tzonoqua Posted October 2, 2009 Share Posted October 2, 2009 Got an enquiry for possible job creating dragon themed handrail for a sweeping staircase. (Not quite spiral, large curvature) How on earth does one measure the curvature accurately? Bear in mind, math is not my strong point!! Am better at "freeform".... Hate to turn the job down because it offers creative expression, and I do like a challenge, but I can't being to think how I might approach it. Anyone got any tips, how to measure/plot it out??? Help.... :o Quote Link to comment Share on other sites More sharing options...
myloh67 Posted October 2, 2009 Share Posted October 2, 2009 Use 8x4 ft sheets of hardboard 3mm thick, cut appropriately and screw or attach together on site. Mark plenty of datum straight lines (good and long) so back at the forge you can reposition accurately. On site take a measurement from wall or edge of thread (step) place a mark on hardboard and consistantly reproduce on each step. Mark on hardboard possible fixing points on site. Back at workshop, its a matter of joining up the dots and creating the curve. The accuracy involved is in the joining up of the dots. Get a step ladder or hop up on a height to ensure no flats occur in your curve. Maybe usefull! Quote Link to comment Share on other sites More sharing options...
unkle spike Posted October 2, 2009 Share Posted October 2, 2009 If you could figure out what radius the staircase arc is at, you could use a nail, a piece of string tied to a pencil to "draw" it out full scale. Without seeing the layout it is hard to come up with a fast and true method.... Where is Jr. Strasil when we need him....? Quote Link to comment Share on other sites More sharing options...
Mick Posted October 2, 2009 Share Posted October 2, 2009 Colleen, when stair makers do this they will pre-assemble the stairs in the workshop and make the railing to the staircase. You will need to recreate the stairs in your workshop with a dummy structure and fit your rail to the curve. measure each tread of the stairs very carefully, (make sure you measure to the same points on each one) also measure the height of each one above the last. On site set up a gauge pole, that is long enough to go from ground level to the top of the stairs, absolutely plumb, (vertical). Position the pole where an extended line from the face of bottom stair and the face of the top stair intersect. Take accurate measurements from the pole to front corner of each stair tread. In the workshop mark the height of each stair on the gauge pole, and set the pole up plumb. Make a pattern of each stair tread (16mm mdf would be good). Using your offset measurements you can then fix each tread to scaffolding (basically joining the dots) You should end up with a very accurate copy of the stairs and a working platform. Build your rail to this. If I were you I would subcontract this portion to a carpenter, for airfare food and lodgings I would be happy to do it for you but I guess it would be cheaper to use someone local. Quote Link to comment Share on other sites More sharing options...
GiFerro Posted October 2, 2009 Share Posted October 2, 2009 I do not have the photo, but if I make it available to everyone, I tried to make you a drawing, THE QUESTION angles round tube and paintings that slips inside each other telescopically with the retaining bolts from the facts. .... meadow On the steps you can adjust both the height of the step tread and of course for SIA Follow the curve of the staircase, in sufficient numbers for all the steps, once blocked ports all bolts in the workshop and you have the outline of REALIZE by Scala a job that could use for future Scala, I'm sorry if not clear in explaining, but I do not speak English well, I'm writing from italy ... Hello Giancarlo. Quote Link to comment Share on other sites More sharing options...
GiFerro Posted October 2, 2009 Share Posted October 2, 2009 here are the pictures I hope you can understand better what I wanted to tell you, with this system you can do all types of scale that you want directly in your workshop. Quote Link to comment Share on other sites More sharing options...
arftist Posted October 3, 2009 Share Posted October 3, 2009 Wow! What a great system GiFerro. Thanks for posting that. I just did an eliptical staircase a few weeks ago. Acording to the plans, there were three different radi, but reality was different. I bent the rail cap onsite. I made it in three sections and carried it in and out of the house till it was done. The cap was .5" by 1.75" hotrolled steel. I bent it cold, using a power roller, a vice mounted on my truck, and big twisting wrenches. If I had known about GiFerros method, I could have avoided driving an hour and a half each way for two days. Quote Link to comment Share on other sites More sharing options...
irnsrgn Posted October 3, 2009 Share Posted October 3, 2009 if the curvature is equal along its full length. You need to find the chord © and chord height (ch). take a straight piece of something a known length, and lay it so its ends touch the curve at each end this is the ©. Then find the exact center and measure the distance to the center of the curve at an exact 90 degrees to the straight piece, this is the (ch). C=72 inches ch=11 inches formula is 1/2 C squared + ch squared divided by ch = DIAMETER OF THE CIRCLE. 36 x 36= 1296 11 x 11= 121 1296 + 121 = 1417 divided by 11 = 128.8181818 inches is the diameter of the curved section divided by 2 = 64.409 is the radius multiply .409 times 16 = 6.5 16ths of an inch, so the radius is 5 ft, 4 and 13/32 inches. Quote Link to comment Share on other sites More sharing options...
irnsrgn Posted October 3, 2009 Share Posted October 3, 2009 To draw the radius on a flat surface just use a stiff board with a nail or other sharp object thru it near one end, measure off the radius and drill a hole for a piece of soapstone or a pencil, mark the center, and have someone hold the pivot while you move the marker around the radius. Quote Link to comment Share on other sites More sharing options...
GiFerro Posted October 3, 2009 Share Posted October 3, 2009 you can do all the calculations possible, but in my opinion will never be equal to the scale to achieve, you will never find a scale accurate to the millimeter, then become a silhouette remains the best remedy, what's better than a template to be reused in the future? trust the gauge can be divided into pieces to mark the exact spot and then reassemble in the workshop .... Quote Link to comment Share on other sites More sharing options...
GiFerro Posted October 3, 2009 Share Posted October 3, 2009 Wow! Quello che un grande sistema GiFerro. Thanks for posting that. I'm glad you like the idea, too bad the council has come late, but could always use another scale ..... I know what it means to make a shape on the ground, and difficulties that you may have with quell'arnese would have saved many trips back and forth ..... Hello greetings from Italy. Quote Link to comment Share on other sites More sharing options...
beth Posted October 3, 2009 Share Posted October 3, 2009 hey colleen interesting thread - i dont have a job like this but was looking at a beautiful staircase on the gallery and wondering how on earth you get the curve right. its the sort of thing that brings me out in a cold sweat because i worry about maths too! let us know how you get on - i bet you ll do a brilliant job - great advice above!! Quote Link to comment Share on other sites More sharing options...
irnsrgn Posted October 3, 2009 Share Posted October 3, 2009 Well, Ok if you say my calculations won't work I guess they won't, I just wonder how I lucked out on the Hospitals front drive railing, it was a 28 foot radius, 35 ft long on a 10 degree incline, I built it in the shop and the alley and hung it from the left side of my 53 Studebaker deuce n a half winch truck and chained it down and drove it up there and had the construction crew help take it off. OH well, sometimes you just luck out, I guess. Quote Link to comment Share on other sites More sharing options...
jeremy k Posted October 3, 2009 Share Posted October 3, 2009 (edited) Curved stairways are challenging to say the least. Triangular measurments onsite never lie if they are wrote down correct and on the detailed drawing/sketch. Take a minute and think of a triangle... if you take the measurements of the 3 sides and replicate it elsewere - you cannot get a different size triangle. Appliing this method along with elevation measurements of each step will result in a fabrication job in the shop that will fit on the job. I've done jobs and have taked 3 point measurements for each tread point from a central reference point ( this has even been a vise grip clamped to the drip edge of a roof on an attatched garage/boat house ). In this photo that clamp was placed on the drip edge between the first 2 posts on the horizintal railing that was the existing railing above the garage/boat house. hand railing - Blacksmith Photo Gallery Like I said 3 point measurements for each step point and elevations of each step. Then in the shop I could replicate those measurements and build the railing as needed. Like mentioned earlier - scaffolding/ladders are used and will add large amounts of time to projects like these - be prepared !!!. This was a stairway that was "NOT" a constant curve - it started out slight at the top and tightened at the bottom. Also each tread riser was not the same - that's the reason for all the measurements. A job like this one -which when done looks like a very simply done railing can amount to easily over 100 individual measurements to keep track of and duplicate. This was done in the shop as a 24ft long (railcap) 1 piece, painted and installed so that no welding onsite had to be done. Finished railing :hand railing - Blacksmith Photo Gallery - - JK Edited October 3, 2009 by jeremy k Quote Link to comment Share on other sites More sharing options...
GiFerro Posted October 3, 2009 Share Posted October 3, 2009 (edited) Maybe I was misunderstood, I did not say that there are mathematical formulas that can solve the problem of scale ecoidali, but the main problem to fit an iron staircase on a structure (certainly uneven) built with concrete, making a silhouette is one of the systems but it could be measured step by step starting from a fixed point, as shown in the drawing .... Edited October 3, 2009 by GiFerro Quote Link to comment Share on other sites More sharing options...
GiFerro Posted October 3, 2009 Share Posted October 3, 2009 Maybe I was misunderstood, I did not say that there are mathematical formulas that can solve the problem of scale ecoidali, but the main problem to fit an iron staircase on a structure (certainly uneven) built with concrete, making a silhouette is one of the systems but it could be measured step by step starting from a fixed point, as shown in the drawing .... Quote Link to comment Share on other sites More sharing options...
jeremy k Posted October 3, 2009 Share Posted October 3, 2009 GiFerro - Posted a pic above(post # 16), of how I did the one in the pictures of "my" above post # 14. What I did forget to say is - The triangular measurements is made up of point to point measurements from the tread nose to the central location and the nose to nose on the treads themselves, so you have a tread point to tread point (2 treads are involved) and the distance from each of those 2 tread points to the central location that makes up the triangle. - I hope this clarifies things better for everyone. - JK Quote Link to comment Share on other sites More sharing options...
tzonoqua Posted October 3, 2009 Author Share Posted October 3, 2009 eeeeek!!! Ok, thanks for all these suggestions, it all sounds bloody complicated!!! Beth, don't worry, I am having a cold sweat just thinking about it!! I have not yet even seen the staircase that my potential customer has enquired about, so until I have I don't know if I can decide which method might work best. I do like GiFerro's idea of the "jig" type way. And I now wonder if my workshop is even big enough to construct this... will give an update once I've been to visit the house. Quote Link to comment Share on other sites More sharing options...
arftist Posted October 4, 2009 Share Posted October 4, 2009 Maybe I was misunderstood, I did not say that there are mathematical formulas that can solve the problem of scale ecoidali, but the main problem to fit an iron staircase on a structure (certainly uneven) built with concrete, making a silhouette is one of the systems but it could be measured step by step starting from a fixed point, as shown in the drawing .... Giferro, please do not take umbrage, your system is foolproof, thankyou very much for posting it. The other two gentlemen are both discussing simple outside guardrails, not attached to treads, an entirely different job than an inside handrail attached to the treads, way less room for error in the second case. I assure you, I will use your system on my next eliptical stair job. Quote Link to comment Share on other sites More sharing options...
jeremy k Posted October 4, 2009 Share Posted October 4, 2009 Arftist - I use my method for interior staiways also - yes the example I posted picures of is outside and "along side" of the stairway, but the process is still the same to get the layout of the curve/s. Your right - on that the mounting on the tread themselves - I do take additional measurements for those issues and still have no problems. As with all fabrications - you can only get it as close as your measurements - provided they are right and wrote down in the right spots. I personally have found the triangular measurements along with elevation measurements to be most accurate to duplicate exact positions of need to know points during fabrication. - JK Quote Link to comment Share on other sites More sharing options...
arftist Posted October 4, 2009 Share Posted October 4, 2009 Jeremy, all that you say is true, yet I know that the posibility of error is much greater with measurement alone than with measurement and a gage. The last stair I did had a strict deadline, in order to stay in good graces with the builder and the clients. The decision was made to do it in the feild to avoid the possibility of a mistake. The job was done on time and well recieved. If I had the gage that GiFerro posted, I would have gotten a bit more sleep that week. I am glad that you have supreme confidence in your measuring skills. We are all different, what is best for me may not be best for you. Quote Link to comment Share on other sites More sharing options...
myloh67 Posted October 4, 2009 Share Posted October 4, 2009 And I now wonder if my workshop is even big enough to construct this... will give an update once I've been to visit the house. Theres always outside ..limitless space there! Quote Link to comment Share on other sites More sharing options...
unkle spike Posted October 4, 2009 Share Posted October 4, 2009 Well, Ok if you say my calculations won't work I guess they won't, I just wonder how I lucked out on the Hospitals front drive railing, it was a 28 foot radius, 35 ft long on a 10 degree incline, I built it in the shop and the alley and hung it from the left side of my 53 Studebaker deuce n a half winch truck and chained it down and drove it up there and had the construction crew help take it off. OH well, sometimes you just luck out, I guess. Jr. I would take your brains over my dumb luck anytime... :) Quote Link to comment Share on other sites More sharing options...
pearstairs Posted October 10, 2014 Share Posted October 10, 2014 · Hidden by jeremy k, October 10, 2014 - spam Hidden by jeremy k, October 10, 2014 - spam hello everyone.. Find the right staircase design for your home. We offer a full selection of bespoke staircase ideas, parts and manufacture a complete range of wooden staircases in UK. Link to comment
AlmonteIron Posted July 16, 2015 Share Posted July 16, 2015 Maybe I was misunderstood, I did not say that there are mathematical formulas that can solve the problem of scale ecoidali, but the main problem to fit an iron staircase on a structure (certainly uneven) built with concrete, making a silhouette is one of the systems but it could be measured step by step starting from a fixed point, as shown in the drawing ....I realize that it is an ancient post - but I'm trying to load the pictures that GiFerro put up for his approach to laying out curved stairs. Does anyone have these?Thanks! Quote Link to comment Share on other sites More sharing options...
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