Benson's Vertical Steam Engine

[J.L.]

Three of the main parts of the engine can quickly be assembled and disassembled during construction. As you can see, a tie rod runs up through the middle of the column fastening everything together.

This will be handy later when parts alignment becomes important. I am refraining from drilling the flange holes in the column until that time.

[b.lindsey]

More nice yet intricate work John. The assembly of those three pieces reminds me of how a lamp goes together

Bill

[J.L.]

Well said Bill. That's exactly the principle involved here. 

[J.L.]

 
Happy New Year!

I wish to depart from the suggested method of making the steel bearing blocks in Anthony Mount's book and try an idea that has worked for me in the past. Mind, you, I was using a much softer brass.

Instead of drilling and shaping two blocks, why not do it just once with a pattern? The trick is to get two pieces of bar stock married together so that they will not move in the machining process. You can see in the third picture that bolts accomplish this. There is also a small bolt in the block area. When the blocks are cut from the bars, they have to stay together without moving so that the bottom of them can be faced.

Here's the setup...

[J.L.]

One drawback to the pattern method is that it takes a beating with the drilling of the hole and the lubricating oil. It can shred up or degrade. So, several patterns made on the printer are needed to complete the project. And they have to be repositioned exactly over the hole. 

[Don1966]

Very nice work JL and I use the pattern method also it works real well. I also built the Benson an enjoyable engine to build but I built mine from scratch. ......

Don

[Steamer5]

Hi John,
 Coming along nicely!
As a suggestion on your pattern getting damaged, have you considered centre / pin punching (lightly) around the pattern lines? that way when the pattern gets U/S you still have something to go by.

Cheers Kerrin

[J.L.]

Thanks Don. Yes, I believe you increased the scale of the engine a bit as well? I may be asking you some questions as we go along here...

Hi Kerrin,
Wonderful idea! As you can see from this photo, the pattern is long gone as I have worked the hole up to its finished size here - 3/8". After I cut out the hole, I will attach another pattern. It should be easy with the open ended hole, but your idea stands. 

[Gas_mantle]

Looks like you are making good progress 

Thanks for posting this thread, I've always thought Benson engines to be very attractive models and would love to have a go at one shortly. In the UK there's the opportunity to buy a casting kit at a reasonable price but I kind of thought about buying the plans and trying to make a bar stock version and possibly simplify it a bit if need be.

Peter.

[Jasonb]

Barstock is quite easy on the Benson and at 1.5 times the size another of thos eflywheels you have just had machined will fit nicely. Buying the book is a better bet as you get drawings for several engines at less than teh cost of one drawing set.

[Gas_mantle]

Thanks Jason, I wasn't aware there was a book on building one. I did consider scaling up though and the RDG wheel castings seem to fit the bill at a reasonable price.

[Don1966]

Thanks Don. Yes, I believe you increased the scale of the engine a bit as well? I may be asking you some questions as we go along here...

Thanks JL but Jason is the one who scaled it up. I made mine to scale but any question you may have we will be glad to try and answer them for you.

Don

[J.L.]

Good interaction and interest here.   I'm happy the thread is a motivating factor in having a go with this pretty little engine.

We were discussing the pattern method of cutting bar stock. The pattern in these photos has become wet with lubricant and will soon fall off. Another dry one should be enough to profile the curved edges of the blocks.

[J.L.]

Being a novice to the art of machining metal, I was totally unaware of their many different grades and machinability until I sourced bar stock at American Model Engineering. The steel I ordered is a mild steel and machines like butter. It's wonderful. Clean with square edges.

It's called 12L14. Apparently it is not as strong as 1018 and cannot be heat treated or welded successfully. But for the profiling work I'm about to do on the bearing blocks, I'm glad it such a mild, workable steel!

[b.lindsey]

John, 12L14 is in a way the standard by which other steel alloys are compared for machinability. Just be aware that it rusts pretty easily so needs to be protected in some way or painted.

Bill