How Not to Produce a Simple Wood Pattern

[carrdo]

Hi All,

More creative bending to finish fit the front rib. The very tight end bends were the worst. One more to go.

One thing I didn't mention was, when bending the straight blank piece, I started the forming in the centre and slowly worked out to each end. And sometimes I had to bend the copper into a shape I didn't want just to be able to get access to bend anything at all.

When finished, I will glue the end ribs onto the wood body.

 

[carrdo]

Hi All,

The most difficult way as usual. I don't want to do this ever again.

 

[carrdo]

Hi All,

The finished brake cylinder pattern(s) which will be going to the foundry. Will see what comes back. It took far to much time and effort but now that it is done.

 

[trevj]

Dowels are almost always oval'ish because of shrinkage. Sad but true when working with wood

Built in clearance to allow the excess glue to seep out! It's a feature, not a fault! LOL!

In all honesty, Pattern Making is actually well deserving of being it's own Trade. There is just SO much that can be affected by bad pattern making choices, that can make a really easy to finish product, or make misery for all involved! You pretty much have to understand wood, and how it behaves, several different areas of metallurgy, relating to shrinkage, as well as how to avoid making hardened white Iron, except when you want the stuff, plus having to allow the draft and cores that will be required on a complex part... And a whole lot more...

 

[PeterT]

@carrdo maybe you mentioned but can you provide any details on the foundry end of things? Where is it going? Cast iron I assume, or...? Is it safe to venture a guestimate cost in public?

 

[carrdo]

Hi Peter,

These are going to be all bronze sand castings. I am mailing out the patterns today.

The foundry cost I don't know yet as it is not a commercial one. It is a very small, one man home shop located near Sarnia, Ontario where I had some previous bronze castings made back in 2015. He does excellent work but I don't know if he has any size limitations, bronze or aluminum only (not iron) etc. or wants to be more widely known. I can make enquiries if you would like. He is quite elderly like me.

Some photos which I took when I was there last.

 

[carrdo]

Hi All,

Just to show what I had cast back in 2015.

 

[Tobho Mott]

Nice work on the pattern! There's a foundry guy from Sarnia who used to post now and then on a couple of foundry forums as Foundry Joe and Joe C... I wonder if they know each other.

Patternmaking-related, (I may have mentioned this elsewhere) Joe's wife runs Village Impressions, a rubber stamp making company. She can make stamps up to I think 8-1/2x11 size from a black and white only image file, which if you tell her it's for a foundry pattern she'll know not to mirror image them like how stamps are. They can be used to make plaque patterns by gluing them to a thin piece of wood, trimming the edges of the stamp, and sanding draft on the sides.

Good luck with your castings, I wish people would bring me such nice patterns!

Jeff