The Shop > Metal Stuff

Making Patterns for a Rider Engine

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Sea.dog:
Incannel and outcannel, now there are two new terms. I have one of each but never knew that they had a specific name, other than gouge, that is  :thumbup:

vtsteam:
Sea.Dog, seems like 95% of gouges you find are out-cannel. I'm definitely going to convert mine some time. Probably need hardening and tempering again. I think with some creative blacksmithing one could also convert a flat chisel to an in-cannel gouge. They seem to command a premium on Ebay.

Back to the pattern....here I'm trimming the flange down:

vtsteam:
And then I added a Bondo fillet on the cylinder side of the pattern. I did have to remove one of the screws. They all get removed and plugged when the pattern is split.

vtsteam:
Well, speaking of splitting, why not now?

Here they are, the two half patterns....

vtsteam:
I cut off two short lengths of 1/8" brazing rod, rounded one end of each and epoxied them into two of the holes left by the screws. They were a tight slip fit.

I "reamed" the holes opposite by wiggling in them another bit of brazing rod, just to make sure there was an easy slip fit for the pegs. You want the halves to separate naturally when you lift the cope, so one half stays in each part of the flask. If the cope pattern falls out after the lift, it can damage the sand cavity, and then you have to re-make it.

For the same reason, I don't make the protruding pegs very long, The pegs only have to locate the pattern when placed together lying flat. With the pattern lying on a table, you should be able to lift the top half off without the bottom half moving at all.

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