Clarkson Horizontal redefined in Metric

[Jasonb]

Having felt for a long time that anyone looking for their first casting kit will get lead down the imperial route even though it may not be familiar to them I decided to redraw the Clarkson 1″ x 1.5″ Horizontal in metric and while I was about it sort out the few anomalies and missing details that the original drawings suffer from.

An updated metric drawing set should soon be available from Blackgates, the castings are available now. It’s not a bad buy when compared to a similar size Stuart No 8 and the cost of materials and fixings is still not going to bring the cost up to that of the Stuart. Build should be in ME at some time in the hopefully not too distant future.

<a href="https://www.youtube.com/watch?v=jIhDdFKNSzA" target="_blank">http://www.youtube.com/watch?v=jIhDdFKNSzA</a>

[crueby]

Well done!         






(not sure where I can  find metric steam on this side of the pond, though!) 

[Kim]

Cute little engine, Jason! 
The colors came out nicely on it.
Kim

[Admiral_dk]

Congratulations 

You have done a great job + there should be some happy customers for the kit + drawings in the future 

Per

[Michael S.]

 
You did a great job with the steam engine. I can well imagine building a set of castings in metric dimensions.

Greetings Michael

[Alex]

Jason; a quick note to say "thank you".

I'm one of these retirees who works in metric; currently finishing off a project drawn in imperial, and hoping it'll be the last!

I started off my model engineering as a teen with a project in inches and BA, then moved to a metric country for a few years, and, (after a few bouts of loudly swearing at the ceiling!) found metric so much easier.  I know that I'm one of few retirees in North America who choose metric, but do think younger people are more so inclined.

JohnS.

[Michael S.]

Since I only use the metric system and have built a few Stuart and Reeves models according to the original inch dimensions, I noticed that many dimensions return in the construction plans. I use a table to convert to millimeters. The table only consists of 2 pages in A4 format.
Maybe the Stuart steam models always look very well constructed to me in terms of their proportions and inch dimensions. In millimeters everyone can do whatever they want and in inches you stay within a certain grid. If you know what I mean now.

Michael

[Jasonb]

Thanks for the comments

As I have said before there are really two types of metric conversion. The first is the simple mathematical conversion where a table like Michael mentions makes conversion quite quick and easy but you are still really using imperial as you are going to pick up a 1/4" drill bit for that 6.36mm hole or use 3/16" stainless steel for that 4.74mm shaft rather than turn down 5mm stock. Oy also makes it harder to work out things like tool offsets in your head.

The type of converson that I do is a complete change to metric so that 1/4" or 6.35mm hole will now be 6mm. It's position from an edge will be 10mm rather than 9.53mm or 3/8" and that 3/16" piston rod will now be 5mm with a metric thread on it. By using 99% whole numbers any calculations you may need to do are easy and for those new to the hobby who have not yet got a DRO it will be easy for them to use the handwheels and keep track of what is going on.

Proportions of the engine should not change drastically, on a casting kit you are restricted by the physical size of the castings anyway so can't deviate that much. And most conversion is only going to be plus or minus 0.5mm to get to the nearest whole millimeter

[Michael S.]

Thanks Jason for explaining the conversion problem. Everything has to be adjusted. In particular, the available metric materials such as shafts and screws. (drill and reamer)
From my own experience I can report that the conversion needs to be taken into account when producing the Reeves Nicholas motor. With such a small steam engine I really would have had to stick to the converted dimensions with three decimal places. If you simply round something up or down without much concern, you will quickly find yourself in trouble. This small steam engine had no scope for rounded metric measurements. In this case I would have had to redraw it.

Michael

[Jasonb]

Just a quick update to say that Blackgates are now able to supply a set of my metric drawings which comprise 14 A4 sheets, one GA one with 3D views, and the remaining 12 of the individual parts. Just mention you want the metric ones when ordering a set of castings.

I'm also half way through writing up the build which will go into ME Mag and I will also give Blackgates permission to include that with any future kits sold.

In time I will also do a set of drawings for the vertical as I now have a set of castings for that, not sure when as another little Clarkson has caught my eye and is now nearer the top of the list.