Making The Crank Shaft - Part 3 Disaster Recovery

Starting Afresh with New Crank Webs

I had to mill down some stock bar to make the new Crank Webs, but that didn't take too long.

This time I drilled the Webs individually using an end stop to position them in the Vice.

Each web was placed into the vice and gently pushed up to the end stop, centre drilled, drilled 4mm then 7mm or 6mm for the smaller holes.

The eagle eye' d will note that I have drilled the pinning holes through one side, this will make it easier for me to drill the final pinning holes right through the assembly.

Mistakes if treated like a bonus, can make life easier the next time around :-)

Using an expandable Reamer to Size the 7mm Holes

I used an expandable reamer to gently size the 7mm holes so that the Crank Web would slide onto the shaft easily without forcing.

It only require a small amount, pretty much like cleaning the hole rather than enlarging things.

I have also started cleaning up the Webs ready to give them a polish before they are assembled.

These do not have to be polished they can be left as they are, it won't affect the running of the engine at all.

Turning The Web Radii

This time I turned the 4 Crank Webs at the same time, saves a bit of time and it means they are pretty much Identical.

Again these do not have to be turned, you could file the corners off by hand or even leave them square as long as they don't hit any other part of the engine when they rotate.

I just need to turn the Big End Journals and size them to fit the 6mm holes and I'll be ready to fit the Crankshaft assembly again.

Photographing Shiny Things

Another way of getting a good images of something shiny, and to show the scale is to hold the item and to take multiple shots to get the right effect.

You will need to use flash for this, especially if your hands are as shaky as mine :-)

A New Main Shaft for the Crankshaft

Had to turn up a new main shaft for the Crankshaft, and luckily for me, I had set up the tail stock for accuracy a few weeks ago, so I managed to turn the shaft accurate to a few thou using light cuts.

A quick rub down with emery cloth "ona stick" then a polish again using a stick to apply the polish and a clean stick to polish it off.

WARNING:

NEVER EVER; use a cloth near rotating parts, the rotating part will grab the cloth and most likely you.

PLEASE don't do it.

Take the shaft out of the lathe, then give it a final polish with a cloth.

The shaft doesn't have to be polished, but I like it that way :-)

Big End Assembly

Nearly ready to assemble the crankshaft again, just have to turn the last Big End Journal.

I turn the Big End Journal to suit individual Con Rods as it is easier to size the bar, rather than enlarge the Con Rod.

I turn the journal to within a few thou of the required size, trying the con rod at each stage.

When the size is just about right, being slightly over tight when the con rod is fitted I leave it there so that I can lap the two parts at the final assembly stage, to get the right fit.

Crankshaft Ready for Pining

The crankshaft has been assembled and fixed with loctitie.

The next stage is drilling and pining which means making 8 steel pins to hold everything together.

I'm always amused when books or plans say "now pin the items together" then go onto other things as if the pining was of no consequence.

Pining objects requires accuracy and care, as well as finding suitable pins to fit.

In this case I am using piano wire pins cut to length with a diamond slitting saw in my Dremel Multitool.

Each pin is 13mm long, and the piano wire has to be reduced slightly in diameter to allow a tight but not too tight fit.

Dremel Drill Mounted on the Lathe Tool post

I've made a bracket from some scrap aluminum channel to hold my Dremel Drill in the tool post, for little jobs like this.

I usually only use the diamond type cutters/grinders/points as there is little grit shed as they work.

The Brown Abrasive wheels do shed a lot of grit as they cut, so I would use paper towel to cover all the bed ways etc so as to stop grit getting into the slides.

DO NOT use cloth to cover the bed of the lathe, as it might get caught by the rotating parts and cause damage to you or the work in progress.

The Dremel really needs a support for the rear to make it more rigid especially if you wanted to drill work pieces.

The set-up works well enough for this job, and makes cutting piano wire a doddle.