At first glance this seems like it's already addressed in the rules:

"A Lathe blade is automatically of the

BlaxicanX said:

Now, I am not sure this is stated anywhere in the rules, but they are meant to be very special weapons that require the strange gravity of the Lathe Worlds to be constructed, so it wouldn't really be possible to add it on to an existing weapon. The very nature of the blade is meant to be very very different… not a little attachment that you can slip onto it.

The two cannot be combined.

I see. Alright, thanks for the info fellas.

Could you have a Lathe Blade Force Sword, does that make any sense?

I'd say so, and my Templar Calix is dreaming of one
(He also wants it to be a "switchblade" sword like the one Lt. Sulu uses in the 2008 Star Trek movie.

However, they'd be Extremely Rare, so most likely the character would need to plan a proper pilgrimage to the Lathe Worlds, and bring some proper gifts and/or letters of reccomendation with him in order to be granted access to the forges.

Here is how friends of mine and others I know decided to run with it. You can take any normal weapon to be lathe bladed like before, JUST if it was BQ or Mono, those qualities are lost, as the weapon is melted down and re-forged in the Lathe Field. This could also be a great thematic thing for a higher level campaign. Another thing is allowing existing weapons to be upgraded in quality, though the ease depends on the weapon (GQ Stub Pistol is a lot easier than getting a GQ Sword)

@Darth Smeg: I know right LoL. Well depending on how you forge a force sword in the first place, I would imagin that you could take any good quality weapon and then do your ingraving and infusing of warp energy into the weapon. But seeing as I don't know the whole of how to make a force weapon from scrach you can just as well say that it as a weapon is being created, that is the same time as you are infusing the weapon with warp energy. So if that is the case then to find someone to be able to forage a melee weapon on the Lathe worlds as well as to infuse it with warp energy would not only be the rarest of the rare but practically unheard of as well possibly.

Or you could just get a power sword instead. Y'know, those things that do more damage than Lathe weapons?

Which make noise, can run out of power, break when unpowered, etc.

We all know Power Weapons are pretty much the top tier, but Lathe weapons are a great alternative

No actually a Force weapon is top tier, and esaily beats a power weapon.

I thought I didn't have to include the Caveat that IF you are a psyker and IF you have made a focus on melee (talents/WS) then yes, the Force sword is the best in a lot of ways, but power swords are still pretty much the top tier for everyone, because of their nature.

@Cymbel: I know power swords are top tier, I'm just being a dork because I play a psyker, that's all.

But you also have to take into account that if you have one attack it doesn't matter what weapon you have, if that one attack gets dodged or parried (it only matters if a power weapon parries a power weapon) you're S.O.L. because your chances of scoring damage each turn is greatly reduced. This is besides the point of this post though.

@Cymbel: I know power swords are top tier, I'm just being a dork because I play a psyker, that's all.

But you also have to take into account that if you have one attack it doesn't matter what weapon you have, if that one attack gets dodged or parried (it only matters if a power weapon parries a power weapon) you're S.O.L. because your chances of scoring damage each turn is greatly reduced. This is besides the point of this post though.

Arguably, it's exactly when the quality of your weapon counts the most, because if you're going to be dodged a lot, you want those times you aren't dodged hurt a huge lot to make up for it.