Posts + Gallows brackets
 

I’m in progress with an external structural timber project.
Part of this is a number of 150 x 150mm (6” square) treated softwood,
which support roof beams.
The posts will have 45 degree struts coming off them aka Gallows
brackets. Again out of same size stock.
The leading edge of the 45 degree joint is to be cut into the
vertical posts, effectively giving it a stop to rest against (and
transfer load I assume) point, the design calls for this stop to be
‘let in’ 20mm (~3/4”)

Sketch of joint is on: http://tinyurl.com/6nr2jp

Is there any technique for doing this type of joint (don’t even know
what they are called), some posts will have one gallows bracket –
others will have a pair .. in both cases there are galvanised steel
plates through bolted providing structural strength.
Sketch of double one is at : http://tinyurl.com/574dhz

I do not have the option to move posts form their now vertical
permanent position, so I am looking for technique for cutting in-situ,
maybe it’s just a case of getting in there with a chisel, but thought
I would ask.


Intent is to glue the joint as well with quality polyuretane glue ...
but mainly to prevent water ingress, steel plates will provide the
strength.

Posts + Gallows brackets
 

Timberframers call theis a "brace".

http://www.tfguild.org/joinery/part4.pdf

Look at the fourth page of this document (upper left). It illustrates brace
joinery which meets your need to install into a preexisting T-shape. The
bottom mortise for the brace is extra tall. The brace it inserted into the
lower mortise, and lifted straight up so that the upper tennon inserts into
the cross-member mortise. A block is then inserted below the lower tennon to
fill the oversized mortise.

The document has a few other approaches to brace joinery that might also
meet your needs.

If you need specific pointers on how to to the layout for these, just ask
I've done a "barn-load" of them.

Cheers,

Steve


"Osprey" wrote in message
...
I’m in progress with an external structural timber project.
Part of this is a number of 150 x 150mm (6” square) treated softwood,
which support roof beams.
The posts will have 45 degree struts coming off them aka Gallows
brackets. Again out of same size stock.
The leading edge of the 45 degree joint is to be cut into the
vertical posts, effectively giving it a stop to rest against (and
transfer load I assume) point, the design calls for this stop to be
‘let in’ 20mm (~3/4”)

Sketch of joint is on: http://tinyurl.com/6nr2jp

Is there any technique for doing this type of joint (don’t even know
what they are called), some posts will have one gallows bracket –
others will have a pair .. in both cases there are galvanised steel
plates through bolted providing structural strength.
Sketch of double one is at : http://tinyurl.com/574dhz

I do not have the option to move posts form their now vertical
permanent position, so I am looking for technique for cutting in-situ,
maybe it’s just a case of getting in there with a chisel, but thought
I would ask.


Intent is to glue the joint as well with quality polyuretane glue ...
but mainly to prevent water ingress, steel plates will provide the
strength.


** Posted from http://www.teranews.com **

Posts + Gallows brackets
 

On 11 Aug, 18:59, "StephenM" wrote:
Timberframers call theis a "brace".

http://www.tfguild.org/joinery/part4.pdf

Look at the fourth page of this document (upper left). It illustrates brace
joinery which meets your need to install into a preexisting T-shape. The
bottom mortise for the brace is extra tall. The brace it inserted into the
lower mortise, and lifted straight up so that the upper tennon inserts into
the cross-member mortise. A block is then inserted below the lower tennon to
fill the oversized mortise.

The document has a few other approaches to brace joinery that might also
meet your needs.

If you need specific pointers on how to to the layout for these, just ask
I've done a "barn-load" of them.

Cheers,

Steve

"Osprey" wrote in message

...
I’m in progress with an external structural timber project.
Part of this is a number of 150 x 150mm *(6” square) treated softwood,
which support roof beams.
The posts will have 45 degree struts coming off them * aka Gallows
brackets. *Again out of same size stock.
The leading edge of the *45 degree joint is to be cut into the
vertical posts, effectively giving it a stop to rest against (and
transfer load I assume) point, the design calls for this stop to be
‘let in’ *20mm (~3/4”)

Sketch of joint is on: *http://tinyurl.com/6nr2jp

Is there any technique for doing this type of joint (don’t even know
what they are called), some posts will have one gallows bracket –
others will have a pair .. in both cases there are galvanised steel
plates through bolted providing structural strength.
Sketch of double one is at :http://tinyurl.com/574dhz

I do not have the option to move posts form their now vertical
permanent position, so I am looking for technique for cutting in-situ,
maybe it’s just a case of getting in there with a chisel, but thought
I would ask.

Intent is to glue the joint as well with quality polyuretane glue ...
but mainly to prevent water ingress, steel plates will provide the
strength.

** Posted fromhttp://www.teranews.com**

Good document .. but I those 'housed' or 'tennoned' joints are too
complex for this job.
The strength in this job is being provided by the steel plates ...
just need a way of 'stopping' the leading edge of the 45 degree brace,
maybe I just have to cut the end timber of the brace to 50 degree
rather than 45, square off the point and try and scribe in this to the
post.

Just wondred if there was a technique to doing this.

Posts + Gallows brackets
 

Good document .. but I those 'housed' or 'tennoned' joints are too
complex for this job.
The strength in this job is being provided by the steel plates ...
just need a way of 'stopping' the leading edge of the 45 degree brace,
maybe I just have to cut the end timber of the brace to 50 degree
rather than 45, square off the point and try and scribe in this to the
post.

Just wondred if there was a technique to doing this.


Just mark the joint out carefully on the three sides of the post, score all
of the lines with a straightedge and box knife, then use a skillsaw to cut
the square shoulder. A few minutes with a sharp chisel and a mallet will
get the rest of the waste down to the lines, and you're done. It's not
rocket surgery.

Posts + Gallows brackets
 

Just mark the joint out carefully on the three sides of the post, score
all
of the lines with a straightedge and box knife, then use a skillsaw to cut
the square shoulder. A few minutes with a sharp chisel and a mallet will
get the rest of the waste down to the lines, and you're done. It's not
rocket surgery.


Yup.

Make the housing a consistent depth rather than tapered, and just cut the
top edge at a 45-degree angle. This way it's easy to cut out the bulk of the
material with a series of through crosscuts with a circular saw. Cleanup
with a chisle becomes much easier

The top edge does not have to be tight as braces are designed to work just
under compression. The side and bottom faces of the housing bear all the
force. Typically a gap will develop there anyway with the inevitable
lumber-yard wood shrinkage.


-Steve



** Posted from http://www.teranews.com **

Posts + Gallows brackets
 

On 12 Aug, 13:46, "StephenM" wrote:
Just mark the joint out carefully on the three sides of the post, score
all
of the lines with a straightedge and box knife, then use a skillsaw to cut
the square shoulder. *A few minutes with a sharp chisel and a mallet will
get the rest of the waste down to the lines, and you're done. *It's not
rocket surgery.

Yup.

Make the housing a consistent depth rather than tapered, *and just cut the
top edge at a 45-degree angle. This way it's easy to cut out the bulk of the
material with a series of through crosscuts with a circular saw. Cleanup
with a chisle becomes much easier

The top edge does not have to be tight as braces are designed to work just
under compression. The side and bottom faces of the housing bear all the
force. *Typically a gap will develop there anyway with the inevitable
lumber-yard wood shrinkage.

-Steve

** Posted fromhttp://www.teranews.com**

To check what you mean here ... the post is meeting beam at a 45
degree angle, if I read you right, I should cut housing a constant
depth, then cut angle on the end of brace to match ? keeping brace
location overall angle at 45 degree.

I

Posts + Gallows brackets
 

On 13 Aug, 11:00, Osprey wrote:
On 12 Aug, 13:46, "StephenM" wrote:





Just mark the joint out carefully on the three sides of the post, score
all
of the lines with a straightedge and box knife, then use a skillsaw to cut
the square shoulder. *A few minutes with a sharp chisel and a mallet will
get the rest of the waste down to the lines, and you're done. *It's not
rocket surgery.

Yup.

Make the housing a consistent depth rather than tapered, *and just cut the
top edge at a 45-degree angle. This way it's easy to cut out the bulk of the
material with a series of through crosscuts with a circular saw. Cleanup
with a chisle becomes much easier

The top edge does not have to be tight as braces are designed to work just
under compression. The side and bottom faces of the housing bear all the
force. *Typically a gap will develop there anyway with the inevitable
lumber-yard wood shrinkage.

-Steve

** Posted fromhttp://www.teranews.com**

To check what you mean here ... the post is meeting beam at a 45
degree angle, if I read you right, I should cut housing a constant
depth, then cut angle on the end of brace to match ? *keeping brace
location overall angle at 45 degree.

I- Hide quoted text -

- Show quoted text -

If I follow you, as per this sketch: http://tinyurl.com/5764b5

Is it worth putting any dowels or biscuits in as well, the steel
plates will be providing the structural strength, just wondedred if
dowels or pins would help keep joint tighter together.
I will be gluing up with Polyurethane (Gorilla Glue)

Posts + Gallows brackets
 

To check what you mean here ... the post is meeting beam at a 45
degree angle, if I read you right, I should cut housing a constant
depth, then cut angle on the end of brace to match ? keeping brace
location overall angle at 45 degree.

I- Hide quoted text -

- Show quoted text -

If I follow you, as per this sketch: http://tinyurl.com/5764b5

Yup... that is what I meant. It's just easier to cut the joint with a
cirrcular saw that way.

Is it worth putting any dowels or biscuits in as well, the steel
plates will be providing the structural strength, just wondedred if
dowels or pins would help keep joint tighter together.
I will be gluing up with Polyurethane (Gorilla Glue)

If you are going to use a steel plate and bolts to keep the brace in the
housing, you don't need to do anything more. The housing itself should
handle all of the primary forces of the joint.

To clarify: braces only work under compression; that's why are generally
implemented in pairs. Each brace resits wracking forces in the opposite
direction. The compressive strength of white pine (really soft stuff) is
around 500psi (side grain) and nearly 10 times that for end grain.

http://www.matweb.com/search/DataShe... c344c&ckck=1

I think your 6x6 brace will do just fine. :-)

Don't even both with biscuits glue or pins.


** Posted from http://www.teranews.com **