Like Butter

[sparky961]

I tend to accumulate broken things that need fixing. Sometimes they get fixed, but more often they're hopelessly toasted and it's a total waste of time and money to fix. Such was the case with the 10hp gasoline engine - complete with 5000W generator. Cause of death? Piston went through the side of the engine with great force. I picked it up at a yard sale last year for $20.

I knew immediately that the engine itself was only good as casting stock. The jury's still out on whether the generator is worth my efforts, because it doesn't have it's own bearings/shaft for the armature.

In my late night "putterings", I decided to cut the one end off the ~1.5" steel crankshaft to use as a support for one end of the armature on it's own. The power hacksaw had no problems with it, and I was happy to discover that the cut was straighter and smoother than I've been getting with other things. Seems my adjustments are paying off.

After that, I chucked it up and took a facing cut over the rough cut - just to see what it was like to machine. As the subject of this post suggests, it cut like BUTTER! Nothing like my attempts at CRS that produce rough jagged surfaces with most of my efforts.

Can anyone give an educated guess what steel is used for this, and a similar metal to ask for next time I need to buy some?

-Sparky

 

[Alphawolf45]

You sure the crank isnt made of cast iron?

 

[sparky961]

That's a definite possibility that had also crossed my mind. Is it common to make gasoline engine cranks out of cast iron? I seems like it could be too brittle for the application.

-Sparky

 

[gilessim]

As far as I know most gas engine cranshafts are made from cast iron, treated in various ways, my Dad, retired now, fixes up old lawnmowers and garden tractors (Briggs and Stratton type engines)for something to do and I've used bits of some of his old cranshafts, and they do turn up beautifully, you can always tell cast iron by the dirty black dust it produces.

Giles

 

[NickG]

I would think it is cast iron also, as suggested, you will be able to tell by the fine dust it creates. It won't always produce a bright shiny finish either but it will be smooth.

Nick

 

[Bluechip]

Hi Troops

Could well be cast iron, from vague memory a type known as 'Meehanite' or sg iron is used for big marine cranks and also camshafts etc.

Very uniform in composition, stronger than many steels.

Not the sort of idea that springs to mind regarding cast iron.

Have not looked, but more info. almost certainly on www if you want to look further.


Dave.

 

[sparky961]

Seems the general consensus is that I've got a few chunks of cast iron here. I'm very impressed with the machineability. I've drilled cast iron before, but never milled or turned it. I'll definitely be looking for more of this stuff before I try another piece of hot or cold rolled steel.

Thanks for the input!

-Sparky