What type of steel to use for the 1/4 inch axles ?

I need to buy some steel to make 1/4 inch axles for stationary steam engines.

1. What type of steel should be used for the axles ?

2. What do you call the flat machined part of the axle where the grub screws of the flywheel make contact ?

Hello Brian

1 In most cases ordinary 'bright drawn mild steel' without specifying a precise composition will be adequate, whether you use them at nominal size or turned down. No point in using expensive silver steel or high-tensile alloys.

2 I've always called them 'flats'.

Neil

Hi Brian, Bn Q sell bright bar which machines ok.

The flats, well there are different types, a sunken flat with sides is usually for key that sits in it, a flat that is not sunk would usually have a gib head key, so you could call it a gib head key flat!

You could also leave the shaft round and gently tighten your grub screw down, then take off you flywheel etc and drill a small dimple where the grub screw has left a mark. This would locate the grub screw and stop the wheel coming off. I like this on small items as the shaft fills the hole in the wheel and looks nice.

Brian

Which raise the question : How to drill the hole for the grub screw in the flywheels ? I do not have a drill press so can this job be done by hand or is this not advisable ? I notice that you do not get much room to manoeuvre as the drill bit, chuck, tap and tap wrench come up very close to the rim of the flywheel.

Don't drill the hole at right angles to the shaft. Drill the hole in the flywheel at an angle such as 45 degrees.

Eric : Yes, I know. But even drilling at an angle of 45 degrees it is still a very tight fit on most of the flywheels that I have purchased.

Edited By Brian John on 14/06/2014 10:25:57

Hi Brian,

Tapping is made easier by using a pion-vice to hold the tap. Alternatively, use a key to hold the flywheel in place

Neil

Hmmm, a pion vice is going to be a bit small -

"Abstract

The pion radius has been measured by direct scattering of 50 GeV negative pions from stationary electrons in a hydrogen target. We find the square of the radius to be 〈r_π²〉 = (0.61 ± 0.15)fm²."

Hugh

Brian, one way to drill the hub is to take a bit of spare round bar, drill into the end of it with your tapping drill then loctite the shank of the drill into the hole. You then have a drill that is long enough to reach the hub at a shallow angle without the chuck hitting the rim/spokes. A bit of gentle heat will get the drill out of the extension. You can do the same with the tap.

It can be done freehand with a cordless drill or if you don't have a benchdrill fix it to an angle plate set at a slight angle on your lathe cross slide and hold the drill/extension in your 3-jaw chuck.

J

Hi Brian. Not sure if you have a lathe? If you have machine a small bar say 8 mm diameter dril a hole in the end just a bit smaller than the square end of the tap, warm it up with a blow lamp or similar and then tap, hammer etc the square end of the tap into the hole, this will make you a long tap holder to allow you to get into the corner.

Bri

Yes, I do have a lathe but it is not set up yet. It is still sitting in its box on the living room floor. I am building a workbench for it which should be ready next week.

Brian, some of my flywheels are drilled when finished, I angle the drill as close as I can to clear the rim, a long drill is handy here, I drill it free hand using an ordinary wheel brace (the battery doesn't go flat). My flywheels are fabricated, and when I remember I drill and tap before assembling the hub. Ian S C