Dunbrody by Mahuna - FINISHED - 1:48 - Cross-Section - Irish Famine Ship

[Mahuna]

Great work Frank, very nice.

Thank you Albert.

[Mahuna]

Looking great, Frank.  I can relate to your comments on intentional grain-raising as part of the finishing process.  I think this is good practice on all woods where a water-based finish - water stains, dyes, acrylic paints, inks, etc. - are used - or even in general for uniformity if glue has been washed off with water.  I do this routinely on model wood and did it for years on furniture work before final sanding - all hardwoods.  I used clean water.  I have not tried alcohol.  If the grain is not raised before finishing, the water in the finish will do it, often requiring more sanding.

 

Those planking clamps really come in handy on that internal bilge planking.  Keep in mind that over-tightening these in these positions can distort the frames outwards.  I did not find that to be a problem, but I believe it could be, depending on the molded breadth of the frames and the amount of stress - probably not a problem with the toothpicks(?) you are using, but with the nails I used, you can put a lot of stress on the frames.  Worth a check.

 

Ed

Thanks Ed, and especially thanks for the warning.  I hadn't thought of that and probably would have learned the hard way.

[Mahuna]

Part 22 – Viewing Ports

 

Installation of all of the Hold Timbers is completed.

 

                        

 

                        

 

The next step is to install the 22 strakes (11 each side) of Floor Ceiling.  I’ve already milled the castello for these planks, but I’m mulling over the best way to install them.  Because of the narrowing of the hull towards the fore and aft ends of the model, I’ll need to install some drop planks at certain points.  I need to do a little studying and planning to pull this off.  Ed’s Young America book will help in this regard.

 

While installing the Hold Timbers I left an opening where the Viewing Port for the hold will be.  You can see the interrupted strakes on the starboard side in the above photos.  The following photo is an external  view of the starboard side.

 

                         

 

I installed only partial strakes of the Bilge Ceiling, leaving the viewing port area open.  Even though the top three Second Stringers would also be partial I installed full strakes so that the stringer would align properly.  After all of the timbers were installed I cut out the middle portions of the second stringers.

 

The following photo is a drawing of the midship frame, showing the arrangement of internal timbers and planking around the viewing ports.

 

                      

 

The lower Second Stringers have been installed as full timbers on the starboard side, and I’m trying to decide whether or not to install all of the floor ceiling on that side as well.  I may leave some of the strakes off to show the framing.

 

The next photo is a drawing of the same area, showing the arrangement of external planking around the viewing ports.

 

                     

 

The Port side of the model will be completely planked.  I haven’t decided on the planking for the starboard side yet.  I could plank everything except the area of the view ports, or I could decide to leave more of the planking off to show more of the frames.  I’m leaning towards the latter, since a lot of work went into those frames.

 

I will need to leave certain frames in place within the viewing ports.  These are the frames that are associated with the deck beams on each deck.  The following drawing shows the view ports outlined in blue and the frames that will be left intact in red.  As you can see, there is one frame that will be open in the hold but the upper part of the frame will be left intact in the accommodation deck area.  This frame supports a beam that is under the windlass on the main deck.  I don’t anticipate an issue with cutting away the lower portion of this frame – that won’t be done until all of the supporting timbers and most of the planking is in place.

 

                        

 

I’m open to (and would welcome) suggestions on how to configure internal and external planking to make best use of the viewing ports.

 

 

Thanks everyone!

[AON]

I wish I knew enough to help with an intelligent suggestion ... but I am one of the students

[Mahuna]

I wish I knew enough to help with an intelligent suggestion ... but I am one of the students

Hey Alan - I'm a student too, never having done anything like this before.  I'm still trying to figure out a lot of things - what planking to leave off is only one of them.

[Omega1234]

Hi Frank

 

If I were you, I'd leave the starboard side completely unplanked. Why? Why cover up such beautiful and intricate work on the frames. Show it off, I say!

 

But, that's just my opinion, of course...

 

Cheers

 

Patrick

Edited June 1, 2016 by Omega1234

[Gerhardvienna]

Hi Frank

 

Just fell in here, I`m amazed!

Think i`ll stay in for a while................

 

Regards

Gerhard

[EdT]

Decisions, decisions.  Isn't it great to keep the brain working.  I would certainly leave some of that beautiful framing work and bolting exposed.  Also, I found that deck clamps spanning the viewing ports were more than strong enough to support the deck beams without leaving those frames in place - blocking the view inside.

 

Ed

[Mahuna]

Hi Frank

 

If I were you, I'd leave the starboard side completely unplanked. Why? Why cover up such beautiful and intricate work on the frames. Show it off, I say!

 

But, that's just my opinion, of course...

 

Cheers

 

Patrick

Thanks Patrick - I always value your opinion.  I am going to leave some of the framing exposed, but there are some areas I may want to cover if I can't clean them up.

 

 

Hi Frank

 

Just fell in here, I`m amazed!

Think i`ll stay in for a while................

 

Regards

Gerhard

 

Welcome aboard Gerhard.

[Mahuna]

Decisions, decisions.  Isn't it great to keep the brain working.  I would certainly leave some of that beautiful framing work and bolting exposed.  Also, I found that deck clamps spanning the viewing ports were more than strong enough to support the deck beams without leaving those frames in place - blocking the view inside.

 

Ed

Hi Ed - the intellectual challenge is one of the things I love about this hobby.  My other hobby - bird carving - is more of an artistic challenge.

 

I was thinking of leaving the frames associated with beams so that the knees would be visible in the viewing ports.  Maybe I'll just do that in the lower viewing port and leave the one for the Accommodation Deck completely open.  I guess this is something that can be decided on later.

[captainbob]

I was thinking of leaving the frames associated with beams so that the knees would be visible in the viewing ports.

 

Yes, let the viewer see how the ship was built.

 

Bob

[Mahuna]

Lessons Learned

 

Planking Clamps

 

I’ve decided that I will leave the starboard exterior mostly unplanked so the frames can be seen.  I’ve already decided to try to use LED’s to provide more lighting in the hold and the Accommodation Deck.  These two factors made me look a little more critically at the interior planking on the starboard side. 

 

I originally planned on the starboard side being almost fully planked, and any errors on the inboard planking on the starboard side wouldn’t be very visible.  The bilge ceiling planks aren’t installed very well - there are obvious gaps between some of the planks.  These gaps will be very visible from the exterior of the ship when the interior is lit by LED’s.

 

              

 

So these planks needed to be removed (more alcohol!!) and reinstalled.  When I started to install them I realized I had made an error when I made the planking clamps:  I had glued the spacers to the top of the clamps – this gave me no flexibility in positioning the tensioning part of the clamp.  I needed this flexibility because of the way the bilge ceiling clamps now had to be installed (working from the bottom up, rather than top down as originally done).  My existing clamps could not be used for this reinstallation.

 

So I made new clamp bodies, each with three different hole locations and with a non-fixed spacer.  In the following photo the old clamp body is on the left and the new version with the separate spacer is on the right.

 

                        

 

These new clamps worked well.  The following photo is of the clamps being used in a very close position – using the closest setting.

 

                        

 

When I reached the next plank up, this short position could no longer be used.  I moved the tensioning rod to the middle, and needed to use a piece of wood behind the clamp to allow it to work.  You can see what looks like a timber above the deck clamp/shelf combination in the photo – this is simply a loose piece of stock to allow the clamp to tension properly.

 

                        

 

I’m very happy with the new planking clamps, even though they won’t get much more use in this build.

 

 

Making Treenails

 

I’ve also decided that the floor ceiling planks and any exterior planks will need to be pinned in place for glueing, as Ed has done in the Young America build.  The holes used for pinning would need to be filled with bolts or treenails.  I’ll be using treenails for two main reasons:

 

1.     It’s more accurate – treenails were more often used on the planking, while bolts were used on the structural timbers.

2.     It’s easier to clean up.  Using treenails will allow me to use PVA glue, which can be cleaned up with water, while using bolts would make me deal with cleaning CA or Epoxy residue – neither is a good choice for me.

 

I’ve played with making treenails in the past and have been very frustrated with the experience – mostly using bamboo skewers.  I decided to try using the same color wood as the planks (castello) so that the treenails would be more subtle.  I had some Pau Marfim (also known as Guatambo) scraps, so I decided to use them – they look very much like castello and are almost as hard.

 

I started by milling the scraps down to a little under 1/32 square, about 8 inches long. 

 

                        

 

In previous attempts at making treenails, I had basically pulled the wood through the Byrnes drawplate with a pair of pliers, and went from one hole to the next in each step.  The pliers crushed the wood and the tension I needed to apply to the wood broke more pieces than I produced.

 

In this process I pulled the wood through with my fingers, and continued pulling through a hole until no more wood shaved off (4 to six times at each hole).  This made the subsequent smaller hole much easier to navigate.  I was able to get down to .030 inch pretty easily, and thought this would be a good size to stop at (2 inches at scale).

 

                        

 

Wrong!  I checked the Crothers book for treenail sizes, and found that I should be aiming for 1.25 inches or less – around .021 to .024.

 

This was much harder to get to. The treenail stock was now so thin that any accidental pressure would break them, and it was much harder to get them started in the holes.  I was able to produce some decent treenail stock in the correct sizes, and I’m sure with more practice I’ll improve.

 

The correct treenails are on the left in the following photo.

 

                        

 

All told not too much progress in building the model since the last post, but good progress in improving my modeling skills.

 

Thanks everyone!

 

[druxey]

Bamboo skewer material is very variable in quality. If you can get a large diameter piece of bamboo cane you will get much better results. Split it, discard the glassy outer 'skin' and use the layer immediately under this. The innermost material is of no use either - it's too soft and fluffy.

[ggrieco]

Wow! You've really made some progress. I'm having a hard time catching up. She is really coming along beautifully!

[Mahuna]

Wow! You've really made some progress. I'm having a hard time catching up. She is really coming along beautifully!

 

Thanks Glenn.  Progress will start to slow soon - I'll need to begin drafting the deck configurations and planning how to build them.

[Mahuna]

Part 23 – Floor Ceiling

 

The next step after completion of the hold timbers is the installation of the Floor Ceiling strakes.  There are 11 of these strakes between the lowest Second Stringer and the space that will be left for the Limber Strake.  Originally I thought I’d need to install drop planks due to the curve of the hold timbers, so that I would have straight planks near the limber strake.  The only thing I actually needed to do was to taper several planks at their ends.

 

The Floor Ceiling planks are made of castello boxwood and are fixed in place using treenails. The treenails will be placed in the same pattern as was used for the bolts holding the hold timbers – one on each of the sister frames, alternating top and bottom edges until a butt joint.  The butt joint will be held by treenails in the top and bottom edges of each plank.  The holes for the treenails are pre-drilled using a #76 drill bit.  These holes will provide a tight fit for the pins that will be used to hold the planks in place until the PVA glue sets, and will later be used as pilot holes for a larger drill bit to expand the holes for the treenails.

 

I thought I’d share the process I use for pre-drilling these holes.  The drilling is performed on the milling machine with a sensitive drilling attachment.  A scrap piece of ¾” plywood serves as the drilling platform, and a piece of straight lumber is nailed to the platform to serve as a fence.

 

                        

 

The Y-axis is locked in place so that the holes are a consistent distance from the edge of the plank.

 

The plank to be drilled is held in position against the previously installed plank, and a small mark is made to indicate the middle of the sister frame.

 

                        

 

A square is then used to draw lines for each of the hole positions on the plank.

 

                        

 

The holes are then drilled at the appropriate locations. 

 

                        

 

On the Port side of the hull, the holes on the forward frame sister are drilled at the top of the plank.  The holes for the aft frame sister are drilled at the bottom of the plank.  This is accomplished by first drilling alternate holes for one side of the plank, then reversing the plank in the drilling fixture and drilling the remaining holes.  The end for the butt joint will have a hole on both the top and bottom edges.

 

                        

 

In the hull timbers, this drilling is followed by inserting and gluing bolts made of copper wire into the holes prior to the timber being installed.  For the floor ceiling the planks are installed immediately after drilling.

 

Glue is applied to the frames on which the plank will be installed and on the edge of the plank itself.  The plank is pushed into position, and pins are then used to hold it in place.  In the following photo, the small pliers with the black jaws is being used to push the pin in place, holding the pin very near the tip (the pins bent fairly easily if they were held too high).  The other pliers is being used to push the new plank against the adjoining plank. 

 

                        

 

The pins were used on every other frame, and at varying positions.  The plank on the left in the following photo has just been installed and glue needs to be cleaned off.  The plank to its right is wet from washing glue off.

 

                        

 

Once all of the planks were installed, the treenails were then inserted.  This was started by expanding the pilot holes using a #71 drill.

 

                        

 

The treenails were then dipped in PVA glue that was slightly diluted with water (about 1 part water to 2 parts glue) and inserted in the pre-drilled holes.

 

                        

 

The treenail was then clipped off.

 

                        

 

And after a few treenails had been installed the glue residue was washed off the plank.  (The toothbrush I’m using is a narrow toothbrush used by periodontists – found on Amazon and very handy for narrow spaces). 

 

                        

 

The following photo shows the hole configuration at a butt joint, and also shows the difference between the pilot holes and the final holes for the treenails.

 

                        

 

So the hold timbers and planking are now completed.  The treenails are almost invisible at this point, but I’m hoping that they will be a little more visible after a finish is applied.

 

                        

 

                        

 

The next step is to configure the mast stub and the mast step.

 

Thanks everyone for following, and thanks for the ‘likes’ and comments – they’re much appreciated.

 

 

[GuntherMT]

Looking great Frank.  I bet that once you clean all the sawdust off with a damp cloth, and then apply your finish they'll be visible without any problem.  Very nicely and precisely done.

[Mahuna]

Looking great Frank.  I bet that once you clean all the sawdust off with a damp cloth, and then apply your finish they'll be visible without any problem.  Very nicely and precisely done.

 

Thanks Brian.  We'll find out soon.  I'll apply a finish once the mast step is in place.

[usedtosail]

Those planks and treenails look great, Frank. I have to really thank you for the photos because I have been thinking how best to mill the slots in the channels for my Connie and your setup will work great for that. I had not thought to use a plywood backing board on the XY table with a wooden fence. I love those sensitive drilling attachments, but I have yet to find one that will fit either my drill press or mill. They seem to all be made for full size milling machines. Oh well, they are pretty expensive anyway. Keep up the great work.

[markjay]

Frank terrific job and progress since the last meeting...really like the clamp solution and your vision of the Dunbrody build is incredable.

[Mahuna]

Those planks and treenails look great, Frank. I have to really thank you for the photos because I have been thinking how best to mill the slots in the channels for my Connie and your setup will work great for that. I had not thought to use a plywood backing board on the XY table with a wooden fence. I love those sensitive drilling attachments, but I have yet to find one that will fit either my drill press or mill. They seem to all be made for full size milling machines. Oh well, they are pretty expensive anyway. Keep up the great work.

 

Hi Tom - glad the photos helped.  My milling machine is a Sherline, and the Sensitive Drilling Attachment is made for it.  I do think, though, that the same kind of setup would work on a mini drill press even without a sensitive attachment.  I didn't use the x-axis feed for any positioning - I simply slid the plank by hand to the correct position under the drill.  The Sensitive Drilling Attachment just kept me from having to continually crank the Z-axis screw feed.

[Mahuna]

Frank terrific job and progress since the last meeting...really like the clamp solution and your vision of the Dunbrody build is incredable.

 

Thanks Mark.  Hopefully there'll be a lot of progress to be seen at our next meeting in September.

[HIPEXEC]

It's really taking shape. Very nice work.

[Mahuna]

It's really taking shape. Very nice work.

Thanks Rich.

[Mahuna]

Part 24 – Mast and Mast Step

 

The last work to take place in the hold is to build a mast step and the main mast that will rest in it.

 

In American Built Packets and Freighters of the 1850’s, William L. Crothers briefly described the evolution of mast steps.  By the mid-1800’s the additional Keelsons and their Riders required that a substantial foundation for support of masts be built.  However, according to Crothers there is very little available information describing how these Mast Steps were constructed – he was only able to cite one drawing that he was able to find.

 

The Dunbrody plans don’t show any kind of mast step – instead the only thing shown is what appears to be a plank laid on the keelson under the main mast.  The plank measures approximately 5” thick and is about 7 feet long.  I’m assuming that this plank would need to be wide enough for the foot of the mast, which is 20” in diameter.  However, the Keelson on which it would sit is only 15” wide, so this doesn’t seem to be a very secure way to support the mast.  In addition, the tenon of the mast would need to be less than 5 inches, or it would penetrate the Keelson.  I didn’t feel comfortable that this was a workable way to secure the foot of the main mast, so I decided to make a Mast Step. I would use the diagram from the Crothers book and the mast step shown in Ed Tosti’s Young America to design my own Mast Step.

 

The first item was to install a couple of timbers laying alongside the Keelson.  These timbers are the same width as the Inner Sister Keelsons, and were sized so that the top of the timbers is at the same height as the Keelson.  (Confession time – these timbers have been installed for quite a while, and have appeared in past photos – I just didn’t bring any attention to them.  I installed them when I discovered the problem with the keelson’s scarf joint – I was thinking of ways to hide that joint.)

 

                        

 

In thinking through how to build the Mast Step, one issue was the fact that the Outer Sister keelsons were a step down in height from the Inner Sister Keelsons and also followed the slope of the floors as they rose from the cutting down line.  This would make fitting any knees to the outside of the mast step problematic at the model scale.  The solution was to mill a couple of timbers that were not square.  They needed to be truly vertical on both sides, but the bottom face needed to be at an angle that would fit to the slope of the floors.  I used a timber that started out square and sanded one face to the correct angle on the disk sander. 

 

                     

 

I then used the thickness sander and, using the angled face as the reference face, reduced the thickness of the timber to the height of the keelson.  These timbers were then glued to the other timbers

 

                        

 

The outer edge of these timbers were still higher than the level of the Keelson, so they were reduced by using a chisel, files, and a sanding block that spanned the entire area of the mast step.

 

                        

 

A bubble level was used to make sure we had a good, level foundation for the mast step.

 

                        

 

I thought it would make sense to make the mast stub before going any further with the construction of the Mast Step.  An existing mast with a tenon already cut would make it easier to correctly size the mortice in the Mast Step.

 

I first decided to make the mast out of cherry to bring a little variety to the appearance of the model.  Unfortunately the cherry I was using had some flaws in the grain, and I gouged out a chunk when I was fairly far along in its creation.  I then made a mast out of boxwood, but didn’t like the pale color – it appeared too weak.  So I made a third mast out of madrone, and it was just right.  The following photos show the process of making the mast, but they may change back and forth between the different woods.

 

The main mast has a rake of about 3 degrees from vertical, so the first step was using CAD to make a template for this angle. 

 

                        

 

I printed this template on card stock and used it to set the miter gauge on the disk sander to the correct angle.

 

                        

 

Since the Byrnes saw and the disk sander both use the same miter gauge, I moved the miter gauge to the saw and cut off the angle on the end of the stock for the mast.

 

                        

 

Using a T Rule and a .3mm pencil I marked lines for creating the tenon – first at the height of the tenon.

 

                        

 

                        

 

Then the outline of the tenon was marked, using the same tools.

 

                        

 

A razor saw was used to cut at the lines.

 

                        

 

                        

 

                        

 

                        

 

A small parallel Barrette (#2) was used to dress the shoulder of the tenon.

 

                        

 

The bottom of the tenon was still at the angle of the rake, and needed to be leveled – this was done on the disk sander at a 90 setting.

 

                        

 

And, having learned my lesson, I marked the forward face of the mast.

 

                        

 

Before finishing the mast, I decided to cut the mortise in the Mast Step.  I decided to use a platform of heavy timbers set across the keelson platform.  I glued them using a squaring jig.

 

                        

 

The following photos illustrate the process of cutting the mortise in the mast step – these photos are of a smaller platform that I made and then decided not to use.  The platform is secured using carpet tape.

 

                        

 

                        

 

                        

 

 As a test, the square mast stock was dry-fit to the mast step.                       

 

                     

 

The next post will continue the description of making the mast, the mast step, and the knees for the mast step.

 

Thanks everyone!

 

 

[druxey]

Nice work there. I believe that the tenon was usually slightly tapered, as was the mortise.

[Mahuna]

Nice work there. I believe that the tenon was usually slightly tapered, as was the mortise.

Thanks Druxey.  I actually tapered the tenon on the first mast that I made but I decided that, given the shallow depth of the tenon, it would fit more securely if I left the sides straight.

[Mahuna]

Part 25 – Mast and Mast Step Cont’d

 

Making the mast out of square stock consists of first cutting the mast to the proper taper and then making the mast octagonal.  Once the mast is octagonal it can be sanded to the final round shape.

 

The tools used for shaping the mast are a good paring chisel (kept sharp), a jig for holding the stock steady while paring it, and a good sanding stick for finishing off the cuts.  The jig has a flat surface on one side and a v-groove on the other.

 

                        

 

The mast stub for Dunbrody has a very slight taper, starting at 19.5 inches diameter at the foot, tapering to approximately 18 inches at the height of the main deck, and then continuing that taper to the end of the stub (I haven’t yet decided how high from the deck the stub will end, so I made it fairly generous).

 

Once the taper is marked on the mast, it is placed on the flat side of the jig and pared to the marks.

 

                       

 

Then a 7-10-7 fan is used to mark the octagonal lines on the mast stock.

 

                        

 

I marked the mast at 2 inch increments and carried these marks around all sides using a square.

 

                        

 

Then the dimension of the mast at each of these points is marked on a tic strip

 

                        

 

The tic strip is then moved to the appropriate spot on the 7-10-7 fan and the inner lines are marked on the tic strip…

 

                        

 

..and the marks are transferred to the mast.

 

                        

 

Once all these points have all been transferred to the mast on all sides the points are joined by continuous lines drawn on the mast.

 

                        

 

The mast is placed in the jig with a corner in the v-groove of the jig to hold the stock steady, and the corners of the mast are pared off to the lines, forming the octagonal mast.

 

                        9

 

This octagonal mast is then sanded to a round shape.

 

                        

 

After the mast was completed, the platform of the mast step was drilled for bolts.  Two of the bolt holes were left open for pinning and the rest of the holes were filled with copper wire for simulated bolts.  The platform was then glued and pinned in place.

 

                        

 

The last step is making knees for the Mast Step.  These knees help to distribute the weight of the mast across the frames and are bolted through several of the floor ceiling planks.

 

The first step is to create a CAD drawing of the knees and to test it for a good shape and fit.

 

                        

 

A tab was left on the drawing of the knee for handling, since the knee is only about ½” on each axis.  I decided to use oversized blanks of 5/32” stock for the knees to allow me to grip them while cutting them out on the scroll saw. 

 

                        

 

The blanks were glued together using Ambroid glue and clamped for drying. 

 

                        

 

After the blank set was dry the drawing of the knee was glued to the stack of blanks using a glue stick.

 

                        

 

The first cut was the shape of the curve of the knee.

 

                        

 

While the blanks were still glued as a set I marked the approximate location of the bolts, so that the knees would appear to be consistently bolted.

 

                        

 

The remaining straight cuts were made, and the knees were separated by a quick bath in acetone (in a closed container).

 

                        

 

Pilot holes were marked on each knee using a small awl …

 

                        

 

…and the bolt holes were drilled in the knees.

 

                        

 

The work-hardened copper wire was 20 gauge, and the drill used was a #70.  The fit was tight enough that no glue was required to keep the wire in place.  I simply grabbed the wire near its end and pushed it into the hole as far as it would go, then nipped off the end of the wire.  The last step was to smooth the end of the bolts using a diamond bit in the rotary tool.

 

                        

 

With the knees glued in place the mast step is completed, and all work in the hold is finished.

 

                        

 

                        

 

                        

 

The next step is to begin working on the beams, stanchions, and knees for the Accommodation Deck.  Some drafting is required, so it will be several days before I have any more progress to post.

 

 

In the meantime, thanks everyone for following, and for the “Likes” and comments.

[Omega1234]

Hi Frank

 

I love reading your updates; this one being no exception.

 

The care and forethought that you put into every piece of the ship is amazing.  I mean, most normal people may have tapered the mast by eye, but you took precision to a whole new level by measuring and marking the taper prior to shaping.  That, Sir, is true attention to detail.  And...don't even get me started on the knees...!

 

Nice!!!

 

Cheers

 

Patrick

[Mahuna]

Thanks Patrick. I guess my life in information technology conditioned me to details. I learned the process for making spars in a seminar by David Antscherl, and enjoy making masts and yards that way.

Edited June 14, 2016 by Mahuna