3 Eared Knock Offs

[gearbox]

Anyone know what material these knock off are made from? I have a used set that I was going to restore and have to weld up some small nicks. I'm thinking brass as I sanded some areas and see gold underneith. It may be just the cooper plating before the chrome, but not sure. Thanks Allan

[UAB807F]

Hi Allan,

Ok, I'll admit I don't know for certain but.... back in the 70s I worked in a foundry making propellors for ships and we used to melt down anywhere between 5-10% scrap in the mix. I distinctly remember seeing Lotus-type knock ons alongside those for Jaguar thrown in the aluminium bronze scrap bins. (I even "rescued" a few nice jag ones to decorate my office in those days).

Aluminium bronze is a much tougher material than plain brass, harder wearing and less prone to corrosion & fracture but still able to be easily cast and chrome plated. Plain castings used to polish to a very pale silvery brass colour and if I were to guess that'd be high on my list.

If the nicks are small then my first thoughts would be if they'd polish out rather than welding in new metal which still needs polishing afterwards ?

Brian

[gearbox]

Hi Brian;

Thanks for the info. I have a set of KO's I wanted to restore and needed to add some material. The cuts are not too terrible, but polishing them out would definetly cause me to lose a lot of detail. Sepecially around the tips and edges. I roughed out the worst one and noticed a brass or bronze color under the chrome. They are not magnetic, so that have to be a non ferrious metal. I just need to know if I can braze bronze on to the part and grind it down, and if it would hold. Needless to say, I am not a welder, but I can braze nice globs and then grind and polish. But is this possible, what rods should I use, and is there a right way? Thanks Allan

[CBUEB1771]

I have a set of KO's I wanted to restore and needed to add some material.

New three eared knock-on nuts are readily available from the usual suspects. I would think long and hard about restoring what you have considering there is no guarantee that yours are original. BTW, the drillings for safety wire are completely unoriginal, however smart they may be.

[UAB807F]

Hi Allan,

Welding (and brazing) of aluminium bronzes isn't difficult but they can be relatively complex alloys so they do present a problem when you're not sure of exactly what we're dealing with.

Welding is straightforward, I think we used MIG (this was the mid 70s, so memory is questionable now) and I can certainly remember using TIG to repair an unusual pressure vessel in the 90s. The general rule is to use a similar composition to the base material which in our case was a reasonably complex Ni-Al-Fe-Mn-Cu alloy. Given the alloy variations around even then and our lack of knowledge regarding what Lotus would have specified, I think we could assume you're not going to pick up a set of rods to match these spinners from your local welding merchant .

You could drop some conventional braze or even silver solder into the holes at the tips and that would work out ok. But remember that the melting point of the spinner will be lower than steel (circa 1000C ? maybe less ?) and closer to the brazing filler so some care will be needed but I'd feel relatively confident doing that.

What I wouldn't do is to attempt to weld in the vicinity of the threads or load bearing sections. I'm sure it can be done and if I knew what I was dealing with then I probably would, but given the limited info we have and the critical nature of the component, well, I'm too risk averse. That's the trouble with having a little knowledge of what can go wrong - I just think about a spinner cracking and the wheel coming off !

Brian

[gearbox]

I have a set of KO's I wanted to restore and needed to add some material.

New three eared knock-on nuts are readily available from the usual suspects. I would think long and hard about restoring what you have considering there is no guarantee that yours are original. BTW, the drillings for safety wire are completely unoriginal, however smart they may be.

Are they? I checked with Ray at RD Enterprises and he tells me that they are out of production for some time now. I wouldn't mind buying a new set, but had these spares and thought it would be fun trying to sort them out. Nothing ventured nothing gained. Just wanted to know if there was a right way of doing it from the experience of others.

[gearbox]

Hi Allan,

Welding (and brazing) of aluminium bronzes isn't difficult but they can be relatively complex alloys so they do present a problem when you're not sure of exactly what we're dealing with.

Welding is straightforward, I think we used MIG (this was the mid 70s, so memory is questionable now) and I can certainly remember using TIG to repair an unusual pressure vessel in the 90s. The general rule is to use a similar composition to the base material which in our case was a reasonably complex Ni-Al-Fe-Mn-Cu alloy. Given the alloy variations around even then and our lack of knowledge regarding what Lotus would have specified, I think we could assume you're not going to pick up a set of rods to match these spinners from your local welding merchant .

You could drop some conventional braze or even silver solder into the holes at the tips and that would work out ok. But remember that the melting point of the spinner will be lower than steel (circa 1000C ? maybe less ?) and closer to the brazing filler so some care will be needed but I'd feel relatively confident doing that.

What I wouldn't do is to attempt to weld in the vicinity of the threads or load bearing sections. I'm sure it can be done and if I knew what I was dealing with then I probably would, but given the limited info we have and the critical nature of the component, well, I'm too risk averse. That's the trouble with having a little knowledge of what can go wrong - I just think about a spinner cracking and the wheel coming off !

Brian

Thanks for the info Brian. While I have Tig and Mig, I feel more comfortable with Oxy Accetoline as I can control it better. Especially when brazing. So go with Bronze rods and flow the new metal in? If they turn out well I'll buy that spinner wrench to avoid smacking the ears again. I'll let youknow how it turns out lol. Wish me luck.

[UAB807F]

I'll certainly wish you the best of luck Allan, and would like to know how you get on with it.

After posting some more of those redundant brain cells of mine fired up and I remembered that in those days we were members of the Copper Development Association. I looked it up and they have more up to date info on the alloys, including a basic welding guide which will be much better than my memory.

http://www.copperinfo.co.uk/alloys/bronze/homepage.shtml#aluminiumbronze

and

http://www.copperinfo.co.uk/alloys/bronze/downloads/pub-85-welding-aluminium-bronze.pdf

Brian

[alexblack13]

Sue M does them fully restored exchange and they are very nice indeed..

Can't remember the price though.

AB...