Are You a From Casting Builder?

[rake60]

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

 

[raym 11]

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.

 

[Bogstandard]

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

 

[Sprocket]

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.

 

[gt2ride]

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

 

[Bogstandard]

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

John

 

[RollaJohn]

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!!!

 

[Tin Falcon]

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 .

 

[tattoomike68]

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

 

[raym 11]

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

 

[compound driver]

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

 

[mklotz]

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.

 

[Bogstandard]

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

 

[mklotz]

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.

 

[Bogstandard]

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

 

[mklotz]

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.

 

[rake60]

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

 

[robert1352]

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.

 

[PolskiFran]

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.

 

[Bogstandard]

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