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[Paul Swainson]

Thought I would take a break from the hull as I will need a bit of space to plank the hull, so waiting for the better weather to clear the garage of the trailer.  So after finding a supplier for the gun barrels, I thought I would make a start on the two sets of gun turrets to see if I could make them my self.  As you can see I am trying to make as much as possible my self with in reason.
 
So from the ship plans I checked and measured the dimensions of the turrets.  The height was  15 mm and the circumference  at the base was 43 mm and at the top 33 mm with an angle half cone of 6 mm.  So went about working out the materials required  to make a turret.  Due to the height of 15 mm the base would have to be 1 mm and the top would be 1 mm.  That left the inside gun assembly to be 13 mm high.  So I cut out on card board the base and the top, then worked out the circumference required for the lower section of the turret wall and the height required was 9 mm and allowing for the half cone top of 6 mm that matched the height of 15 mm.  With the card board cut outs it seem to work out but was a bit fiddle, but do able.  But to make 16 of them was a bit much, but never say never.
 
So with the above information cut out my first turret and bonded the base and side as the first step. Then cut out the cone shape and bonded the ends to from the half cone.  Then bonded that to the top of the base section.  Once the unit had been truly bonded trimmed the over lap to create a nice smooth round turret.  Worked out the size of the gun opening and cut way the area need.
 
The turret is now ready to receive the gun barrels and the movement arrangement require to allow the barrels to move up and down to an angle of 80 degrees.   This was done by making a three sided square with 1.5 mm styrene. The three sides was cut 19 mm long and 13 mm high, making the two side 20.5 mm long and the back section with an inside measurement of 16 mm.  Each of the barrels would be held in a 6 mm wide by 10 mm thick sold bit of styrene. To achieve this I cut a strip off a 3mm thick sheet of styrene with a width of 11 mm and cut it into sections 11 mm square. Stuck two together and marked out the centre spot and marked a 5 mm diameter circle.  This was then trimmed to remove the square and ready to be placed on a drill and rounded down to a nice smooth circle 6 mm wide and 10 mm in diameter.  Each had a small 1/8 hold drilled through the centre to allow for a brass rod to be passed through. Then each of these was drilled in the centre of the 6 mm wide section; a hole 3.2 mm half way down to accept the gun barrel.  This would allow the gun to pivot up and down on these drums. In between each of this drums a 4 mm section 13 mm high and 12 mm long to give the middle support for the turret and strong pivot point for the barrels.
 
Once all this was in place this assemble was positioned in the gun turret to the correct point and then the top of the turret was bonded in place.  The cut out area of the barrels was finished off with 0.3 mm styrene to clean and straighten up the gun aperture.  The final base of the turret was ringed at the base to show the seating of the turret into the deck. 
 
Hope the photos reflect the work carried out.       These photos show dry fit to correct any errors

[radiojoe]

Well done Paul, well worked out by the time they are glued together and cleaned up they will do very nicely. 

[ballastanksian]

I take my hat off to you for the geometry used to create the conical sections! I would have done it solid to hide my poor maths:O)

[Paul Swainson]

Thanks guys, the first was trial and error and hopefully as I do more they will become much better and will look the part.  Once I have done one or two and primed and pained them a new photo will show what they look like.

[Paul Swainson]

the first trail turret with the next one being done to a better quality of build but have come across a small problem so back to the drawing board.  But can be solved.  Will have to shorten the barrels as the breach section of the barrel is too long and the barrel mounting pivot is not perfect so looking for a supply of 10 mm sold styrene rod to use which will give me a much better quality of finish.  But the turret assembly line is working well. 15 more to go.

[ballastanksian]

This is the thing I have learnt with WW2 and surrounding era ship modelling, you have multiple turrets/mountngs to build especialy when building a capital ship. So, getting the first one right as a proof of concept does save a lot of snot and tears later in the build!

The new mantlets will look much better. I hate working with tube as it is hard to keep the edges parralel and perendicular.

[dougal99]

For 10mm rod I have used plastic knitting needles. Saws and glues OK.


HTH

[Paul Swainson]

I would never have thought 10 mm knitting needles, I off to the wool shop thanks for the tip will try that out.

[Paul Swainson]

Yes the first one was the trial an error unit.  But the only real fault with it was the division plate in the  which  is out of alignment and cut poorly and the hight inside was a bit low.

[AlexC]

Yes the first one was the trial an error unit.  But the only real fault with it was the division plate in the  which  is out of alignment and cut poorly and the hight inside was a bit low.

Hi Paul,

The best way I have found for keeping all holes in true alignment is to assemble the outer frame and the centre division.. then drill though them as a unit.
Just be sure that the whole unit is square with the drill spindle and mark the centre accurately on one side.

Shame about the barrels being a bit too long... easily sorted though.

Keep Happy.

Best regards.

Sandy.

[derekwarner]

Paul.......I have experience with more modern [circa 50's design] Vickers twin 4.5" mountings.....essentially these and earlier versions were a single gun mount, however with twin barrels 

A possible solution to your alignment issue is to fabricate the barrel mantlet curved plate from one continuous tube for both barrels

As Sandy suggests, mark the OD of the mantlet tube and drill both holes in one setup......drilling the holes vertically down, then rotate the mantlet plate to achieve your desired representation of xx elevation

To further aid in visual alignment, actually mill then drill through the full diameter of the mantlet tube & spot the opposite inboard face....this can be used as a location for a plastic  spike between the ID of the barrel & the inboard or opposite face of the mantlet tube

Instead of reducing the length of each barrel, could you not locate & secure each barrel further inboard within the turret? ...if you must shorten the barrels, crop from the inner ...not the outer 

Only other thought is that the mantlet plate outer surfaces should be represented as very dark charcoal grey....not black.....this was actually an early layer of TEFLON...however called Peradite X  by Vickers and subsequently also by the RN..... Derek

[Paul Swainson]

Hi Derek,
Read your comments with interest and I had looked at the option of moving the gun barrel set up further back by extending the length of the two side walls from 19 mm to 25.5 mm  and with the mantlet curved plate drilled so that it sits on the centre line.  Checked the position of the gun barrels and found that the breach section of the barrel (last section) would look too long and the recess would be too great.


I thought about putting one single 10 mm mantlet in but then decided against it as you would not be able to move each barrel on its own.  As the attached photo shows this would  be needed to clean the barrels, and as this was a feature I wanted to use on the display of the model to show it at work.


So I have arranged to have the barrels reduced to allow for them to fit the set up I have made.  Also the scale will look correct when you picture the section of the barrel in the gun drawing.


I do not have the ability to mill so that will have to come later so I am left with drilling with my Dremel upright drill stand and the model clamp holder to work with.  Also looking at the Dremel   flat table top router which also will help with sanding to a flat and square surface.

[derekwarner]

Morning Paul......that last image is interesting as it show junior ratings with the chimney sweep steel brushes we spoke about in another thread last week..it shows the pairs of barrels from each turret at differing elevations, however both barrels from individual turrets are at the same elevation

With respect to the Vickers 4.5" mountings ...the mantlet plate was one casting simply with one hole for each barrel

The elevation of the gun was achieved via one curved mirror reversed angular rack attached to each side of the cast steel mantlet plate [naturally in real life this mantlet plate was an arc of less than 120 degrees]....so to actually elevate the gun, DC electric motors drove the corresponding rack drive wheels...[the elevation drive also had backlash compensation to achieve and maintain positional accuracy sub seconds of a degree]

So remember there two breaches, two shell hoists, two rammers....and two barrels but all about one mantlet plate in one turret...so if the mount is elevated, both barrels retain the same angle of elevation.....

[Every mechanical component interface on 4.5" mounting was shimmed and fitted with individual tapered dowels ...which made refit work a logistics nightmare in tagging say 100 individual shims and their dowel sets with their location and sequence position ...yes every individual dowel had a horizontal line scribed to designate the required depth of engagement when being refitted .....

Remember.... ...30 years ago it was a criminal offence to take your BROWNIE box camera and take pictures of your work.........Derek

[Paul Swainson]

Morning to you too Derek,


That is very useful information, I will see it I can make a single mantlet  for a turret by using the centre support to support it and pivot at each end on a coper spindle.  If that works then I will have both barrels moving together as per the real gun. 


Thank you very much for the information, as I always thought that these 4.5 and 4.7 guns moved indepent of each other using the HA sighting system.
 

[Paul Swainson]

Well the barrels have been reduced in length and I have a 10 inch knitting needle in  plastic and now working on this double mounts.  The centre mantlet mount is OK and I have the double mount barrel holder in place. 


Can any one advise what would be the best way to drill plastic so that I have a nice clean hole.  The speed of the drill must be important as on my test drills the plastic either on slow speed binds and stops the drill or  on fast speeds enlarges the front hole and seems to heat up the section and residue bonds to the drill.  Is there a secret to drilling this stuff (APS) 

[hmsantrim]

Hi Paul.
 do you drill the hole to size with the one bit or do you start  with a small drill and work up the sizes.  Maybe the bit is not sharp enough to clean cut the plastic at the speed you have it set at. Back in the 70`s when I worked in the chain factory I  remember what was called "cutting fluid" was used to cool the tool being used on some jobs maybe you need some on yer tool.   
Frank
 https://www.google.co.uk/#q=cutting+fluid

[Paul Swainson]

Well I have racked my brains and really had a hard job to find a way to drill the gun barrell access holes, which are clean and straight.  Then just like any other thought, up pops the idea.  I made a jig using a square block of wood with a 10 mm hole drilled through the centre.  Then cut the square to 16 mm in length to match the size of the tube.  Then drilled 3 mm holes in a position 3.5 mm in from each end on a straight line draw down the center.  I put each section into the center of the jig and then using my small hand held RS drill; drill it using the holes already drilled.  Job done test worked fine so onwards and upwards.

The other problem I have been struggling with hence the quiet spell is the stern of the keel.  Trying to find a way to insert the 8 mm thick prop shaft into the keel and through the bulkheads.   Well this has been done and I am now bonding the bulkheads to the keel.  Can only do two a day to ensure the glue bonds and cures to ensure a strong bond.  So as I progress will post photos for the work as I go along.  Will not boar you with photos of each frame will show sections as I go along.

[ballastanksian]

Just do some photos of the knarly bits as that is where you have been applying your most intense efforts and thoughts and thus of the most interest and education for us. Then one or two of the whole framework. Then if there are any questions about a particular frame, you can add an image of t if the answer warrants it.

I look forward to seeing your jigs and frames Paul.

Ian:O)

[Paul Swainson]

Hi Ian,  Here is the jig I made and the end result with all the gun barrels mounted.

[ballastanksian]

You know when a project is a setrious undertaking when the assemblies are stacked up like you see in engineering firms! Thanks for sharing your methods with us Paul.

The turrets look good and just illustrate how large the model will be when complete.

[Paul Swainson]

Here are the frame section from 13 to 24 now in place and bonded with the prop shafts located and in position ready to be bonded once the bilge keels are in place and the location for the position of the two 'A' frames have bee recorded in bulkhead 19. 

[Paul Swainson]

I am sure some of you will notice the cut out sections along both side of the frames.  These are the platforms for the boat decks, quarter deck and aft side deck ready for supporting  the decks when fitted.  There will be no need to use supports for these decks as I have put them in at the planning stage.  This will save a lot of hassle and fiddly work later, just build the decks and slide in and bond.

[Perkasaman2]

How about block foam between frames then cut and sand down to final hull shape to make the plug for the bow and stern. This may be easier and cheaper than using balsa wood block.

[John W E]

hi ya Paul, very neat workshop and very neat build.   May I ask you one question, why have you built it keel down with this build being an Aircraft Carriers the flight deck is reasonably flat so therefore would it not have been better to build it upside down and maybe easier to build the frames true and square.

aye

john

[Paul Swainson]

There is no correct way to build the frame  John, but after reading a few books and looking at other builds I felt this would be the best way due to a few reasons.  The stern part of the flight deck slopes downwards by about 1 inch from the center prop shaft and the has a flat section untill you get to the bow.  Also when planking they say you should blank from the top down and from the keel up and meet in the middle where you will then have to match with steelers.  So I was limited for space for half the year it made sense to me to put the keel down first, just as they do with the real build and work from there.  The only problem I really had difficulty with was drilling the propshaft and if it was the other way up it would have been much easier.   So we live and learn, and so far the build has been fun.