Apparently weapon type is determined in OLC under values:
WEAPON
value 0: The weapon type, one of:
0) GENERIC - no weapon proficiency will take effect.
1) Axe
2) Hammer
3) Club - and other 'non-weapons'
4) Polearm
5) Sword - also daggers, knives, small sword
6) Large Sword - also bastard swords, twohanded swords
7) Whip - and flail
Knuckles - and other 'hand' weapons.
value 1: Number of damage dice
value 2: Size of damage dice
value 3: Weapon type for damage messages, one of:
0 hit/hits
1 sting/stings
2 whip/whips
3 slash/slashes
4 bite/bites
5 bludgeon/bludgeons
6 crush/crushes
7 pound/pounds
8 claw/claws
9 maul/mauls
10 thrash/thrashes
11 pierce/pierces
12 blast/blasts
13 punch/punches
14 stab/stabs
15 impale/impales
Except that when choosing values for a weapon in OLC:
-- Item number : [19106]
1) Namelist : cutter
2) S-Desc : cutter
3) L-Desc :-
This is a cutter
4) A-Desc :-
<not set>
5) Type : weapon
6) Extra flags : NOBITS
7) Wear flags : TAKE WIELD
Weight : 0
9) Cost : 0
A) Cost/Day : 0
B) Timer : -1
C) Values : 0 0 0 0 0 0
D) Menu ---> : Applies
E) Menu ---> : Extra Desc
F) Innate : (0) UNDEFINED
G) Smell Desc :
It doesn't smell too interesting.
H) Taste Desc :
It tastes just like it should.
I) Feel Desc :
It feels normal, as far as you can tell.
J) Material : base-material
M) Min Level : 0
S) Script : Not Set.
Q) Quit
Enter choice :
c
Number of damage dice :
20
Size of damage dice :
50
0) hit 1) sting
2) whip 3) slash
4) bite 5) bludgeon
6) crush 7) pound
claw 9) maul
10) thrash 11) pierce
12) blast 13) punch
14) stab 15) kick
16) gore
Enter weapon type :
8
You can choose damage dice and hit type but it skips Value 0, leaving weapon type set at the default value of 0. I don't know why OLC would do that.