very old Wedlake and Dendy steam engine.  The engine is a large (to me anyway) stationary engine, which is run on steam several times each year.  The oilers for the cross slides were missing.

We searched the Internet for pictures of W&D steam engines, but could find no pictures or diagrams of the oilers.  So Tom sketched a design, and I drew a CAD diagram.  The dimensions were finally determined by the materials which I had available…  some 1.5″ brass rod and some 1.5″ copper tube.

This is the almost finished product.


Just needs 1/4″ BSPT fittings and and oil wick tube so they can be fitted to the engine.


The copper tube silver soldered to the brass cylinders (top), the brass blanks for the lids (bottom) and the mandrel to hold the assembly (bottom centre) during CNC turning and drilling.


The mandrel to hold the body (left) and the mandrel for the lid (right).  The cap screw head and hole in the mandrel have a 2 degree taper.  The slits were cut with a 1mm thick friction blade.


Rough turning the base.


Turning the lid.  The mandrel is held in an ER32 collet chuck


Engraving the lid.  Using a mister for cooling and lubrication.  16000rpm, 200mm/min, 90 degree TC engraving cutter.


The oilers work by wicking the oil from the reservoir into a tube which drains through the base onto the engine slide.  When the wick tubes are fitted the oilers can be fitted to the engine.


The 1865 Wedlake and Dendy



My lathe is a Boxford TCL125, using Mach3.  The G code is generated using Ezilathe.

Below is a link to an oil cup from “USS Monitor”, of American civil war fame.   One of the first ironclads, powered only by steam.

(ps. The  lathe which I was converting to CNC was the subject of previous posts and is now working, but needs some guards fitted and a bit of fine tuning.)

OK, so guess the purpose


A pair of sheet metal pliers, to which I welded a steel tab.   Why?

For the answer click on the link.

For some reason the auto link is not working.  You will have to type the link manually.

Later update…   I dont get this.  Even the manually typed link to the explanation does not appear.

OK.   The explanation is that these sheet metal pliers have been converted into canvas stretching pliers for my daughter who likes to make her own canvases for oil painting.  Youtube sucks sometimes.

Try searching “Thomas Baker’s canvas stretching tutorial” to see how the pliers are used.








This mechanism was discovered in 1901, in a Roman era shipwreck, off the Greek island of Antikythera, which is a bit north of Crete.

It has been dated to between 100BCE and 205BCE, with the older date considered the best estimate.  ie, about 2200 years old.  Experts believe that its makers were Greek.

It is currently housed in the Greek National Archeological Museum in Athens.


Not much at first glance, but when it was examined with modern scanning and X ray techniques…

Look it up on Wikipedia..

According to the Wikipedia entry the gear teeth are too irregular to have been machine cut,

but watch the computer reconstruction.   Could you make this machine without a lathe and gear cutters?

How much more technology did the ancients have that has not survived the ravages of time?   A lathe for example.


I recently had a light globe switched on in my brain.

I was holidaying in Athens (the one in Greece), and was gobsmacked by the huge, fabulous collection of statues, mosaics, ceramics, gold jewellery and masks, bronze and iron weapons in the National Archeological Museum.   I took many photos, and might post some in later blogs.

Three items sent shivers down my spine.

  1. The gold death mask of Agamemnon (probably not Agamemnon’s but that is another story).
  2. The Antikythera machine.   More about that in a future post.
  3. A gynaecological speculum.

There was a display with many surgical instruments.  These have been found at various archeological digs in Greece, and while not precisely dated (at least not labelled) they are mostly from 500-200 BCE.

My eye was immediately drawn to an instrument which looked very familiar.  I was a gynaecologist in my previous life, and this could have come from my instruments. (except that the dark bronze surface might not have been acceptable to patients).


Not a great photo, through a glass cover, and ISO cranked up to several thousand.

The instrument is labelled a vaginal dilator, but I am quite certain that it is a vaginal speculum.  A speculum is used to inspect the vaginal walls and uterine cervix.  (That might be too much information my metal working/ engine making/ machinery minded readers.  If so, too bad.)

It is said to be made of bronze.  The Ancient Greeks were highly skilled at metal casting, as evidenced by the many complex and beautiful bronze statues and weapons and implements on display.

It interested me for several reasons.  Bear in mind that not many archeology museum visitors are gynaecologists who know about making threads in metal.

It looks quite functional, and if cleaned up, given a shiny surface and sterilized it could be used today.

The threaded section is very regular and smooth.  I would loved to have taken some measurements of the thread with a micrometer, but had to be content with a prolonged inspection through the glass case.  The thread appears to me to be so regular, that it could not have been hand filed.  It must have been machine made.  I have seen hand made threads on medieval machines, and they are crude compared with this one.

Either this is not an ancient Greek instrument but a more modern instrument accidentally included in the display (pretty unlikely, considering the professionalism of the people involved).  (ps.  If you Google Pompeii speculum, you will see that similar instruments have been unearthed at Pompeii…  buried since 79ce.)

Or…..  the ancient Greeks had screw cutting lathes.

Ridiculous you say?

Wait until my next post about the Antikythera machine.  If if you just cannot wait, look it up.   It is mind blowing.



CNC Lathe conversion -16

The wiring of the lathe is complete.  (Except for limit switches.  They can be added at any time).

Mach 3 is configured.  The wireless hand control is installed and working.  Ezilathe installed and waiting for input.

Some covers to be made.


Hook ups in progress.  That’s the faulty VSD on top of the electronics enclosure.  The CNC engineer lost his hair trying to figure out the problem.

Still some testing and fine tuning required.

But nothing much will happen in the workshop for the next  3 weeks.