Forging straight blades

quint

quint

Joined
Nov 29, 2011
Messages
1,396
So I have been forging some blades off and on for a little while now but have not gotten to take any courses or anything so pretty self/internet/book taught.

I am having trouble forging my blades straight basically. I can get some distal taper and can forge in the bevel some and profile is relatively easy or getting there. It just seems no matter how hard I try I just cant get a perfectly straight blade. Once the blade has cooled and I go back to check them out there is always somewhere that I missed.

So any suggestions on how you guys get those nice straight blades.

I dont have a surface grinder. I have a couple nice anvils, a good gas forge, and several hammers- ok ones that I have dressed up some.

Thanks for any help with this.
 
If your this far along straight blades are not far off. Having consistent distal taper is one thing you want to shoot for in getting the blade straight overall. Switching to a lighter hammer after the primary stuff is done helps. Use light rhythmic strokes down the blade, letting the hammer rebound.
A good friend apprenticed at my shop; he got himself an anvil and forge and forged 100 blades in about three months. That man can forge blades like no one I know now. In the end like most things its practice.
 
I have the same problem, so I don't have any sure fire answers for ya, but I have seen some people use a good post vice and work there way down the knife to straighten them out. Seems to work pretty well.
Hope it helps
Cody
 
Thanks guys, every bit helps Cody. Fred Ill keep at it.

I have scene that post vise thing before, Ill have to maybe try that or get something setup to put a little squeeze on them.
 
A flatter is very helpful for planishing and straitening on the anvil. I use one on my powerhammer with flat dies, but you can make one that works well for one person use by taking a piece of thick flat stock and welding a "handle" vertically on to it, so that you can hold down the work with the flatter and strike the handle end.

A traditional flatter is ideally used with a striker, although if your anvil is the right height you can hold it in your crotch, as with many other tools, or if you're fast and have a hold-down tool, you can use it the regular way.


One thing that's hard about sighting forged blades, is that any inconsistency in the taper or a deep hammer mark at the spine, will cause the appearance of a bend, when in-fact you may be straight on one side and just low on the other. That's one reason why planishing is important. Beyond that, you have to train yourself to look for consistency in a perceived bend, if you look at both sides of the blade and they both bend, it's a bend, if only one side looks bent and the other straight, it's a low spot or rather, inconsistency of thickness at some point of the taper.
 
Makes sense thanks Javand. Ill have to try out some of that stuff, see if I can come up with some ingenuity for a one man flatter. Thanks.
 
Check ebay for used flatters. You can pick one up for a reasonable price. Also a common trick for sighting down the blade to check for straightness is to use chalk or soap stone. Rub it on the spine and edge of the blade to make it more visible. When sighting down the length of the blade the white edge will make it much easier to see where the wiggles are.
 
One thing that's hard about sighting forged blades, is that any inconsistency in the taper or a deep hammer mark at the spine, will cause the appearance of a bend, when in-fact you may be straight on one side and just low on the other. That's one reason why planishing is important. Beyond that, you have to train yourself to look for consistency in a perceived bend, if you look at both sides of the blade and they both bend, it's a bend, if only one side looks bent and the other straight, it's a low spot or rather, inconsistency of thickness at some point of the taper.[/QUOTE]

This is always a problem.. I would imagine for a lot of people. I have no problem with most aspects of forging a blade its that stray hammer blow that is a little deep than others.. I guess this is where being self taught is a handicap. Little tricks like this a seasoned bladesmith knows about and would help you correct in one session. Thanks for the tip !
 
FWIW Mark, I still struggle with straightening, most Bladesmiths I know do to some degree or another, with the exception of a few that just make it look stupid easy. I heard a story that Joe Keeslar (current ABS President), said that if he won the lottery, he'd hire someone to straighten all his blades for him. Smartest sounding investment I ever heard of. Apologies to Mr. Keeslar if I got that wrong.


Personally, I can't straighten a blade unless I'm stone sober. I usually drink some whisky at night while I'm forging, get them to what looks like dead straight before I go to sleep, and am *always* amazed how crooked they are when I look at them the next day. I nearly quit making knives in the first couple years because I was so frustrated with straightening, but finally learned enough ways to avoid warp, or fix warp that I'm starting to feel comfortable.

Bear in mind, that if you're an obsessive like I am about "dead-nuts straight", life as a beginning smith is going to be hard, but worth it in the end. Many many many knives I look at, by many well regarded makers, don't pass my expectations for that, but it's up to each maker to decide how straight is enough. Like everything in life, it's not as black and white as it seems though. Especially when you start pursuing perfect distal tapers and grinds.


Stock removal guys, especially those that farm out HT, don't know how good they've got it on this front. Every once in a while I gotta make a stock removal knife just to remind me not to beat myself up so much and have fun, and that's what smithing is supposed to be about right?
 
Glad to see (I guess) that I am not the only one who struggles with this. Javand you describe just about exactly what I go thru for the most part :D, sometimes I think that being off just a tad is ok but it drives me nuts. Ecspecially when I go to grind them out.

I am looking for a flatter but in the mean time I have been using my imitation hofi hammer and going carefully to do the best I can. I forged 3 blades out today one which was reforged to get rid of a little bend in it. Probably took me 3 hours lol. I would hazard to guess about 2/3 of that was playing with taper and straightening.

Thanks all for the suggestions and information. Much appreciated.
 
One trick I use is to get the blade hot, not screaming hot, but hot enough to work, and then run down the blade with a wooden mullet. It doesn't leave deep marks in the steel, and yet it's strong enough to straighten the blade. I can also vouch for the effectiveness of using a flatter. Another trick is to work the blade, say, four or five hammer blows, then flip it, repeat again and again as you work down the blade.
 
Also, straighten between normalizing heats. There may be warping during cool down from forging stress, this may help.
 
I'm only suggesting this because it's been thrown out there a couple of times in the Anvil ID threads of IFI when an individual scores an anvil that's been rode hard and put away wet. Heavily used sway-back wrought iron anvils are apparently the ticket to straightening out blades. Seems to warrant some viable logic though... The wrought iron is noticeably softer than the tool steel top, and over the course of 150 + years of workload they start to sag under the most-worked parts of the anvil. Usually 2-3" behind the horn. Good thing about them is you can talk them down in price. That Soderfors is just too awesomely flat and will be that way forever. The same thing can be said about any other cast anvil, as they don't sag under a centuries of perpetual workload.

Considering Aspery's Cow-Poop theory, drawing out anything of length on a dead-flat-straight surface, the forces at work are going to move the steel every-which-way except flat and straight... I also see a flatter going a long way to correct curvature issues too, especially if the steel is in an annealed state.
 
Thanks guys for the help and insight. Since this thread started I have made some good strides in flattening out my blades. Still using the soderfors but am using about a foot long section of RR track as a flatter. Works pretty good. Plus i have improved a bit on my forged blade profiles which helps some. All in all practice but also practicing good technique helped.

Sine that is very true. my older PW which is somewhat bowed did help make straightening easier.
 
Aspery is one of the greatest teachers out there.
Anyone interested in forging blades shouldn't pass up a chance to attend a blacksmithing conference, there's so much understanding of how to move metal being shared.

Quint, if you were to post a video of yourself forging a blade, chances are that more than a couple people would spot what is making things go not so straight and offer quick to-the-point tips on where to go with it. When I teach blacksmithing basics, it's often surprising what I take for granted that a beginner never thought of, and likewise whenever I go to a class.
 
elementfe said:
Aspery is one of the greatest teachers out there.
Anyone interested in forging blades shouldn't pass up a chance to attend a blacksmithing conference, there's so much understanding of how to move metal being shared.

Quint, if you were to post a video of yourself forging a blade, chances are that more than a couple people would spot what is making things go not so straight and offer quick to-the-point tips on where to go with it. When I teach blacksmithing basics, it's often surprising what I take for granted that a beginner never thought of, and likewise whenever I go to a class.
Click to expand...

His books are nothing short of stellar, and I look forward to the opportunity of being taught by him... I attended my first conference in Madison, GA this past year and it was definitely a rewarding experience. I wish I was able to watch more demos than I did, but I was unfortunately hung up tending to a truck full of anvils... I wont be putting myself in that position again. :grumpy:
 
Element I did have some videos of forging Ill have to dig up or try and shoot some new ones. Not gonna have much forging time in the near future though as I am starting work again soon thankfully. Plus gonna have to figure out how to edit them so they arent drawn out waiting inbetween heats. By the way Ive got family who live in Anacortes, looks like a stone throw away from Guemes.

Thanks for the links to the videos, I have already picked up a couple of things watching him forging.
 
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