So... how do you hold a Chicken Head Knob?

[Shox Dr]

That got you interested

So need to hold this knob. To be able to remove the stub and drill to take a shaft.

 

[BrokenBiker]

4 jaw in the lathe

 

[Shox Dr]

I took me a while, but a bit of lateral thinking and a came up with this. Using the lid off a can, and a mop, I roughly centred it, using a bit of double sided sticky tape (thank god for blue peter). Then holding the the knob, in the mill, the knob is now centred. that's all well and good but how to hold it. WS8 I hear you cry. yup that's what I thought as well.

In all the excitement I forgot to take pictures of molten stuff, and the pouring of.

So a few hour to cool, and there you have it. I can now hold the shaft in the lathe, true it up, then spin it around and bore for the shaft. More tomorrow.

 

[Shox Dr]

4 jaw in the lathe

No good, part too not to be marked, and it holds better in a 3jaw

 

[doubleboost]

molten wax glass fibre resin

 

[Shox Dr]

molten wax glass fibre resin

Not sure wax would be stable enough, and how would you get the resin off.

Cured and out the lid

 

[doubleboost]

that is not wax looks like resin and sand mix

 

[Shox Dr]

I never said it was

 

[doubleboost]

I am just thinking out aloud
Clever idea whatever you used

 

[Shox Dr]

I used WS8 it's used for bending thin wall tube

 

[doubleboost]

Very clever idea
We used to use silver sand and plug the ends
Has this WS8 got a link

 

[hotrodder]

Cool, another use for tube bending resin I've still not got around to buying any, i take it it sets up pretty hard then as you didn't bother casting it in a tube offcut to leave it with a metal shell?

 

[MrFluffy]

Theres products just for this job, theyre mostly based round woods metals because of its low melting temperature, cerrobend for instance, but if the toxicity of lead and cadium worries you, pick a fields metal alternative (Cerrolow 136?)
Theres a few pages in machinist tips and tricks showing some of the ways you can use it to hold awkward/delicate things that most would consider un-machinable due to their shape or delicacy (theres one where they are machining a lip onto a thinwall transparent perspex U bend).

Or you could have just welded it to a bit of scrap bar and gripped that (joking)

 

[Shox Dr]

Very clever idea
We used to use silver sand and plug the ends
Has this WS8 got a link

let me Google that for you

 

[doubleboost]

Found it
http://www.johnnealeltd.co.uk/Resin WS8 TDS.pdf

 

[Shox Dr]

Cool, another use for tube bending resin I've still not got around to buying any, i take it it sets up pretty hard then as you didn't bother casting it in a tube offcut to leave it with a metal shell?

I thought it might slip so, as it feels waxy when solid, so I'll true it up and cross drill it for a little drive pin, just to stop it from spinning.... now where is that chicken heads knob, in there

 

[mcostello]

Drill hole through a piece of steel then split so it clamps.

 

[CRB]

Soft jaws of polypropylene/polyethylene. Warm the surfaces which will contact the part and squeeze. Once cooled, rigid but easily split grip.

I had never heard of WS8, so something learned today. Thank you DrShox.

Another way to hold my MZ ignition keys, in case the worst happens.

 

[Shox Dr]

Soft jaws of polypropylene/polyethylene. Warm the surfaces which will contact the part and squeeze. Once cooled, rigid but easily split grip.

I had never heard of WS8, so something learned today. Thank you DrShox.

I don't think you could guarantee the part to be on the lathes axis?

At least this way I can true it up, before holding it

 

[CRB]

With the shaft gripped true, forgot.

Your way with the resin/wax is certainly a quicker method, and more easily centred.

I will remember it for next time.