Tangent Handrailing - Prismatic Solid

[sbebuilders]

Understanding the tangent handrail system.

Billy Dillon, Joe Bartok and I have just started discussing Tangent Handrailing from the book
A Simplified Guide to Custom Stairbuilding and Tangent Handrailing. Which should be read before reading and understanding the book.

Treatise on Stair Building & Handrailing

quote from
A Simplified Guide to Custom Stairbuilding and Tangent Handrailing

The tangent handrailing principle is a geometric method used for laying out tangent lines to make exact joints and patterns for any inclined turned handrail section.

After doing a Google search, there's not really any information on Tangent Handrailing on the web. Here's a link to a you tube video of a German carpenter making and installing the Tangent Handrailing. However, he really doesn't show how the Tangent Handrailing is carved from a solid block of wood.

http://www.youtube.com/user/TopKnotCarpentry

Then I was looking at Keith Mathewson picasaweb site and discovered he's been holding out on us. So Keith, I see your drawings of the face mold, but what about some pictures of you laying out the plank of wood used for the face mold?

https://picasaweb.google.com/Seattle...59183391453874

Attached is an example of an Prismatic Solid from the book A Simplified Guide to Custom Stairbuilding and Tangent Handrailing. The other attachment is a drawing based on Keith's drawing and the geometric development of the Prismatic Solid for Keith's drawing.


Sim

[Jim Baldwin]

Re: Tangent Handrailing - Prismatic Solid

I know this post is directed for Keith but...

The handrail on youtube is mistakenly referred to as "tangent rail". I had some correspondence with the poster and apparently he was under the impression that all curved (wreathed) stair railings are called "tangent rail".

As for the machine shaping of curved handrail, unless you're talking CNC, this is a subject you'd rarely get specific information on since most methods are jig-built fixtures or machines and proprietary concerns. There are of course a couple of factory machines or tools available but I believe quite limited in their application.

Plate 68 of your DC book shows the layout and specific application of the face mold. Keith and I have had several interesting discussions thus far.

www.handrailer.com

[sbebuilders]

Re: Tangent Handrailing - Prismatic Solid

I know this post is directed for Keith but...

The handrail on youtube is mistakenly referred to as "tangent rail". I had some correspondence with the poster and apparently he was under the impression that all curved (wreathed) stair railings are called "tangent rail".

As for the machine shaping of curved handrail, unless you're talking CNC, this is a subject you'd rarely get specific information on since most methods are jig-built fixtures or machines and proprietary concerns. There are of course a couple of factory machines or tools available but I believe quite limited in their application.

Plate 68 of your DC book shows the layout and specific application of the face mold. Keith and I have had several interesting discussions thus far.

www.handrailer.com

Jim, it was only directed towards Keith, because he was the only one on the internet with drawings of the process. Please step right in and tell or show us what we really need to know about tangent handrailing.

We plan on hand shaping the material. No CNC machines. This is a study of tangents that can be applied to elliptical valley rafters as well. The Prismatic Solid is something that we use in roof framing geometry. However, getting the correct layout on the plank is what were after.

diamond hip post or Prismatic Solid
http://forums.jlconline.com/forums/s...=45402&page=12

The geometric layout of the Prismatic Solid is basically the same as our roof framing kernels.


Sim

[olllee]

Re: Tangent Handrailing - Prismatic Solid

Jim, Thanks for getting involved . I saw that you did some work for United Rockland stairs. I used them quite a bit years ago .
I was just able to finally understand sliding the mold in plate 70
Billy

[Jim Baldwin]

Re: Tangent Handrailing - Prismatic Solid

There are great similarities between roof framing and tangent handrail, in fact here is a picture from an old book illustrating that fact. The cutting and beveling of rafters however is an area which should be studied using the text specifically available for that subject.

The elevations for roof rafters are based upon simple projection lines and not tangent elevations. It's a little confusing but Keiths' drawing shows (on the right side) a tangent floor plan along with its' tangent elevation. On the (left side) however is a simple projection-line drawing. These two sets of drawing which are really two different methods, are not normally used in conjunction with each other.

Roof rafter joints along with their bevels almost always stand plumb but handrail joints and bevels (in the tangent method) are butt-joints and made square to the pitch. Therefore, you should not be using elements of the tangent system to design rafters.

There are quite a lot of books on the subject of roof framing including complex cases like domes, steeples and elliptical configurations. The layout and elevations for complex rafter plans occupy page after page. I would suggest getting such a book.

I think Keith would agree with me on this...

[olllee]

Re: Tangent Handrailing - Prismatic Solid

Jim , I am always interested in roof geometry and have many great books on the subject . However developed drawing is what I am most interested in . Tangent hand-railing is a logical progression for some of us who feel comfortable with roof framing and a passion for working with wood .
One of the finest books on developed drawing Traite Theorique Et Pratique De Charpente
by Mazerolle has some very fine drawings of stairs however, I can not quite figure out some of the drawings as related to curved stair work . Hence the interest it Tangent Hand Railing

[sbebuilders]

Re: Tangent Handrailing - Prismatic Solid

There are great similarities between roof framing and tangent handrail, in fact here is a picture from an old book illustrating that fact. The cutting and beveling of rafters however is an area which should be studied using the text specifically available for that subject.

The elevations for roof rafters are based upon simple projection lines and not tangent elevations. It's a little confusing but Keiths' drawing shows (on the right side) a tangent floor plan along with its' tangent elevation. On the (left side) however is a simple projection-line drawing. These two sets of drawing which are really two different methods, are not normally used in conjunction with each other.

Roof rafter joints along with their bevels almost always stand plumb but handrail joints and bevels (in the tangent method) are butt-joints and made square to the pitch. Therefore, you should not be using elements of the tangent system to design rafters.

There are quite a lot of books on the subject of roof framing including complex cases like domes, steeples and elliptical configurations. The layout and elevations for complex rafter plans occupy page after page. I would suggest getting such a book.

I think Keith would agree with me on this...

Jim, what book is that drawing from?

We know there's a big different from handrailing tangents to roof framing tangents, but we are interested in the tangent handrailing method as applied to handrailing.

Sim

[sbebuilders]

Re: Tangent Handrailing - Prismatic Solid

Here's some pictures of the Prismatic Solid fold out geometric drawing for the tangent handrailing.

http://picasaweb.google.com/SBE.Buil...ntHandrailing#

Sim

[Gary Katz]

Re: Tangent Handrailing - Prismatic Solid

Sim,
What book are you using?
And isn't the tangent system the same approach Jed Dixon uses?
http://www.thisiscarpentry.com/2009/...wing-a-volute/

Gary

[sbebuilders]

Re: Tangent Handrailing - Prismatic Solid

Sim,
What book are you using?
And isn't the tangent system the same approach Jed Dixon uses?
http://www.thisiscarpentry.com/2009/...wing-a-volute/

Gary

Gary,

We're using the book

A Simplified Guide to Custom Stairbuilding and Tangent Handrailing

Yes, Jed Dixon is using the tangent system.

However, the video of Mike using the paper patterns to cut the wreath out on the band saw is priceless.

You need to edit that article and insert the words Tangent Handrailing so Google will find the page.

Sim

[Jim Baldwin]

Re: Tangent Handrailing - Prismatic Solid

Oops! the picture I posted came from "The Stairbuilders Guide", Morris Williams 1914.

The TIC Jed Dixon article does not address tangent handrail specifically but focuses on volute layout and the elevation of its' quarter-circle into an elliptical pattern. The bandsaw cut is a simple oblique-cut through an inclined plane and not from any "square-cut tangent" approach.
As far as I can see, this is also true about Keiths' pictures and posting

The subject of "prismatic solids" do indeed include roof slope angles and bevels but in stair work, the prismatic solid also encloses a vertical (right) cylinder not normally associated with of any roof plan. The drawings are complex enough without having to consider this. As for myself, I believe I could answer most questions with regard to T-Rail but roof cutting is another subject entirely.

I haven't been able to view the French book but it looks interesting. As far as I know, the "square-cut tangent method" was first developed in England in the mid 1800's by Robert Riddell who based his work largely on the books of architect, Peter Nicholson. "Simple projection line systems" including "orthogonal projection" were well known long before any of this.

If any one's interested, I can probably answer specific questions with regards to t-rail, but they need to be asked (specifically) otherwise, I just ramble on (like I am doing now).

[sbebuilders]

Re: Tangent Handrailing - Prismatic Solid

After watching the first video at
http://www.thisiscarpentry.com/2009/...wing-a-volute/

we should have bought a book by Gilbert S.B. Townsend

Stair Building: Design and Construction, Bevels and Face Molds, Self-Help Questions

Sim

[sbebuilders]

Re: Tangent Handrailing - Prismatic Solid

I drew out the bevel joints according to the book. Still don't understand where I'm going to use them.

Bevel Joints AMB & ALB for the butt joints of D & A are equal for a quarter turn plan

Their also equal to the 90° - pitch tangent in this examle drawing.

Sim

[sbebuilders]

Re: Tangent Handrailing - Prismatic Solid

Attached is a drawing of an volute. Based on the excellent instructions by Jed Dixon in his article

Drawing a Volute
by JED DIXON on JULY 15, 2009

http://www.thisiscarpentry.com/2009/...wing-a-volute/

Sim

[Jim Baldwin]

Re: Tangent Handrailing - Prismatic Solid

Quite a few of the ancient books from the golden era of stair building are now being digitized and made available online. I haven't found Gilbert Townsends' complete book yet but I do have excerpts of it in another book.

It's all the same stuff however with very few differences. No matter what the titles say, there's nothing "simplified" about any of it. The best book on the subject is therefore any of these books you happen to have on hand. If you can get through one book and understand the principles involved, you will understand any of them.

The only completely different approach is in the "normal section" or square-sectional" method which is not based upon any elliptical, sliding face mold but upon a pair of molds attached to both faces of the plank. This is the only method I would trust while working with the aid of a helper since no layout or thinking is required on their part. All the helper has to do is cut to the edges of the patterns.

By understanding and utilizing these old tangent methods, you could accurately layout and make a beautifully descending volute which could spiral down through 360 degrees! The several conjoined pieces, each flowing into each other and becoming part of the total spiral (for woodworkers, this is called "fun").