Schedule 1.50 Merge Jig

The hardest cut in header building, jigged. A 4-1 merge has four tubes arriving at one throat, each on a compound angle. Get one wrong and the whole collector is scrap. This fixture holds all four in position while you tack.

There is nothing else like this, printed or machined. Merge collector fixtures are not something you can go and buy — which is why most people tack four tubes by eye and find out it is wrong after the weld cools. The thing this saves you is not a tool purchase; it is the collector itself, plus the hours in it.

What you download

• STL file for the configuration you choose — or the Bulk Pack with all eight
• T3, T4 and T25 flange collectors at 4.00" overall height
• 3.00" tall with 2.00" round or T25 square exit
• 4.00" tall with 2.00", 2.50" or 3.00" round exit
• Built around schedule 1.50" pipe primaries
• Instant download at checkout. Nothing ships.

Print settings

My official settings for every G1Pro fixture: 2.5 mm walls, 2.5 mm top and bottom, 20% cubic infill, support-free, printed in Inland PETG-CF.

Licence — Shop Use

Print as many copies as you like for use in your own shop, including on paying customer jobs. You may not share or resell the file, or print copies of the fixture to sell. Print-and-sell licences available — ask.

Drawn by James Goertz, G1Pro. Building intake manifolds by hand since 2009; these are the fixtures off my own bench.