Opinions about straightening a bent blade (UPDATE)

[John C]

As a reminder, I had received a blade that was pretty badly bent (pic 1 with reference lines). There was also a noticeable gap visible between the guard and the saya (pic 2) due to the guard being bent and twisted.

I decided to go ahead and try to straighten the blade and guard. The result was that it was far easier than I thought it would be (see pics 3 and 4 with reference lines). After disassembly, I clamped the blade into a vise with blocks of wood for support (sorry, no pics of the naked bent blade and guard). I used very gentle pressure and was able to straighten the blade fairly well. Seems like the metal is rather malleable. I then put the guard in the vise and, using duct tape covered pliers, straightened the twisted and bent guard. Note the gap is no longer there (see pic 5).

All in all, a successful attempt.

 

John C.

[Bruce Pennington]

That's really good news, John!  Glad it worked.  A little surprised no heat was needed.

 

You got me to searching, because I'm pretty sure someone else was wanting to try this.  Could find the one tickling my memory, but found a good one where a Type 95 blade had be straightened.

 

When the moderator situation gets straightened out (ha! pun not intended), I think this should get pinned for future reference.

[John C]

2 hours ago, Bruce Pennington said:

A little surprised no heat was needed.

What surprised me was how easily it moved. Both the blade and the brass seemed really malleable. I made sure I used very little pressure in short bursts, to ensure I didn't work-harden the blade, and it straightened up easily...maybe a little too easily. This blade would not have survived any form of combat without deforming or bending, I feel. But at least it looks 100 times better than before.

p.s. There were a lot of "assembly" numbers on the parts - 6 tick marks on the nakago and the number 8 (hachi) marked over the ticks; a number 8 (again, hachi) marked on the tsuba; something in pencil scratched out on the tsuka and the number 7 (shishi) marked on the opposite side; and a few other non-numerical marks on the nakago. It's been around.

John C.

 

[PNSSHOGUN]

It sounds like it may have indeed been an un-tempered blade, which was apparently common with the police & shore patrol sabres.

[John C]

Quite possibly, John. It's pointy and stabby, however if it hit another sword or stick or something, I'm sure it would bend. On the other hand, it probably wouldn't break. So as a police weapon that doesn't require actual combat, it would work fine. 

 

John C.