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Brian why can't you just turn the piston to size ?

Bentwings , I think you need to check some of your facts re boiler pressure testing . Model boilers should pass a hydraulic test at TWICE the working pressure which should hold steady for 10 minutes. A steam test should follow at one and a half times the intended maximum working oressure . Soft...

I have owned both Perfecto and Adept hand shapers , these machines were popular in the days before milling machines and cutters became readily available at affordable prices. I understand that obtaining small used machinery suitable for model engineering is more difficult in the US than in...

Glass does exactly what you have said , but it is not a flux which cleans the melt and refines the grain structure. The zinc boils and and tries to leave the molten brass , this is good because it prevents hydrogen entering. When I first started foundry work some 50+ years ago I lived quite...

Potash is potassium carbonate , I mix equal amounts of borax and potash , if you have chloride add that as well ! grind some wood charcoal nice and fine , I have a lightning struck oak tree not too far away with large lumps easily detached but I am sure you can source some. Mix the ingredients...

Melting and casting gun-metal (red brass) has no secrets . It runs well without the zinc fumes often associated with yellow brass. Make sure you can reach a temperature of around 1150°C , use a crucible that has only been used for copper alloys , use a flux , this can be made from borax ...

Add to the above that energy prices have gone through the roof and casting is very energy consuming. Dan.

I suggest a 2 or 3 inch diameter hole in the top and a similar sized hole in the door with a rotatable damper for adjusting the air flow. I have no chimney fitted and during the summer months the steam is not a problem in my large workshop. The winter is different , the steam condenses...

A well constructed build Mark , may I suggest that you include a venting facility. My own burn-out kiln , although very similar in construction , is much larger and can accomodate 4 flasks which are 6" diameter and 12" high. A full kiln load equates to about 21 lbs of water , which eventually...

When we walked to school in the 1950's , we we're too poor to have snow or be attacked by wolves , sometimes we would be accosted by Jehovas witnesses and we would fend them off by waving our log table books . Dan.

Not sure what you mean by a "slider" but from the gist of your first post I am thinking a slide valve steam engine , is this correct ? Slide valve engines are more advanced than "wobblers" in so much as they are able to utilise the fact that cooling steam expands. This introduces the concept of...

The cylinders of steam engines require steam oil which is applied either by a mechanical oil pump or by a displacement lubricator. Any good model supplier should have steam oil but a quick google shows a multitude of ads. Dan.

I will just point out that cast iron bar is continuously cast through a graphite die as already stated , but , unlike steel it does not get rolled , drawn or have any other physical treatment except in some instances it may be pickled to remove scale. In another post cutting fluids for cast iron...

Please don't start the which lathe is best argument , they are all better than nothing. Hi M where in the WM are you from ? I am near Cov. Dan.

Meehanite is a trademark for an engineering process to make a range of cast irons produced under specific and carefully controlled conditions to precise internationally recognized specifications. According to the Meehanite Worldwide company, when correctly followed the Meehanite process will...

Gunmetal , so called because it was developed for cannon barrels before cast iron , is as already stated red brass in the US and has a composition of 85:5:5:5 Cu :Pb:Sn:Zn. It is good for any steam fittings including boiler bushing and cylinders. Brass should not be used as the zinc is gradually...

I have a large collection of BA stuff from 16 BA which I have never used up to 2 BA which I use very often. Here in the UK BA stuff is very readily available from the workshops of retired or deceased ME's so it makes economic sense to use it , I even have a Coventry diehead with several sets of...

Although I have a set of insert tools for my Boxford lathe I really don't rate carbide tooling for model work , except perhaps for roughing out. I use good quality HSS , mine was all produced in the UK many years ago. It can be sharpened to a razor edge with a diamond hone and can remove a...

Brass does not suffer with hydrogen absorption problems, the vapour pressure of zinc prevents gas absorption. The porosity is caused by incorrect feeding , in the case of brass casting keep the feeder liquid for as long as possible by agitating with a piece of brass rod , this should keep the...

I had a quick look and did this 3D cad which should explain , I have left out the valves and springs.