A few months ago I started a thread about a 165 OT that my dad had given me, originally purchased at a hardware store about 1971 or 1972.
http://www.bladeforums.com/forums/showthread.php?t=424051
I have, since that time, purchased another unmarked 165 OT. On this one I noticed an odd grind near the guard. See picture:
Upon closer inspection, it was obvious that the blade was slightly thinner in this area. I marked the blade every 1/8" and took thicknesses. Results below:
At the guard: 0.161"
1/8" 0.147"
1/4" 0.141"
3/8" 0.139"
1/2" 0.140
5/8" 0.140
3/4" 0.141
7/8" 0.141
1" 0.142
1 1/8" 0.144
1 1/4" 0.147
1 3/8" 0.150
1 1/2" 0.152
1 5/8" 0.153
1 3/4" 0.154
1 7/8" 0.157
2" 0.160
I have taken out my other unmarked 165 and notice the same dip in the grind line (please help with the technical term) up near the guard. It is much less noticeable, but it is there. I will post thicknesses later. I do believe that both MAY be 2nd quality. My older one has a loose guard and a dent on the top of the blade (although unused), and the one pictured above, on the other side of the blade, has an inconsistent texture to the steel.
Curious if anyone else has one of these which appear to have had the markings removed.
Bridgy
http://www.bladeforums.com/forums/showthread.php?t=424051
I have, since that time, purchased another unmarked 165 OT. On this one I noticed an odd grind near the guard. See picture:

Upon closer inspection, it was obvious that the blade was slightly thinner in this area. I marked the blade every 1/8" and took thicknesses. Results below:
At the guard: 0.161"
1/8" 0.147"
1/4" 0.141"
3/8" 0.139"
1/2" 0.140
5/8" 0.140
3/4" 0.141
7/8" 0.141
1" 0.142
1 1/8" 0.144
1 1/4" 0.147
1 3/8" 0.150
1 1/2" 0.152
1 5/8" 0.153
1 3/4" 0.154
1 7/8" 0.157
2" 0.160
I have taken out my other unmarked 165 and notice the same dip in the grind line (please help with the technical term) up near the guard. It is much less noticeable, but it is there. I will post thicknesses later. I do believe that both MAY be 2nd quality. My older one has a loose guard and a dent on the top of the blade (although unused), and the one pictured above, on the other side of the blade, has an inconsistent texture to the steel.
Curious if anyone else has one of these which appear to have had the markings removed.
Bridgy