HMS Bellona 1760 by SJSoane - Scale 1:64 - English 74-gun - as designed

[michael mott]

Mark I am still giving the chuck operation some thought.

That said, looking at what you are working to accomplish I would approach the fabrication of the axles differently. from the photograph of your set of axles the round portion appears to be the same diameter as the square section is wide.

 

I am not sure of the way the full size axles were made, on the model however the junction between the square or rectangular section and the round section is hidden by the wheel, unless of course the wheel is left off.  this then leads me to suspect that there would be very little ability to determine if the stock(axle) were made from one solid piece or assembled from two or three pieces. from a manufacturing process there is a much greater difficulty of getting a clean smooth finish at the junction of the rectangular section and the round section using a lathe, purely from the physics of the cutting action on the fibers of the wood no matter how fine the grain.

 

The way I would approach this is to use an assembly method by combining a dowel and a rectangle or square section, for the following reasons.

 

1, The ability to cut and sand to accurate length all the rectangular or square sections first (square can be reduced to rectangular after gluing in the dowel). This method has already been accomplished with the wheels so square section is a breeze.

 

2, The dowel can also be cut to accurate lengths. this eliminates the need to reverse the work in the holding device whether a 3 or 4 jaw chuck with any number of sleeves to accommodate the section. (and some of the ideas suggester are great.)

 

3, The square or rectangular piece can be set up in a jig in the vice to drill a through hole or from each end to accommodate the dowel, the important thing here is to use a brad point bit especially ground for drilling into wood. in the case of the round part being the same diameter as the width of the rectangular make the part wider to begin with to allow a full hole to be drilled. After the dowel is glued then you can either sand or cut the extra side material away to reduce the width down to the diameter of the dowel.

 

4, A simple stop type jig can be used to position the dowel in the center of the square or rectangular section, in preparation for either a tiny pin (brass) to ensure that it stays where you put it or a touch of glue.

 

5, If the wood used to make the rectangular section and the dowel are from the same stock it would be impossible in my view to know that it was not made from a single piece of wood.

 

All of the above is of course only my opinion and the way I would approach this element of the whole.

There are so many ways to approach the building of our models, and the sharing of all these ideas is what makes this such a wonderful site.

 

Michael

[dgbot]

There are many ways to skin a cat.

David B

[SJSoane]

Hi Michael,

 

Very interesting idea, breaking it down into parts. You are right; the wheel covers the joint and so no one would be the wiser.

 

Here is a cross section of the carriage; you can see that there is a slight offset from the cylinder and the rectangular piece behind. At 3/16" scale, it is not very much.

 

I had to use a #40 twist drill bit for the wheels, and so it would be the same for drilling into the rectangles for added dowels. This is a dumb question, but are there brad point drills that small? Otherwise, I don't know how I would control the tolerances on this without accidentally breaking through one side or the other of the rectangular part.

 

Machining is a fascinating process. You learn new things on every setup!

 

Best wishes,

 

Mark

 

Edited March 2, 2015 by SJSoane

[michael mott]

Hi Mark there are some brad points that do go as small as 2mm this tool company has a great variety of miniature end mills and drills that could also work.

 

Pricey but very good quality.

there is also Lee Valley with a good selection

 

michael

[bizibilder]

Sorry for being so slow to reply!  In answer to your question about my "tube" method of holding square stuff in the lathe - you simply tighten the chuck or collet enough for the round tube to close onto the four corners of the square (or rectangular) workpiece.  It should just grip on the corners.  The brass "tube" remains round - just a couple of thou is enough to close it tightly onto the square stock.

 

You would need to make a new brass "tube" for each size of square or rectangular stock.

Edited March 8, 2015 by bizibilder

[SJSoane]

Thanks, bizibilder, I will try that on the gun carriages for the upper deck.

 

I managed to cast a plaster holder for my gun mould as recommended in David Antscherl's Fully Framed Model vol. II. I now see the wisdom of that approach, after having my first pour spill out of the mould when the rubber bands burst. After the plaster dries, time to try melting some metal again.

 

I also built a little jig for assembling the gun carriages. I haven't decided yet if I will stain each piece and then assemble, or assemble and then stain. Masking each part for separate staining in tedious, and I have no place to hold each piece when staining it all over, without putting my fingers in the fresh stain. But it is also difficult to get the stain into each nook and cranny when it is already assembled. I already tried it the first way, and I'll try it the second way tomorrow, and see what happens.

 

Mark

 

 

 

Edited March 15, 2015 by SJSoane

[michael mott]

Nice jig Mark. would it be possible to hold the assembled carriage on 4 sharp pins into the bottom of the axles  by just pushing it onto the sharp pins or needles? that way the axles are not touching any other wood.

 

Michael

[SJSoane]

 

Hi Michael, thanks for the thoughts on holding it on pins. With paint it might work, but with stain I have to put a cloth on every surface and wipe it off. It is challenging. In the end, I had to mask each piece, and hold it while staining, then wiping. Tedious, but here are the first results. Ironwork still to come,, and I look forward to seeing the darkened pewter for cannon rather than the resin and brass seen here.

 

Mark

[mtaylor]

Wow.. I didn't know they made a pure red stain.   I think it was Hahn used to use RIT dye.  Looks super impressive and better than paint in my opinion.

[SJSoane]

 

Hi Mark,

 

It is a few drops of TransTint Bright Red dye, mixed into General Finishes Gel Topcoat wipe on urethane. I got both at Rocklers Woodworking. Ed Tosti has warned that this may be transient and fade over time, but I decided that faded red would be better than way too intense red paint. I had to throw away my first riding bitts when I painted them and hated the look.

 

Mark

[SJSoane]

Perhaps early days for thinking about this, but I am beginning to wonder how I am going to attach the carriages to the deck, and the cannon to the carriages at a set angle.

 

Since I am not planking the deck, I will need to put spacers under the wheels 4" thick to lift them to the correct height relative to the gunports. And how do I pin them down, rather than relying on glue alone? I can see, with the weight of the pewter cannon, how these might break free over time. Pins all the way through the wheels seems challenging.

 

And how do I fasten the cannon down onto the quoins parallel to the deck? I could glue the cannon to the quoins with epoxy, but will this come loose over time without a pin?

 

More construction details to ponder! Any thoughts?

 

Mark

 

[dgbot]

How about pinning the wheels to risers first then gluing risers in place.  This will be the easier way of doing it. Drill a hole in the carriage where it will not be noticed. and then through the deck.  as for the cannon a drop of epoxy on the trunnions shul do the trick.

David B

[michael mott]

 

Perhaps early days for thinking about this, but I am beginning to wonder how I am going to attach the carriages to the deck, and the cannon to the carriages at a set angle.

 

Since I am not planking the deck, I will need to put spacers under the wheels 4" thick to lift them to the correct height relative to the gunports. And how do I pin them down, rather than relying on glue alone? I can see, with the weight of the pewter cannon, how these might break free over time. Pins all the way through the wheels seems challenging.

 

And how do I fasten the cannon down onto the quoins parallel to the deck? I could glue the cannon to the quoins with epoxy, but will this come loose over time without a pin?

 

 

Mark there seem to be no end to the challenges. the Idea of gluing the spacers to the wheel first seems like a good idea I would be tempted to make a small piece of deck under each cannon with a wavy edge on either side like one does on a drawing to show the cutaway, this would then give a much larger gluing surface and would also give you the opportunity to make some small adjustments in the positioning without it looking untidy which it might with all sorts of spacers.

 

Michael

[SJSoane]

 

Hi everyone,

 

Well, I finally cast some pewter cannon. Or one, to be exact. It is finished with Jax Pewter Black which appears to work very well. I mechanically cleaned the barrel after casting, with a 3M spider abrader, and then a dip in jeweler's pickle, a rinse in water, and then Jax brushed on. I will live with it for a while; I think it might want some final finish to give it a tiny bit more sheen. It is dead flat black right now. A mean looking cast iron monster....

 

And thanks, David and Michael, for ideas about how to mount these with spacers. That will be my next challenge.

 

Mark

[AON]

verrrrry nice!    

[EdT]

Looking great, Mark. You may be able to buff the barrel a bit with a soft cloth to give it some metallic sheen.  Are the guns going to be set at deck height or beam height?

 

Ed

[Mirabell61]

Lovely work Mark

 

Nils

[druxey]

Excellent!

[SJSoane]

 

Hi everyone,

 

Ah, a short-lived victory. I started casting more cannon today, and the further along I went, the worse the castings. They were starting to lose detail (see first photo). I looked more carefully, and a sticky brown sludge was building up on my mould (see the third picture, where I scraped some of it off). And then when I was trying to clean the mould, part of it ripped away at the muzzle face. So, time to make a new mould...

 

I really wonder if the pewter metal I obtained at a local jewelry supply store was too hot for the rubber mould material. So, I either need to switch to stronger mould material, or find softer metal, perhaps at MicroMark. Or, switch to resin. The learning curve continues.....

 

Before all of this emerged, I started the day building a successful jig (shown being set up in photo 2), to make a wooden collar with an inside diameter tapered to match the taper of the barrels, so I could chuck the cannon in the lathe for cleaning up the front face and drilling the bore. I cut the inside taper by putting the rotating table on the angle table, and then rotating the blank past a mill cutter inside the hole.  It worked really well on a trial; I just have no cannon at this point to use it with!

 

Mark

[druxey]

Is the 'brown sludge' you describe dross that rises to the top of the molten metal? This oxidation product needs to be skimmed off before pouring. The metal you pour should look bright and shiny, like liquid mercury.

 

I skim the surface of the metal with a wooden stir stick before each pour. A quick flick gets rid of it.

 

The mould will brown slightly after a time, but there should not be any build-up of anything in it.

Edited March 21, 2015 by druxey

[SJSoane]

 

Hi druxey,

 

I skimmed the dross each time, showing the shiny metal. But in the time it took me to put down a skimming tool and pick up the ladle and pour, oxidation was already forming again.

The sludge is surprisingly sticky, like it was beginning to break down the surface of the rubber. 

 

Mark

[SJSoane]

 

Now that I am having to remake my mould, I have a few thoughts about making it better:

 

The first thing I notice is that the rubber flexes enough when putting plaster around it to allow the end of the barrel to come out a little oblong. Ed Tosti, you advised me, and I regret I didn't follow your advice, to use the 10:1 rubber RTV from MicroMark. Would it perhaps be less squishy than the 1:1 Rapid that I used, and therefore hold its shape a little better?

 

And/or, perhaps I should leave the master inside the RTV mould when pouring the plaster around it. That would keep it from squishing.

 

I also wonder about the pewter I bought locally. It has a downright nasty scum on the surface when it cools (see photo). Does anyone have a suggestion for an online supplier for reliable metal?

 

Mark

[druxey]

Shouldn't have that much dross on top, Mark. All pewter will have a thin scum that should be flicked off with a wooden stir stick just before pouring.

 

Leaving the master inside the RTV while casting the outer plaster jacket is a good idea. I've used 1:1 RTV rubber without an issue.

[SJSoane]

Hi everyone,

 

A long time away from the shop; pesky real work gets in the way...

 

I am zeroing in on these cannon. I think my sludge problem was from using an electric melting pot with a cast iron ladle; somehow the cast iron polluted the pewter. So I switched to a Lee bottom pour melting pot, and it works very well. No sludge, no dross to skim off the top.

 

I have also learned to leave the pour in the mould for maybe 5 minutes. Pulling it earlier leaves small pockets in the cast where the metal pulls away from the mould before it is fully solidified. the photo of the cast cannon also shows that I changed my gunhead to look something more like the 18th century engravings showing gun casting. I don't know if it makes any difference, but it saves the amount of pewter I pour.

 

I built a little collar to clamp the cannon in the lathe for cleaning up the muzzle and drilling the bore. I am showing how I clamp the extension of the bore from the cast into a small Jacobs chuck, to ensure the muzzle is centered in the lathe.

 

And a few shots of the red carriages starting to line up. The jig shows the tedious masking on the carriage parts to ensure a clean glue surface.

 

Mark

 

[Siggi52]

The cannon looks great Mark, at least you got it. 

 

Regards,

Siggi

[druxey]

Well done, Mark. That melting set-up you have looks interesting. Much more sophisticated than mine: I use rubber bands rather than clamps, and just an iron ladle!

[SJSoane]

 

Thanks, Siggi and druxey. This has been a steep learning curve, working with metal casting.

 

Part of the challenge is that I have been unable to use an open flame propane torch in my shop to heat the metal. So I had to dig into the bullet casting hobby sites to learn about electric melters. The Lee melter is not terribly expensive, and appears to work well.

 

Mark

[druxey]

Yes, I checked that Lee melting pot out on line. As it will achieve a temperature that melts lead-free pewter, that's a great solution if one is doing a quantity of casting work which, for a 74, is certainly the case! Of course, you will now be deluged with requests from others to cast cannon for them....

[michael mott]

Mark your work on the cannons seems to be paying good dividends. The concept of looking to other hobbies for solutions to design or manufacturing issues, is where the value of the internet comes to the fore. I believe that many different hobbies have benefited greatly from this development.

 

Michael

[SJSoane]

Hi everyone,

 

I managed to stain and assemble the carriages for the entire port battery. Starting to look like a busy gundeck. Much iron work and casting still to do...

 

Mark