Free Tube Coping Calculator: get the notch right the first time
Joining tubes on a roll cage, chassis, bull bar or frame? Enter the tube sizes and joint angle, and the calculator draws the exact fishmouth (saddle) profile as a wrap-around template you print at 1:1. It's free and you don't need an account.
What it saves you
- Guesswork: no more eyeballing the notch and grinding a bit more off each time. The profile is calculated from your actual tube sizes and angle.
- Rework: a cope that fits first go means no gaps to fill and no re-cutting a tube that's ended up too short.
- Time: fewer trips between the grinder and the test fit on every joint.
- Material: fewer ruined tubes from over-cut notches.
How it works
- Enter the main tube OD, the branch tube OD and wall thickness, and pick your units.
- Set the joint angle, any offset from centreline, and a notch allowance if you want one.
- Check the joint preview, then hit Print 1:1. Check the 50 mm calibration bar measures correctly, wrap the template around a square-cut end of the branch tube, mark the solid line and cut.
Frequently asked questions
How do I cope a tube at an angle for a roll cage?
Enter both tube diameters and the joint angle into the Tube Coping Calculator, print the wrap template at 1:1, wrap it around the branch tube, mark the line and cut to it.
Can it handle different tube sizes joining each other?
Yes. The main and branch tube diameters are entered separately, so you can join, for example, a smaller brace into a larger main hoop.
Does it handle offset joints?
Yes. Set the offset from centreline for branches that don't meet the main tube dead centre.
Does it allow for wall thickness?
Yes. Enter the branch wall thickness and the template shows both the outer cut line and the inner wall edge.
Do I need a tube notcher?
No. The printed template lets you mark the cope and cut it with a grinder, bandsaw or file. If you do use a notcher, it's a handy check on the fit before you weld.
How do I make sure the template prints to size?
Print at 100% ("actual size"). The template has a 50 mm calibration bar. If it doesn't measure 50 mm, adjust your printer scaling and reprint.
Is it free?
Yes. It's free to use and you don't need to sign up.