Waterjet Cutting Tech Tips

Why you should use A Short Stop Filter (Thimble Filter/Diamond Guard Filter)

We are all aware of how important the quality of water is when it comes to precision cutting with your waterjet machine. To ensure a high quality of water, we put in a lot of effort by changing filters, use softeners and in some cases, put RO filtration system.

However, the problem in waterjet cutting is we do not filter the water once its pressurised at 60,000psi or even at 90,000psi. Within the internal components of every waterjet system, there are stray particles which flow through the high-pressure line and these particles end up at the waterjet orifice impacting, or potentially damaging their edge.

What are the problems usually faced by machine operators?
  • Blocked or damaged orifices.
  • Untimely failure of cutting head components.
  • Reduced jet stream relating to inefficiency in cutting.

Where Thimble filter fits


It is very important to use a Thimble Filter which protects and enhances the life of the parts, especially if your orifice continues to damage fast. Using a thimble filter will catch the contaminants in the water preventing it to enter the cutting head and enhance the life of the orifice. It is designed to capture contaminants larger than orifice hole size (0.14mm) from impacting or blocking the orifice. When debris is larger than the hole in the orifice, the orifice assembly becomes plugged or partially blocked. When it is paired with diamond orifice, the thimble filter ensures precision cutting throughout every job.

What is a thimble filter?

Thimble filters are a small conical part which is installed in the back side of the HP cone. It is a small stainless-steel part with multiple small holes. It fits into a ¼” female x 3/8” male adapter and in some cases into 3/8 female x 3/8” male adapter.

Thimble Filter Assembly

Where is it installed?

It is installed nearest to the orifice assembly in a high-pressure adapter inside the cavity of the HP Cone which fits into the valve body of the cutting head.

Written by Hemanshu Dawda
GMA Manager – Waterjet Division