[Devil]

Hello. I was curious if you can make a cyberarm into a weapon focus? And no, I dont mean cyberweapons attached to a cyberarm.

[Medicineman]

If I spend Essence for the Cyberarm it becomes part of my Body.
can I turn my natural Leg into a Weaponfocus ?

with a focused Dance
Medicineman

[Sendaz]

If I spend Essence for the Cyberarm it becomes part of my Body.
can I turn my natural Leg into a Weaponfocus ?

with a focused Dance
Medicineman

Well, in the Presidio Sean Connery's Character beat a guy with his Right Thumb because the Left Thumb (Weapon Foci maybe?) was as he stated 'too powerful'. 

[Top Dog]

A cyberarm isn't "a weapon" is it? I mean, you can hit stuff with it, harder then a normal arm, but it's as much a weapon as a normal arm is.

On the other hand, could you make it into a weapon focus before it's attached? (It's sort of like a club then?) And does it magically become a non-focus once it's attached?

I think it's one of those points where the logic of a fictional set of natural laws break down.

[Xenon]

Hello. I was curious if you can make a cyberarm into a weapon focus? And no, I dont mean cyberweapons attached to a cyberarm.

No

[martinchaen]

I'd allow it...

[Namikaze]

I'm back, baby!

I would say no way can this work.  Foci cannot be cybernetic, nor can they be a part of a person.  Qi foci are a notable exception to the last bit, but the focus is not tied into the person, but rather the tattoo.

[Sendaz]

I'm back, baby!

That's it, we gotta move that spare door key from under the doormat.


Err... we mean Welcome Back! 

[martinchaen]

A weapon focus always has, unsurprisingly, the form of a melee weapon.

Simple logical check:
Is a knife a melee weapon? Yes.
Is a knife a processed object? Yes.
Can a knife be used in physical combat? Yes.
Can a knife be made into a weapon focus? Yes.

Replace all those mentions of "knife" with "cyberarm", and you'll see why I'd personally allow it. If it can be done for knucks and a knife, why the hell not a cyberlimb.

[Namikaze]

If it can be done for knucks and a knife, why the hell not a cyberlimb.

Because knucks and knives are simple weapons.  Because knucks and knives aren't a part of a person's body.  Because knucks and knives don't take up Essence.  Because knucks and knives have no moving parts.

[Sendaz]

I would say no way can this work.  Foci cannot be cybernetic, nor can they be a part of a person.  Qi foci are a notable exception to the last bit, but the focus is not tied into the person, but rather the tattoo.

Sorry.. got called away..

Actually there is precedent in a cyberlimb being used as a foci.  4th Edition FAQ had this to say:
Edit: didn't get all the paragraphs in first time around

Can I have _____ as a focus? How much does it cost?

A focus can take any form: a ring, a dagger, a commlink, a cyberlimb, etc. For most foci, it is assumed the cost of the telesma (the physical basis of the focus) is incorporated in the cost of the focus. If the player wants the focus to be anything particularly large or expensive, however, then the cost of the item should be added to the cost of the focus.

Snowblood wants a Force 2 monofilament sword weapon focus; the talismonger tells her it would cost 20,750¥-750¥ for the telesma (monofilament sword) and 20,000¥ for the enchantment (Force 2 weapon focus).

Can you enchant cyberware and bioware? What about nanotech or genetech?

You can enchant cyberware, but this must be done before it is implanted (after it's implanted, it's a part of you). Such a focus would be considered Mundane Telesma (pp. 83-84, Street Magic). Bioware is a living material and may not be enchanted.

I can not imagine it would be cheap though with the components involved to make it that way.

Edit:  A possible issue from a game balance issue could be for the cyberadept/cyber mysticadept down the road loading up with all sort of cyber foci, then rebuilding his mojo with a lot of initiation so he can focus those points on specific effects cyber doesn't offer giving him all the strength of cyber, the magic of adept plus built in foci that are not so easily removed. 
But that would be a very long term plan/campaign to really pull it off ad that's assuming something does not break them along the way.

[ZeConster]

Firearms can be turned into weapon foci, so I don't see any harm in allowing cyberlimbs, although making it yourself would be annoying due to Object Resistance.

[martinchaen]

If it can be done for knucks and a knife, why the hell not a cyberlimb.

Because knucks and knives are simple weapons.  Because knucks and knives aren't a part of a person's body.  Because knucks and knives don't take up Essence.  Because knucks and knives have no moving parts.

What about weapons like the Victorinox Memory Blade, or how about a shock glove? Both fit the criteria of melee weapons while also being highly processed, complex items.

The only argument left is the Essence part, and with Sendaz find from the FAQ I really don't see that as a deal breaker because there is no stipulation in the Foci rules that a melee weapon that costs essence (like a cyber spur implanted in a natural arm) can be made into weapon foci.

Like I said; I would allow this because I see absolutely no reason not to.

[Lusis]

IIRC, there's stipulations on making foci out of complex objects. A knife is a simply a three pieces of metal plus tje handle. A gun is a much more complex. A cyberlimb is ridiculously complex by comparison.

[martinchaen]

Only if you count the entire arm as the weapon focus. Take the hand; yes, it'll have more parts than a simple knife, but then look at something like a survival knife which has:
a GPS monitor, mini-multitool, micro-lighter, and a hidden compartment, and wireless functionality including the ability to make commcalls.

A Memory Blade can entirely change it's shape from a shoe to a knife. A Shock Glove has the ability to discharge current into an opponent. The survival knife is essentially a blade with a commlink. A chaincsaw is a freakin' chainsaw...

Bottom line: no one has yet given a succinct reason for WHY they wouldn't allow cyberlimbs to be taken as weapon foci beyond "because complexity".

I have provided my reasoning for why I would (namely because I don't see a reason not to, because I don't think the rules preclude it (i.e. makes no mention of object complexity), and because even if complexity is considered there are other complex items that can most certainly be used as weapon foci on the one condition that they are "melee weapons").

To the OP; take it up with your GM. You're not going to get a consensus here, because some people like to argue for arguments sake. And with that, I'm out.