Stud Bolt Length — Companion Article
Open the tool: https://pipingdesigners.com/tools-training/stud-bolt-length/
What this tool does
Stud Bolt Length adds up the parts of a bolted flange joint to give a stud length, then rounds it up to a shop length. It also draws a star tightening order for 4 to 48 bolts.
No flange chart is stored. You type the dimensions.
When to use it
Use it for a joint that is not in your bolt chart, such as a flange against a valve, a spacer, or a mixed facing. Also use it to show a fitter the tightening sequence.
Inputs
- Thickness of each flange.
- Raised-face height of each flange, to remove from the grip.
- Gasket thickness.
- Nut height.
- Projection, the thread you want past each nut.
- Number of bolts, for the tightening order.
- Units: metric or US customary.
How it works
Length = (flange 1 − raised face 1) + gasket + (flange 2 − raised face 2) + 2 × nut height + projection.
The shop length rounds up to the next 5 mm, or the next 1/4 in.
Understanding the result
You get the exact length and the shop length. The star diagram numbers each bolt in tightening order. For eight bolts the order begins 1, 5, 3, 7.
Engineering considerations
- Check how your project counts projection, and whether it sits on each end.
- Spacers, blinds and wafer valves add to the grip. Include them.
- Tightening order is a sequence, not a torque. Follow your bolting procedure for passes and values.
Example
Two 30 mm flanges with 2 mm raised faces, a 3 mm gasket, 20 mm nuts and 10 mm projection give 109 mm, which rounds up to a 110 mm shop length.
Standards/references (licensed vs interim)
No standard table is stored. The page uses your dimensions only. Check stud lengths against your flange standard’s bolting data and your project bolting spec.
Limitations/disclaimer
- No flange chart on the page.
- No torque or bolt load calculation.
- The result is preliminary and needs engineering review.
Use the tool
Calculate now: Stud Bolt Length
Related tools
- The flange datasheet tool for flange dimensions. Read the flange datasheet companion article.
- The gaskets tool. Read the gaskets companion article.
- Quick reference, which uses this tool for a shop length (new tool, being added to the site).