I've recently got the urge to make a model steam engine, and many years ago (I was probably about 15) I borrowed a book from the local library called "Building Model Steam Engines" by Tubal Cain......and just to confuse you the Tubal Cain who wrote these books was British and not the American who does the Youtube channel. I managed to lose this book somehow, so I bought a new copy, took it to the library, and explained I'd lost it and this was a replacement I'd bought, which they took off me....then a year later they sent me a fine for the overdue book, but they let me off when I explained what happened.
so I recently got this book again and the book 2 version for the sum of less than £4.00 from ebay, and the one I want to do is called Jenny Wren, which is named after the bird because of its tiny size. this is a photo of it from the book
These have been commercially available for a few years from companies like Philcraft with their version shown below
so the engine design has the following features (in metric based on the imperial dimensions)
the cylinder is 3.2mm bore x 4mm stroke,
the fly wheel is 19mm diameter
the boiler is 45mm tall x 25mm diameter
the overall height is 75mm
so it really is small, and the size will make it an interesting challenge.
its something I'll be doing over several weeks, so it'll be a slow process.....
for the lathe work I've decided that it'll probably be best to use 1/8" square tooling. and the first thing was how to make a small boring bar, bearing in mind that the cylinder bore is 3.2mm
so the 1/8 square tool was clamped in a collet chuck and ground down to the tip being 3mm diameter and the main body being 2.4mm diameter
and the back and bottom of the tip are reduced to the diameter of the main body, by rotating the blank while grinding through 90 degrees.
this was done using the 12v grinder
that I made in this thread
http://www.mig-welding.co.uk/forum/threads/small-grinding-spindle.79598/#post-1129755
the cutting face and side face were then ground freehand on a diamond wheel (100mm diameter)
and the finished boring bit held in my toolholder. normally I use 8mm square tool blanks, so used a spacer with a 3mm square cutout to mount the 1/8" square cutter.
I was originally going to use a 1/8 machine reamer, with the taper lead ground as short as possible, but think this will be a better option for boring out a 3mm hole.
think the next bit will be the parts of the boiler
so I recently got this book again and the book 2 version for the sum of less than £4.00 from ebay, and the one I want to do is called Jenny Wren, which is named after the bird because of its tiny size. this is a photo of it from the book
These have been commercially available for a few years from companies like Philcraft with their version shown below
so the engine design has the following features (in metric based on the imperial dimensions)
the cylinder is 3.2mm bore x 4mm stroke,
the fly wheel is 19mm diameter
the boiler is 45mm tall x 25mm diameter
the overall height is 75mm
so it really is small, and the size will make it an interesting challenge.
its something I'll be doing over several weeks, so it'll be a slow process.....
for the lathe work I've decided that it'll probably be best to use 1/8" square tooling. and the first thing was how to make a small boring bar, bearing in mind that the cylinder bore is 3.2mm
so the 1/8 square tool was clamped in a collet chuck and ground down to the tip being 3mm diameter and the main body being 2.4mm diameter
and the back and bottom of the tip are reduced to the diameter of the main body, by rotating the blank while grinding through 90 degrees.
this was done using the 12v grinder
that I made in this thread
http://www.mig-welding.co.uk/forum/threads/small-grinding-spindle.79598/#post-1129755
the cutting face and side face were then ground freehand on a diamond wheel (100mm diameter)
and the finished boring bit held in my toolholder. normally I use 8mm square tool blanks, so used a spacer with a 3mm square cutout to mount the 1/8" square cutter.
I was originally going to use a 1/8 machine reamer, with the taper lead ground as short as possible, but think this will be a better option for boring out a 3mm hole.
think the next bit will be the parts of the boiler