HMS Unicorn by ianmajor - Corel - Scale 1:75, 1748 to 1771

[ianmajor]

Grant,

 

No problem. Actually the rivets made with the MK II tool look better in real life than in the photo above. I can't get a decent view with my camera.

[JohnB40]

Hi Ian,

 

All the recent Unicorn upgrades are great. I appreciate the detail all the more when I'm sat at my work table after viewing them and see in person just how small items such as the guns are.

 

The rivet press and dies are a nice piece of kit.

 

I know it doesn't not pertain to the forum,but I would love to see some examples of your railway engines.

 

John

[ianmajor]

John,

 

I put a couple of photos in the "Other Hobbies...." thread. Have a look at http://modelshipworld.com/index.php/topic/1940-other-hobbies-interests-or-pastimes-that-you-enjoy/?p=46650 .

 

The first engine was the one with the two rings of rivets. It is complete but needs a trip in to the paint shop.

 

It and my other locos are waiting on Unicorn.

[Landlubber Mike]

Very nice work Ian - you have a lot of creative ways to come up with jigs and templates.  I'm going to have to file your caps jig for future reference, it is perfect!

[ianmajor]

Hello Mike,

 

Glad you liked the jig. It produces reasonable results and it is a nice and easy thing to make - it has to be for me to cope with it.   

 

I had a good session at Telford and got stocked up with metal bits and pieces.

 

The following photo taken there is of a good example of ship and railway modeling coming together in 1:43 scale. The bridge stands over 5ft tall.

 

 

Back to the cannon. I finished off the quoins with handles. These I made from tooth picks passed through my draw plate until they were 0.8mm in diameter. 

 

 

I also started on fitting hooks to 2mm blocks. I cheated with these. I drilled 0.4mm through the block then glued the tail of the hook in the block. I used a length of 0.2mm thread. This was twisted slightly to open up it up then the tip of the hook passed through it. The two ends of the thread were then spliced together around the other end of the block.  

 

 

Time to start assembly of the cannon on the jig. First was to finish off the breaching rope. The ends are attached to rings with a simplified anchor knot with the free ends lashed to stop them coming adrift. This was done with the cannon in the "run in" position.

 

I tried a couple of the hook/blocks around the cannon for size. It looks like I need to make the next breaching ropes slightly shorter and possibly make the hooks about 1mm shorter.  Any thoughts on this? 

 

 

I then put the cannon in the "run out" position. I need to ensure that the breaching rope is twisted tighter to stop it opening up when the cannon is in this position.

 

The rings on the carriage for the side tackle I had mounted in the vertical position. But hooking the block on to it was difficult - so after the next photo was taken I changed them to being horizontal. Now the hooks drop in easily from above.

 

 

This cannon is starting to look a little careworn, with all the experimentation done on it, but hopefully the others will get better treatment when I get in to assembly line mode.

 

 

[gjdale]

Nice work Ian. On the question of hook length, I reckon you could afford to halve the length of the shank.

[Landlubber Mike]

Very nice work Ian.  It's very hard to get the cannon blocks to be in proper scale, particularly with the hooks I've found at this scale.  I think the shanks could be shortened a bit, but your cannon rigging is looking fantastic.

[ianmajor]

Mike, Spyglass and Grant,

 

Thank you for the input and thanks for all of the likes.

 

The consensus is that the hooks can be shortened - so I made a set with the hooks shortened by 1mm specifically for cannon rigging - then I rigged up one of the side tackles. For this I used one hook/block plus the second block without hook. For practical reasons the blocks at the bulwark I am lashing directly to the ring in the bulwark. I didn't think I would be able to engage a hook with the cannon under the overhanging deck in the waist area.

 

I will use the long hook blocks for the tackle falls where I think they will be OK. 

 

The following photo has this side tackle in place. The ring in the jig is not permanently glued in place so I can't pull the side tackle tight without pulling the ring out - so it is rather slack in the photo I am afraid!

 

I have been debating with myself about the position of the rings in the bulwark. I have seen them illustrated in various positions including all four rings in a horizontal line with the breaching rope rings outermost. With the side tackle in place I think I have the rings too high. In practical terms the loaders would have had great difficulty getting at the muzzle of the barrel  with the tackle at this height.

 

Any thoughts? When I get their position right I can produce a small drilling jig to help prepare the final holes in the ship.

 

 

    

[ianmajor]

Thanks for the likes guys. 

 

I have made up the sets of tackle for one gun. I am including a train tackle. I have looked at the debate as to whether to include this or not. I decided to go with them.

 

I put each set of tackle under an external stress test ie a good stretch. This was to see if anything such as the hooks would let go before I assemble them on the ship proper.  The photo shows a couple of sets under test. The upper one is a set of side tackle. The left end has no hook but is lashed straight on to a homemade split pin. The lower one is the train tackle set with hooks each end.

 

No working sheaves like Grant's 1:90 Victory (here) I am afraid.

 

Thus far everything is holding.

 

 

Next is to decide on the height of the rings in the bulwarks. I have spent a fair bit of time today looking at examples of rigged guns (full size and model) on MSW and elsewhere. No two set ups were the same. I think I could safely say I could drill the four holes in almost any pattern and it will agree with someone somewhere.

 

Then I will find out if I can (or not) successfully hook the tackle up in situ. Watch this space for some embarrassed coughing.

 

 

 

[Landlubber Mike]

Hi Ian, the hooks and tackle look great.  For the height of the bulwark rings, maybe take a look at zu Mondfeld?  If you don't have a copy of the book, you can get a preview at the following link on Google (I typed in "zu Mondfeld cannons" into the search field).  It looks like your height is in the ballpark, but your picture is at a slight angle to really tell relative to zu Mondfeld.

 

http://books.google.com/books?id=5nrXLkfLBGcC&pg=PA167&lpg=PA167&dq=zu+mondfeld+cannon&source=bl&ots=HdLqdMjksX&sig=CYhhB9IWuU-FqUDZcclLBXLCang&hl=en&sa=X&ei=khYXVOKCFK61sQSZ24GgCA&ved=0CDgQ6AEwAw#v=onepage&q=zu%20mondfeld%20cannon&f=false

 

Hope that helps!

[JohnB40]

Hi Ian,

 

The gun tackle looks great. I think you are correct that the tackle rings on the bulwarks are too high and would indeed interfere with the sponging out of the barrel and reloading. Logically they would be at about the same level,but 1-2 feet further apart.......Low enough to step over,but not hindering access to the muzzle. I remember reading that to lower casualties with gun crews in close action,they would close the gun port lids whilst reloading,using mops and ram rods with heavy flexible rope shafts to overcome the confined space in front of the muzzle. The lid was raised as the gun was run out for firing.

 

Your locos are a pleasure to view. Hard to believe now that steam locos were an everyday sight until I was about 12,still think of them with a lot of nostalgia.

 

John

[ianmajor]

Mike, Spyglass and John, thanks for your input. It has helped me immensely. 

 

I decided to go with the side tackle being horizontal so changed the drilling jig accordingly. The breaching tackle will be mounted lower and wider appart which I think fits in with what you guys are saying.

 

Re the blocks. They are rather meaty for these cannon but I decided to go with "off the shelf" blocks. The wood that I possess is too crumbly for making small blocks and (since I am only ever going to make one ship) I don't want to stock up with good quality wood that would get little use - a bit negative I am afraid. The smallest ones that I could lay my hands on were 2mm as in the photo.

 

John, glad you liked the loco models. When I get back to them I am/will be making models of actual locos that I saw and traveled behind in my youth. Nostalgia is not what it used to be.

 

 

Meanwhile, back in the workshop I stole and modified another of Dafi's ideas. Because the bulwarks are pretty inaccessible I made an extended drilling tool which can be fed through the gun port opposite to the one being drilled. With the usual no expense spared approach it is made from a kebab stick. The end is drilled to hold the bit. The other end I gripped with my normal collet holder to give a hand grip.

 

It is in the following photo along with the modified drilling jig.

 

 

It worked well - too well. The third hole that I drilled went straight through and out the other side of the bulwark. Pathetic really.

 

So I used some brass tube with an internal diameter that was an easy sliding fit over the bit and cut a length of it such that only 3mm of bit protruded beyond the end. This set the maximum depth of the hole.

 

The next photo is the tube alongside the bit.....

 

 

....and with the tube fitted.

 

 

Drilling the holes was then simple. With the jig plugged in to the gun port the tool was used without the tube in place just to spot the 4 holes. Then the jig was removed, the tube fitted on the bit and the holes drilled to their final depth.

 

You can see on the jig that two of the original holes are blocked up and the new holes marked blue to avoid confusing myself.

 

The adjacent port has the holes already drilled.

 

 

Then it was time to fit the first rigged cannon. I went for one of the easier positions first. Using hooks in to rings actually made it much easier that I expected.

 

I fitted the side tackle in to the bulwark first (without the cannon in place) then roped them out of the way. The breaching ropes were fixed with the cannon in the run in position to give room to get at the ends of the ropes. Then the cannon was glued in place in the run out position. Finally it was just a case of dropping the side and train tackle hooks in to their

respective loops/rings.

 

Of course I made a couple of boo-boos.

 

The first was that I had the cannon with its rear slightly too far forward so it was not directly in line with the train tackle. The second was that I used liquid super-glue to pin the breaching tackle to the deck in its final position. I had used the applicator on some blackened parts and I think it must have picked up some of the "black" (despite my burnishing the blackened parts). This was carried by the glue in to the rope and darkened that part of it. Doh. I will revert to dilute PVA for the ropes in future.

 

This all became apparent after everything was glued up solid.

 

 

Yet to be done on that cannon is to put some rope coils in place.

 

It is now going to be a lot more of the same. I have gone in to production line mode for the remaining cannon. I made a component list for all the bits I need to make for the rigging. It is amazing how their numbers build up. I will be rigging 16 of the 24 cannon and will require:

 

96 off large split pins

64 off small split pins

16 off deck rings

64 off hooks

96 off blocks

32 off caps

 

...and of course another 15 cut splices for the breaching tackle. I may be some time.

 

In the meantime I am off to Anglesey for a week with my wife. Hopefully the weather will be kind to us.

      

 

 

 

[Piet]

Hi Ian,

 

Your gun tackle is coming together just fine.  I like for people making their own tools and jigs.  I try to do the same but then again I am a certificated too and die maker.  never earned my living with it bit it sure came in handy when i was running an aircraft repair business 

Great show and tell, may help someone in the future.

 

Cheers,

[gjdale]

Nicely thought through and executed Ian. Once you've got the process figured, the production part goes very quickly, despite the seemingly large numbers.

 

Enjoy your trip away - hope you have nice weather for it.

[ianmajor]

Gosh! Was it really September when I last updated this log? I must be slacking.

 

I have been making progress on the Unicorn - despite the odd distraction - mostly repetitive stuff rigging cannon. I have now finished the 12 cannon on the main gun deck that I intend to do (positions 2 to 7 counting from the bow).

 

I made up some Flemish coils (as I believe they are called) which were added to the cut ends of the cannon rigging. I have seen the debate about how the excess rope should be handled but decided that my cannon were laid out as for an inspection.

 

I also rigged one cannon in the "run in" postion. I have debated this with myself. This looks OK from above but when the ship is viewed from the side it looks like a smile with a missing tooth. I think I will get used to that.

 

 

The quarter deck rail is now fixed permanently in place. I did a dry assembly of the pump cluster which revealed two coils foul of the pump bodies - it is a bit cramped around there. So the coils were moved.

 

 

With the pumps and ladders in place the rigging on the cannon in position 7 is fairly well obscured. The lack of rigging in position 8 is not very obvious through this cluster either. 

 

[ianmajor]

I turned my attention to the stove. Due to the restricted headroom it was difficult to fit it under the fore deck. So as part of final assembly I reduced the lengths of the legs such there was only 2mm clearance between the stove bottom and the brick base. I also reduced the height of the fittings on the still. 

 

 

A down side was that the stove now sits low against the drip try by about 0.5mm. It is not immediately obvious so I will leave it as is.

 

 

The stove now slid under the fore deck easily.

 

To fix it in place I put super glue on the underside of the base. To avoid getting glue on the adjacent grating as the stove slide in I laid in a strip of polythene which I was able to pull clear once the stove was in the correct position. The flue was glued in place through the fore deck.

 

I also added the deck beam under the rear edge of the fore deck. Of course the deck supports the beam rather than the other way round. This has got rid of the ripple effect in the deck. As can be seen in the next photo the beam protrudes beyond the deck in places so needs some final dressing. Sadly with the beam in place the still is now completely invisible.  

 

 

[ianmajor]

Initially I was concerned about how the lack of rigging on the remaining cannon would compare. In the event it is hard to see that there is any rigging in place when viewed through the ports. The non rigged cannon are also in deep shade under the decks.

 

To illustrate this, in the next picture the left hand cannon is fully rigged, the right hand cannon has no rigging. It also shows that if you get air trapped in the cannon bore when blackening it the bore remains bright. Doh! Plus what lovely off centre bores the Corel cannon have.  

 

 

A couple of errors/problems encountered.

 

The first was that when I pre drilled all the holes in the bulwarks for the side tackle I had the holes about 1mm too low. The result was the side tackle blocks closest to the bulwarks try to occupy the same space as the front trucks hence the side tackles don't sit neatly as shown in the next picture. Note how the far blocks are pushed out sideways through approx 90 degrees.

 

These blocks are fairly well obscured so I can live with this but I must make sure I get this correct on the cannon on the quarter deck where the tackle is in full view.

 

 

Another issue was that the deck planking was varnished long ago (it was in theory finished 30 years ago). This meant that it was a struggle to get the ropes to stick down and stay down using super glue. So after several attempts more glue was used than desirable. In places I will try to remove some of it with Isopropal Alcohol.

 

Next is to finish the pumps. Then I can climb back out of the waist area.....at last.

[Blue Ensign]

Great to see an update Ian, Unicorn is looking fine and it's good to see some more examples of your innovative approach to ship modelling.

 

Cheers,

 

B. E.

[gjdale]

Great to,see you back with an update Ian. What a shame that your lovely stove is now hidden from view. At least you have the pictures, and we have all seen them.

Edited February 1, 2015 by gjdale

[jwvolz]

Nice to see an update Ian. Great work on the stove. She's coming along nicely. 

[JohnB40]

Ian,

Well done on the construction progress,lovely work. It was getting kind of lonely in the Unicorn world,glad you and your log are back.. I am holding off mounting and rigging the waist guns until I have more or less finished the quarter deck. I find the small scale of the guns tackle hard to make looking realistic with blocks that "look right" and will have to think some more about how to approach it. Your set-up look great,I guess I will have to get stronger Optivisors and try harder. I just rigged  breaching ropes on the guns under the quarter deck,which are not visible through through the ports. Hopefully by the time I finish the waist guns I will have had enough practice to be able to make the ones on the quarter deck look presentable. The stove looks great in place,as Grant said it is a shame to hide its detail from view. I look forward to updates.

 

John

[Ferit]

Nice to see you again with some updates and especially the great STOVE one more time... :-)

[dgbot]

The Unicorn makes into a real beauty. How I missed this log this long is sad. You are doing a great job. If you want there a couple of books that should interest you and give you some insight on your build. They are The First Frigate by Robert Gardener & The Heavy Frigate by Robert Gardener.

David B

[Landlubber Mike]

Nice update Ian - your Unicorn is coming together very nicely.  Your decision to open up the waist worked out very nicely.  Too bad the stove will be a little more hidden, but you and your fans know it is there.

Edited February 9, 2015 by Landlubber Mike

[ianmajor]

Thanks guys for the likes and wonderful comments. Time to start on the pump mechanisms.....

 

The first components for the chain pump mechanisms were the sprocket wheel sides. I got my info from a variety of sources including the diagram <here>

 

and <here>....   

 

and <here>.

 

Each wheel side has 8 off 0.5mm holes in a circle with a PCD of 8mm.(PCD is the Pitch Circle Diameter being the diameter of the circle that passes through the centre of each of the holes). A 1mm hole is also required in the centre for the shaft. I tack soldered four blanks of 0.2mm thick brass together and drilled them using the X/Y co-ordinate wheels to locate the holes.

 

 

You will note there is a hole that I drilled in the corner that is outside of the circle. This is the my datum point (0,0). I used this if I "lost" my place, just winding the co-ordinates back to 0,0 then winding back out to where I should have been.

 

To work out the X/Y co-ordinates of the holes I created an EXEL spreadsheet with formulae. I use the Scrooge's version of EXEL which is very limited. It doesn't support macros so I can't use Danny's rigging and masting spreadsheet which is full of them. 

 

You may be interested in my process. If not skip to the next entry.....

 

Starting with some geometry......

 

 

In the diagram the datum point is at X/Y co-ordinates (0,0). The circle of radius r around which the holes will lie touches both the X axis and Y axis tangentially so its centre lies at co-ordinates (r,r).

 

The first hole I arbitrarily set where the circle touches the X axis (r,0).

 

The remaining holes are located using the incrementing angle ϐ. The increments to this angle depend on the number of holes, in my case there are eight holes giving increments of 45 degrees (360 divided by 8).

 

To calculate the X coord (x) and Y coord (y) of each hole:

 

Note the right angle triangle with sides a, b and r with angle ϐ opposite a.

 

a = r * sin(ϐ)

b = r * cos(ϐ)

 

...and....

 

x = r - a

y = r - b

 

...replacing...

 

x = r - (r * sin(ϐ))

y = r - (r * cos(ϐ))

 

In my case r = 4mm and ϐ has incremental values 0, 45, 90, 135, 180, 225, 270, 315.

 

In the last two equations remove the "x" and "y" characters which leaves the "=" as the first character (gives a function). These can now be used as basis for the formulae in the spreadsheet.

 

The next picture is a screen grab of my spreadsheet with EXEL in formula evaluation mode so that the formulae are displayed rather than their calculated values.

 

 

       

The red cells are for input information. 

 

Cell E3 is where you type in the number of holes required (I have set a default of 360).

 

Cell E4 is where you type in the radius of the circle (default of 10).

 

The next cell down (E5) is the first formula (=360/$E$3) which will display the result of taking the fixed value of 360 divided by the content of cell E3 (number of holes required) giving the angle between each pair of holes. The "$" signs make sure that we always point to column E, and always point to row 3.

 

Cell A10 is our first value for ϐ ie set to 0.

 

The remainder of the cells in this column add the content of the cell above (previous increment of ϐ) to the content of cell E5 (angle between pairs of holes). For example cell 

 

A16 contains =$A15+$E$5. 

 

Columns B and C contain formulae derived from our geometry work above.

 

Example in column B, cell B2 relates to "x = r - (r*sin(ϐ))" so contains:

 

=$E$4-($E$4*SIN(RADIANS($A10)))  

 

$E$4 is the cell containing the radius.

 

$A10 contains the value of ϐ. Note the cell ID has no $ in front of the 10 (row number), so the formula in the next cell down will have $A11 ie pointing to the incremental angle generated in this row.

 

EXEL works in Radians but my angles are in degrees. There is a built in EXEL function (RADIANS) that converts degrees to radians. This is used in the above function.

 

Column C formulae only differ in using COS rather than SIN.

 

For the main table you only need to manually type in the formulae in rows 10 and 11. To generate the remainder select cells A11, B11 and C11, copy them then paste in the cells below. EXEL will automatically increment the row values that are not prefixed with a "$".

 

(More quickly, select the three cells. Note in the bottom right hand corner of the rightmost selected cell is a tiny black square, position the curser over it (the curser will change to a thin black cross) press and hold down the select button then drag the square down as far as you want to copy, then let go of the select button. The copy will take place.

 

The next picture shows the same EXEL sheet in normal display mode. 

 

 

I have selected the number of holes as 8 and the radius of 4 (mm, inches, 1/64ths whatever).

 

It has worked out the angle twixt the holes (45) and calculated the X/Y co-ordinates for the different angles. In this case I only need rows 10 to 17 but to cater for any number of holes the formulae go way beyond this going round and round......

 

To make this info usable, I copied the appropriate X/Y co-ordinate cells, including headings, copied the cells then on a new sheet did a paste special/values which strips out the formulae and leaves the calculated values. (In my case I copied columns B and C between rows 9 and 17). I added an extra pair of entries on the end with the radius in each to mark the centre. (In my case (4,4) )

 

Then selecting all of the cells on the new sheet I did a sort - "sort by" X axis followed by "then by" Y axis as shown on the next picture.    

 

 

This gives the X values in ascending order, and the Y values in ascending order within each X setting. (see for X value of 4, Y has 0, 4 and 8) .

 

Drilling the holes in this order ensures the the X co-ordinate wheel is always progress in the same direction. Shuttling back and forth will cause large errors due to the backlash in the leadscrew.  The Y co-ordinate can be worked in one direction for each X setting. When moving on to the next X setting, The Y co-ordinate needs to be wound back beyond the datum value then wound forward again to take the backlash out.

 

The diagram shows the order I drilled the holes along with the direction the drill took. 

 

 

Well enough of this.......

 

 

[ianmajor]

Next up was shapeing the sprocket wheels. For this I made some filing jigs. The photo shews the jigs along with sprocket wheels at various stages.

 

 

The first up was a straightforward button. This consisted of 2 cylinders each 10mm in diameter which I turned up on the lathe. One part has a 1mm hole drilled through the centre the other has a 1mm stub. To use it the part to be filed is trapped between the buttons then filed down to match the buttons.       

 

 

The first stage produced discs large enough to cover the bosses around the periphery of the wheels. The second pair of buttons were 8.5 mm in diameter. These I used to produce the curves between the bosses. With the buttons in place the ring of holes was just obscured making it difficult to keep track of where the bosses should be. To overcome this I cut a 

slot across the two buttons to allow a piece of rod to pass through one of the holes. It was then a simple matter to file around. The next photo shows this in place.

 

 

Next up was a jig to enable the spokes to be filed. This consisted of two identical parts. Each had two holes 8mm apart ie the distance between two opposite holes on the wheel. Between the holes the edge was milled down to form the filing edge for the spoke.

 

 

The next photo shows the jig in use. The left side of the wheel has been filed down to the spoke - the right side has yet to be started (other than a pilot hole). Care has to be taken to avoid filing in to the centre hole.

 

The part is then rotated through 90 degrees and filed again. All 4 spokes have one edge filed at this point. The part is rotated 90 degrees again and the part filed. This shapes the opposite edges of the first two spokes. Finally this is repeated leaving all 4 spokes dealt with. This technique works for any even number of spokes - as long as you can get the files in between them!

 

 

[ianmajor]

Next is to make the components for the chain. The challenge is both in holding small parts when filing and to get them (as far as possible) identical in size and shape. I feel another jig coming on.

 

The chain links go around an arc that has a radius about 0.7mm greater than the wheel. I calculated the linear distance between adjacent holes on the chain to be 3.44mm.

 

The jig has two identical parts. Parallel to one edge are two holes 3.5mm apart. Between the holes the area is milled down to a line tangential with the top edges of the holes. The area around the holes is shaped as a curve with the two ends running straight down.

 

Blanks were cut from 0.2mm brass with holes at 3.5mm apart. These were then clamped in batches between the two parts of the jig with a spacer at the lower part of the jig to keep things square. The blanks are then filed down to the shape of the jig - they are then rotated through 180 degrees with the filed edge downwards so that the opposite edges could be filed.

 

The next picture shows a batch of blanks loaded in the jig ready for filing.

 

 

The next picture shows the two halves of the jig, some blanks awaiting filing, and a set of completed chain links around a wheel. The wheel looks like it needs a little more work. Nothing like photographs to show up weaknesses.

 

 

[ianmajor]

The pump chain is like a cycle chain with alternate single and double links. The difference is that some of the single links have a disk fitted which lifts the water. I have been trying to decide how far apart they were.

 

The diagram shown <here>  has the disks every 6th link.

 

Dan Vadas indicates a "saucer" every 4th link - see <here> but as he says only one need to be fitted since the adjacent ones will be in their tubes if the saucer is top dead centre.

 

I decided to go with every fourth link.

 

To make the saucers I turned some brass rod down to 2mm diameter. Then transfering the chuck and rod to the milling machine I used my thinnest slitting disc to cut the horizontal slot along the rod.

 

 

Then mounting the rod vertically in the vice I used the same slitting disc to cut off thin slices.

 

 

The result was less than pleasing. The slitting disc is thin steel and tended to wander producing curved cuts. This effect can just be made out in the previous photo where the slot in the rod runs out to the right as it moved downwards. A soldered one of these saucers on to a link and it was all lopsided.

 

I will be using this slitting disc later but will make some backing plates for it to stop it flexing.

 

 

Back to the drawing board. I turned a fresh length of rod to 2mm and simply sliced off some 0.2 mm blanks. These were then cut almost right across their diameter using a piercing saw. To hold the blanks whilst sawing I drilled a 1.8mm hole near the edge of a thin piece of scrap brass. The hole was then carefully reamed out until the blanks made a good interference fit in it. Then I filed the edge until the hole just broke through.

 

 

The piece of scrap (with the blank fitted) could then be clamped on to a thin piece of plywood on to the edge of the bench then used like a pin to enable the saw cut to be made. 

 

The bit of plywood stops the blank being pushed down (on the cutting stroke) and out of the jig.

 

 

The whole assemble could then be mounted vertically in the vice to use as a soldering jig, simply add a link in to the slot.

 

Soldering with the wooden backing in place...... 

 

        

 

....soldering without. 

 

 

The result was a much better saucer/link.

 

 

 

[ianmajor]

Then it was time to assemble the chain. The double links were soldered to the cross pins, the single links were left free. To stop the links getting soldered up solid I used cigarette paper between the parts of the link with the paper lightly oiled. Cigarette paper is very useful stuff in the workshop. It comes in various surprising accurate thickness. I use it as above plus I use it to set the right backlash in the gears of my locos - however I don't "roll my own" since I don't smoke.

 

 

Having completed a length of chain I assembled a sprocket wheel......

 

 

Then tried them for fit in one of the cisterns. I hadn't got the chain sat down properly when I took the photo. The chain is a little bit fat.

 

 

Then I made sure the lid still fitted with the sprocket and chain in place. It did! 

 

 

The cistern now requires a couple of tubes and a bung fitted. I am wandering off again for a while (I will have no tools or Web access) so they may have to wait for my return.

 

Now for the proof, if proof be needed, that Ian's brain is definitely going soft with the onset of old age.

 

The sprocket wheel in the photos above was the second one that I made. The first was nearly complete so I decided to give it a good burnish with the glass scratch brush. To hold the wheel I used a large, sprung, wooden clothes peg. Now I managed to select one that didn't close squarely. So as I was burnishing away the peg sheered. It was instantly converted from a clamp to a catapult and promptly fired the wheel across the workshop. It searched high and low but the wheel was gone. I think there is another lesson there.

 

This means that although I had prepared components for two pump mechanisms I had lost the sprocket wheel for one of them. So I decided there were three options:-

 

1) Simply fix the lid on the second pump and only have one with a mechanism (simplest).

 

2) Make fresh components for the second wheel.

 

3) At the time the real ship was built the pump mechanisms were changing. Earlier mechanisms had a sprocket wheel in the form of a wooden cylinder with 8 off "Y" shaped pieces of metal set in to the circumference of the wood. The chain consisted of small oval or twisted figure of 8 links. Along the chain were either cups or latterly saucers as with the mechanism I have produced. If I make one of these I could have one of each type of mechanism.    

 

I will have to give it some thought. Anybody got any views on this? 

[NenadM]

Oh, boy ... breathless