Tedder Axel

[printcom]

I have just cut 20 acres of grass for hay, went out to turn it today and I've managed to break one of my tedder axels, you know the format - just when you need it the most - s**t happens. These axels are case hardened, I know that from trying to turn one down last year - getting a new one from a dealer isn't going to happen until at least Tuesday and the other option is to turn one down from a bit of 40mm EN8 which is all I have in stock. Do you thing that EN8 will be strong enough or am I wasting my time.
The shaft is 35mm dia 450mm length and is connected to the casing with a 12mm roll pin. This thread which has some pictures was last years fiasco

 

[rtbcomp]

Ar least if you try it you'll find out for next time whether it works or not.

 

[awemawson]

EN8 is a good tough machine steel. If the original was case hardened it only gives a tough skin. The EN8 is capable of being through hardened, but I doubt it needs to be. I think that the advice to 'give it a go' is good. Can't miss the dry spell and spoil the hay.

 

[Bill Edwards]

I would have thought so.
The one that has just snapped has lasted for many years, so if you can get this to last a week to get this crop in then you're far better off than you are now. Presumably if it does break then there is not a high chance of further damage, the main loss being your time. Well worth the risk, especially compared with not turning the hay in the weather window.

In any event, case hardening isn't going to make any significant difference to the strength, only the wear characteristics which in your circumstances will be the least of your worries.

 

[rtbcomp]

Would hardening be more likely to make it snap rather than twist a bit?

 

[Bill Edwards]

I think that through hardening may do that, but case hardening won't. It has no effect on the core of the metal but leaves the surface very hard - but only a few thou deep. It is designed for applications where through hardening would leave a part brittle but a hard surface is required.

 

[rtbcomp]

Could you make a repair piece, such as a sleeve, rather than a whole axle?

 

[Bill Edwards]

I would have thought that any means of fixing it in place i.e weld/through pins etc) would weaken things unless done by simply being a very tight fit (pressed on/heated etc).

 

[printcom]

Thanks for you input chaps, I spent the day making a new axle and putting it all back together. I will try it out tomorrow -fingers crossed

 

[awemawson]

Very best of luck - hope it goes well.

 

[printcom]

For the record EN8 for tedder axles works just fine. Just done 20acres, no problemThanks for all the input chaps.

 

[awemawson]

Excellent news !

 

[candor]

Nice one, any pics?

 

[printcom]

Sorry chaps, I didn't think to post any.

Nice one, any pics?

Well here's one of the snapped shaft and one of the repaired tedder after a hard mornings work. I was flapping too much too think of taking pictures whilst I was repairing it, sorry.
The last pictures are the next job from the same tedder, as you can see it been not quite right for a while - hence the wear. I am not sure if I can be bothered to mount it on the mill, bore it out, sleeve it, somehow fix the sleeve in place without breaking the casting all to save the £140 needed for a new one. I recon just mounting it and lining it up for boring in the mill will be a pig of a job.

 

[AndyStobbs]

Thats a greedy tedder! I just put new bearings in a Polish copy of the classic pz two rotor type.