Any advice out there on laying out the tread pattern on a curved stair stringer . I know the rise and run for the treads . I am just looking for a good way to transfer from a flat framing sq. to a curved stringer.
I am also looking for a good way to make the router template for the wedged treads and risers. maybe bending plywood ? I have the form walls built and am getting ready to do the glue up. The inside radius is 33″ and the outside is 65″. The staircase will be freestanding. I’m planning on using 5mm luan 16″ wide in seven layers per side.
Any advice would be helpful.
Ken
Replies
Draw the layout on mylar (for dimensional stability) and glue it to the stringers?
Ken,
I'll see if I can dredge up some photos tomorrow of my layout jigs in the mean time you might want to reconsider the the 5 mm luan; it just doesn't have the load carrying capacity for a free standing stringer. Been there done that, much to springy for my taste.
I think that you'll be okay with stringers of that size.... 16 inches is a pretty stout depth. If you plumb your stringers you could use a horizontal laser beam to layout elevations for the treads. If you have or can get one that also gives you a vertical beam then you can use that to layout the risers but a level would work for the risers. the nice thing about the laser beam is that it will follow around the curve for you. Use a nice straight batten as a straight edge that will wrap around the curve to mark the tread levels. You can raise and lower the laser beam or just reference measure it from one location.
Clay, The laser beam is a great idea. I lay 1/8 inch masonite on the floor and make a full sized drawing of the treads and stringers, then plumb up onto the stringer to generate my riser lines. The tread height is transfered from a story pole and marked on the riser lines, to connect the dots I use a plexi straight edge. I also check the spaceing between each riser with trammel points tweeking them a little if necessary to get a uniform distance between each one.
You guys can do what you want, I have built dozens of these, luan does not cut it for free standing stringers, when is the last time you seen an LVL or gluelam built out of luan?
Armin,
is any plywood type material suitable for the stringers? What about 1/4" baltic birch scarfed to length? It would make for alot of scarf work but the plys could be left exposed on the edge for a conteporary kind of look.
Any suggestions on the routing template?
Ken
Ken,
I use 1/8 baltic birch with staggered butt joints. 1/4 inch is to stiff to bend. In those applications where I need max. strength I resaw maple or birch to the required bending thickness somewhere between 3/32 and 3/16 thick. Phote below of a spiral using all maple laminates.
Nice job! That is'nt your average Yooper shack! Is that floor birch?
Brudoggie
Thanks Brudoggie, actually things have changed this is a yooper shack, as a matter of fact it's one of the more econo shacks I have worked on lately. Floor is hard maple.
Sorry Ken, I can't find the photos of the router jig I have been searching for, I'll keep looking. They were originally posted in the photo gallery can't seem to locate them there either.
Photo of staircase under construction in my shop & corresponding installed view.
Photo of installed staircase.
Hey Armin those shots look great! It looks like those are solid wood rails (as opposed to bending rail) am I correct? Are you shaping your rails using the tangent handrailing technique George di Christina has written about?
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"Function is based
on more than utilitarian factors. Ambiance invites use."- Sarah Susanka
The handrails are hard maple laminates, inside rail is 22 plys the outside rail is 16 plys. The inside stringer and handrail were laminated on a section of 12 inch dia. PVC pipe. Photo below shows the rail being trimmed with a router jig.
Armin; Your work looks beautiful! Thanks for sharing it. I have posted a couple pics below of a recent handrail project that I did. The stairs were existing but the homeowners tore out the handrail and balusters cause they didn't like them. They had some juniper logs that they thought maybe I could use to build a new handrail with. As you can see, I did. I also inlaid zircote leaves to cover the old baluster mortises. It was GREAT FUN!!! I have a question RE: laminating baltic birch (which I recently did for a round table skirt). Do you run the plies alternating the long and short grain? <(how I did it) Also I used titebond extend for glue but I'm guessing that would set too fast for your projects..... what would you use?
Clay, You are very talented and creative. I have a client who is having a new log home built and would love a handrail like what you did. How did you blend in the splices?
Gluing up a baltic birch substrate: It depends, for flat work I will alternate the face grain but for curved work I run the grain the direction it bends the best. The 1/8 inch material bends very nicely yet has lots of strength. Titebond is not the best choice for laminating a lot of plys since it injects a large amount of water into the core, eventually the water has to come out possibly creating a host of new problems weeks or months down the road. I use Unibond 800, a resin, powder catalyzed glue, it's water cleanup while wet but water resistant when dry. The down side is min required temp of 68 degrees and 5 hour set time. On the plus side there is no cold creep under load, (as in laminating bending stock) the glue joint remains rigid eliminating the tell tale bump at the seam formed by titebond.
Armin; There are only two joints in the handrail. Most of the bends were natural growth formations. I just butt joined them to make the alignment of the cuts simpler (still far from easy). Then I drilled about three inches by 3/4 inch into the center of the butt ends. I used an 18 inch long spade bit to help me sight the right angles. I cut some 6" lengths of oak dowel and test fitted them before gluing. I had to adjust the angles of the face on the butts sometimes (a little) with a 4 1/2" grinder fitted with about a 40 grit sanding disk. Then I assembled them with gorilla glue. The logs were not quite fully dried yet so that worked good and as they fully seasoned they tightened down on my dowels. Lastly I used a filler that I made up with Golden acrylic molding paste tinted with acrylic paint to match the wood tones. It takes several coats to get a good fill with this recipe because it shrinks ... but it's quick to apply and 'sandable' and retains just enough flex to stay where I put it, and it is a pretty strong bonding agent too. If an area of grain is too obvious at the joint I make a double tapered v shaped cut that removes the offending grain (at the surface anyway) and then fill it so that the resulting patch extends through the joint and visually ties the two pieces together. I have also done the same sort of repair where I used a deep v gouged chip from a similar piece of wood as the filler instead of my acrylic. When using this method it is important to keep the sides of the cut the same as the angle of the v gouge which will cut the filler chip. The filler chip is also cut a bit overlength and the ends are sanded off after the patch is glued in and dried. I hope that helps ... nice work you are doing. I can see that you are like myself in being stimulated and attracted to challenging projects. Thanks for your info. Oh, by the way, I left the cross sections at the joints a little larger than I ultimately wanted them to be. Then after joining I shaped them down together so that the curves flowed pretty smoothly. I mostly used the above mentioned disk sander on grinder to do that (and then smooth sanded, of course).
Edited 2/21/2003 10:25:35 PM ET by Clay
Cool!
Make a tred template, hold it level against the curved stringer and scribe your horizontal cuts. Just a thought.
Let me know if it works and where to send the bill.
If you know your inside and outside run, and you also know your rise can't you just lay the treads out on a 16" x 1/8" or 1/4" sheet of plywood just like a regular staircase. I'm building a set rate now and that's what I've started to do. I've been thinking that this will work. Hope so.
Rick, you can't layout rise , run on a flat board and bend it around. The curved tread lenght at the stringer will be slightly longer than the flat layout. In other words your flat layout is the tangent of the arc between the two riser points.
Armin, you had me worried. I had cut my inside and outside stringers already, and you said it wouldn't work. I must not have explained that I took the radius change into account for each lamination, my radius was also quite large, which helps with the tangent. Once I had enough layers I used a router to cut the rest ( open stringers). I've sent a photo, these steps will be used as construction stairs and covered in oak at finishing stage. Your photo's were very impressive.
Rick,
I took the radius change into account for each lamination
Proof again there is more than one way to skin a cat. Yes your method should work ok if everything is right on. I have tried a similar method in my early stages of stair building however the thought of a laminate shifting or getting torqued out of shape at the critical moment was to unnerving for me. I draw a full scale layout on the floor anyway so the time it takes to transfer the layout is minimal. Thanks for the compliments. Looking forward to seeing more of your work.
Edited 2/28/2003 11:11:37 AM ET by Armin a.k.a. The Laminator
Clay and Armin.....awesome work.
I have built several free standing stairs that have curved housed stringers. I have always built my own patterns for routing the stringers using the same techniques that I learned from a master stair builder who was my teacher when I was in trade school.
The process involes making a pattern for your riser and treads with room underneath each of the parts for your wedge blocks out of 3/4 inch plywood. I recomend using a plywood that has a large numbr of veneers to it for the best stability and smoothness along your actual pattern edges (because any imperfections in these edges willbe transfered by your router's bushing guid to yhe stair stringer.)
As in the case of radiused stringers, you must make a pattern that has the same radius, so what I have done in the past is laminate several layers of 1/4 inch plywood together using the stringer as a pattern for the pattern.
Quite honestly, finnished stairbuilding is the most difficult aspect of carpentry,it is a true art form and housed stringers on a radiused stair is the pinacle of the art. I would suggest not to attempt this unless you are positive that you have the skills to accomplish this project
Sincerely,
Ryan
Do your complete stair info, rise and run etc. on the lamination of ply that will be housed, "before" you glue it up. And yes, this works and is probably the most accurate method, you must allow for the change in the radius as this increases or decreases depending on the position of the lamination. The jig for routing the housing is done the same way, lay it out on the flat material, allowing for the change in the radius again, then glue it up on your form.