Permaswage® D10256 & D10258 90° Elbow Fittings: Complete Technical Guide & Part Number Reference
Permaswage® D10256 and D10258 90° Elbow Fittings are permanent tube fittings used throughout the Permaswage® 3,000 PSI Tube Connecting System. These fittings are designed to permanently connect two sections of tubing while changing the direction of flow by 90 degrees, making them one of the most common fitting styles used in aerospace hydraulic and fluid conveyance systems.
The D10256 series covers tube sizes from 3/16 inch (-03) through 1 inch (-16). For larger tubing sizes, the D10258 series continues the same fitting family for 1-1/4 inch (-20) and 1-1/2 inch (-24) tubing.
Because many aircraft hydraulic and pneumatic systems require tubing to change direction within confined spaces, Permaswage® 90° elbow fittings are widely used throughout commercial aircraft, military aircraft, helicopters, and aerospace manufacturing.
In this guide, we'll explain what the Permaswage® D10256 and D10258 fitting series are, how they work, where they are commonly used, and provide the complete manufacturer part number reference.
What Is a Permaswage® D10256 90° Elbow?
A Permaswage® D10256 90° Elbow is a permanent elbow fitting designed to connect two tubes of the same size while changing the direction of flow by 90 degrees.
Unlike threaded elbows or flare fittings, Permaswage® elbows are hydraulically swaged onto the tubing, creating a permanent mechanical attachment without welding, brazing, soldering, or tube flaring.
The result is a compact, leak-resistant connection capable of withstanding the demanding vibration, pressure cycling, and fatigue loads encountered in aerospace service.
Why Use Permaswage® 90° Elbow Fittings?
The D10256 and D10258 elbow series offers numerous advantages over traditional tube connection methods.
- Permanent leak-resistant tube connection
- Changes tubing direction by 90 degrees
- No tube flaring required
- Designed for 3,000 PSI fluid systems
- Excellent vibration resistance
- Outstanding fatigue performance
- Reduces the need for multiple fittings
- Ideal for confined installation areas
- Proven reliability in commercial and military aircraft
Permaswage® D10256 & D10258 90° Elbow Part Numbers
The following table lists the standard Permaswage® 90° elbow fitting series by tubing size.
| Tube Size | Dash Size | Part Number | Series |
|---|---|---|---|
| 3/16" | -03 | D10256-03 | D10256 |
| 1/4" | -04 | D10256-04 | D10256 |
| 5/16" | -05 | D10256-05 | D10256 |
| 3/8" | -06 | D10256-06 | D10256 |
| 1/2" | -08 | D10256-08 | D10256 |
| 5/8" | -10 | D10256-10 | D10256 |
| 3/4" | -12 | D10256-12 | D10256 |
| 1" | -16 | D10256-16 | D10256 |
| 1-1/4" | -20 | D10258-20 | D10258 |
| 1-1/2" | -24 | D10258-24 | D10258 |
Available Tube Sizes
The Permaswage® D10256 and D10258 elbow fitting family supports the following tube sizes:
- 3/16 inch (-03)
- 1/4 inch (-04)
- 5/16 inch (-05)
- 3/8 inch (-06)
- 1/2 inch (-08)
- 5/8 inch (-10)
- 3/4 inch (-12)
- 1 inch (-16)
- 1-1/4 inch (-20)
- 1-1/2 inch (-24)
Permaswage® D10256 & D10258 90° Elbow Dimensions
The following manufacturer dimensional reference table provides the overall elbow dimensions for the Permaswage® D10256 and D10258 fitting series.
| Tube Size | Part Number | Dimension A | Dimension B |
|---|---|---|---|
| 3/16" (-03) | D10256-03 | 0.860 | 0.325 |
| 1/4" (-04) | D10256-04 | 1.050 | 0.390 |
| 5/16" (-05) | D10256-05 | 1.120 | 0.465 |
| 3/8" (-06) | D10256-06 | 1.190 | 0.550 |
| 1/2" (-08) | D10256-08 | 1.755 | 0.705 |
| 5/8" (-10) | D10256-10 | 1.960 | 0.866 |
| 3/4" (-12) | D10256-12 | 1.990 | 1.041 |
| 1" (-16) | D10256-16 | 2.344 | 1.385 |
| 1-1/4" (-20) | D10258-20 | 2.535 | 1.697 |
| 1-1/2" (-24) | D10258-24 | 2.778 | 1.885 |
Approximate Weight by Material
The following table lists the approximate fitting weights published by the manufacturer.
| Part Number | CRES (lbs.) | Aluminum (lbs.) | Titanium (lbs.) |
|---|---|---|---|
| D10256-03 | 0.014 | 0.005 | 0.008 |
| D10256-04 | 0.025 | 0.009 | 0.014 |
| D10256-05 | 0.033 | 0.011 | 0.019 |
| D10256-06 | 0.048 | 0.016 | 0.027 |
| D10256-08 | 0.116 | 0.040 | 0.066 |
| D10256-10 | 0.167 | 0.057 | 0.095 |
| D10256-12 | 0.234 | 0.081 | 0.134 |
| D10256-16 | 0.541 | 0.195 | 0.307 |
| D10258-20 | 0.797 | 0.265 | 0.451 |
| D10258-24 | 1.179 | 0.403 | 0.672 |
Common Aerospace Applications
Permaswage® 90° elbow fittings are used anywhere tubing must change direction while maintaining a permanent, leak-resistant connection.
- Aircraft hydraulic systems
- Fuel distribution systems
- Pneumatic systems
- Lubrication systems
- Environmental control systems (ECS)
- Landing gear hydraulic circuits
- Flight control systems
- Engine fluid routing
- Military aircraft maintenance
- Aerospace manufacturing and MRO operations
How the D10256 & D10258 Elbow Fittings Work
After the tubing has been properly cut, deburred, and prepared, the Permaswage® elbow fitting is positioned on the tube ends and permanently attached using the approved swaging process. Once installed, the fitting becomes a permanent part of the tube assembly while providing a 90° change in flow direction.
This installation method eliminates threaded joints and flared tube ends, helping reduce potential leak paths while providing excellent resistance to vibration and fatigue.
Related Permaswage® Fitting Families
- D10036 & D10136 Union Fittings
- D10045 Union Reducers
- D10355 & D10356 90° Elbow Reducers
- D10559 & D10155 Tee Fittings
- D10023 & D10223 Tee Reducers
- D10564 & D10254 Cross Fittings
- D10164 Bulkhead Union Fittings
Frequently Asked Questions
What is a Permaswage® D10256 fitting?
A D10256 fitting is a permanent 90° elbow used to connect two tubes of the same size while changing the flow direction by 90 degrees.
What is the difference between D10256 and D10258?
D10256 covers tube sizes -03 through -16, while D10258 continues the same elbow fitting family for the larger -20 and -24 tube sizes.
Can these fittings be reused?
No. Permaswage® elbow fittings are designed as permanent fittings and should not be reused after installation.
What pressure system are these fittings designed for?
The D10256 and D10258 series are part of the Permaswage® 3,000 PSI Tube Connecting System.
Why Buy Permaswage® 90° Elbow Fittings from Top Flight Tools?
Top Flight Tools specializes in sourcing new, surplus, and hard-to-find Permaswage® fittings and aerospace tube tooling. Whether you need a single elbow fitting or assistance identifying the correct part number for your application, our team can help.
Conclusion
Permaswage® D10256 and D10258 90° Elbow Fittings provide a permanent solution for changing tubing direction in high-pressure aerospace fluid systems. Their proven reliability, broad size range, and permanent swaged installation make them one of the most widely used fitting families within the Permaswage® 3,000 PSI Tube Connecting System.
When properly installed, these fittings deliver dependable performance in commercial aviation, military aircraft, helicopters, and other demanding aerospace applications.
⚠️ Disclaimer
Top Flight Tools (TFT) is an independent reseller and is not affiliated with, sponsored by, or endorsed by Permaswage® or Precision Castparts Corp. (PCC). All product names, trademarks, and registered trademarks are the property of their respective owners. Any reference to Permaswage® products, specifications, or part numbers is provided for informational purposes only. All Permaswage® trademarks and part numbers remain the property of their respective companies.
While every effort is made to ensure the accuracy of the information provided, it is the customer’s responsibility to verify all specifications, compatibility, and suitability of products for their intended application prior to use. TFT assumes no liability for errors, omissions, or the misuse or misapplication of this information, and disclaims any responsibility for damages resulting from reliance on it.