Making the Crank Shaft - Part 2

Tidying the Crank Webs

At this stage you can use emery cloth to clean up the Crank Webs, removing any burs or unevenness, and they are then ready for construction of the Crankshaft.

Polishing the Crank Webs

As you may have noticed, I do like a bit of polishing.

So the following is just for those that like to polish up their parts. :-)

Please note:

Polishing the bits will make very little difference to the working of the finished engine, it just makes it "SHINY".

Here is the set up I use for rubbing down.

Basically a nice thick piece of glass, and various grades of Emery Cloth and Papers.

Thinner glass is OK but you have to be more careful how you support it on the bench.

I put mine on a rubber mat, stops it sliding all over the place.

I find a rubber mat invaluable on the work bench, especially the type that has little square sections, it helps keep all the little bits from falling on the floor.

Making a wooden polishing jig

Very simple to make and use, as you can see from the picture.

Basically two screws with the right sized heads, screwed into a piece of waste wood.

Makes life a lot easier.

Polishing Underway

With a bit of patience and several grades of Emery, gives a nice basic finish.

The next step

Finer and finer grades of Emery Paper, until satisfied that all of the blemishes are removed.

The high Tech Polishing Wheel

A bit of dowel glued to a softwood disc, mounted in the chuck, dressed with abrasive stick and run at a fairly slow speed.

A different wheel is required for each grade of abrasive, to ensure that the coarse grits, don't scratch the finer finishes.

I find this stage quite satisfying - but I don't try and get a perfect finish straight away.

It's better to do a bit, then leave it, come back and do a bit more, and so on.

Not quite finished

Good enough for now.

Now you have to decide how you are going to assemble the Crankshaft, and what method of holding every thing together.

Turning the Big End Journal

As you can see in the image, the Big End Journal is turned in one hit, without moving the original bar.

This ensures that the Journals are truly concentric.

This makes building the fabricated Crankshaft easier and more accurate.

This blank is in need of a final polish before being cut off and trimmed for assembly.

Measuring the Big End Journal

The Journal has been turned close to size, allowing enough metal to polish and to hone to an exact fit for it's corresponding Con Rod.

You can see my finger prints in chalk on the Micrometer, I can't use a micrometer with latex gloves on, as I can't feel the measurement properly.

Getting Ready to Assemble the Crankshaft

Well the Journals are turned and matched up with their corresponding Crank Webs, every thing fits together, after a bit of scraping here and a little judicious file there.

I'm going to use Loctite to hold the Crankshaft assembly together, it's a very effective agent for holding metal in well fitted parts, but things have to fit well for it to be effective.

Luckily I still have the small bottles of Loctite from my engineering days, so the few drops it requires are available and to hand.

The other advantage of Loctite, is that my nice polished parts wont be blackened and marked by silver soldering.

The advantage Silver Soldering has, is the fact that it will fasten parts that are maybe not quite so accurate, and is more forgiving in use.

So I'm not knocking Silver Solder, I have a healthy respect for the strength that it imparts to an assembly and it may be that I will use silver solder if anything goes wrong with my Loctited Crankshaft.

Assembled Crankshaft

Here is the assembled Crankshaft, It still has to have the excess metal removed between the Crankshaft Webs.

Protecting Polished Surfaces

When working with polished or delicate surfaces, using masking tape to line the vice works well.

The masking tape protects the surface finish but still maintains a good grip.

Removing the unwanted metal

I'm using a slitting saw to slice the unwanted metal from the crankshaft.

I had to use a hacksaw as well as the slitting saw was not big enough to cut all of the way through, without the chuck hitting the work piece.

The Crankshaft Centre Punched for Drilling to take Cross pins

The central rod has been cut through and filed flush between the two webs.

The cut sections have been rough polished and will be finally polished just before the engine construction phase.