Frame width for the Bounty at 1:48 scale is confusing

[AdamA]

I'm planning to scratch build the Bounty at 1:48 scale. At that scale 1/4" is equal to 12 inches. The Bounty has 10 inch wide frames. How do I convert that to actual inches? The math is telling me its close to 6.66/32" but how do is set my saw for that exactly?

[AdamA]

5.29 mm. I think that's the best way.

[Gregory]

I don't think anyone will notice if you make it 5.3 ..😁

[Don Case]

.0208 (.o21) inches is one inch in 1:48 if that helps. 10 scale inches would be .21".

This leads me to question. Isn't a "smidge under 1/4"" close enough? Is that 40 thou going to make that much difference?

Edited February 18, 2021 by Don Case

[allanyed]

Looking at some assumptions....   91 feet over all, thus about 90 frames if on 12 inch center, including the space between frames which may be as much as 2"  I have never seen framing disposition drawings of a collier but surely there was some space between many if not all of the frames. 

  

 If the frames are made out of scale at 12", there would either be no room for the space between frames in order to wind up at 91 feet, or,  if the 2" space is maintained with the 12" frames, the  hull would be about 15 feet too long which would lead to problems in making the keel the correct length, beam locations, deck furniture and mast locations.  Even if the space was cut down to 1" the hull would still be over 7 feet too long.  

 

5.3mm (.208") is not so hard to do but not with just a saw.  You can cut boards to something more than 5.3mm then use a thickness sander or carefully set a planer to  yield the thickness you want.    Same thing can be done when cutting wood for things such as beams, bottom planking, wales, quickwork, deck planks and so forth.   

 

Allan

 

 

Edited February 18, 2021 by allanyed

[Don Case]

If each space is a little small and each room is a little big then there is no harm done. I can see compounding errors being a problem some times but if there is a way around it why not take it. Setting anything up to cut wood that accurately is not easy although a thickness planer can skim off a tiny bit. Moving the fence on a saw .021", not with my hands🙂

[Gregory]

Make what makes you happy.  What are the chances the inspector general will be coming after you with a micrometer?  😁

[Jaager]

A 12" digital caliper is a friend here.  They show  mm -  inch as fractions - inch as decimals

An electronic calculator and inch as decimals -   never have to deal with how many x/32" or x/64" anything is.

The Byrnes saw has a mechanical caliper with x/1000 based increments.  Now if only there was a digital version for old eyes.....

Use sticks of known thickness as a gauge to set a fence on a saw with a ruler gauge on the slider.  Use the digital calipers to measure the thickness of the product.  What that ruler says is fine for full size furniture, but is totally inadequate for our needs.  Also, precision is more important than accuracy.  Whatever thickness comes off a table saw ( for framing stock, this is a wasteful tool. ) a bandsaw ( less loss to kerf, much thicker stock can be cut in one pass ) or a  thickness sander  - it must all be identical or you will go crazy.  Reproducible results are vital.  On a bandsaw, even if it is a Wood Slicer blade, the surface will need refining to 120 or 220 grit smoothness.  A table saw with a hollow ground planer blade will also need refining.  In most any situation, a final planing function is necessary. 

An on going task for me is to find the necessary thickness from the bandsaw.  How many 1/1000 ths  of an inch will have to be planed on both plank surfaces to remove the blade scares and yield a smooth surface?  The ideal is to set the fence just that much thicker.  A little buffer is probably wise, too much buffer and it is several more passes thru a sander.  Not enough buffer, and you have stock for the frames  of a smaller vessel future project.

 

4 hours ago, Don Case said:

Isn't a "smidge under 1/4"" close enough? Is that 40 thou going to make that much difference?

Oh yes, it will make a BIG difference.  For Navy Board framing - where all the frames are bonded in sequence, even the thickness of the glue layer is a factor.   The general range for the number of frames is between 60 and 120.  Any error is additive.

0.04 x 60 = 2.4"   2.4 x 48 = 115 inches - almost 10 feet.  on a liner that would be 20 feet.

Edited February 18, 2021 by Jaager

[druxey]

The problem of cumulative error can be dealt with. However accurate your thicknessing, there is the added thickness of the glue lines to consider. The best method is to measure cumulative length carefully after, say, five or six frames and then either make the next frame a whisker thicker or thinner to compensate. This will not be noticeable in the finished model.

[Bob Cleek]

7 hours ago, Don Case said:

Moving the fence on a saw .021", not with my hands🙂

 

This is where the Byrnes saw and thickness sander start to look a lot like scratch-building essentials. 

[AdamA]

21 hours ago, Bob Cleek said:

 

This is where the Byrnes saw and thickness sander start to look a lot like scratch-building essentials. 

Is there any benefit to his 230V over his 120V? Is the 6 inch wide that much more useful than the 3 inch wide machine? I'm definitely getting one but there's a $100 difference which can buy a lot of wood.

[AdamA]

Ok i was confused but I figured it out. 

I just purchased the Byrnes thickness sander. They are both 6 inches wide. One is a smaller radius drum and a wider opening. 

[Jaager]

1 hour ago, AdamA said:

Is there any benefit to his 230V over his 120V? Is the 6 inch wide that much more useful than the 3 inch wide machine? I'm definitely getting one but there's a $100 difference which can buy a lot of wood.

I have been thinking that the 230V was intended for countries where 230V was standard house current.  If you are US based, 120V is sufficient.  It is a 3/4 HP motor.    The 18" table is more than I would need for any billet that I would use it to cut.  The main advantage if you are not cutting wide boards would be that the sliding table can be used without having to remove the fence. 

 

It looks like the 6" Luthier drum has a smaller diameter. The standard is much more suited to my needs.  $8 for a 6" wedge covers any need for getting it to mount 6" wide sanding material.

 

As for $100 - that is only about one and a piece of a board  8x4 by 8" by 8 feet of Hard Maple.  10-12 bf.   

[Bob Cleek]

2 hours ago, AdamA said:

Is there any benefit to his 230V over his 120V? Is the 6 inch wide that much more useful than the 3 inch wide machine? I'm definitely getting one but there's a $100 difference which can buy a lot of wood.

 

There is no difference between the 230VAC and the 120VAC Model Machines saws. The 230VAC machine has a 230 volt motor and the 120 volt machine has a 120 volt motor. Both motors are 1/3 horsepower. The two options exist because two-phase and three-phase alternating current voltages vary from country to country in the world. The voltages aren't standardized. The two most common two-phase "mains voltages" are 120VAC and 230VAC. For example, North America and Mexico run on 120VAC, while much of Europe and South America run on 230VAC. (See:  https://www.generatorsource.com/Voltages_and_Hz_by_Country.aspx)  

 

I'm not sure what you are referring to when you ask "Is the 6 inch wide that much more useful than the 3 inch wide machine?" I am only aware of a size difference in the Byrnes saws tables. The standard "Jim Saw" has a 12" wide table and the new "extended table" option has an 18" wide table.  The new wider table makes cutting wide stock more convenient, to be sure, and if you had bucks to burn, it would be nice to have, but it's probably more useful for people who customarily cut larger pieces of stock than most modelers do. It probably would appeal to luthiers more than modelers. Before I would spring for the extended table, I'd certainly buy the cross-cutting sled. It is very finely made and as accurate as the basic saw and accuracy at high tolerances is what the Byrnes saw is all about. You can make your own cross-cut sled out of wood, but it won't be as accurate as the CNC machined Byrnes cross-cut sled. 

 

I'd advise anybody buying a Byrnes saw for modeling to "bite the bullet" if at all possible and purchase the basic saw or the extended table model with the following accessories because you'll eventually buy them anyway and you'll probably save a fair amount on shipping if it all comes in the same shipment:

 

Sliding table (cross-cut sled)

 

Extended rip fence

 

Miter gage adjustable extension

 

Rip taper gage

 

Micrometer stop ("standard" inch measurements or metric, as might be your preference)

 

Miter bar (extends miter gage)

 

Replacement belt

 

Accessory pack (Extra screws and miter pin some of which you will eventually drop, never to be seen again. Worth twice the cost in saved aggravation.)

 

Zero clearance insert (One for the stock blade comes with the saw. You'll want one for each of the kerf widths of the thinner blades you buy.) 

 

Additional blades as required. (You'll want two or three thin ones, probably. Read this PDF before selecting blades: Byrnes Saw Operation.pdf 6.42 MB · 444 downloads  .  Also, read this entire thread before you decide on which accessories you want to purchase. It's full of good information and discussions on which accessories are best for ship modeling. 

 

 

I know that's going to add somewhere around $300 to the cost of the basic saw, plus what you add in blades and inserts, or $160 or so if you pass on the sliding cross-cut sled, but these accessories are really what one would want to get the greatest use out of the machine. What's the point of buying a saw that is accurate to thousandths of an inch and not springing for the $55 micrometer stop that will make measured .001" fence adjustments for you? 

 

If you read the above threads, you'll see that nobody has a bad word to say about the Byrnes table saw. As they say, it's the gold standard. It will hold its value, as well, so if you ever find yourself with no further use for it, you will be able to recover a good portion of your investment on resale. For the difference in the quality and accuracy of this saw over any others on the market, there's really no excuse for not paying a bit more for it except simply not being able to afford it an if that's a problem, consider that it will probably pay for itself in the savings realized by being able to mill your own wood. 

 

 

Edited February 20, 2021 by Bob Cleek

[Bob Cleek]

Ah, ha! I thought you were talking about the table saw! Duh!

 

As for the sander, as explained above, the luthier model will sand a thicker piece of wood. I wouldn't think it would be any more useful for ship modeling unless someone was working in very large scales.

 

However, that said, the "three inch - six inch" distinction with the sanders mentioned in their website actually refers to the width of the abrasive sheets used on the drum. (It's a bit confusing in the website photo.) Both sanders will take two three inch sheets or one six inch sheet on the drum. The two three inch sheets are intended for sanding up to three inch wide stock, the two three inch sheets being different grits, so you could mount 80 grit on one side and hog off a lot of material and then move over to the other side of the drum and sand a finer surface with 180 grit or whatever grits you wish. The two 3" abrasive sheets are held on the drum with two metal wedges held in place with two screws, one wedge for each sheet. (Look closely at the picture. Alternately, on either model sander, one can mount a single six inch wide sheet on the drum and sand with a single grit of abrasive sheet, allowing sanding a flat piece of stock up to six inches wide. For this application, they have an optional six inch wide wedged bar to more easily load and hold the six inch wide abrasive sheet. You can mount a six inch sheet using the two three inch bars, but for eight bucks, the convenience of the six inch wedge is worth it. (In ensures getting an even tension on the abrasive sheet, as well.)

 

I'll leave the screed on the Jim Saw posted in case somebody is interested.