Organ Supply has some of the various valve covers, on page 6-6 in the
current catalog.  They do not have the hole in the middle but you can
easily cut the hole or make it larger.  I have enlarged the hole
several ways depending more on my mood than any other reason.

I do like using a step drill and have been using it more than in the
past; it's easy to center and cuts fast.  (I would recommend you buy
a good quality step drill bit).

  http://www.mcmaster.com/#step-drill-bits/=ne1ox9 

Recently I wanted some Coinola valve covers made of red fiber so
I had to buy a sheet of red fiber.  I used a die and punch press to
punch these.  These are threaded with a 5/8-40 inside hole for a brass
top seat.  I threaded them with a Procunier tap holder in the milling
machine using wax as a lubricant.

http://www.rockford-ettco.com/Default.aspx?tabid=1459 has the Procunier
information.  Tap-Matic is another type of tap holder.

I hold the valve cover with a simple jig.  I cut a small relief into
a block the diameter of the valve cover to hold the cover centered
under the tap.  I then use two clamps to hold the cover while taping.
You can also use this jig for drilling the inside holes a larger
diameter.  Clamps: http://www.mscdirect.com/product/76988146?fromRR=Y 

The last valve covers from Organ Supply were actually more of a plastic or
phenolic material: http://www.franklinfibre.com/industrial_laminates.html 

If you really want to make the valve covers out of actual fiber
material then there are one or two suppliers left in the US.  One
distributor is McMaster Carr.  These are gray in color and quick spray
painting with a can of Krylon can match the original color as well as
help seal the fiber from moisture.  This material is basically a paper
product that will dull punches rather quickly in a punch press.  (I
punched about a thousand covers with one punch and die set).  See

http://www.mcmaster.com/#fiber-sheets/=ne1l43 

Don Teach - Shreveport Music Co
115 Kings Hwy, Shreveport, LA 71104 (shipments)
P.O. Box 5295, Shreveport, LA 71135 (mail)
musicguy@nwla.com.geentroep [delete ".geentroep" to reply]