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| Fitting the remachined injector steam valve on Cochrane |
The next few shots show measuring the slide valve lead on HL No.2, prior to reshimming
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| Peter demonstrating use of a trammel to determine piston front dead centre |
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| The fixed valve face is vertical (part seen picture centre). The horizontal valve rod pushes the slide valve across the face. The valve itself is the right of the shot (flat against the face). The 'lead' is the (dark) vertical gap between the face and valve. 'Lead' admits steam as the piston reaches the end of its stroke; this steam is compressed and reduces knock in the motion. |
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| Peter using feelers and a vernier to measure the lead at front dead centre in the left hand valve. |
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| Chris doing similar. If you've been following, you can fill in the detail. |
