Valve Cap Corks

I have a practical question. On some older horns the valve cap takes a cork washer.





.4 wide, .3 inner hole, .2 deep


Since I haven't found a supplier that has anything like that, what is a good way to cut one?


They require good quality cork, or they will break. I've made a simple tool of an old disused telescopic car antenna to cut the holes, a thin brass tube with sharpened edges will do the job.


A centering tool can be made on a lathe.


Some champagne corks are good for that use. Also, wine corks if they have not been opened with a corkscrew. There are some corks made of glued cork chips in chipboard manner, they are not good for any brass wind use.

The cork should not have too large veins, or it will crack at these veins when being cut to shape.

Sometimes model builder stores have cork in larger pieces for landscape making. This would be useful with larger items, but there is a lot of useless cork in these pieces.


I have made many of these corks by using standard corks from Ferree's. I simply sand down the outside diameter until it fits tight in the cap, then use a round file to open the center as needed. The final step is to adjust the valve height by sanding down the thickness. You don’t want to use one with a defect as a lot of material is removed in the process.

I've taken to using Piccolo head cork. It is usually close to the outside diameter and doesn't need much sanding, and then just cut to the right thickness. I widened the interior hole with the sharpened piece of tubing that Kim recommended with the cork in the valve cap for support.

I use water valve cork rods sanded to proper o.d. The center hole is then punched with a leatherworker’s variable size punch. Once I have the i.d. and o.d to proper size, I use medium fine sandpaper on a sanding block to adjust the thickness. I have a close friend who owns a very upscale restaurant. He saves me all the wine corks. These are fine, as his waiters use a needle piercing and co2 to force the corks out. This leaves a perfectly centered very small hole. I then cut these to approximate thickness on my woodworkers 14" bandsaw, although, a hacksaw would work just as well for those who don't have a well-equipped wood shop. The above method is used in the making of valve alignment corks for the tops of valves.

Valve Cap Corks

I have made many of these corks by using standard corks from Ferree's. I simply sand down the outside diameter until it fits tight in the cap, then use a round file to open the center as needed. The final step is to adjust the valve height by sanding down the thickness. You don’t want to use one with a defect as a lot of material is removed in the process.

I've taken to using Piccolo head cork. It is usually close to the outside diameter and doesn't need much sanding, and then just cut to the right thickness. I widened the interior hole with the sharpened piece of tubing that Kim recommended with the cork in the valve cap for support.


This is what i used to do (though I am not sure where I got the cork washers). Dimensions tend to differ, depending on the maker and even between two instruments of the same maker.

The piccolo cork is a good tip, I will try that next time I need to make new corks.