Decided to use castings

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Hello

My last post was making models using bar stock and lost interest, looking at some parts made that took hours Ive decided to make for the first time using castings.

Ive always used metric will I need BA for these castings or ME

Stuart, Reeves and Blackgates, what recommendation’s for castings please.

 

Thanks Bob

[noel shelleyParticipant @noelshelley55608]

May be I’m biased but I would say Stuart. They are not cheap, but I have been in the foundry and seen them made. They make their own castings, the others farm the work out. Good luck.  Noel.

[JasonBModerator @jasonb]

With Stuarts as you get all the barstock and fixings included there is the urge to use what you have aid for so BA and ME taps & dies will be needed. Or put the suppled bits in the back of a cupboard and use metric.

Reeves and Blackgates only supply the castings so it is not too hard to substitue sizes, so you can use what you already have

1/16″ becomes 1.5mm and M1.6

3/32″ becomes 2.5mm and M2.5

1/8″ becomes 3mm and M3

5/32″ becomes 4mm and M4

3/16″ becomes 5mm and M5

1/4″ becomes 6mm and M6

Etc

I’ve built from all three of those suppliers and there is not much difference. Good and some bad from all three.

[JasonBModerator @jasonb]

This thread about the 2×2 Clarkson may be of interest. Might need to register to see the attached image sif you are not already a member

https://www.modelenginemaker.com/index.php?topic=12425.0

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Thanks for the replies.

That Clarkson looks to large for me but I would of scaled it down for the flywheel I have but I’m going back to bar stock building and that’s where I could lose interest again and then more unfinished projects in the cupboard.

A 2/3rds scale Stuart Half Beam 40% done with a mistake ,also a half finished Colt revolver.

I quite like the Reeves as some use Gun Metal, never machined Gun Metal but Reeves states that any hard spots on the cast iron castings they will not take them back. I’ve had hard spots with flywheel castings so I would not want any problems with a cylinder casting.

Stuart, I would not use the bar stock , as stated in the posts I need BA or ME, I have a few ME used for fine threads 3/8th 5/16th, and quite a few BA but never used them as I keep to metric and all my brass and steel is metric

As I’ve never machined Gun Metal is there much difference to brass ? I have a 2incn dia x 18 inches long bronze bar, I tried to make something out of that but gave up.

If Gun Metal wont be to difficult to machine I think I will go for Reeves.

Thanks Bob

 

 

 

[bernard towersParticipant @bernardtowers37738]

What problems did you have with the bronze bar?

[JasonBModerator @jasonb]

GM needs good sharp tools, can me soft so watch out for chuck jaws marking it or excessive clamping force on the mill. It can also grab drills.

You are unlikely to get hard chilled areas like you do with iron but it can have blow holes or oxide inclusions which are very abrasive and will take the edge off a tool.

Otherwise it machines easily, I tend to use the **GT inserts and carbide on the mill too. This one was all GM castings

[BOB BLACKSHAW 1Participant @bobblackshaw1]

I found that drilling deep holes around 5mm binding up even though the cutting angles were for brass. If it is some type of tough bronze I don’t know.

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Thanks for the replies.

Having not machined castings and being self taught with bad habits I will check out a few you tube videos . Any small parts I usually mill it still on the bar so haven’t tried to machine a small part like these castings .

Nice looking Horizontal engine.

Bob

[Neil AParticipant @neila]

The binding effect you are have drilling deep holes sounds as if your bar could be phosphor bronze. I have had experience of drills grabbing in phosphor bronze when making boiler fittings, I don’t know if anyone else has had the same happen to them?

I have found Reeves gunmetal castings to be very nice to machine, I’m not sure what the actual specification for their castings would be though, but it is easy to get a good finish with sharp tools.

Neil

[duncan webster 1Participant @duncanwebster1]

Phos bronze, horrible stuff, it shrinks onto the drill and grabs. I use Colphos for boiler fittings, lovely stuff, machines just like brass.

[duncan webster 1]

On duncan webster 1 Said:

Phos bronze, horrible stuff, it shrinks onto the drill and grabs. I use Colphos for boiler fittings, lovely stuff, machines just like brass.

Colphos 90, which is a Phosphor-Bronze, is nice. Aluminium and Manganese Bronzes can give you nasty surprises.

JA

[Nigel Graham 2Participant @nigelgraham2]

The nature of the material does not dictate the thread standards, within reason.

The old published designs are almost all in Imperial dimensions and use British threads but you can metricate them.

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Hello. Looking at the Stuart Victoria engine I could use metric  but if I use BA what taps and dies will I need.

You get what you pay for but Ive seen single taps £13 each to £ 1.50 each any recommendations please.

Thanks Bob

[JasonBModerator @jasonb]

From my Stuart Chart you need the following taps

7ba,5ba, 2ba,5/52×40, 1/4×32

Dies

5ba, 2ba,

Not bought BA stuff for a number of years but found the taps from EKP were quite nice.

I used metric fasteners on the Victoria that I made. The smaller fixings that are listed as 7BA were changed to M2.5, 5BA to M4 and as I feel the 2BA fixings look much too large I went with M4 for those. M4 and M6 fine will do for the others.

Metric taps I like the YG-1 Spiral flute 804 series, you just need the one not a set of 3

https://www.cutwel.co.uk/threading/machine-taps/general-purpose-machine-taps/general-purpose-metric-coarse-machine-taps/uncoated-bright-finish-metric-coarse-hss-5-percent-cobalt-spiral-flute-universal-machine-tap-tc804-series-yg-1-tc804

Dies Volkel seem to work OK and anre a bit cheaper than Dormer etc

https://voelkel.com/en/products?properties=876f8b8a4dab4635bc3b906a6b4fe161&p=1&order=name-asc

[Roderick JenkinsParticipant @roderickjenkins93242]

Cheap taps are carbon steel (CS) and the more expensive taps are High Speed Steel (HSS).  HSS taps are generally tougher than CS which in small BA sizes means that they are less inclined to break in the job – which is a severe pain.  One advantage of CS that is not often mentioned is that it will soften if heated to blue, which is about 300°C, with the result that a broken tap can be drilled out with a normal HSS drill.

Having said that I have become a fan of HSS spiral fluted taps and these are available in BA sizes.  These taps pull the swarf out as they are fed into the hole so can used for blind and through holes.  They self guide very well so it is not necessary to buy sets of taper, second and plug taps – spiral fluted taps do it all in my experience.

Looking at the Stuart website they sell fixings in 2,4,5,6,7 and 8 BA but I doubt you will need all these for Victoria.  I would buy a spiral fluted HSS tap for anything smaller than 2BA.  Carbon Steel from a reputable supplier will be fine for anything larger and also for any dies that you need.  The same goes for any ME threads that are needed for pipe fittings.

High Speed Steel is often thought to be “better” than Carbon Steel.  HSS gets its name form the fact that is is more resistant to the heating resulting from machining steels at high speeds which would soften carbon steel.  These conditions for tapping and thread cutting with dies are not met in the home workshop.

Just my tuppence worth,

Rod

 

EDIT: Spiral flute BA taps are available from Rennie

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Thanks chaps for your replies, advise very much appreciated.

As I have metric, yes a mix of the two is the best option.

Bob

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Hello, I’ve gone for Kennions Tina engine, having a look at the drawing and this is my first casting kit a bit of advice please.

The crankshaft has 3/8th for the bearings with 1/2 inch for the fly wheel, I was thinking of a 1/2 inch through and making the throws 1 inch dia overall bigger. My question is would enough material on the casting of the bearings take 1/2 inch.

The reason for this question is that the crankshaft could have errors with lathe work, with 1/2 inch no work needed and will be more accurate with both bearings on the plinth.

Thanks Bob

 

 

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