I’ve installed tons of curved stairs but never built anything myself. Since I’m getting set to build a small addition on my home with a home office going in on the second floor I’ve decided to take the plunge and try something I’ve never done before. I’m going to build my first curved staircase to access that office but before I get into it I want to make sure I cover some of the questions I still have.
1. What is the best material for the stringers laminations? Should they be 3/16 thick or 1/8 or does the thickness of the material depend on what you use?
2. What’d the best glue for for gluing up the laminations
3. I know when wrapping the laminations around my forms that they will “creep” (is that the word I want to use?) up and down so how after they have all set up do you level the top and bottom of the stringers so you have a smooth continuously flat surface that you can attach a veneer to to hide the lam edges?
4. Any other layout and setup hints anyone wants to throw at me I am all ears.
Replies
With any luck Stan or Armin will be along both are very accomplished in spiral stairs
John
1. What is the best material for the stringers laminations? Should they be 3/16 thick or 1/8 or does the thickness of the material depend on what you use?
What do you want your stringers to be, paint or stain grade? If your painting you can use popular, works good.
The thickness of the material depends on the radius of the stairs, if its tight then you need the laminations thinner, if the radius is large then you can get by with thicker laminations. Having to many laminations wont hurt you but it may create work that you don't need.
2. What'd the best glue for for gluing up the laminations
I usually use regular old yellow wood glue, I know that others use the urea formaldehyde(sp?) glues, but the yellow wood glue has served me well.
3. I know when wrapping the laminations around my forms that they will "creep" (is that the word I want to use?) up and down so how after they have all set up do you level the top and bottom of the stringers so you have a smooth continuously flat surface that you can attach a veneer to to hide the lam edges?
I take a power planer and clean the edges up. If I was using popular and cleaned up the edges with the power planer then that'd be all that I would do. If stain grade is needed then you could veneer the edges depending on what you used for your laminates and what you considered acceptable for the edge.
Have you given any thought to how your going to attach the treads and risers?
Are you going to have open stairs or are the risers and treads going to be trapped inside the stringers?
Doug
Thanks Doug with respect to the popular are you talking about solid (3/16 or 1/8) poplar? I was thinking of 3/16 and 1/8 ply. Any ideas as to where would I go about getting solid 3/16 or 1/8 poplar (central Connecticut).I was thinking of using a power planner to level out the stringer but with the toe an the heel of my planner riding on the stringer I don't think I will I get the depth I need from the cutter head. And do you have any hints on how to keep it on the right plane angle as you work you way up or down the stringer?<<Are you going to have open stairs or are the risers and treads going to be trapped inside the stringers?>>I'm planning on going with a closed stringer stair housing the treads and risers. I have seen photographs of a professional stair makers tool that routs out the ploughs for curved stairs and I was thinking of building my own curved homemade jigs (one for the inside stringer and one for the outside) that would allow the templates to be positioned correctly and creating a custom base for my router that fits the radius of the curves. What are you going to suggest or am I on the right track?
Edited 6/7/2005 9:45 pm ET by John NYCT
John
I've resawn the popular to get my 1/8"-1/4", doubt that you could buy it that way, maybe so, don't know.
I've built curved stairs using 1/4" ply(cant remember the type), the radius wasn't all that tight and the bend was no strain on the wood.
I think Bear suggested using Unibond glue, I've never used it, heard good things about it though. I always use yellow glue, you can get slow tack if you think you'll need it, I always managed with the regular.
I've heard of some people using epoxy but damn that stuff is to messy!
You will need to approach with some caution when using the planner, take it easy and you'll get the hang of it. I free hand it, if I'm off a bit(and I usually am) I can fix it.
You have the right idea making a jig. Obviously placement is the key.
Doug
Edited 6/7/2005 11:23 pm ET by Doug@es
<I've resawn the popular to get my 1/8"-1/4", doubt that you could buy it that way, maybe so, don't know.> Well you've got a much bigger and better bandsaw than I do then.< You will need to approach with some caution when using the planner, take it easy and you'll get the hang of it. I free hand it, if I'm off a bit(and I usually am) I can fix it.>I still don't know about the planner fro leveling the top and bottom of the stringers though. I made a small test curved stringer to try out the technique and I found it clumsy. There has to be a better more precise way. What do the big stair shops do? I am pretty sure the stair stringer on the stairs we've installed from Staircase & Millwork (Mr. Stair) weren't trimed and leveled by a handheld power plane.
John
We'd bandsaw the wood and then run it through the wide belt to make it "nice".
I think I seen that you were doing paint grade? If so don't worry about bandsawing then, use ply. Quicksilver gave you some very good info.
Yea the hand held planner can be a pain but we do it just like it says, "free hand". I suppose that you could make some sort of jig for the planner if you wanted to.
I don't know how the big shops do it, I don't work in one of them.
Make a post to Stan Foster, I've seen pictures of his stringers with the power planer, I think he does it free hand, not 100% sure. Maybe he has some technique that were missing. He builds curved stairs all the time and does so with out a lot of fancy equipment, I'm sure he has some method worth hearing about.
Doug
Stan is probably busy flying around in that copter he is always talking about.
A lot of stairbuilders are now using 1/8 or 1/4 inch birch ply for laminating the stringers. This size depends on how tight the radius is. Using solid poplar in these sizes is an option but you will have to plane it down to size or do some very difficult resawing. The more laminations you use the less spring back you will experience.
Yellow glue will not give you enough open time to get your work done unless you are very fast. Buy some Unibond 800 which is designed for vacuum bagging put will work just as well without the vacuum press. You will get a lot less spring back with unibond 800.
You can use a power plane to dress the top edge, you will have to skew it to get the blades to make contact.
You do not need to make a special base for your router, make a template from 1/4 inch ply and clamp it into position. Your mortise will be slightly deeper at the front and rear but that does not matter.
Bear
Right,...Unibond 800 I had forgotten all about that stuff, thanks for the brain jolt. I'm pretty sure I've heard that recommended for lamination before.<You do not need to make a special base for your router, make a template from 1/4 inch ply and clamp it into position. Your mortise will be slightly deeper at the front and rear but that does not matter.> Or vice versa on the inside stringer. I think I'm going to make the jig and template anyway since I love making jigs and templates and my shop is full of them. Plus I would think having the ploughs be a consistent depth helps setting the treads and risers tight which in turn helps set and keep the stair the right width and eliminates chances for squeaking developing on down the road.
I would build the stair in place. Lay out both radiuses. inside and outside. Then measure in 12'''s in from the inner (smaller) radius and strike another radius on the floor. This is the walk line. Most codes require 9'' 's on the walk line. Plumbing down the upper landing and some trial and error will help you find the center of these arc's. Using trammel points step off the walk line very 9 '' 's. Now snap a line from the center point through these marks on the walk line. This will describe the treads rise to rise. Now use these lines, where they cross the inside and outside radius as a layout to build two curved 2x4 walls. Use plywood to cut the plates and a centering head and combination square blade to mark the endcuts on the plates. Once the walls are built take another 2x4 and lay out the rise sequence on it. Add subfloor to finish floor onto the bottom the subtract the tread thickness and cut the story pole. Now take a water level or laser and transfer theses marks to you studs. 1st rise to first stud 2cd rise to second stud and so on. Mark the front of each stud. Now if its paint grade I've never worked on a stain grade stringer with this application, we use 1/4 '' luan 5 plys if there a support wall 7 if not, and yellow glue rolled on with a seven inch roller. We staple the plys to the studs using the marks as a guide. When you get to the last layer shoot the staple through some half inch plywood strips. This will help you remove the staple after the glue dries. This is for the smaller radius of an open tread stair. For a close tread you have to use this trick with the plywood for the last three layers so that you can pull the staple an allow the stringer to be routed. Then using the same story pole you can figure out how to mark the treads, Put a mark at the front of the tread and one from the back and connect with a flexible rule. We use a sawzall (Is that PC to call it a sawzall here) to cut out the toothed stinger and a homemade router jig to cut out the mortise at the larger radius.
Edited 6/9/2005 10:25 pm ET by quicksilver