Friday, July 30, 2010

Building a Staircase.

It has been a while since I have built a staircase, so I am absolutely delighted to have one to do now as my current major job. There is a lot of maths involved in building stairs, so it is a workout for the brain as well as for the body - the timbers are big and very heavy!

Getting started - the planning.
My first task was to plan the staircase and start doing the maths after obtaining the essential measurements of the empty stairwell space in the house. I did a heap of drawing and presented a few options, and my customers opted for a staircase with winders - that is, there is an upper and lower straight flight with radiating treads around the corner newell post mid way up. This would increase the size of the pantry underneath the upper flight, which was their reason for chosing this option.

The maths in a staircase are really interesting, to make it egonomically right. Ever been on stairs which don't feel right? Here's how we'll get this one right: The height difference between the top and bottom floors on this job is 2655mm (the total Rise), and the plan shows 15 treads. This means the "Rise" height (the height of each step) must be 177mm, regardless of the style or configuration of this 15 tread staircase. The vertical surface at the back of the tread is called a "Riser". The length of the step (from riser surface to riser surface) is called the "Going". Long ago allegedly someone determined that it takes twice as much energy to walk upwards as it does to go forward. Hence the relationship between the Rise and the Going is determined by a formula, these days called "The Rule of 585":
  GOING + (2 x RISE) = 585mm (to a maximum of 625mm).
Hence for this staircase the maximum Going on the straight flights would be 250mm and the minimum would be 231mm. Given the requirements from my customers to maximise the size of the pantry underneath, we opted for a 230mm Going in addition to the Winders around the bend. With a 30mm overhang of the tread beyond the front of the riser, this would give a total tread depth from front to back of 260mm. Armed wth this information, I created a set-out board - a full size drawing of the detail, to determine the various angles.

Time to play with timber!
My customers live in a house in Augusta with lots of jarrah, so they wanted something different, a lighter colour. The opportunity came up to purchase some American White Ash for a very good price, so that is the timber I am working with for this job. Interesting stuff, I understand it is what is used for baseball bats in North America.

The next task was to sort through the stack of rough sawn timber. The pic above shows some of the sticks on saw stools during my sorting process. All 2" thick, the widths varied from 14" to 6". Sorting through the pack involved seeking out the imber suitable for the stringers, treads, etc. The sticks which had a "wind" (propeller twist) I docked to length for making treads and other short components. The straighter sticks I left that way and pre-dressed. I then spent 4 hours machining, on the buzzer and thicknesser at the Perth Wood School. I was kindly given access to their gear, including the 12 inch long bed buzzer, so this enabled me to dress the first batch of timber. My 6" buzzer is too small to handle these big sticks! I pre-dressed all of the sticks except for the last 12 which I have left rough sawn, which I will access later as I need them.

 This pic shows the pre-dressed timber in the back of my ute on my arrival home. The longer ones here are 2.5m long, which was the length of all the original lenghts. Now the work really starts!

Making the Newel Post.
In my planning for this staircase design and construction, I decided to laminate up an octagonal newel post. In this way the winding treads on the bend will each radiate out from a flat face on that rising bend. The octagonal post will have a 170mm diameter up to a point above the widers where it will morph down into a 100mm diameter turned cylinder. One lamination will be missing below a certain point inside the pantry, inorder to house the chest freezer at the back of the pantry.

   You can never have enough cramps! This glue-up involved 50 cramps and 4 lamination layers, making a post just over 3.2m long.

Once the cramps were removed the next morning, I squared up one edge to the faces. This is one massive stick, so the easiest way to square the post was to shoot one edge by hand (using the trusty Stanley No.7). I then lugged it to the thicknesser and completed the squaring up and dimensioning by sticking it through the machine. Handling this stick on my own, I was sweating!
Another view of that beautiful No7 jointing plane. My Dad was given this by his father when Dad commenced his apprenticeship in 1945. Last year Dad handed it on to me ... I am so priveledged to have custody of this wonderful tool with such a significant history. Nice one, Dad! Thank you.

The next stage after completing the squaring of the post to 170mm was to turn it into an octagon. To achieve this, I cramped a straightedge along each of the 4 faces in the right possie to use this as a guide for my trusty 9 1/2 inch makita power saw. This worked a treat to accurately remove the waste. Once again the No7 was used to shoot two of the new faces at 45 degrees to the original square faces, and then the stick was put through the thicknesser several times carefully to create an equal sided octagon at 170mm from face to opposite face. If I wasn't stuffed before, I certainly was now! This beast is damn heavy!!

With the machining and dimensioning completed, the marking out of the housings for the treads and risers was commenced on the newel post. This pic shows the marking out in progress.
Meanwhile, as the newel post was being created I was also working simultaneously on making the treads and stringers. To create the 42mm treads which are 260mm deep, I need to glue up most of the treads, using a butt joint with a double spline in the joint. The splines are  of 6mm thick plywood. In the foreground of this pic there is a pair of treads in the cramps still.


As mentioned earlier, the top section of the newel post will be turned down to around a 100mm diameter. How to do this? Well my solution has been to create what you might call a temporary long bed lathe. With the post being 3.2m long, the way I created this was to use about 40 cramps, a few big blocks of wood, and a bunch of long sticks out of my timber racks. When I made the Hill 60 columns, I used a similar method. It works well. By using cramps and the whole thing constructed on a couple of pairs of saw stools, when I have finished with it the cramps will come off and the timber will go back in the rack. This time I have used a spare lathe headstock at one end (attacehd to it's bed!), and a workhead bolted onto a stack of blocks at the appropriate height.

Only the top metre of the post needs to be turned in this way. To create a nice parallel top end of the post at the right diameter, a wide board is cramped parallel to the axis of the post (which is held between centres), and a sliding toolrest fabricated out of bits and pieces from around the workshop in order to hold an angle grinder with an Arbortec disk in it. This assemply then has both X and Y axis movement, with another cramp providing an adjustable depth stop.

       
This pic shows the Arbortech at work. Although the top of the post is mounted on a faceplate in the headstock, the variable speed lathe has a slowest speed of 500rpm - and this is way too fast for this huge lump of timber in a temporary bed held together with cramps! So the post is revolved by hand initially, then the forward motion of the Arbortech provides enough friction on the timber to turn the post while simultaneously reducing its diameter into a nice cylinder. It works OK.  
This pic is a close-up of the arbortech at work in it's assembly on the sliding toolrest.

With this timber, I couldn't get a smooth enough finish off the Arbortech, so I decided to power the rotation of the post. With the lathe unable to turn slow enough, I used the arrangement which worked for the Hill 60 columns. I once bought an el-cheapo wood lathe at a garage sale. I kept the headstock and chucked the rest. The headstock spindle protrudes from a box which houses the motor and an enclosed 4 speed pulley arrangement. So using yet more cramps, I put this power source behind the post and had a v-belt running around its headstock spindle and then around the bottom end of the post. I set it on the fastest speed that I dared without the whole lot vibrating too much, and then was able to get a much smoother finish off the arbortech. I then used the belt sander, random orbital sander, and hand sanding to sand down the 100mm cylinder and a nice transition from the 170mm octagon poast. It is a winner!   


This pic shows the cylinder prior to motorising the post, which would prove to give a smoother finish.

Here's a shot of the motorising department. It also shows the workhead bolted to the block of timber and housed in the piece of 3/4 inch ply which was screwed to the bottom end of the post. This motorising set-up may look rough but it worked like a dream. Spinning a 3.2m long solid stick of timber in a 170mm octagon. Serious weight to it and that dinky little headstock off the cheap lathe turns it well from straight off the spindle. I only paid $20 at the garage sale for the cheap lathe too. It has paid for itself many times over!

I love this amazing and weird shot! My I-phone camera takes all these pictures. The spindle was turning at the time, so it was an action shot. I expected it to be a blurr - but instead it came out looking like a spiral!!

This is a pic of the post once the turning and sanding of the cylinder was completed. It has been sanded to about P240 grit, in the line of the grain. Nice. You can see this whole thing took place in the patio adjacent to my little workshop. Lucky it was a fine day. That is Rosemary's red stripey hammock pulled out of the way and tied to the pole. This patio is affectionately know as "The Tearooms" by us - but it is a wonderful spillover for me when I have stuff to do which is too big for my workshop! Not that Rosemary is thrilled about that...

Another view along the completed post from the bottom end.

This pic shows the transition from the 170mm octagon to the 100mm cylinder. Not bad, eh?

The next stage for newel post is the chopping of the housings for 5 of the stair treads and risers, and the housing for the top end of the bottom stringer. The housing for the bottom end of the top stringer I will chop on site after the bottom flight and the three widers have been assembled in situ. At this point the newel post will be totally fixed in position. There will be lots of fiddly stuff to make and fit on site, so I am being careful at this stage. The location of the transition point from octagon to cylinder I had calculated from the full-size drawing I did on my set-out board. ...hope I have drawn if right... Fingers crossed, eh?!

So I got on with things and was too busy to take pics as I went - I have to remember to do this as I go!
Here is a pic of the housings in the newel post for the treads and risers. From out of 5 of the 8 faces of the octabon, a tread emerges. Once this was done, there was nothing more to do on the post until I got on site.
Meanwhile, it was back onto making the bottom straight flight of stairs.

  
Here the bottom flight are cramped up. the bottom riser is not in place, as the stringers have been left an extra 10mm long, in order to scribe the base to fit the floor, which may not be level. Once the stringers have been scribed to the correct level, the riser will be cut to height and inserted prior to the bottom flight being bolted to the wall in position.

 
This pic shows the bottom flight completed ready to be taken to the job site. With the newel post done, the bottom flight completed, the material machined up for the top stringers, and the remaining treads and risers made, it was time to pack up and head south to Augusta for the installation. This was going to be a big load on the trusty ute. The other pic is a closeup of the housed treads and risers. All a very nice fit!

Like I said, it would be a load!! It rained that day with a for cast for a storm, so I had to have it wrapped up pretty well for the 320km (200mile). It was very heavy too. I can't even lift the bottom flight, but I got the whole lot loaded onto my ute, wrapped and secured before the rain arrived that morning. It was a mission. Sometimes working on your own has down sides - like when you have to load up. The ute is pictured here at the junction of Sues Road and the Brockman Highway, only about 50km from the final destination.  

Yep, it was loaded, and very heavy (did I mention that?). Fortunately, it kept dry too.

Here is the timber and components unloaded on site in the adjacent kitchen space, ready to go. In another room are the many boxes of tools, fixings and other equipment that I also had unloaded from the ute.

This pic shows where the staircase is heading!


This pic shows where the staircase begins... the hole we are going to fill. I say "we" because my wonderful Dad, who lives next door to the job site, has been itching to give me a hand. At 82, he still has heaps to teach me - though I can show him a trick or too as well these days - and we really enjoy working together. He is hard of hearing too, so that always makes it entertaining as we communicate on the job! See the floor sander, well I brought that down on the back of the ute too. First task was to sand the jarrah floor ready for the staircase to be fitted. This pic shows the end of that travel day. It begins in earnest tomorrow, with the sanding to be completed first up.

  
Here is the bottom flight in place. The floor was sanded, the bottlms of the stringers scribed and trimmed to height, and the bottom riser trimmed and fixed. Now to fit the post.

The post here has been fitted. It was like a jigsaw and had not been assembled previously. It had all be done by measurement and working off my fill sized set-out board, so I was very pleased (and relieved) that it all went together so well. Nice to no longer have to move that very heavy poast around anymore, too! That's Dad surveying our progress.


This pic shows the tenon of the stringer and the top step of the bottom flight fitting nicely into the mortice and housings in the newel post. So satisfying when it all comes together!!

 
With the stringer and post joint pulled up, the fixings were put in place to hold it there.

The first of the winders had been fitted and the second one is about to happen. This is fiddly work, and we also first used Dad's machines for a couple of hours to create the flooring which we will use on the winding steps.

Two of the winders are in, and we are working on the third and fourth. Dad here measuring the length of a riser. Framing had to be fixed to the walls to support the flooring/winding treads, so there is plenty to do!


This pic shows the winders completed. Now for the top flight!

 
The top stringers were then made, and the first of these fixed to the wall in the appropriate location.


The big tenon on the end of the centre top stringer fitted beautifully into the mortise on the newel post. With the cramp pulling the stringer tight into the joint, the measurements could be taken to cut the top flight treads and risers to length. The cramp was removed adn the top centre stringer taken down. Then each of the treads and risers were individually fitted for their housing, as they would need to each be inserted after the stringers have been fixed in their respective positions.

Meanwhile, we laminated up the two posts and the pantry door jamb. The 2 posts would be structural supports for the upper centre stringer, which transitions to a small flat landing before it meets the wall and doorway above. Dad here checking the cramps after we have done the glue-up togther. One post will be 90 x 90mm and the other 90 x 70mm, at nearly 2.7m long.

These pics show the posts in position and the top stringers in poace for a "dummy run". Check, check, then check again... once we start putting it all together there will be no turning back without major grief!

Here most of the treads and risers have been inserted and fixed in position. It was left overnight cramped in position while the glue dried. The prop against the opposite wall applied the pressure needed to keep everything in exactly the right position. Next day the remaining treads and risers, the top landing and other structural elements were completed. After the final sanding, a sealing coat was added. The treads and risers were now completed! We're not finished yet with this staircase, but we are most of the way there...

This pic shows the top flight from the corner of the first winder. Still no balaustrading, handrails or cover strips around the wall on the winders or the top landing yet. 


I am very pleased the way the winders come out so cleanly of the faces of the octagonal newel post base. It looks great and was a good way to construct it. Essentially the line of each riser face passes through the centre point of the newel post. The drawing on my set-out board was beautifully transfered into reality!
The picture on the left shows the top of the stringer against the wall terminating up in the air. The 45 x45mm cover strip referred to earlier will pick up the end of the stringer and follow the wall all the way to the top stringer, going up and along each of the winders on the way. There will be much scribing to do around the tread nosing. One of the finishing jobs to do...

Another job still to do is to make and fit the balaustrading, the mid posts, and handrail for the top stringer. This pic shows the completed upper middle stringer with the structural support posts below. We are considering what would be a nice top for the newel post - as yet undecided. I am likely to turn something up as it could be quite a feature I reckon.

  
Well, this is a big change from the empty hole which was there about 5 days ago.
The pantry is also coming together on the right. Doorway opening is rebated on the inside, as I will be making a nice pair of doors to go in the opening, which will open inward. The triangular space between the top and bottom centre stringers will be filled in with some vertical WA Blackbutt lining board. That's another task to do - as is the shelving in the pantry and 3 big drawers which go under the bottom flight of stairs.

It's been a brain teasing but very satisfying project, which I have been enjoying immensely. I have also really enjoyed working with Dad again. It is nearly time to get back to Perth, once I have laid adequate protection on the stairs and put up temporary fall protection. The painter, tilers, sparkies, plumbers, cabinetmaker and other tradies are still to finish off their work upstairs in the master bedroom.


I will be returning to Augusta to complete the staircase in a few weeks, when I bring and install the carcasses for the new kitchen I am about to start building. I don't really do kitchens anymore, as my workshop is too small to set them out. However I am pleased to do this job for my son and his partner, for whom I have been building the staircase. The kitchen will be no "chipboard special" of course. It will be a cross between a modern kitchen and a large piece of furniture! ...Stay tuned for more developments with the staircase as work on this job resumes in due course!...

2 comments:

  1. An exceptioal piece of work Greg and an inventive use of the arbortec tool I,m sure they would be very interested
    John A

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  2. Come on Greg, waiting for the next instalment.
    Heard you are now looking after our two black bantams too. elijah will be pleased.
    Phil

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