Is within a net site which will show me how to turn a wood turning lathe into a metal turning lathe?
Well, the only way to do what you're asking is to trade-in your wood-working lathe for a discount on a "real" lathe.
The are numerous considerations why this cannot be done, some of them being:
1. Stiffness (metal lathes are stiffer)
2. Strength (metal lathes have need of to be stronger)
3. Torque and power (metal lathes would require higher torque and power ratings)
4. Accuracy (metal lathes are generally more accurate)
5. Tooling (more robust, and harder tooling required for metal)
If you can address respectively of these issues, only then can you hope to convert your wood turning lathe to a metal turning lathe.
The best course seem to be to purchase a separate metal turning lathe.
I seriously doubt it.
While you can turn wood on a metal lathe, the reverse is not usually true.
Metal lathes have calibrated tool movements. Wood lathes own none of that, simply a bare rest on which to brace the cutting tools, which are intended to be paw held.
Your best bet is to keep an eye on eBay and other resellers, looking for a nice used metal lathe