Spring Tool Joint Question

[iron quake]

Why don’t spring tools have another joint in them? I’m new to this blacksmithing /power hammer game but it occurs to me there needs to be another axis of rotation in the top arm/tool half. In building and using these tools in my hammer, it’s clear to me when you make any kind of tool like this the top part of the tool is always getting hammered parallel to the bottom. This is in spite of the part you are forging prying the two apart and trying to force the upper half off on an angle. This puts a bending moment and high stress in the top part of the spring, right behind the point of attachment of the spring to upper tool half. This is the place the tools fail at when they do I’m guessing. If you are machining heat treating and then welding the tools to formed mild steel springs like I am, why not make a hinge in the upper spring just outside the die area. This would allow the upper half to pivot rather than bend the spring, right behind the weld joint. I think the joint/hinge would need to be long and made pretty tight to keep the upper tool from moving out of position relative to the lower half in that axis. What am I missing? Your thoughts please before I go off and waste a bunch of time making a tool like this, only to go…. DUH that’s why not ….? Yes I’d love to post a sketch of this but I’m still struggling with that whole picture posting deal and you are all smart enough to get what I’m asking anyway. Thanks again for spending your time, to answer my neophyte questions

[clinton]

If there were a better way it would be common practice. Blacksmiths have been using spring tools for many years, I doubt that reinventing the wheel will occur.

[MLMartin]

If you believe that your idea for a spring tool is better than all the more plain spring tools out there then you should build one and test it out next to a regular spring die. Find out which works better. I am not going to say that your idea wont work, but I don't think its going to be a revolution that puts all other spring tools to shame. Industrial smiths have been making vary simple spring, or clap dies to use with power hammers for a vary long time. I would guess they have been used sense at least the 1600s. The reason these tools have not changed much in the last 400 or more years is because they work well.
Your right about there being a lot of stress right were the dies transition to the spring. But this is normally pretty simple to deal with. Very good dies that are going to see extensive use are forged from one piece of steel and the die to spring transition is a nice even taper.

[bigfootnampa]

Such movement is generally VERY small... the looseness created by a hinge joint likely to be a much larger problem than the small one that it's intended to fix. The spring should be of sufficient length to easily absorb the flexing needed. A more common cause of failure is the weakening of the die to spring joint by welding there. A better way is to drill a slightly oversized hole in the edges of the dies and fix the spring ends into it by upsetting round rod to get a dovetail and then using a center punch to secure it into the hole in the die edge. Afterward the spring is flattened and bent. This method leaves the spring with a round section at the point of connection and a mechanical joint that does NOT weaken the metal... resulting in longer service life. The metal to be worked in the dies should be preformed to an approximate size and shape so that the dies are used for final refinement... thus minimizing the needed vertical movement. So you can try it the way that you describe... but this is a way that has been developed by skilled smiths and is likely to be quite successful.

[iron quake]

Well I don’t know if it’s a better idea or not that’s why I posted the idea. I’m in a little different situation than many of you being , that I need to make tools to be able to make tools. I have a machine shop and welding equipment so that’s what I use and I’m good at it as well. I don’t get any real satisfaction in making tools either. I need to make tools to make things to sell to make money. I don’t have the skills to make three foot long drawn out parts off the end on the tool to make a spring out of it. It must be real nice to be able to do that but I can’t. I watched Clifton Ralphs DVD and most of the tools looked to me like they are welded to springs. So the real question is do the current tools break or not, and if they do why do they, and if it can be avoided why not do it. I don’t have a problem fixing broken tools, just getting hit by them as they get ejected from the hammer because they failed. Following logic that says that’s the way we do it because that’s the way it’s always been done and it can’t be improved on. If that kind of thought was adhered to in the past we would still be cutting our meat with stone tools and you boys would be hammering bronze out over a stone, instead using a power hammer run by……ELECTRICTY.

[Randy]

I know what you mean. I've had several old spring tools snap on me in use. Probably used tool steel for the springs. I make all of my spring tools using mild steel and I have not had that problem. I did make one texturing tool with top and bottom textures with mild steel, but on the top half, about 3" or so back from the dies, I twisted the mild steel spring material to make bosses that I then riveted together to make a hinge. I like the way this works for this application. At least now any flattening of the power hammer is at the joint, not at the weld and the dies come down nice and flat. I tried to draw up what I mean.

[MLMartin]

" I don’t have a problem fixing broken tools, just getting hit by them as they get ejected from the hammer because they failed. Following logic that says that’s the way we do it because that’s the way it’s always been done and it can’t be improved on. If that kind of thought was adhered to in the past we would still be cutting our meat with stone tools and you boys would be hammering bronze out over a frigging stone, instead using a power hammer run by……ELECTRICTY. "

I did not say you should abuse tools until they break and hurt yourself. Yes tools break but that's only because people make them wrong or they use the tool past its working life. It is not historically correct that every smith just used a tool until it broke and hurt themselves. If you think people in the past were just dumb and chose to hurt themselves frequently because they did not know any better then you are vary wrong. Yes many people have injured themselves because they did not take the time to make a tool right, or they did not inspect there tool for cracks or damage or they did not through a tool away after its usable life. I know it can be pretty hard to determine how long a tool will last but it is possible to a reasonable point. No tool last forever, they will all ware out in time and need replacing. I am sure in the past there were many people that broke there spring dies just like many people have broken them today. But there are also many people that have carefully made there tools and used them effectively and then discarded them when they show sines of failure because they took the time to closely inspect them.

Welded tools can last a long time, I have used many mild steel spring tools with a welded tool steel dies. After reading your post a second time I see that you are making your dies then heat treating them, and lastly welding the spring on. You may have longer lasting tools if you make sure to first pre heat the dies then weld on the spring, and lastly heat treat the dies. Trying to weld things onto already heat treated parts is not always the best option.

[peacock]

You will all ways wonder untill you try it. The simplest way that I have found to deal with that issue is the grind or machine a nice radius on top of the top die the upper die, hitting on a round surface will take most of the flexing out of the spring. Normalizing after welding on the handle will help alot. If you must fix this completely then build a die set with a base plate with guide pins, springs and bushed holes in a top plate and mount the dies one to the top one to the bottom exactly like you would make for punch press or close die forming. You will most likely need to remove the bottom die completly and build a male dove tail directly on the base plate to have enough room for all of this. It does work I have done it. It's cheaper and much eaiser to use a spring die. If you will rough out the stock on open dies first so the spring die don't have to move a large volume of material they will last longer.

[Herb Upham]

In BP1042 Forging 1-1/4 inch ball and spring tool Uri Hofi describes crowning the top die which releives stress on the weld and allows a simple spring confguration. My experience is that flat tops on the upper die stresses the weld and can lead to the weld failure.

[dan_m]

If there were a better way it would be common practice. Blacksmiths have been using spring tools for many years, I doubt that reinventing the wheel will occur.

Now that's some narrow-mindedness right there, jeez.

Ironquake, may as well give it a try and see how it works out, you never know what you'll come up with.

[JNewman]

You sould give it a try, I know what you are talking about with the bending forces. The one problem I can see is if you hit the die hard the top swage will flip back on the spring, you should put a stop on it to prevent that. The swage flipping back could be more dangerous than a swage that breaks off because if you hit it again it is going to break off while sitting on an angle. As long as you are paying attention often you will notice when a spring on a swage is cracking even when they break unexpectedly the steel you are working on keeps the top swage in place for a blow or two.

I make runs of 1-100, only occasionally a couple of hundred and I often don't know if the job will come back even though a lot of them do so I cannot afford to make dedicated dies like Stuart does. So I do use a lot of spring dies. When I bought my hammer I got a lot of swages with the hammer for $.28/lb. and a lot of them are quite heavy and are up to about 3" round, So I am not going to replace them with integrally forged springs. The swages I bought are set up with dowels and a long handle for a helper to use. As I need them I cut the handle off and weld a light spring and hardy shank to them. Because of the pins I can use lighter springs than I would use for these large swages without the pins. These lighter springs seem to break a little less often although the dowels may also be part of the reason. The dowels also help keep the top half of the swage in place although if they are hit too hard it can be bounced off the pins. I also have lots of swages that I have made that are just springs. I have one that has been very heavily used and the last time I used it the steel in the spring was so heavily fatigued that it broke every couple of parts in a different location. Next time I need it I am going to replace the spring before I use it and I plan on welding a tapered stub to the swage as well to help spread the load to a larger area on the spring.

Unfortunately due to the nature of forging tools being hammered on and the vibrations to the springs, they need a lot of maintenance. If you are sucsessful in finding a better solution I will be happy to hear it.

[ThomasPowers]

When it comes to tooling there are other things to factor in use-life, cost, ease of use and ease of construction.

It could be quite possible to make a a much enhanced tool but if it's more expensive and the "cheap" way of making one tends to outlast the life of the die face then maybe the "best" isn't economically better than "good enough".

With modern materials and processes you possibly could come up with a "better" way; you just have to be willing to expend the time on trying things out.

Just think how modern materials like cheap high carbon and high alloy tool steels and new processes like arc welding have changed how tooling was made compared to back in the wrought iron with thin steeled faces all forge welded together days.

And as for Clifton, well give him a big power hammer and a rock on a stick and he'll probably figure a way to do jaw dropping work with them...

[doc]

Seems like there are two similar posts going on here. Check out Forgemasters solution to your problem. http://www.iforgeiron.com/topic/26126-power-hammer-tooling-question/page__pid__268463#entry268463

Lillico also suggests this.

[peacock]

Stewarts method is the very best for long runs no question about it. If you can afford the steel and can machine it yourself there is no better way to go, if you only have one hammer and only need a few parts you may spend most of your time changing and setting dies.

[nuge]

I like the op's idea, let me know how it works out. Most all of my power hammer tools have welds whether they are handheld, spring, bottom, whatever. My big trick is to make two. I still produce them to the best of my ability but with all that shock they are gonna break at some point and it's nice to keep rockin' when it happens. Then the broken one goes into the to be "to be redressed" pile, then to the "to be rewelded pile".

[peacock]

When I build a new spring tool the first thing I do is forge what I call a master I forge a piece of stock without turning it. take it out trim the flash reheat and reforge again with out turning. These are stored so when the spring breaks or gets out of aliginment I can put the master between the dies clamp in a vise while I weld it this give perfect line up very quickly amd easily. You can also use the master to produce another die set without haveing to grind relief as the master has coiped that from the first one. If the spring breaks striaght across I line the ends up but I weld down the center of the spring lengthways with a bead 3 times the width of the stock then another bead on each side of the first 2 x the width then one more bead on each side of the second this time 1x width this makes a diamond shaped patch without stress lines running across the spring. Also when forging a item that will be round If possible I like to start with square stock on the diamond (corner up and down) turn 90% from diamond to diamond till it rounds up. By hitting the corners the steel only has to moveabout 45% instead of being extruded out the ends. This makes for lots fewer blows which means less stress on the die, quicker forging, and less breakage and wear.

[forgemaster]

This is one of these problems that you can lie awake at night in bed thinking about, but here is what I have found from 30 years of doing this stuff
The handle will always normally break of on job No 10 of a run of 10, or job 15 of a run of 15 it does'nt really matter it will break in the last few minutes of the job, or break in the 1st minute of a run of jobs,

Just cause you have drilled upset and peened is not a guarentee of no breakages (see the photo)

Sometimes it will be the top tool which breaks off, sometimes the bottom, there is very little logic to which one is going to break next.

Putting a few beads of weld along the handle at right angles to the axis of the main weld seems to help as some guys have suggested

I have been told brazing the handles on works well also.
Even our stopper pads which have a short piece of 50 x 6 flat welded onto them to go on to the pad holder, break off after a while (in the second photo you can see where it has broken off and we have just turned the pad 90 deg and rewelded it).
I think the jarring effect of the hammer also helps to fatigue the heat affected zone of the handles, we have found the better the mateial that the handles is made out of (ie certified K1020 material) seem to last longer than just common old garden variety MS. Maybe due to the errant alloys being controlled better in the certified steel.
If you put a hinge in the top handle itis going to be exposed to a lot of jarring, twisting vibration etc, and you still have to attach the hinge to the tool, I doubt if the extra work in making a hinge is going to be justified in the long run. Try it and see, then let us all know, it will save us the hassle of doing it if it fails, if it works you'll be a hero.
See I have'nt solved any problems but I may have cancelled out some doubt.

Phil

[iron quake]

Ok I'm going to make a spring tenon tool with a butcher today and I'll try this joint idea out. The top half will be "1.25 longer and stick out past the die area. I'll ream a .501 hole in that end for a hardedend shoulder bolt and machine a yoke to match and attach to the top spring. I'm going to put a couple ears on the other end of the die set to retain the top half from moving out of position in the axis of the tenon holes. I'll let ya all know how it comes out. The real proof may take some time I guess.

[iron quake]

Machined, welded, heat treated the tool today. I ran one part this evening after the tool came out of the oven and I think its an improvement. The top half of the tool being able to get level at all four tool positions takes most of the stress off the upper spring. I'll run a part and post a video or some pictures tomorrow.

[iron quake]

Here are a couple pictures of the tenon tool. I think it worked great, will it last any longer, I guess I'll see about that.

http://www.iforgeiron.com/gallery/image/36333-tenon-spring-tool/

http://www.iforgeiron.com/gallery/image/36332-tenon-tool-with-a-2nd-joint/

[evfreek]

Very interesting. This looks a lot like the tool that Erin Simmons showed at the CBA blacksmithing clinic last week. The purpose of the pivot was for flatness and accuracy. It held a die system that put a double fuller longitudinally into a knife blade. I think that the comments above were not meant to discourage innovation. They were just another way of saying that if you are clever enough to figure something out that's new, it probably is not new, and someone is probably even demo'ing it as you are posting a thread.