When a fitting fails on a 100,000 PSI waterjet line, the clock starts ticking. Every hour the pump sits idle is lost cutting time, and the OEM parts desk is not always quick to respond. The good news is that you do not have to wait on a single source. GPP manufactures KMT compatible fittings in Webb City, Missouri, and most parts ship the same day.
This guide shows you how to identify the exact fitting you need, how to read GPP part numbers, and how to avoid the one mistake behind most replacement headaches: mixing pressure families.
What “KMT Compatible” Actually Means
Two connection families dominate ultra high pressure waterjet systems running above 90,000 PSI, and GPP builds both:
- 94K PSI fittings, compatible with Flow equipment
- 100K PSI fittings, compatible with KMT equipment
“KMT compatible” means the fitting is machined to match the connection geometry used on KMT style 100K systems, so it installs in place of the original part without adapters or rework. It is a dimensional and pressure match, not a vague “fits most systems” claim.
Here is why that matters. On a workbench, the two families look almost identical: same materials, similar shapes, similar size codes. But they are built to different connection geometries, so a 94K part and a 100K part are not interchangeable. A mismatched cone or thread can feel like it tightened normally, then leak or fail once the system starts cycling. For a broader look at how these components work together, read our complete guide to 100K PSI fittings and tubing.
How to Read a GPP 100K Part Number
Every GPP ultra-high pressure fitting follows a simple three-part code. Take AE-100K6 as an example:
- AE is the component type (elbow)
- 100K is the pressure family (100,000 PSI, KMT compatible)
- 6 is the tube size (3/8″)
The size codes are consistent across the whole line: 4 = 1/4″, 6 = 3/8″ and 9 = 9/16″. If you see 94K in the middle of a part number, you are looking at the Flow compatible family. That middle block is your first safety check before anything goes into a cart.
KMT Compatible 100K PSI Fittings: Part Number Reference
Use this table to match the part you are replacing. Every item listed has a downloadable drawing on the product page, so you can check dimensions before ordering.
| Component | What It Does | 1/4″ | 3/8″ | 9/16″ |
| Gland | Threads into the port and drives the tube cone into the seat | GND-100K4 | GND-100K6 | GND-100K9 |
| Collar | Threads onto the tube end so the gland has a shoulder to push against | CLR-100K4 | CLR-100K6 | CLR-100K9 |
| Plug | Seals an unused port | PLG-100K4 | PLG-100K6 | PLG-100K9 |
| Cone | Sealing cone adapter for the connection | CNE-100K4 | CNE-100K6 | CNE-100K9 |
| Coupling | Joins two tubes in a straight line | AC-100K4 | AC-100K6 | AC-100K9 |
| Elbow | Turns the flow 90 degrees | AE-100K4 | AE-100K6 | AE-100K9 |
| Tee | Splits or joins flow three ways | AT-100K4 | AT-100K6 | AT-100K9 |
| Cross | Four-way junction for gauges or branch lines | AX-100K4 | AX-100K6 | AX-100K9 |
| Bulkhead | Passes a line through a panel or guard | N/A | N/A | AB-100K9 |
Step-by-Step: Finding the Right Replacement Fitting
Step 1: Confirm the Pressure Family
Check the pump nameplate or equipment manual. A KMT style system rated at 100K PSI needs the 100K family. A Flow system needs the 94K family. If you are not sure, send the GPP team a photo of the old part or its markings before you order. A quick check now costs nothing, while a wrong part on a 100K line costs a second shutdown.
Step 2: Measure the Tubing OD
Use calipers on the outside diameter of the tube, not a guess from memory. Many shops run more than one tube size on the same machine, and a 3/8″ line feeding a 9/16″ header is common.
Step 3: Identify What Actually Failed
Is the problem the fitting body (elbow, tee, cross) or the connection hardware (gland, collar, cone)? A leak at a joint is often a worn gland, a tired collar or a damaged cone on the tube end, not a cracked body. Replacing the right piece saves money and downtime.
Step 4: Match the Part Number and Check the Drawing
Pull the part number from the table above, open the drawing and compare the key dimensions to your old part.
Step 5: Inspect the Tube End
A new fitting on a damaged cone or worn thread just moves the leak. If the tube end is scored or the threads are chewed, re-cone and thread it or replace that section of ultra high pressure tubing. GPP can supply tubing coned, threaded, bent or coiled to your layout.
Step 6: Confirm Stock and Order
Call, email or order online. Most GPP valves, tubing and fittings are in stock and ready to ship the same day.
Installation Tips That Protect Your New Fittings
- Keep everything clean. Grit on a cone seat is the fastest route to a leak. Wipe the port, the cone and the threads before assembly.
- Thread the collar fully onto the tube. Collars on coned-and-threaded connections are typically left-hand threaded, so confirm the direction on the drawing before you force anything.
- Lubricate the gland threads, not the cone. Use the thread lubricant your equipment manufacturer recommends and keep it off the sealing surface.
- Torque to spec, not to feel. Follow the value in your equipment manual. Over-tightening galls threads and deforms the cone, which shortens the life of the whole joint.
- Never plug a weep hole. Weep holes vent escaping fluid so you can spot a leak early and safely.
- Support long runs. Vibration fatigues connections. In high-vibration zones, anti-vibration gland assemblies are worth the small extra cost.
When to Replace and When to Look Deeper
At 100,000 PSI, every pressure cycle stresses the metal. If the same joint keeps failing, the fitting may not be the root cause. Check these three things:
- Tubing condition. Tubing that has not gone through autofrettage carries higher wall stress and tends to fatigue sooner in high-cycle service.
- Valve health. A valve with a worn seat or stem can create pressure spikes downstream. Pair your fittings with properly matched 100K PSI valves.
- Size and end transitions. Forcing a connection between mismatched ends puts stress where it does not belong. The right high pressure adapters solve this cleanly.
This is where engineering experience pays off. One long-term GPP customer reported that after the team applied fatigue-focused design changes to their parts, they had not seen a single high pressure fatigue failure on the components GPP produced.
Why Waterjet Shops Source 100K Fittings From GPP
- In stock, fast shipping. Most parts ship the same day, so a failed fitting does not turn into a lost week.
- Made in the USA. Every part is machined in Webb City, Missouri by American machinists.
- Drawings for every part. You can verify fit before you buy.
- Steady pricing. GPP has held its prices through the current inflation climate.
- Real engineering support. The team works with high pressure fatigue every day and can help you troubleshoot beyond the part number.
Whether you need a single gland or a full set of waterjet replacement parts for a rebuild, you can order online or talk to the team directly.
Frequently Asked Questions
Q1: Are KMT compatible fittings as reliable as OEM parts?
A: Reliability comes from material quality, machining accuracy and process control, not the logo. GPP fittings are precision machined for ultra high pressure service and each piece goes through quality checks. Always match the correct pressure family and install to spec.
Q2: Can I use a 94K Flow compatible fitting on a 100K KMT system?
A: No. The two families are built to different connection geometries and pressure ratings. Mixing them can cause leaks or failure under pressure. Check the middle block of the part number: 100K for KMT style systems, 94K for Flow.
Q3: What do the numbers at the end of a GPP part number mean?
A: They show the tube size. 4 is 1/4″, 6 is 3/8″ and 9 is 9/16″. For example, GND-100K9 is a 9/16″ 100K PSI gland.
Q4: Should I replace the gland and collar when I replace a fitting body?
A: If they show wear, thread damage or have been through many assembly cycles, yes. They are low cost compared to the downtime a repeat leak causes.
Q5: Why is my new fitting leaking right after installation?
A: The usual causes are a damaged cone on the tube end, dirt on the seat, a collar that is not fully threaded, or incorrect torque. Inspect the tube end first, since a new fitting cannot seal against a scored cone.
Q6: How fast can GPP ship 100K PSI fittings?
A: Most valves, tubing and fittings are stocked and ship the same day. Contact the team to confirm availability for your part numbers.
Get the Right Fitting the First Time
Not sure which part you need? Send the GPP team your old part number, a photo or your equipment model and they will confirm the match before you order. Call 417-673-1919, email sales@graceprecision.com or request a quote online.
KMT and Flow are trademarks of their respective owners. GPP is not affiliated with or endorsed by these manufacturers. References are made only to indicate compatibility.