Questions about Building curived railing...

[mreza Salav]

As mentioned earlier, we are building a new house and I am taking on some of the tasks myself. Some of you who have not already called me crazy might do so if i tell I'm planing to do the railings (curved) for the stairs, newel posts, etc myself. So please bear with me with the questions I have.
I know there are some here who do these on a daily basis. I am a not a pro and have never done this type of job but I have done some research and I think I have figured out most parts. Just want to run them by you to see what I am missing. I will likely start this in a couple of months.

Attached are the main floor and 2nd floor area where the stair/railings will be. The stairs are contracted out; they will be carpet grade with stain grade maple stringers. I will be building the railing, newel posts, shoes, with iron wrought balusters. They will be out of maple and stained (with the rest of mill work in the house, like doors, trims, etc). The stairs will have carpet treads but I'll probably add a plywood face to the risers.


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I have already resawn some 16' and 8' maple for the curved railings (here are some photos):

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and I think I have figured out how to do the glue-ups (angle brackets to the stairs, clamps, etc). I think I will shape/route the profile for the flat curved pieces in my shop on a router table or shaper but for the curved railing on stairs I'll have to jig-up something to do it by hand. The difficult part is to "plane" the piece after the glue-up to get consistent thickness on all 4 sides and a smooth surface before starting to shape the profile. That one too I think I have figured out using a flush trim bit and multiple passes from two sides, but if you have suggestions/comments about this part, please let me know. Things I am not sure about are:

- Should the curved (but flat) shoes for the second floor also be made using bent lamination? I could do that or make them using solid pieces.
Any reason not to make them out of solid? The second floor railing will be broken into 2 or 3 pieces with a post between.

- The type of iron wrought to use: there are different types, most 1/2" ones you'd have to drill a square hole at the bottom and then either use glue or a small set screw to secure at the bottom. To drill the holes and chisel them square I'd have to make a block/jig I suppose.
There are others who have a shoe (or a shoe pitch) at the bottom. I am not sure which one would be easier to work with. For the ones with a shoe pitch is the angle of the shoe going to match the angle of the stairs or they come in different angles?

- How would you secure a post to the floor if there is no floor joist right below it? Should I install a block and glue/screw to the floor and then slide the newel box over the block and secure/glue/screw it to that block?

We are still at framing stage of the house so have plenty of time before starting this project, but will have more questions as I get closer to this.
thanks. I will likely build the posts too.

[Jerry Miner]

This is a big undertaking, especially if you are unfamiliar with building stairs and railings. Curved stairs in particular are a specialized trade. I admire your courage. Gluing up the blanks is the easy part! (Probably too late for this, but have you considered making your life a little easier and using bending rail?)

I would suggest a couple of books on the subject:

"A Simplified Guide to Custom Stairbuilding and Tangent Handrailing," by George Di Cristina

"A Treatise on Stairbuilding and Handrailing," by Mowat

"Modern Practical Stairbuilding and Handrailing," by George Ellis

Note that the pitch of the stair (and railing) will be different at the inside and outside, so one "shoe angle" at the bottom of the balusters will not work on both sides of the stair.

For the bottom post (you are using a "box newel"--hollow inside to slip over solid post?) I always like to secure to the framing underneath when possible. Block between joists and anchor as firmly as possible.

Good luck with this. Would love to see progress photos.

[Mel Fulks]

The shoe moulds are done out of solid or bent . Sometimes both methods used on same job site. You said the stairs are being contracted out . I understand many of them are made by out of state specialists,but if they are being made locally I would look into getting the rail glued up on their form instead of using the actual stair. If that is your main stair carefully consider the pitch. A circle stair made with the "walk line" the same too steep common modern pitch as straight stairs are attractive but not pleasant to walk.

[Mel Fulks]

The books Jerry recommends are all good for stair geometry but your stair is not that geometrically complicated . I agree it is a big job as far as the amount of work compared to a straight stair. The books do have some applicable info on the pitch thing. The books are not really construction info as much as they are ways of figuring changing curves, complicated transitions, landings ,etc. If you buy just one get the Di Christina as it is more modern design oriented.

[Mel Fulks]

I agree gluing the blanks is not difficult. But it's just easier to work on a form than the stair , it's messy and the mess you make on the stair itself will be yours to clean up or fix. Most these days do use the bending rail.

[mreza Salav]

Thanks for the comments. A few points:

- I did consider buying bending rail but couldn't find a local supplier and getting it shipped (given the 16' lengths I needed) made it quite expensive.
One challenge I have is to send those pieces through the drum sander in my basement shop! I need about 33' of space for this task.
I got a quote for the railings/posts from different local suppliers and the price tag for the railings/posts (not the stairs) were around $30-40k for what I wanted (plus another $8-10k for the stairs). A bit too high for me.

- There will be spindle/railing only on the inner circle of the stairs mostly (except a small piece).
Are the spindles with a pitch shoe all come with a fixed pitch or can I choose one to match my job? Where to find ones with specific angles?

- Yes, I will have a few boxed (hollow) newel posts, plus a few smaller solid. I thought of using blocking between the joists (like a box) to beef up the floor to which the posts will be bolted down.

[Mel Fulks]

The bending rail glue up leaves you with a lot of scraping and sanding to do .A LOT. But avoids all the shaper work. Not sure I under stand your question about the spindles . They can be pitched ,but that is most unusual . Most of the time the lower spindle turnings are all the same size and you just order two lengths. Some of the factory turned ones have funky designs ,poorly executed without the nice crisp flats ,deep coves . I was on a job once when the home owner proudly showed me the spindles ordered from a glossy brochure. I'm not one of those " yeah , that's beautiful" guys. I told him they were horrible because they were. Coves not deep enough on highly modernized urn. Fillets and cove all just one big fat ugly line,etc. We had some GOOD ones locally turned and he sent the others back. He later told me that was best money he spent on the whole house. Plain tapered spindles with proper entasis can be quite beautiful. In modern houses I think painted spindles look best. And rail looks better real dark instead of the too common match to light color floor, and it best conceals the bending rail glue joints.

[mreza Salav]

I shouldn't use term spindle (confusing with wood), as they are balusters. Here is an example of what I mean by pitch shoes Mel:
http://www.woodstairs.com/psh02-12-iron-pitch-shoe-with-set-screw-p-2498.html

I am not familiar with these and am trying to figure out if installation would be easier with these as I don't have to worry about how the bottom hole looks; they will be covered with the shoe. Or should I simply drill square holes, and glue in the balusters at the bottom...

[Jim Andrew]

Years ago I built a house with a curved stair, for the jacks I used 1x12's and just doubled them. Bought about all the c clamps I could find, used spruce 1x12's as they bend pretty easily and just glued and screwed the pieces together right to the walls in the house. The open side I just put some temp walls up to fasten everything to. Used the bending rail, made a bracket for each step and clamped the rail at each step, then added clamps between. The thing is, you can't hardly use enough clamps as the railing has to twist slightly as you go towards the top. If I were to build my own, would buy the router bits MLCS makes for railings, and would use something like biscuits to line everything up. You would probably have to set up a temporary stair or wall to be able to glue the rail up off site. Easier to do it on the job. If I were building my own newels, would go with hollow posts, maybe with raised panels to fancy them up, or with trim. Have done it a few times, due to the cost of the fancy stair parts. Last time I built hollow newels, I made posts from 2 2x4's with 1/2" spacers between. Bolted them in place before the sheetrock was applied, then just put the finished parts in place at time of trim. Had to use a few shims to make the posts square and plumb, even though I installed the center parts as straight and plumb as possible.

[Ken Andersen]

Can't help you with the "curved" part. I built and installed the railings, newel posts, and shoes for my daughter's new house. Used maple and 1/2 inch square black iron balusters. The railings were essentially straight, except for offsets where the railing passed a higher flight of stairs. Apart from that, the only other (flat) curve was for the "balcony" of the cat walk joing two bedrooms on the second level.

I don't know about "should", but I made the (flat) curved shoe for the catwalk section starting from flat stock with mitered dowel joints.
The rail for this was done similarly, except I used (horizontally) laminated stock with the mitered dowel joints of the top and bottom layers staggered.

I'm not sure if you can, but I was able to build each section of railing/shoe and then install between the newel posts. Thus, I had access to the bottom side of the shoe. I made square maple plugs about 1 1/2 inches long to go inside each end of the balusters. The balusters and plugs were cut to length (with appropriate mitre angle). The plug to be used on the railing end was secured to the railing first with a wood screw through it's length. With a small dab of construction adhesive inside the end of the baluster, it is then slid over this plug.The plug on the shoe end is placed in the baluster first (again with adhesive) and receives a screw from the underside of the shoe.

Wherever there wasn't 2x material directly under the subfloor where a newel (and brace) was to be installed, I opened the subfloor sufficiently to install a piece of 2x to the underside of the subfloor with construction adhesive and screws (from the top) and then patched the subfloor. I then attached a stub post, sized to fit snugly inside the newel, to the subfloor using construction adhesive and a lag bolt through the length of the stub into the subfloor and underlying 2x material. The stub was pre-grooved along its length on one side to accept one leg of an 8"x8"x1"x1/4" steel 90 degree brace; a similar groove in the subfloor receives the other leg of the brace. The brace is screwed in place along with construction adhesive on both legs. Once that adhesive is cured, the stub is covered with construction adhesive and the newel put in place (with temprary bracing if necessary to maintain plumb while adhesive cures). This gave an incredibly sturdy installation.

[Mel Fulks]

Mreza, I just looked at them . They are new to me. I don't generally like iron interior balusters ,but I can see some practicality in the trim shown. All kinds of theories on installing balusters, for wood I like double end screws at tread and dado with fillets at handrail. If you make the handrail dado deeper than normal and fillets thick ,you can install all the balusters at one time and then set the rail on them. Need several people for that,but only for a few minutes. But just several years ago I worked for a guy who still insists on dovetailing the balusters.

[Richard Wolf]

Like others have said, this is a big project to undertake with little experience.

The wrought iron shoe only come in one angle and will most likely not be the angle you need. If you use aluminum shoes, you can sand the angle to match what you need, but that is a difficult job. If you decide to not use shoes, I drill a 9/16" hole and square it up by driving a cut off piece of wrought iron baluster into the hole. The down side of this is you will have to drill an oversize hole in the rail to push the baluster in and then pull it down into the square hole.

If you are determined to make you own rail instead of using bending rail you should profile the outside lamination before you glue up your rail. They can be profiled and then resawn to the thickness you need. Trying to profile a curved stair rail after it is bend is very difficult without the right equipment. It is also very important that when you bend your rail that you over bend AND over twist it. Spring back will always happen and is difficult to predict how much will occur.

The balcony rail can be laminated or made from solid, I like to laminate because if you cut from solid you will always have areas where you are trying to shape runout grain which will love to blow out.

Box newels that are hollow are easier to install, most come with a block that can be secured to the floor and the post slipped over it and secured with construction ad. Make sure you purchase hollow post. Some manufactures make solid box newels which are much more difficult to cut and mount.

If you have any questions just ask.

[Richard Wolf]

That estimate for 30 to 40K for the rails seems absolutely ridiculous. I have been in the stair business for over 25 years and when I hear prices like that I can only assume one of two things. They have no idea what they are doing or they don't want the work. I work in a high price market and from your drawing can tell you that a job like that is worth about 10K, tops.

[mreza Salav]

Many thanks Richard. I knew you are one of the pro's in this business.
For balusters, I was thinking of using 1/2" drill at the bottom and then square them up with a moritiser chisel and mallet. For the flat ones I perhaps do them in my shop on the mortiser. If I may ask a few of questions:

Q1- I am planning to use epoxy for the glue-up and plan to have the lamination pieces thin (around 1/8"-3/16"). I have done several bent laminations of smaller sizes (like 5-6' for furniture) but nothing this big and have never had issues with spring back when taking things out of the form. How much spring back should I account for in this case? the radius of the circle is 4' 2" and the height of ceiling is 9'.

Q2- About the "twist": when I think about the railing I felt that the top of the railing should be always parallel to the ground (or thread so to speak). As someone who hasn't done this before, my thinking tells me that the slight twist is a by-product of rolling the laminations around a cylinder and so unavoidable. Is that the case or are you talking about adding a twist intentionally? (I suppose not). Also, my thinking says the twist will be very very slight and will appear during the bending/glue-up. Is there something I should plan for this?

Q3- I have seen the Scheer router jig and one that a fellow creeker made (with your help):
http://www.sawmillcreek.org/showthread.php?56604-Handrail-Router-Jig
I am planning to build something like that (but easier) for hand held routing. Is that what you are talking about?

thanks

[Mel Fulks]

I don't speak for Richard but I got the same impression you did until I reread it. Spring back is not a problem with commercial bending rail because the plys are thin,have a tongue and groove type registering , and are pre moulded. If you glue up your own rail from plys you will have to shape post glue up. The twist is automatic when glued up on proper form,it's something you don't normally think of . Picture the rail finished and lying on the floor, in that position some don't even recognize what it is .It will look more like a twisted mess than good rail. Much of the books referred to earlier deal with making circle and ELLIPTICAL rail from solid pieces several feet long and then bolting the ends together, that's why I said I thought you didn't need but one...if any.

[Richard Wolf]

The railing on a curved staircase is not only bent to a curve but must twist from top to bottom. Take a small piece of wood in your hand and bend it into an arc, now hold the arc at about a 40 degree incline and you will be able to see that this is not what you need for the staircase, but it needs to twist.
Epoxy will work fine, I have used it but prefer Weldwood plastic resin glue. Which ever glue you use, use plenty of it. It is easier to clean up over glue than try to fix a glue starved lamination.
The router is what I am talking about, because you must be able to rotate the router down the twist of the rail while you move it along the curve. Then repeat the same move on the next pass.
I am almost temped to say that you should cut enough material for two rails so you have a back up. You will learn a lot from your first attempt and then have enough rails to go at it again. This is not a reflection on you, but experience helps when doing something like this.

[mreza Salav]

Thanks again.
Yes, I'll use lots of glue, and I think I have enough veneers to make two if I screw up the first.
There are a few smaller pieces to make (for 1st floor to basement) which are shorter. I probably start with the smaller pieces.

As for "twist" I think I understand what you are referring to. For example in the following picture:

http://www.woodworkingtalk.com/attachments/f2/16562d1283437722t-curved-stairwell-rolestairs.jpg

the stringers (if looked at as a piece of wood) are not only bent but also twisted a bit, if that's what you mean. How I view it is they are wrapped around a big cylinder from bottom of the cyilnder to the top, and the top of the stringer (where the balusters go) is always parallel to the thread/ground.

Richard: to account for spring back, if the railing is over the smaller (i.e. inner) stringer, do you suggest to install the angle brackets (for glue up) so that the rail lamination will be past the stringer (instead of directly over the stringer) so that it is forming to a slightly smaller circle? For a 4' 2" circle how much do you typically adjust your form?

I will start a new thread when I start ths project.

[Richard Wolf]

That's a good picture that shows the twist. It comse natural as you bend the rail around the form. I always keep the rail over the stringer at the middle of the stairs and over bend it at least an inch at the top and bottom. Another tip I always do is to wrap the entire lamination with shrink wrap after I apply the glue and before I bend it on the forms. I saves you a real mess with glue on your hands and dripping all over clamps and forms.
You also many want to do a dry run without the glue to see if it is going to be a wrestling match or not.

[mreza Salav]

I always keep the rail over the stringer at the middle of the stairs and over bend it at least an inch at the top and bottom.

I see, thanks.
Yes, i had planned to wrap the laminations after applying the glue in shrink wrap to keep them intact before clamping. Epoxy is a mess to work with.
And yes, I definitely will dry run the whole thing to make sure I can manage it with one extra person as helper.