# Are You a From Casting Builder?



## rake60 (Aug 1, 2007)

This is a new area for me personally.  All of my models have been built
from bar stock.  But I have been looking at a few casting kits.
Especially these. *Purveyor of Machinery*


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## raym 11 (Aug 2, 2007)

I don't know if the castings i've dealt with were from poor patterns or I dont have the patience to set them up properly, but I have more fun building from bar stock. Often times the stock available determines the final design :?  When you display engines an often asked question is"did you build it or just buy a kit?" I can tell them it was cooked from scratch. :wink: They not realizing it sometimes takes more skill to machine with decent castings.


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## Bogstandard (Aug 2, 2007)

I have been building from castings for a long time now, and people think that building from castings is an easy option.
This is a greatly misunderstood fact.
Unless you can get 'good' investment castings you usually hit a problem straight away.
Castings are not made 'square', usually they are tapered because they have to be able to pull the plug from the mould without causing damage to the casting sand.
So you have to get at least one face square and flat before you can carry on, otherwise what happens is that you end up chasing your own tail to keep things square, and still have enough metal to be machined to get to finished state.
The way I do it on a major casting is to find one datum face that can be used to get as many other datum faces from it, and once machined set that up on an angle plate or 3,2,1 blocks, and then work from that. I use the smallest angle plate I can fit the casting onto, because it is no joke when you have just used it on the miller and find that you can't mount the angle plate onto the lathe faceplate because it is too big.
Another major problem is the workers at the foundry. The last casting set that I used had been over 'fettled' and I had to get the casting built up by a friend to be able to machine it to the correct dimensions.
Here is my last engine, still in uncleaned state and on its run in stand.












This is a four stroke, single cylinder, water cooled side valve engine. I made up a set of electronic igniton for it to get it to run a little better. It is called 'The Whippet'. 
Don't get me wrong here, I am not trying to put people off building from castings, but just showing a few pitfalls that you can expect if you want to try it.

John


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## Sprocket (Aug 2, 2007)

Well, yes and no.  A couple of years ago at Iron Fever, I bought a 1/4 scale casting kit for a Galloway. I started, but felt like I was making more fixtures to hold parts than parts. I decided I'd go back to building bar stock engines for a little while. I've been working on this one




for almost a year, hope it will run this fall. My goal is to make it _look_ as though it was made from castings. This is my version of the Zero-Six, which I guess I'll call Zero-Six _Beta_. because while it is mechanically like the original, it looks nothing like it.


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## gt2ride (Aug 3, 2007)

Bogstandard    Do you have a Boxford Lathe?  I have a Boxford IS 280


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## Bogstandard (Aug 3, 2007)

No, just an old Atlas 10F lathe, but it does use the same nose fittings as the boxford.

John


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## RollaJohn (Aug 3, 2007)

A word to the wise:
.  .  . For those who are going  to form their molds with casting (green) sand, store the supply of sand in a covered container. I learned that the cats loved their new litter box!!!


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## Tin Falcon (Aug 16, 2007)

castings
     So far I have only completed one engine from a casting kit. I have a second kit  PM mill engine. One of the older now discontinued bronze .


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## tattoomike68 (Aug 16, 2007)

I am wanting to do my own castings. I have worked in a foundry and we did make some cool stuff at lunch time out of core sand.

this site has a bunch of info.

http://www.backyardmetalcasting.com/index.html


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## raym 11 (Aug 17, 2007)

Tin;
Small world! I have what I think might be the last brass drill engine PM sold. They didn't have a cyl for it so they made me a special deal on a cast iron cyl. It looks kind of weird but so does my workmanship at that time. :lol:  

raym


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## compound driver (Oct 19, 2007)

Hi
I think one important point to look at when choosing castings or bar stock is scale looks. No matter how hard you try a machined part will always look machined. On a cylinder block from say a Burrell a large part of the block is left rough cast with no fetteling past removing sand inclusions.
If the scale block is machined and then heavily sand blasted it does start to look cast but in truth will still not have the pleasing look of a casting.

On crankshaftes its very much a good thing to use a casting if you can. I have seen machined crankshafts in mild steel that never ran true after the first few runs in the engine mostly due to the bar not being normalised before machining. cast cranks on the other hand always seem to be fine and true.
fabricated cranks are another matter and almost the first choice for me on a non splined crank.

Holding a cylinder block for machining is as a rule made easy if you have a Keats block and a good sized face plate. Once you have one face machined flat it should become your datum for all the other faces. chasing your tail isnt a problem if you always work from one face.
Life gets a bit more interesting on a traction engine block due to the large radius required to mount the saddle on the boiler. Finding the cylinder center line becomes your first job after your master face is machined.

cheers kevin


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## mklotz (Oct 19, 2007)

When I was building the various PMR machine tool models from casting kits, I decided to make my life easier by making what I refer to as "clamp on reference surfaces".

I made a block






which fits in my milling machine vise in all three orientations.  The casting is clamped to the block using the miniature T-slots.  Rough orientation is accomplished via the fences which are removable (after the part is clamped, of course) in the event they interfere with a cut.  The block is also fitted with (removable) stops so that, when necessary, it can be removed from the vise and replaced in its original position.

Once the casting is clamped, it's easy to machine orthogonal datum surfaces by merely flipping the block around.  In addition, the block is small enough to grip in my 8" four jaw so features can be turned precisely to the milled datums.

Kevin mentioned a "Keats block".  I'm not familiar with that term but maybe my device is merely a reinvention of whatever he's on about.


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## Bogstandard (Oct 19, 2007)

Hi Marv,
That is an ingenious bit of kit, must have a go at making one.
A keats angle plate is basically like having a v-block attached to your faceplate
http://www.rdgtools.co.uk/acatalog/info_688.html
I use mine mainly when I want multiple parts, all the same. Like when I am making single cylinders with offset bores. I can bang off a dozen in no time, all exactly the same, unlike if you are using a four jaw where you have to tweak each time you put a new part in.

John


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## mklotz (Oct 19, 2007)

John,

Thanks for the clarification.  Actually, I've made something quite similar and used it several times before passing it along to a friend.  The "Keats" name must be a British thing.  While these devices exist on this side of the pond, I've never heard them referred to by that name.


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## Bogstandard (Oct 20, 2007)

Hi Chuck,
We call them 123 or 246 blocks, that refers to the size in inches.
It depends just how rich you are as to which ones you own, most people use the 123 size.

http://www.chronos.ltd.uk/acatalog/info_6302001.html


John


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## mklotz (Oct 21, 2007)

Speaking of 123 blocks...  One of my more useful additions to the model building tool armory has been a set of half-size (1/2 - 1 - 1-1/2) blocks that I made.  Can't count how many times I've used those to great advantage in a setup.


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## rake60 (Oct 21, 2007)

I bought my 123 blocks from LMS
For the price it would be tough to justify the time in making your own.

Marv, your 1/2 size blocks will be going on my to do list!


Rick


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## robert1352 (Dec 8, 2007)

This is an intresting topic. Has anyone here made your own engine castings from scrap metal?? If you have please tell me about your experience since I find the idea of making a steam engine from absolute scratch fascinating.


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## PolskiFran (Dec 9, 2007)

I have done engines from casting and barstock. It is a lot easier to replace a piece of bar stock than a casting. I have made engines that were originally intended to be a casting kit from bar. My marine engines are an example. After looking at the plans I realized there really wasn't too much that had to be a casting. So I decided to start "whittling" out of brass/bronze bar stock. I think the amount of chips outweighed the finished part. The larger engine was built to the original size specs, the small one is half size.


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## Bogstandard (Dec 10, 2007)

Frank,
Lovely pair of engines there, it goes to show that castings are not a necessity.
I appreciate them more because 'whittling' metal and marine engines are two of the things closest to my soul in model engineering.

John


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## cfellows (Dec 10, 2007)

robert1352  said:
			
		

> This is an intresting topic. Has anyone here made your own engine castings from scrap metal?? If you have please tell me about your experience since I find the idea of making a steam engine from absolute scratch fascinating.



I've done some casting although not a lot. Aluminum is pretty easy to cast, requiring furnace temperatures on the order of 1500 degrees F to melt and pour. Zinc / Aluminum alloys, typically called ZAMAC melt at even lower temperatures, around 900 - 1000 degrees F. I've used an 88% zinc / 12% aluminum alloy that yields a metal that's reasonably good for flywheels since it's only a little lighter than cast iron. I've never tried Brass or Bronze since those both require temperatures more in the 2000 degree F range. And of course, cast iron requires temperatures of about 2700 degrees F. 

There are lots of home foundry sites on the web and several casting forums on Yahoo Groups.

Chuck


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## robert1352 (Dec 10, 2007)

Thanks for the info Chuck. Did you make you own foundry ?? If so was it terribly difficult? Also, what other problems did you encounter that you didn't expect? Did you use sand for the molds? Thanks again, Robert.


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## Powder keg (Dec 10, 2007)

Did you make your own alloy? did you melt the aluminum first then add the zinc? Please explain?

Thanks, Wes


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## cfellows (Dec 10, 2007)

robert1352  said:
			
		

> Thanks for the info Chuck. Did you make you own foundry ?? If so was it terribly difficult? Also, what other problems did you encounter that you didn't expect? Did you use sand for the molds? Thanks again, Robert.



Building your own foundry furnace is not terribly difficult. Basically, you start with a container, like a large coffee can, popcorn can, 5 gallon bucket, etc. They can be powered by electricity, charcoal, or propane. I would refer you to one of the following sites for more detail:

http://metalcast.boorman.us/foundry_1.html
http://myhomefoundry.com/
http://www.backyardmetalcasting.com/

I would also caution you to read and observe all the safety concerns. A quart of molten aluminum has a lot of stored up energy and can cause devastating burns if it gets away from you.

For the molds, you can buy oil based casting sands or you can make you own from silica sand, water, and a few other ingredients. Again, the above sites have more information.

Chuck


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## cfellows (Dec 10, 2007)

Powder keg  said:
			
		

> Did you make your own alloy? did you melt the aluminum first then add the zinc? Please explain?
> 
> Thanks, Wes



Wes, I did make my own alloy. I had some zinc bars that I had picked up on ebay. I just put the zinc and the aluminum pieces in the crucible and melted them together. One variant of the alloy is also called pot metal, which is used in a lot of products. Unfortunately, pot metal isn't viewed as a very strong alloy, but the problem is that it's usually cast in a very thin cross sections which makes it weaker. 

Chuck


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## Powder keg (Dec 10, 2007)

I have a bunch of zinc. Were those measurements by weight or volume? Probably weight:O)

Thanks, Wes


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## cfellows (Dec 10, 2007)

Powder keg  said:
			
		

> I have a bunch of zinc. Were those measurements by weight or volume? Probably weight:O)
> 
> Thanks, Wes



As I recall, it was by weight. If you Google ZAMAC, you can find info on the different alloys at a number of sites. ZAMAC, as listed by the various sites, also has other traces of elements in it. However, I just used aluminum and zinc and it worked fine.

Chuck


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## robert1352 (Dec 11, 2007)

You are a wealth of information Chuck. Have you ever tried to melt iron? Best regards,Robert.


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## cfellows (Dec 11, 2007)

robert1352  said:
			
		

> You are a wealth of information Chuck. Have you ever tried to melt iron? Best regards,Robert.



No, never tried iron. Iron requires temperatures in excess of 2700 degrees fahrenheit. Also, you have to use Silicon Carbide (expensive) or fired clay (easily broken) crucibles to melt it in whereas you can use homemade steel crucibles for aluminum, zamac, or bronze.

Chuck


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