Axle Shaft Key

[Tod]

Where can I purchase 2 Axle Shaft Keys to suit the  late Heavy Axle.
Or does someone have a drawing / sketch of the key.
Tod

[John Raeburn]

Tod, Give Robin Taylor (Big Seven Register) a ring, he might be able to help.
01332 700629
J

[Tod]

Hi John,
Thanks for the reply, I will give Robin a call.
Tod

[Bob Culver]

Many proclaim that on a correctly fitted axle the key does next to nothing even on an early Seven, so the key should do even less on a long taper, so material pobably not criticall. If making anything up it is important the hub does not ride on the key.

[Tod]

Hi Bob,
Many thanks for your advice, I will bear it in mind if I have to make keys.
Tod

[dickie65]

I always thought they were a standard woodruff key.
Still in use today on machinery shafts you just need to find imperial sized ones.
I have got a jam jar full of them in assorted sizes.

https://technifast.co.uk/woodruff-keys

[Tod]

Hi Dickie,
Like yourself I have various woodruff keys of the standard pattern. However in this case it would appear to be a "special"
It measures 3/16" thick an estimated 5/16" high but the length is about 1-3/4" which takes it out with the standard range.
Tod

[Colin Wilks]

As anybody reading my posts will have guessed, I am not an engineer. However, something about Tod's key seems wrong to me. A Woodruff key is a segment of a circle and the height of the flat surface of the key, or the chord of the segment, from the furthest edge of the circle is usually less than 1/3rd of the circle's diameter. If my maths is correct, at 5/16" high with a length of 1 3/4", Tod's segment would require a circle with a diameter of about 2 3/4", about nine times the height of the key. I.e it would be very long and thin, whereas a typical Woodruff key is short and fat.

I am at a loss to understand why a key would be designed in such a way, having very little penetration at both ends, and requiring a very large diameter but relatively thin keyway cutter to mill the shaft. Can any of the engineering sages on here explain please? 

I apologise if this question appears arcane, but being virtually confined to barracks is making my mind latch onto anything vaguely engaging!

[Howard Wright]

Hi Colin

May not apply in this case but I’ve seen a key made from a rectangular bar.  I think making a key is relatively easy, making a Woodruff slot is much harder.  You really need a special cutter set up in the mill. In the case of the rectangular bar I guess it was easier to just run a standard mill cutter up the taper.

Cheers

Howard

[Duncan Grimmond]

The key I needed yesterday for my lack of drive was made from a slice of 38mm bar that my landlord/neighbouring works parted off for me. A slitting disc to cut a sector, a file to adjust the curve slightly and a flat file to make it fit the available space. Cleaned up on a piece of 120 wet&dry on the guillotine table.
I'll be making another two today as handy spares and keep them in the car with the hub puller.