When it comes to aerospace hydraulic systems, Permaswage® fittings are trusted for their precision, reliability, and permanent seal integrity. At Top Flight Tools, we specialize in DLT series Permaswage® tooling — including swage heads, power units, dies, and pumps — and we’re here to help you maintain that trust with proper inspection, maintenance, and product knowledge.

Here’s your expert guide to inspecting, maintaining, and understanding DLT Swage Head Assemblies, based on official PCC documentation and frequently asked questions.

🔍 What Is a Permaswage® DLT Swage Head Assembly?

A DLT Swage Head Assembly is a precision-machined component used in conjunction with a DLT power unit to cold-work Permaswage® fittings onto aerospace tubing. Each assembly includes:

A yoke

Lower die block

End plates (inboard and outboard)

A matched die set

DLT heads are available for tubing sizes ranging from 3/16" to 1-1/2"

✅ Key Inspection Criteria for Permaswage® Swage Heads

Visual Inspection Checklist:

Ensure die halves have matching serial numbers — this confirms they are a proper set.

Check that the die slot areas are clean and free of debris.

Confirm proper lubrication of the yoke and die block using Deutsch Swage Lube (DLTSWLUB0001).

Verify correct end plate installation based on die size (see MCP-016, Table 2).

Inspect for over-compressed or damaged die slots (over 50% compression = replace).

Look for excessive wear or cracks using both visual and dye penetrant methods.

Slot Width Tolerance: For sizes -03 to -24, the standard slot width is 0.035"–0.040"Permaswage Head Assy In….

🛠️ Maintenance Best Practices for DLT Swage Tools

To ensure safe and proper operation:

Monthly: Clean and visually inspect dies.

Annually: Perform dye penetrant crack inspection.

As needed: Clean and inspect yokes, lower die blocks, and end plates for wear or damage.

Replace any component that is worn, cracked, or gouged — especially the Upper Outboard End Plate, which prevents fittings from passing through the tool during swagingPermaswage Head Assy In….

🧠 Top Permaswage® FAQs – Answered

Q: Can I swage a painted tube?

A: No. Swaging painted tubing may cause stress risers and lead to fretting failures.

Q: What hydraulic fluid is used in Permaswage® pumps?

A: MIL-H-5606 or MIL-PRF-83282.

Q: Is 9,000 psi output acceptable?

A: No. Pumps must reach 10,000 psi (+/- 250 psi) for safe operation.

Q: How many times can I swage a connection with DLT tooling?

A: Up to three times max. Re-swaging beyond that is not approved.

Q: What’s the purpose of the blue paint inside some fittings?

A: It’s PTFE-based Teflon paint for identification and alignment during installation.

Q: Can DME30 be used where MS21922 or NAS1760 is specified?

A: Functionally interchangeable, but dimensional and procedural differences exist.

Q: Can DME fittings be re-swaged?

A: No. DME fittings are non-reusable once swaged.

Q: What’s a DLT Power Unit?

A: It’s a hydraulic actuator that transforms pump pressure into swaging force, consisting of a piston, springs, and seals.

Q: Are MS and AS torque values the same under ARP908?

A: Yes — especially when one component is aluminum.

🧰 Additional Permaswage® Tooling You Should Know

Tube Deburring Tools: Prevent contamination with expandable plugs and removable stems.

Tube Cutters: Ratcheting handles for tight installations.

Marking Templates: Ensure proper tube insertion depth.

Inspection Gages: Confirm that a complete swage was made.

🚨 Safety First

“The equipment in this system is subjected to extremely high pressures during swaging. Improper use may result in tool failure or personal injury.” – MCP-016, Rev. GPermaswage Head Assy In…

Only trained and certified technicians with a Permaswage® Level “A” training card should operate this equipment.

🧰 Need Help With Permaswage® Tooling?

At Top Flight Tools, we offer:

Factory-new, New Surplus, and certified used Permaswage® tooling

90-day warranty on all tools

In-stock tools ready to ship fast

Expert advice based on OEM standards

👉 Shop Permaswage® Tools Now or Contact Us for expert support.

⚠️ Disclaimer Top Flight Tools (TFT) is an independent reseller and is not affiliated with, sponsored by, or endorsed by Permaswage®, Precision Castparts Corp.®, or any of their subsidiaries. All product names, trademarks, and registered trademarks are the property of their respective owners. Any reference to Permaswage® or PCC® products, specifications, or part numbers is for informational purposes only. TFT assumes no responsibility for the misuse of this information or any misrepresentation of affiliation.