P100 Valve Thread Mandrels
For many years we had requests for a tool that would straighten and reset the threads on either bent in, bent out or worn out valve casing caps… top or bottom. Ferree’s Valve Thread Mandrels will do this, prevent many accidents from happening in the first place, and even more.
The worst thing you could do to a valve casing in this condition is to use a die, thread chaser or grooving tool. This will remove brass where the brass is needed. Valve casings are very weak in the threaded areas to start with.

Reforms Metal
Ferree’s Valve Thread Mandrels don’t have any abrasive or cutting action. They are basically a forming tool to reform threads into their original positions, smoothing up any burrs or waviness. Because of their solid design, these Valve Thread Mandrels can be started on a ruptured part more easily than if they were slotted. They have a hex handle which makes them easier to control than a T handle.
Our Valve Thread Mandrels leave a smooth burnished finish that can’t be obtained from any case hardened cutting tools. Instructions are included with the order. The valve thread mandrels are used with either a tapered mandrel to help form the threads or, better yet, an expandable tool of proper size

Listing Of Sizes
We have the Valve Thread Mandrels listed by sizes in the 27, 32, 36 and 40 threads with notations telling you what horns the various sizes will fit. If your shop only works on one brand of instrument, it would only be necessary to have the correct size and one size over. But if you work on many brands as most shops do, it would be more convenient to have at least a set of ten.
New Asian sizes will be available as they are established.

NOTE: For information on sizes for instruments CLICK HERE

Preventing Accidents
Most repairmen take out knuckle dents with our N54 Knuckle Tools and N80A Balls. Sometimes, while working on a knuckle between valves on a horn with thick brass, it is easy for the tools to slip causing a little expansion of the valve casing threads.
If one of our Valve Thread Mandrels were screwed on the end where you insert the knuckle tool, such a mishap could be prevented.

Special Orders
If you need a special size, larger or smaller or a different thread, we can make it for you at no additional charge. We would prefer that you send the horn, but if this is not possible, we need:
▪Outer diameter of the threads on a good casing
▪Number of threads per inch on the casing

You can use P19 Micrometers and a G15 Thread Gauge to get this information.
Order Individually Or In Sets Of Ten, Your Choice Of Sizes.
P100S Set of 10 Valve Thread Mandrels (You pick your sizes)

P100A Individual Valve Thread Mandrels (Specify size)

P100A Internal Valve Thread Mandrels (Specify size)