OpenLock 2.0 Spiral Stair Infinite Tread by Start2

Last crawled date: 3 years ago

A spiral stair tread, 30deg/8.4mm tall and 38.1R (3in dia/1.75R)
Wanted to set up a spiral stair that could hold figures. Use as many as you need to get as high as required.
Kudos to Printablesceneryhttp://www.printablescenery.com/product-category/rampage-system/
Rampagehttp://www.thingiverse.com/thing:1821631
OpenLock 4.0http://www.thingiverse.com/thing:1833963
DevonJoneshttp://www.thingiverse.com/thing:2034428
Cobble Pattern by Siennahttp://www.thingiverse.com/thing:1921325
Using Devon Jones Curved wall "cut_stone.wall.TA.1.5rx0.5.curved.openlock" which is a wall made to fit the H floor tile (a 2" inside radius) and the .5inch wall has a 2" outside radius. Created the stair to fit within this open 3in diameter (1.5 in radius).
You would need to use OL2 HE to finish a 8"dia tower floor or 9"dia. with walls.
Here: http://www.thingiverse.com/thing:2055430
Design: Started with 38.1 dia tread and peg was to be made to fit the "hole". As I made the initial set of treads, I had to print upside down as to not use supports. After printing, realized I could use filament as the peg through the treads. They individually would spin around and I had to glue together to make the picture.
2nd Gen tread had pattern, and I still printed upside down, but used 3.3 hole. Was tight for a 3mm filament as the filament expanded when I used a heat gun with the filament in the "V" of a metal shelving unit leg. Still had to glue. I have changed the tread to have a "key" to set the 60 degree tread to have a 30 degree overlap. Also set the attachment to the round middle support to the outside dia.for greater strength as I broke a few on the bed at that point. (Use the tread end to remove from the bed, not the peg end) Still had to print upside down.
3rd Gen tread had pattern, and supports to allow printing right side up. Still using 3.3 dia hole as the dia is a snug fit for the filament. If you use 1.75dia filament, you can print a 3mm peg, or resize the hole. Also a nail, wood dowel, or other metal support will suffice.
This method used filament for no real good reason.
4th gen had tread pegs and side risers separate and to glue together. Added tabs to locate side risers and treads properly to each other as you build up the stair. Very fiddly, thus rejected.
5th gen. Finally a good all round solution. Set tread to print peg and side risers UP. This allowed one piece treads again, with good fidelity on the stair pattern. No side riser and a spacer peg needed on first tread may not have the best stability for many very heavy figures, but works quite nicely. Top tread needed to have no peg or riser to fit under second floor. Detail obtained was worth it. Tabs in treads space the 60deg treads to 30deg each step which allows a 1" base to fit well on each tread. If you make a very high staircase, the original tread may provide the most stability, (or scale a plain tread with peg and side riser to 5.4mm in z and use that as the base peg and side riser support you may need to stabilize the staircase.)
Spiral Stair Base
Provided all bases plain for your own pattern.Spiral Stair F is round 4" dia (=4x OpenLock "F" tiles clipped together) and Spiral Stair "round" is 3in dia to fit within the Devon Jones walls. As the treads are spaced at 8.4 high, they should (at 5 treads) fit just under the 2nd floor if the floor is set at 50.8mm resting upon the walls. To go higher, just add additional treads. I believe you will have to glue the treads to make it work, although you could always use painters tape on the outside edge to keep the treads together.
"Base" is just a bottom of the stair with a hole for the treads support peg.
"Down" has a clip to allow a fill piece to be added to make it a ground floor "Base", or left out to allow you to go "down".
01/23/17 Updated bases to correct clip size. Added BASE FROUND and DOWN FROUND which is a 3" halfround married to 4" halfround (2xF Tiles)
01/23/17 Added 4x4 U tiles, both BASE and DOWN styles. Took out concept model as it was large and not needed with as built pictures available.
01/25/17 Corrected "math" and clarified notes.
01/27/17 Corrected Treads to match original design size. New treads have supports to print right side up, and tabs for spacing.
2/2/17 Re-thought, why have supports/tabs etc. Why print upside down? Now treads print right side up. Only issue...need to have a different top tread, and a spacer at the bottom. Spacer, 10 cobble treads, 3 tops + plain/top set (for both plain printing or to add your own pattern) and the same plain/top set with a tab with the correct spacing for 30deg treads as shown in the picture. Bottom of tread Tab hole may need cleaning. Spacer can be resized to the height you need to make up any difference you may have in your floor design. Plain top treads or add your own floor design, are now the same tread.
This should complete this design, but still may tweak for ease of use. Typical wall height is 50.8 and you will need spacer first, then 4 treads + 1 top tread to utilize. Tread heights are 8.4. If you use floor supports, add an additional tread in the 180deg stair, by cutting off the tabs and rotate counter clockwise equally to add in the extra tread.
2/16/17 https://www.flickr.com/photos/nigel_brown/9708771924 Added photo example (by Nigel Brown) similar to the memory that was lingering in my head on the spiral stair design.