The Maximum Critical Threat Range

[Irk]

To begin with there is this line from the SRD:


Multiple effects that increase a weapon's threat range
If you want to stack factors increasing a critical threat range, it must explicitly state that the factors stack.

EDIT: the below is using 3.5 AND 3.0 material.

Firstly, it ought to be noted that improved critical stacks with the iron power ability of the Disciple of Dispater. In addition, improved critical stacks with the abilities of weapon master and psychic weapons master (PWM) as well as the benefit provided by the Hero’s blade spell. Thus, by the transitive property, they stack with iron power. When combined, improved critical, iron power, and hero’s blade multiply a critical threat range by five. The PWM ability adds two. In this scenario, the order is all that matters.

First, take an 18-20 weapon. Improved critical brings it to 15-20, and weapons master PWM brings it to 13-20. The question is how exactly DoD and hero’s blade interact with this reduced range due to the way in which multiplier stacking works. This is one interpretation. Doubling a threat range of 18-20 brings it down to 15-20. Tripling the same threat range brings it down to 12-20, and quadrupling it brings it down to 9-20. Therefore, hero’s blade, iron power, improved critical, and the PWM will bring it down to (6-20)-2, or 4-20. The other interpretation is similar, though this time, the threat range is decreasing by 5 each time, because PWM has added extra range to the improved critical, which is then considered to affect a threat range by doubling it then adding 2. With this interpretation, the threat range effectively becomes 1-20.

There you have it, maximum critical threat range. Many people forget about that blanket ban in keen edge, and try to apply things like serrated, but that does not exactly work. Depending on your interpretation, the maximum threat range on a weapon is either 4-20 or 1-20, using the components above.

EDIT: Arcane duelist is another multiplier increaser from 3.0, just putting that out there.

EDIT: Heliomance pointed out that weapon master has been updated and is therefore not legal to use in the above combo.


Highest 3.5: 9-20 with a human psychic warrior 6/ Psychic weapons master 7/ street fighter barbarian 7
highest 3.5 ONLY threat range is 9-20 with a human psychic warrior 6/ street fighter barbarian 7/ psychic weapons master 7 with a hero's blade continuous item while charging with an 18-20 weapon.

Highest 3.P: 1-20 with a human psychic warrior 5/ DoD 8/ psychic weapon master 7 (see above in initial thoughts)


Hero's blade spell (doubles)
PWM or WM (+2)
improved critical (doubles)
DoD 4 and 8 (doubles and triples)
Arcane Duelist 7 (doubles limited time)
Mythic exemplar 2 (+1 limited time)
Streetfighter Barbarian 7 (+1 while charging)

[geekintheground]

just another reason fumbles shouldnt be a thing...

[TuggyNE]

Everyone knows that Improved critical stacks with the Iron power ability of the Disciple of Dispater.

Beg pardon. Who is this "everyone" that apparently knows this? It certainly does not include myself, since I consider that DoD, as a 3.0 PrC, needs to be updated to the 3.5 assumptions, including the new rule that Improved Critical does not stack.


Thus, by the transitive property, they stack with iron power.

What transitive property is this? Stacking rules are by no means equivalence relations. To give an obvious counterexample, any shield bonus will stack with any armor bonus, but shield bonuses do not stack with each other.

[Irk]

I'm sorry Tuggy, You are correct, my initial post was rather presumptuous. The iron power ability of the DoD says it stacks with improved critical, but I will amend the above to make it less brazen in tone.
In this scenario, since improved critical stacks with iron power and improved critical stacks with, for example, hero's blade, then hero's blade stacks with iron power. That's what the transitive property says.

Also, I absolutely concede that DoD should've been updated or errata'd, but it wasn't, which forms the basis for my initial post.

[Heliomance]

Problems:
Psychic Weapon Master requires a crystal weapon. DoD requires an iron one.

Weapon Master was officially updated into the CW Exotic Weapon Master. Never mind that it's a completely different class, WotC says it's the official update, so the Weapon Master is not valid for play.

[2xMachina]

Iron can be crystalline.

Ding!

[Irk]

Iron can be crystalline.

Ding!

I think there is something that counts as both, but I do not remember the name.

[Heliomance]

Iron can be crystalline.

Ding!

Crystal is a defined special material for weapons. A weapon cannot be both iron and crystal at the same time under D&D rules. The metellurgy of iron is not part of D&D rules.

[Irk]

Actually, psychic weapon master is phrased in such a way to allow the expanded threat range to a type of weapon rather than a crystal weapon. It says that you must have a chosen weapon, and the requirement for the class is to have a crystal version of that weapon, though the abilites of the class can be used with that chosen weapon if of another material.

Relevant bits from the article:


The only material requirement for the class is a crystal version of her weapon.

To gain the special abilities of the psychic weapon master class, a character must use her weapon of choice.

If she uses any other weapon, she can use none of the special abilities of the prestige class.


The psychic weapon master gains the Improved Critical feat for free. If she already possesses this feat, add an additional +2 to her weapon of choice's threat range for critical hits.

Emphasis mine on the last one.

@Heliomance: Yeah, you're right, crystal is an actual material so crystalline iron won't function.

[Heliomance]

Fair enough. My point about Weapon Master stands though.

(This might be circumventable with the Oriental Adventures Kensai. Not sure.)

[Irk]

My point about Weapon Master stands though.


Absolutely, in fact I'll change that in the initial post now.

[TuggyNE]

I'm sorry Tuggy, You are correct, my initial post was rather presumptuous. The iron power ability of the DoD says it stacks with improved critical, but I will amend the above to make it less brazen in tone.

OK. Sorry for the slightly snappish tone.


In this scenario, since improved critical stacks with iron power and improved critical stacks with, for example, hero's blade, then hero's blade stacks with iron power. That's what the transitive property says.

Well, yes, that's what transitive means. But it doesn't necessarily apply here; in my previous example, the shield bonus from a shield spell stacks with the armor bonus from bracers of armor, and also stacks with the armor bonus from mage armor, but that doesn't mean that the armor bonus from bracers of armor will stack with mage armor. Basically, transitivity doesn't work with stacking rules.

[Irk]

OK. Sorry for the slightly snappish tone.

No problem, sorry for my presumption.




Well, yes, that's what transitive means. But it doesn't necessarily apply here; in my previous example, the shield bonus from a shield spell stacks with the armor bonus from bracers of armor, and also stacks with the armor bonus from mage armor, but that doesn't mean that the armor bonus from bracers of armor will stack with mage armor. Basically, transitivity doesn't work with stacking rules.

Hm, I understand now, I didn't get it at first. I guess it's a bit different though, since you aren't stacking bonuses, but multipliers, which has a different set of rules, as these multipliers do not have a type; I suppose they are 'untyped multipliers', really, if you think about in terms of the stacking rules, as they're never specifically named named.

Besides that, you are correct, the transitive property cannot usually be applied to dungeons and dragons.

[Heliomance]

How is it that taking out Weapon Master hasn't changed your numbers at all?

[GreenSerpent]

I think the weapon material you're looking for might be Riedran Crysteel... not sure about that though, since I'm AFB. It's from Eberron.

[Irk]

How is it that taking out Weapon Master hasn't changed your numbers at all?

Because psychic weapon master does the same thing,as I mentioned above, sorry should've clarified that

[Irk]

I think the weapon material you're looking for might be Riedran Crysteel... not sure about that though, since I'm AFB. It's from Eberron.

That's the one, I think it might work without the exploit I suggested above.

[Crake]

Who needs crit range when you have Surge of Fortune and Bless/Corrupt Weapon :smalltongue:

[Phelix-Mu]

Alright, let me take a shot at it.

20
19-20
18-20
17-20
16-20
15-20 = All of these are pretty standard achievable in the core rules. No problem here.

14-20
13-20
12-20 = The DM starts double checking your math and scratching his/her head before finally conceding the point.

11-20 = DM chokes on his/her sip of soda when you explain your character rolls critical threats on 50% of attacks.

10-20
9-20
8-20
7-20 = DM starts mumbling about how certain restrictions of the campaign setting prevent this from being possible.

6-20
5-20 = DM: "WHAT? NOO, DEFINITELY NOT."
....
1-20 = DM's head explodes.

So, according to my calculus, the practical max crit threat range is 7-20. But, in reality, I'd have trouble allowing anything past the 50% crit range (and I'm pretty generous). Maybe I'd allow it if it isn't paired with greathammer shenanigans or Lightning Maces or the like.

[Irk]

Alright, let me take a shot at it.

20
19-20
18-20
17-20
16-20
15-20 = All of these are pretty standard achievable in the core rules. No problem here.

14-20
13-20
12-20 = The DM starts double checking your math and scratching his/her head before finally conceding the point.

11-20 = DM chokes on his/her sip of soda when you explain your character rolls critical threats on 50% of attacks.

10-20
9-20
8-20
7-20 = DM starts mumbling about how certain restrictions of the campaign setting prevent this from being possible.

6-20
5-20 = DM: "WHAT? NOO, DEFINITELY NOT."
....
1-20 = DM's head explodes.

So, according to my calculus, the practical max crit threat range is 7-20. But, in reality, I'd have trouble allowing anything past the 50% crit range (and I'm pretty generous). Maybe I'd allow it if it isn't paired with greathammer shenanigans or Lightning Maces or the like.
Right, I meant he idea is to have infinite damage or something of the like, so it's not really conceivable. I think I'd probably just start throwing things immune to crits, until they got some weapon augment crystals/ wand chambers.

[Phelix-Mu]

This actually dovetails in an interesting way with some revamped archery rules I was working on, with the intent of a "one hit, one kill" style rather than the "unending rain of arrows" style, which is the typical op with how the RAW shakes out. I'd be using a crit-expansion regime not unlike DoD.

Increasing crit ranges has a place in the game, but I'm not sure it's in melee. Power Attack/Leap Attack/Shocktrooper already has some pretty whacky calculus on its side; while Lightning Maces is pretty cool, it's also pretty stupid to try to play (as there will either be lots of rolling/slow combat or lots of "you hit it, so it dies sometime later in the same turn"). THF and such already can kill a lot of anything, crit immunity be damned. I do like the concept of having more than one way to skin the proverbial cat in melee, though.

A nice bit of TO, to be sure. Tuggyne's comment about the 3.0-ness of DoD troubles me, but if a player was going to jump through the hoops to get into the PrC (and give me so many delicious story hooks), then I'd probably let them play it as written (barring Lightning Maces).

[Heliomance]

Because psychic weapon master does the same thing,as I mentioned above, sorry should've clarified that

But I thought you were originally using both WM and PWM. Crit range has come up before, many times, and WM, PWM, and OA Kensai have all come up. And yet, I've never seen anyone claim a crit range larger than 9-20. I think it's more likely that your maths is off.

[Irk]

WM and PWM have the same effect. stacking both of 'em with DoD would go into epic or gestalt.

here: DoD x3, Improved critical x2, Hero's blade x2 comes to x5

If you add in the -2 from PWM it comes down to 4-20 or 1-20, depending on your interpretation.

[Gazzien]

Pathfnder, so not sure how favorable it is, but the Dread power Dispatch (http://www.d20pfsrd.com/psionics-unleashed/psionic-powers/d/dispatch) doubles a crit range for the AoO it grants you, with the first augment. Explicitly stacks, too.

[Plerumque]

The Arms & Equipment Guide has the Stump Knife, which doubles it's crit range (to 17-20) if you've attacked with it the previous round. Don't know if that works here or not.

[Irk]

The Arms & Equipment Guide has the Stump Knife, which doubles it's crit range (to 17-20) if you've attacked with it the previous round. Don't know if that works here or not.

unfortunately it does not, but I've seen many people leap to the conclusion it does. Keen edge says things that expand threat range don't stack, so we've gott to search for things that explicitly state they do stack.

[Plerumque]

I'd think that Improved Critical would make the natural threat range 17-20, which the Stump Knife would then double if you'd attacked with it the previous round. Is that not how it works?

[NeoPhoenix0]

Right, I meant he idea is to have infinite damage or something of the like, so it's not really conceivable. I think I'd probably just start throwing things immune to crits, until they got some weapon augment crystals/ wand chambers.

Just checking, You do realize that you still have to actually be able to hit the creature with the initial critical and all the confirmation rolls. That the only auto hit is a natural 20, right.

[Angelalex242]

Bless Weapon/Corrupt Weapon negates the need for critical rolls. It's one of the best things for a Paladin to cast against high AC foes. That way, if he does hit him in the first place, the blow will surely crit.

Even better if it's on a weapon permanently (BoED version. The other version is trash.)

[Bavarian itP]

There's the feat "Better Lucky Than Good" from Complete Scoundrel, which allows you to treat a natural one on an attack roll as a natural twenty.

[AMFV]

Bless Weapon/Corrupt Weapon negates the need for critical rolls. It's one of the best things for a Paladin to cast against high AC foes. That way, if he does hit him in the first place, the blow will surely crit.

Even better if it's on a weapon permanently (BoED version. The other version is trash.)

It adjusts confirming not actually scoring the hit in the first place.

[danzibr]

Alright, let me take a shot at it.

20
19-20
18-20
17-20
16-20
15-20 = All of these are pretty standard achievable in the core rules. No problem here.

14-20
13-20
12-20 = The DM starts double checking your math and scratching his/her head before finally conceding the point.

11-20 = DM chokes on his/her sip of soda when you explain your character rolls critical threats on 50% of attacks.

10-20
9-20
8-20
7-20 = DM starts mumbling about how certain restrictions of the campaign setting prevent this from being possible.

6-20
5-20 = DM: "WHAT? NOO, DEFINITELY NOT."
....
1-20 = DM's head explodes.

So, according to my calculus, the practical max crit threat range is 7-20. But, in reality, I'd have trouble allowing anything past the 50% crit range (and I'm pretty generous). Maybe I'd allow it if it isn't paired with greathammer shenanigans or Lightning Maces or the like.
Made me laugh. Nice.

[Chronos]

That's actually a standard usage of the word "calculus". All it means is "system of calculating". The subject usually called "calculus" in school is more precisely titled "calculus of fluxions", but it's not the only calculus.

[Silvanoshei]

So wait...... you can actually do this? :smallconfused:

Nobody has really refuted it, does crit threat stacking actually work in this manner?

[Irk]

So wait...... you can actually do this? :smallconfused:

Nobody has really refuted it, does crit threat stacking actually work in this manner?

Yes. Tah-dah.

[Chronos]

Assuming that your DM lets you import Disciple of Dispater and other 3.0 material as-is, yes. There are arguments both ways as to how a DM should import them, and in the end, it of course comes down to each individual DM.

[Silvanoshei]

Assuming that your DM lets you import Disciple of Dispater and other 3.0 material as-is, yes. There are arguments both ways as to how a DM should import them, and in the end, it of course comes down to each individual DM.

Ahhh. So from a strict 3.5 material only, no, this doesn't work. Gotcha.

Whats the max 3.5 only threat range?

[prufock]

Working on this now.
Kukri/falchion/anything else with 18-20 crit range.
Improved critical = 15-20.
Disciple of Dispater 8 = 9-20.
Weapon Master 7 = 7-20.
Mythic Exemplar 2 = 6-20.
Arcane Duelist 7 = 3-20 (limited rounds 1/day).
Streetfighter Barbarian 7 = 2-20 (charging only).
Better Lucky than Good feat = 1/day treat nat 1 as nat 20 = 1-20 crit range on a charge when using Arcane Duelist false keenness.j

That's level 31. Not sure if you can meet all the feat prereqs in that space though.

Best practical I can come up with at level 20 is Human Warblade 3/Fighter 2/Weapon Master 7/Disciple of Dispater 8 with 2 flaws. With kukris you have 7-20.

Max 3.5 (ignoring Disciple of Dispater) would be something like
Kukri, 18-20
Improved critical, 15-20
Psychic Weapon Master 7, 13-20
Mythic Exemplar 2, 12-20
Arcane Duelist 7, 9-20 (limited rounds, 1/day)
Streetfighter Barbarian 7, 8-20 (charge only)
Better Lucky than Dead

At level 20, practical, you'd have something like:
Human Fighter 2/Psychic Warrior 7/Psychic Weapon Master 7/Mythic Exemplar 2, with 2 flaws. You'd get 12-20. That's the best I can do, anyway; someone else might have more ideas.

[Irk]

Best practical I can come up with at level 20 is Human Warblade 3/Fighter 2/Weapon Master 7/Disciple of Dispater 8 with 2 flaws. With kukris you have 7-20.

Max 3.5 (ignoring Disciple of Dispater) would be something like
Kukri, 18-20
Improved critical, 15-20
Psychic Weapon Master 7, 13-20
Mythic Exemplar 2, 12-20
Arcane Duelist 7, 9-20 (limited rounds, 1/day)
Streetfighter Barbarian 7, 8-20 (charge only)
Better Lucky than Dead

At level 20, practical, you'd have something like:
Human Fighter 2/Psychic Warrior 7/Psychic Weapon Master 7/Mythic Exemplar 2, with 2 flaws. You'd get 12-20. That's the best I can do, anyway; someone else might have more ideas.

Mythic exemplar 2 will give you the critical threat expansion for only 2 rounds. Also, you can fit two more levels into the 3.5 build.

I did not think of arcane duelist. W/ DoD, you could do hero's blade, DoD 8, improved critical, and false keenness for x6 to a threat range of 18-20, bringing it down to 3-20.

Warblade 3/ Fighter 2/DoD 8/ Arcane Duelist 7 is exactly 20 and has a threat range of 3-20 if you have an item of continuous hero's blade.

Without DoD, just sub in psychic weapons master and try something like
psychic warrior 6/Psychic weapons master 7/ Arcane Duelist 7, make your race human, take two flaws, and get a continuous item of hero's blade to expand your critical range by a factor of 4 then subtract 2, giving you 7-20, which is a little better than 12-20, but you could also cast psionic lions charge to get pounce, so it's pretty good.

So there you are. Using only 3.5, the lowest critical threat range possible is 7-20 with a Human Psychic warrior 6/Arcane Duelist 7/ Psychic weapons master 7. Use magical training + precocious apprentice to meet the duelist prereqs, and the rest is easy.

[Chronos]

Arcane Duelist is also 3.0.

[Irk]

Arcane Duelist is also 3.0.

Actually, 3.5 was released in 2003, and they updated the duelist, (or preserved it), here (https://www.wizards.com/default.asp?x=dnd/re/20030224a) so it's still valid.

[Chronos]

That page was from February 2003. 3.5 didn't start until June 2003.

[NeoPhoenix0]

So wait...... you can actually do this? :smallconfused:

Nobody has really refuted it, does crit threat stacking actually work in this manner?

To argue with the OP, only arguably. The OP's transitive stacking doesn't necessarily work. There is no rule that says it doesn't, but there is no rule supporting it either, leaving it entirely on the whims of the DM.

[Irk]

To argue with the OP, only arguably. The OP's transitive stacking doesn't necessarily work. There is no rule that says it doesn't, but there is no rule supporting it either, leaving it entirely on the whims of the DM.

I guess transitive stacking was kind of dumb, but they do stack, as they aren't bonuses.


That page was from February 2003. 3.5 didn't start until June 2003.

And I though I was being clever. Yet again, my mistake, sorry about that. I guess that means the best threat range comes from a human psychic warrior 6/ psychic weapons master 7/ street fighter barbarian 7 who is charging with a continuous item of hero's blade and an 18-20 weapon for a threat range of 9-20.

[danzibr]

That's actually a standard usage of the word "calculus". All it means is "system of calculating". The subject usually called "calculus" in school is more precisely titled "calculus of fluxions", but it's not the only calculus.
I wonder if that's less common in America. Anyway, thanks for the lesson!

My earlier comment still stands. I'm thinking of differentiating functions involving crit ranges :P

[prufock]

Mythic exemplar 2 will give you the critical threat expansion for only 2 rounds. Also, you can fit two more levels into the 3.5 build.
Right, I forgot about that limitation.


I did not think of arcane duelist.
I thought it was 3.5 too. Oh well, live and learn.


Warblade 3/ Fighter 2/DoD 8/ Arcane Duelist 7 is exactly 20 and has a threat range of 3-20 if you have an item of continuous hero's blade.
Unfortunately, DoD requires BAB 6, which you aren't meeting with Warblade 3/Fighter 2. I don't think there's any way to cram in both of those PrCs in 20 levels.


Without DoD, just sub in psychic weapons master and try something like psychic warrior 6/Psychic weapons master 7/ Arcane Duelist 7, make your race human, take two flaws, and get a continuous item of hero's blade to expand your critical range by a factor of 4 then subtract 2, giving you 7-20, which is a little better than 12-20, but you could also cast psionic lions charge to get pounce, so it's pretty good.
Also doesn't work, as you need 3rd level powers and BAB 5 to get into psychic weapon master. You need to hit psychic warrior 7 before you can take it. Arcane Duelist requires BAB 6. So again, can't really cram in both of those.


human psychic warrior 6/ psychic weapons master 7/ street fighter barbarian 7 who is charging with a continuous item of hero's blade and an 18-20 weapon for a threat range of 9-20.
Same problem as above. You need PsyWar 7 before taking PWM.

Human Psychic Warrior 8/Psychic Weapon Master 7/Mythic Exemplar 2/X3 is the best I can get, then. Two flaws, Improved Critical, kukris. You'd get 13-20, 12-20 limited rounds per day with ME.

[Kelb_Panthera]

Problems:
Psychic Weapon Master requires a crystal weapon. DoD requires an iron one. As someone else mentioned, Riedran Crysteel is an alloy of the crystal special material with iron. It should fit the requirements for both DoD and PWM.


Weapon Master was officially updated into the CW Exotic Weapon Master. Never mind that it's a completely different class, WotC says it's the official update, so the Weapon Master is not valid for play.

Where is this stated?

[NeoPhoenix0]

I guess transitive stacking was kind of dumb, but they do stack, as they aren't bonuses.

The rules say they stack with something, but don't say explicitly say they stack with each other. The rules do not mention anything about such things stacking, so any interpretation that they do stack is your own invention. The rules simply fail to say anything on this subject.

[Naanomi]

Gestalt? Egoist 5/Psychic Weapon Master 8/Disciple of Dispater 7 on one side... Fighter 2/Psychic Warrior 2/Barbarian 1/Warblade 15 (crit focused maneuvers) on the other? May need to be Human and/or use flaws for Feat Count still I think.

[Irk]

The rules say they stack with something, but don't say explicitly say they stack with each other. The rules do not mention anything about such things stacking, so any interpretation that they do stack is your own invention. The rules simply fail to say anything on this subject.

I completely agree. The only way to get around this is to say that they are all stacking with improved critical rather than interacting with each other, and that's a bit shaky.


Gestalt? Egoist 5/Psychic Weapon Master 8/Disciple of Dispater 7 on one side... Fighter 2/Psychic Warrior 2/Barbarian 1/Warblade 15 (crit focused maneuvers) on the other? May need to be Human and/or use flaws for Feat Count still I think.

crit-fishing does work best in gestalt, as do many things.

[NeoPhoenix0]

More on topic, optimizing this much seems almost pointless. After a certain point it seems better to optimize rerolls. The reason i say this is a 2-10 is much less likely to actually hit so it isn't neccasary to optimize that much. Also a nat one never threatens or confirms, so the only way to get the nat one is with things like that luck feat.

Also, i thought there was a 17-20 threat range weapon, or was that something special. I'm gonna look for it.

[Irk]

More on topic, optimizing this much seems almost pointless. After a certain point it seems better to optimize rerolls. The reason i say this is a 2-10 is much less likely to actually hit so it isn't neccasary to optimize that much. Also a nat one never threatens or confirms, so the only way to get the nat one is with things like that luck feat.

Also, i thought there was a 17-20 threat range weapon, or was that something special. I'm gonna look for it.

I don't think that there is a 17-20 weapon, but if you find one, awesome.

Optimizing this comes down to using lightning maces and aptitude to generate nigh-infinite attacks. In reality, it's more of a thought exercise than anything else, BUT there are some pretty awesome feats that trigger on a critical if you look for them. As an example, though you have to meet some weird prereqs, there is this feat (http://dndtools.eu/feats/libris-mortis-the-book-of-the-dead--71/death-master--537/), which could render your opponent frightened forever in a critical loop.

[NeoPhoenix0]

I don't think that there is a 17-20 weapon, but if you find one, awesome.

Optimizing this comes down to using lightning maces and aptitude to generate nigh-infinite attacks. In reality, it's more of a thought exercise than anything else, BUT there are some pretty awesome feats that trigger on a critical if you look for them. As an example, though you have to meet some weird prereqs, there is this feat (http://dndtools.eu/feats/libris-mortis-the-book-of-the-dead--71/death-master--537/), which could render your opponent frightened forever in a critical loop.

do keep in mind you need some to-hit optimization and the feat to make nat ones, nat 20s. Or some extreme reroll cheese. Because it doesn't count as a threat if the attack roll couldn't hit, unless it is a nat 20.

Edit: found a 17-20 weapon... sort of.
The stump knife is unupdated 3.0 material from the arms and equipment guide, so it won't pass for a 3.5 only solution, but it's there. It's threat range is 17-20 against any foe you have dealt damage during a "continuous melee". Note it doesn't say you have to damage them with the knife.

Edit2: it's normal threat range is 19-20.

[Irk]

do keep in mind you need some to-hit optimization and the feat to make nat ones, nat 20s. Or some extreme reroll cheese. Because it doesn't count as a threat if the attack roll couldn't hit, unless it is a nat 20.

Edit: found a 17-20 weapon... sort of.
The stump knife is unupdated 3.0 material from the arms and equipment guide, so it won't pass for a 3.5 only solution, but it's there. It's threat range is 17-20 against any foe you have dealt damage during a "continuous melee". Note it doesn't say you have to damage them with the knife.

Edit2: it's normal threat range is 19-20.

Optimizing for to-hit is pretty easy, though. Just look at X stat to Y bonus.
Also, the stump knife doesn't explicitly state it stacks, sadly.

[Heliomance]

Where is this stated?

It's in the official Sword and Fist 3.5 update document. Unfortunately, I can't remember where the update documents are, and I can't seem to find them.

[Kelb_Panthera]

It's in the official Sword and Fist 3.5 update document. Unfortunately, I can't remember where the update documents are, and I can't seem to find them.

Okay, this is important; did it specifically say it updated the S&F version? OA was printed 9 months -after- S&F, so if the update booklet specifies that version then there's a solid argument to be made that OA's weapon master is still available.

[Karnith]

It's in the official Sword and Fist 3.5 update document. Unfortunately, I can't remember where the update documents are, and I can't seem to find them.
The 3.5 update Booklets can be found here (http://www.wizards.com/default.asp?x=dnd/dnd/20030718a), and errata can be found here (https://www.wizards.com/default.asp?x=dnd/er/20040125a). There is no 3.5 update booklet for Sword & Fist, and neither its errata nor that for Oriental Adventures mention the Weapon Master PrC at all.

However, the (Complete Warrior) Exotic Weapon Master PrC is the 3.5 revision of the 3.0 Exotic Weapon Master, Master of Chains, and Weapon Master PrCs, per the revision guide on the mothership (http://www.wizards.com/default.asp?x=dnd/dnd/20050110x). That document doesn't cover the 3.5 versions of Oriental Adventures material, though.

[Heliomance]

the revision guide on the mothership (http://www.wizards.com/default.asp?x=dnd/dnd/20050110x)

That's what I was referring to. I just completely forgot where it was and what it was called.