ADJUSTING THREAD RING GAUGE LOCKNG DEVICE per ANSI B47.1:2004

Drawing Legend

Item 1: Locking Screw
The locking screw is an extended shank bolt with a slotted head.

Item 2: Sleeve
The sleeve is a short tube that works as a spacer and locating dowel.

Item 3: Adjusting Screw
The adjusting screw is threaded externally and internally and is split longitudinally.

Item 4: Body
The body is the main part of the thread ring gage in which the thread ring gauge threads are located.

Item 5: Adjusting Slots
The adjusting slots allow the thread ring gage body to flex as the thread ring gauge is sized.

Item 6: Adjusting Slot Terminal Hole
The adjusting slot terminal holes allow the thread ring gage body steel to be annealed near the major diameter to facilitate flexing as the thread ring gauge is adjusted.

Item 7: Locking Slot
The locking slot functions similar to an adjusting slot during thread ring gage sizing, allowing the threads within the body to be opened or closed.

Adjustment Process

To work with the locking screw assembly, remove the seal. If sealing wax has been used, it can be dug out or melted out. If hot glue has been used, it is easier to remove, but still needs to be pried out.

After the sealing wax has been removed, unlock the locking assembly by turning the locking screw to the left, counterclockwise, a few turns.

The adjustments to the thread ring gauge body are made by turning the adjusting screw. Turning the adjusting screw to the right, clockwise, exerts pressure through the sleeve against the shoulder inside the thread ring gage body assembly hole. The shoulder is visible on the left hand side of the thread ring gauge body as shown above. This pressure opens, or spreads, the thread ring gage body. Conversely, turning the adjusting screw to the left, counterclockwise, reduces the pressure through the sleeve against the shoulder inside the inside the thread ring gauge body assembly hole. The reduction of pressure allows the thread ring gage body to be closed, or constricted. This opening and closing of the thread ring gauge body allows the thread size to be adjusted.

Once the thread ring gage has been properly adjusted against a truncated master thread setting plug gauge, the locking assembly needs to be activated. The locking assembly is activated by turning the locking screw to the right, clockwise. The tightening of the locking screw exerts a pull between the shoulder immediately under its head, and the internal threads of the adjusting screw. The locking action is accomplished by the locking screw forcing the adjusting screw to expand which forces the external threads into the threads in the wall of the thread ring gage body. The thrust of this action is absorbed up longitudinally by the sleeve. The clamping action is accomplished by expansion of the adjusting screw equally in all directions and not by the application of any eccentric forces that tend to distort the thread ring gauge or upset the adjustment. The locking pressure is taken up centrally in the locking screw itself as the reacting support is directly under the head of the locking screw in the form of the shoulder in the thread ring gage body.

A properly fitted sleeve serves as a dowel to maintain the alignment of the thread ring gauge body.

To avoid tampering with the completed adjustment, either sealing wax or hot glue needs to be used to cover and conceal the adjusting mechanism.

Other related pages:
Using Truncated Setting Plug Gages.
Procedures for Setting Thread Ring Gages with Truncated Setting Plug Gages

COMMENTS
This data current as of March 2007
Refer comments/corrections to gageguy@gagecrib.com.