Warpage, How much is too much?

[unky_gumbi]

I was just going over Rick's straighten during temper thread, and decided to check out a blade that I had home HT'd some time ago just as a test. I never finished the blade, just filed it out, hardened it, and ran it through a couple of temper cycles. Back then it looked good to me so I never thought about it till reading that thread. Well last night I put it up against a straight edge only to see what I thought was straight, wasn't. It has a .021" bow in it, looks fine when sighting down the spine, but put it up against anything and it stands out like a sore thumb.

All this got me thinking, just how much bow is acceptable? I know dead flat is the goal on every knife, but I am sure there is an acceptable amount of bow. Then there is the question of how much of a bow can you correct? And how much flex can a HT'd blade take? I ask this because while reading Rick's thread I saw all the comments about how stressful it was for the makers when they would try fix the bow with the vise and 3 point jig.

On last question, what would be a fair price for a post vise and RR track anvil?

 

[Brian Ayres]

I'll let the experts answer the warpage question. I see post vises around here going for $100 or so. I'd pay less than that for a 3.5"-4" vise and more if it was a 6" or large in good shape. I recently bought my 6" that was "like new" for $160. It was a fair price, but not a steal at all...You can always forge and spring temper a new spring if it's bad...
RR anvils go for around scrap price. .60 cents a pound(ish)... not sure how all that converts to Canadian....

 

[JMJones]

I am not an expert but my feelings about fit and finish are that if you can see it or feel it, it is a flaw. If you need tools or measuring devices to locate it, it is not a flaw and just a part of being hand made.

 

[David Stifle]

Guys,

This is just my opinion, but I think any warpage/bow in a blade is unacceptable, especially if you are going to sell the knife. And if I were making a knife for myself, I just couldn't accept any warpage, because, quite simply, I would always know it's there. I just wouldn't be happy with it.

Dave

 

[Battle Creek Knives]

just don't put anything against it ...

well now that you know its warped you probably cant live with it, I would also agree and say I have a zero tolerance for a warped knife, even if I kept it I'd always know its there and would have to rectify the situation..

I'm anxious to see if you're able to true it up..

keep us posted..

 

[Patrice Lemée]

I also tried to work with minimal warpage in a blank but quickly realized that it also creates all kind of problems as far as the symmetry of the grind/ricasso/plunge/etc...

 

[james terrio]

Any is too much. Every little bit will multiply into bigger problems later, as Patrice said.

Having said that, I have yet to make a perfectly straight, perfectly parallel, perfectly evenly-ground etc. knife. But I do keep trying

 

[unky_gumbi]

Luckily this isn't anything that I plan on selling its just one of my early test pieces. It has been sitting around HT'd for over a year now. It was Rick's thread about straightening during temper that made me pull it out and look. I always do my absolute best to get my pieces of steel arrow straight before cutting anything out of them let alone grind on them and I am in the near prefect as possible camp, if I can measure it I can fix it attitude. I am just give straightening it in a vise a try to see how well I do with a hardened blade.