How to Adjust a UNC Thread Gage to a Truncated Setting Plug Gage
To establish the pitch diameter of a UNC thread gage it’s accomplished by fixing the UNC thread to a truncated thread setting plug gauge. Ensure the plug gauge has been freshly calibrated and has present certification.
Now follow these methods on how to adjust a UNC thread gage and make sure the pitch diameter setting is right:
- First clean both UNC gauges and Plug gage with a fine cleaning solution.
- Now Visually check them to ensure there’re no burrs or nicks
- Lubricate the setting plug with a little thin film of oil earlier assembling it with the UNC thread gage
- Loosen the locking screw of the ring but don’t remove it
- Turn the fixing screw on the ring thread clock wise to open the UNC thread to a bigger pitch diameter
- Turn the UNC thread onto the setting plug until it’s totally engaged with at least 1 thread of the UNC extending beyond the last on the back end of the complete form section of the setting plug.
- In this step turn the locking screw counter until it loosen
- Now move clockwise, this locks the fixing screw so that the measurement of the UNC thread remains fixed.
- Unscrew the Truncated Setting plug gauge from the UNC thread gauge
- Screw the Truncated setting plug into the UNC thread about one and half turns and try to move it from every side to check the UNC thread for a taper condition. When testing for shake be certain to use light force on the setting plug gage to avoid any issue to the gage
- Now screw the UNC thread gage over the truncated setting plug gage. The condition should remain about the similar as in the earlier step.
- Eliminate the Truncated setting plug from the UNC thread gage and replicate this on the other side
- The assembly of the thread ring gauges and the truncated setting plug gage should feel similar from both sections of the thread. This’ll assure that you’ve a flat pitch measurement
- When the UNC thread gage is adjust to the setting plug with identical feel over the full dimension of the setting plug, including there being no-end thread shake, it’s then rightly adjusted with the setting plug.
Remember that because of tolerances in the manufacture of both thread gauge and the setting plug gauge that unless they’re made at a similar time to be matched with each other, allowance has to be made in the assembly fit or feel to compensate for any little difference.
Lastly, if the UNC thread gages is set to the truncated side of the setting plug first instead of the reverse process mentioned above and it fails to pass over the primary full thread of the complete form part of the setting plug, this indicates main diameter interference in the UNC thread gage. It’d be changed with new gauge otherwise the thread UNC will not engage rightly.
Contact :
Chenchuan Tools Co.,LTD
Chenbei Industry Zone,
Longgang Road,
Huangshi,Hubei
China,435202
Tel: 0714-7321211
Fax: 0714-7321210