Duncans Metal Pages
Seal Major - liners and ports
Last updated: 30 Nov 2016

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The liners and valve ports are pressed in items made from mild steel and SAE660 leaded bronze respectively.  It's possible to use other materials such as cast iron but cast bar is normally sold in 25mm+ diameters which means lots of machining to make the ports.

Liners1 25-Nov-2005: The cylinder liners are made from 1-1/8" mild steel bar.  These will be bored slightly undersize before being pressed into the block and have been drilled to 3/4" ready for boring.  Shown on the right is a plug gauge which has been made to 13/16" diameter with 5 smaller sizes, each reducing by 0.0005" at a time.
Liners2 27-Jan-2007: No work for a while on this project due to making the Versatile Dividing Head and the Quorn, but things are starting to pick up again.  One of the liners has been pressed and glued with Delta 88 high strength retainer - the other liners will follow shortly.
Ports 4-Feb-2007: These are the last of the ports to press in.  Again, these will be fixed with high temperature high strength retainer.
Skim A quick skim over the top brings the deck down to the correct height.
Ports2 8-Feb-2007: This is the setup for machining the ports - the same 5/16" ball nose cutter that was used for the top of the ports is being used for the side.
Problem There are two places where the studs are at 90 degrees to each other and too close for comfort.  The solution here is to tap 2BA for an oversize ended stud and re-drill and tap from the top face through the side stud.
 

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Warning: These pages consist of images and descriptions of equipment which can reach high temperatures creating hazardous and potentially dangerous situations.  These pages should not be taken as a step by step guide on how to construct any items or carry out any particular procedure, nor should any references to safety contained herein be taken to guarantee safety in all situations.