DIY J-Cups for Dip Bars – 3D Printable Rack System for Bench Press & Squats

Turn your standard dip bars into a fully functional barbell rack!

This is a 3D printable J-Cup system designed to mount securely onto standard parallel dip bars. The cups feature slots to insert two wooden beams, which reinforce the structure and provide the vertical load support needed for barbell exercises like Bench press & Squats. Force is transmitted straight through the wooden beams to the dip bars. 

The system is compact, cost-effective, and surprisingly stable – I personally use it regularly and it works great.

Files included:

• J_Cup.stl
• J_Cup.step (original CAD file for modification)

Designed to grip standard dip bar diameters (≈ 40mm diameter) and 38x58mm wooden beams, but can be scaled freely. 

The size of the J-Cup is 10x20x26mm (adjustable with scaling). 

Optimized for strength and safety

Additional materials needed:

• 2x short wooden beams (~70 cm) with a profile of 38x58mm (adjustable with scaling)
• 1x wooden beam connector (length depending on barbell length and dip bar distance)
• 2x screws
• 2x rubber bands for attaching cups to dip bars

Assembly:
Slide the wooden beams into the J-Cups to transfer load directly to the bars. Stabilize the wooden beams at the other with the connector beam. Place the assembly onto your dip bars and secure the J-Cups with one rubber band each. 

Tested:
I use it for benching and squats with 80+ kg safely – no wobble or cracks. Make sure your material and print quality are solid!

⚠ Disclaimer:
Always use common sense when training under load. Test with light weight first. Use at your own risk.