Pipe strap drawing package
- Problem
- A pipe strap is a small part with a few things that must agree: the arch has to fit the pipe, the feet have to stand clear of the steel before the bolts are tightened, the washers have to sit flat past the bends, and the flat has to come out the right length.
- What we solved
- One pipe size gives three shop sheets (PDF and CAD) and the strap’s cut file, drawn from a 3D model of the strap built in the browser: the section, the views, the flat and the weight all come from the same solid, and the third sheet tells the press brake operator where, how far and which way to bend each line, in an order checked against the tools.
- Result
- The flat is checked against the solid at every pipe size, and the cut file can be checked by the independent script in the download: 22 checks pass on the sample.
Try it yourself
Free, no account. Type your sizes on the drawing and download the set. If anything looks wrong, press “Found a mistake?” on the page and tell us.
What we solved
- Drafting time: pick NPS 1/2 to 8 and the strap, bolts, washers, nuts and the holes to drill in the steel redraw; the bar, bolts, end distance, gaps and liner can each be changed on the drawing, and the punch, the die and the foot bend radius follow the bar.
- Mistakes before the shop floor: the feet stand 0.063 above the steel for a grip (or the strap clears the pipe for a guide), each washer sits past its bend, the end distance meets AISC 360-16 Table J3.4, and a bar too thick for the pipe is refused with the reason.
- Ready for the brake: the arch bent in hits with a standard punch, the springback taken from a beam model that a CalculiX finite-element check agreed with within 0.02°, and the bending order checked step by step so the bent part clears the punch and die.
- Files ready for the cutter: the strap’s flat at 1:1 in inches with both holes, the arch’s hit lines on BEND_UP and the foot bends on BEND_DOWN.
How it is checked
- A separate script (Python, ezdxf) works the flat, the bend lines and the holes out again from the inputs and checks the metal round the holes and the weight: 22 checks on the sample. The script is in every download.
- The browser model was compared with an independent CadQuery model at five inputs from NPS 1/2 to 8: strap volumes within 0.05 % and every derived size equal.
Responsibility
The strap, bolts and steel are not sized for any load, and it is not a rated pipe hanger. The flat uses K by inside radius over thickness: make a test bend before cutting a batch.