Author Topic: Critique my patterns, please  (Read 2873 times)

Offline chucketn

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Critique my patterns, please
« on: August 29, 2013, 12:49:11 AM »
I'm building patterns for 3 tools I need/want. The tools are a follower/traveling rest and steady rest for my 7x lathe, and the body and banjo for the L.H. Sparey Dividing Head.

Please look at my patterns and offer any advise/criticism as appropriate. No draft has been applied yet to any of them. Do I need it? Do they need to be split?

Pic's here: http://s571.photobucket.com/user/chucketn/library/patterns

Thanks,

Chuck

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Re: Critique my patterns, please
« Reply #1 on: August 29, 2013, 09:27:20 AM »
Hey Chuck,

Are you pouring your own?....or bringing it to a foundry?....you can have a bit more leeway with a home pour as far as loose patterns are concerned.

I would consider mounting the steady pattern on a match plate on it's right side and draft towards the left...1 degree should be enough with green sand molds.

The dividing head pattern I would split right down the middle.   If your going to pour iron at a foundry, I would consider a core as round sand cores are standard in 1/8" increments and the foundry will have them on the shelf....not so for Aluminum foundries.   To take advantage of that, you will need to add core prints...make them as long as they are round.  Paint them a different color like red.

knock the sharp corners off everything, it's far easier to pull from the sand with fillets and radiuses and looks better too.

Bondo with a piece of dowel works wonders for fillets.




JMHO....worth what you paid for it... 8)

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline chucketn

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Re: Critique my patterns, please
« Reply #2 on: August 29, 2013, 03:55:00 PM »
Dave, these will be sand cast in Aluminum.  As they will most probably be a one off, I don't think the pattern board is necessary. If  anyone likes the result I may put them on a pattern board.
Still have to build a furnace, burner, sand box and greensand, so I most probably have the cart before the horse here.

Chuck

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Re: Critique my patterns, please
« Reply #3 on: August 29, 2013, 04:00:26 PM »
No worries Chuck....I have this small pile of knowledge gained from my episode of pattern making....if I can share I'm glad to.

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline chucketn

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Re: Critique my patterns, please
« Reply #4 on: August 29, 2013, 04:12:20 PM »
Dave, I wish I was closer. Love to pick your brain... I am trying to find folks close by to help me in my adventures.
Closest I get to you is my brother's place in Albany, NY. Try to get up there a couple times a year for fishing.

Chuck

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Re: Critique my patterns, please
« Reply #5 on: August 29, 2013, 04:34:15 PM »
That doesn't look that complicated Chuck....between you and the forum...it'll get sorted out.

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline Tjark

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Re: Critique my patterns, please
« Reply #6 on: August 29, 2013, 05:24:20 PM »
Chuck looks not bad at all.

As Dave said you need some draft to the site walls
I have made this mistake many times.
The sand will beak when you remove the pattern out the sand.
If the pattern is flat on the bottom I think that you not need to split it.
This depends mainly to the form off the pattern.
The included picture has also extra patterns who will be removed when the bottom flask is put on the top flask and is filled with the molding sand.
Have drawn a black line on the part where I revere to, last picture.