Making the Crankshaft

Pinned Crankshaft

Click on any Picture to connect to my Flickr Site

To see enlarged images

Pinned Crankshaft

Crankshaft with the pins inserted so everything is ready for me to cut out the surplus material between the crankshaft webs.

Making the crankshaft took longer than I thought, probably because I'm so fussy about the finish :-)

Removing the Unwanted Metal

Use some scrap softwood to clamp the crankshaft in the vice, you can hold the wood with some masking tape or any other type of sticky tape.

Make sure that the big end journal is below the vice jaws, to ensure that you don't cut into it by accident.

Using a hack saw cut out the unwanted pieces of the crank shaft.

Leave yourself plenty of clearance from the crankshaft webs.

I found it was easier to use a junior hacksaw for this, as the smaller hacksaw is less likely to jump out of the starting grove.

Protecting the Big End Journals

It is a good idea to protect the Big End Journals before starting to file the waste metal.

I used some thin aluminum strip cut from a Litho Plate (the old style printing media), any strip of soft metal will do.

Tape the strip around the Big End Journal and you are ready for the task of filing the waste material.

Filing the Crankshaft

Mount the crankshaft in between the wooden blocks in the vice with the Big End Journal below the level of the vice jaws.

Using a file, preferably one with a safe edge (no cutting teeth on one side) slowly and carefully file away the waste metal.

Don't try and do this job all in one go, pace yourself so that you don't hurry.

I quite enjoy hand filing if approached in a relaxed sort of way.

If you have polished the Crankshaft Webs brace yourself, they are going to get scratched, just try to keep the marking to a minimum.

Complete the rough filing on all four web faces of the crankshaft.

Then using a small flat Swiss file smooth the waste metal until it is flush with the webs.

Next use finer and finer Emery Boards until you achieve the polish you require.

Emery Boards or Sticks

These very useful little devices are easy to make and make smoothing and polishing much easier.

You can find suitable strips of wood in Model Shops or in one of the big DIY sheds if you don't have any available.

Stick different grades of emery cloth/paper on them using PVA glue trim the edges with a sharp knife.

I make up a few at a time and either clamp them in the vice or place a heavy weight on them just to make sure they stick really well and make sure they are flat.

Some can be useful with the emery stuck to the bottom and on one side, I use a square stick for that.

The finished Crankshaft

The Finished Crankshaft

A picture of the completed crankshaft with the Journal Protectors still in place.

Please Note:

None of the polishing, that I indulge in needs to be done for the correct running of this engine, it won't care if the crank webs are scratched or have saw marks as long as there is clearance for the connecting rods it will work just fine.

I just like to use the skills that I learned as an apprentice many years ago, and I get great satisfaction out of creating a polished finish.

It is also helpful for my migraines, as I can concentrate on some easy but slow task and it helps to distract me from the pain.

Also I have the time available for the somewhat lengthy polishing tasks.

So if you just want a running steam engine, disregard all the polishing stuff.

Crankshaft Assembled

Just a bit of fun showing the crankshaft with the Con Rods in place.

Cranckshaft and Connecting Rods

Polished and ready for assembly, the Connecting Rods have been fitted to their corresponding big end journal.