Gaskets with CNC, and progress on the Trevithick Dredger Engine.

by John

Tomorrow I start silver brazing the 6″ vertical boiler.

But today I started machining the bronze end plate of the Trevithick Dredger Engine.

First I prepared a 100x25x200mm sacrificial aluminium block to hold the expensive bronze disks which will become the end plate and flange of the Trevithick boiler.


CNC drilling the 8mm thick bronze end plate and the sacrificial mounting block.


This thicker bronze disk (13mm thick) will become the flange which is brazed to the boiler shell.  The holes were also CNC drilled, then threaded using a battery drill, held vertically in my shop made threading jig.  The flange and the end plate require more holes and shoulders.  The mounting block will assist with repositioning.

Earlier I had called on GSMEE president Brendan, who happens to possess a CNC laser cutter.  I had discussed the possibility of CNC cutting some gaskets for the steam pump which will be made for the 6″ vertical boiler.  “No Problem”, said Brendan.


Taping the gasket material to the CNC laser cutter table.


Starting the cut.


The 15 gaskets accurately cut out.  Cut out by hand would have been a half day job.  The laser finished it in about 3 minutes, perfectly (plus maybe an hour drawing the pattern using a CAD program).  It is a 40 watt laser, and will cut through 3mm plywood.  No problem with this 0.4mm gasket material running the laser at 25% power.