Some observations about twist method for making tongs

[evfreek]

I recently read an interesting article on the Incandescent Ironworks web page about a secret about how to make twist method tongs that don't have the problem of the weak point at the twist causing the jaw to fall off later. I have never been really happy with this method, because it seems to leave a juncture which is weaker than the rest of the boss-bit area. This article made me think about it a little more. The main point is that the twist has to be made smoothly. Hot isn't enough. A little bit of smoothing as the jaw gets twisted around keeps ridges from getting compressed into weakening cold shuts.

This seemed to make sense, but it involved thinning down an area which already is too thin. Then, I think that I figured out what was necessary. The twist will only be strong if the cross-section of the twisted area is circular. In essence, you have to be twisting a round bar. That means, if one is maintaining thickness, the transition between boss and jaw in a pair of tongs made from 1 x 1/4" must be 1/4" round. No wonder why it is so weak. That makes a lot of sense. And that is why 1 x 3/8" bar seems much better, even though much drawing is required later for the reins.

It also explains why flat bar does a much better job as starting stock for tongs that don't require this thinning twist, such as z bit tongs or scrolling tongs. Tong designs such as the farrier tongs whose instructions are given on Mark Aspery's site are not subject to this limitation, since they are upset at then ends, and they are essentially made with the classic method once you get past the boss. They are just great (I tried making a pair).

As an experiment, I tried a hybrid method in which I partially formed the jaw by setting down, then upset back down into the boss. This looked good on paper, and seemed to work when I tried it out, but I ended up getting a horrible cold shut (on both halves) at the original weak point. After filing it out, it was OK. Now, why didn't that show up in my drawing??????? They say that if you can't draw it, you can't forge it. And I couldn't draw that cold shut

For good transitions, it seems that Mark's method, laborious as it might be, is the best one for achieving this result.

[Francis Trez Cole]

Here is a link that will help you the size of the tongs should be made in relation to the size of stock you are working with. For twist I use a pipe wench with the teeth ground off and a bar welded to the head the jaws are adjustable and the frame is strong. http://www.anvilfire.com/bookrev/ind_pres/tongs_chart.htm

[Frank Turley]

I've made a few hundred pairs of hand-forging tongs for flat work and farriery, and I use the three shoulder method as shown in "The Blacksmith's Craft" and "Plain and Ornamental Forging." I think the twist method is cheesy looking and requires nearly as much work as the three shoulder method. I normally lap (forge weld) the reins, simply because it is good practice. The scarf face is on the 2nd shoulder side of the blanked jaw about 3" back from the 3rd shoulder.

I don't think the twist would affect the strength all that much on mild steel, but there is something called "grain flow" which is affected adversely in a twist. It is difficult to find a layman's definition of grain flow. The crystaline structure and other constituents in the metal do align themselves in the direction of hot working. The flow is not as gross as the fibrous structure of wrought iron, but is analagous.

As an example of food for thought, if you take a newspaper sheet and tear it following the line of print, it tears easily in a fairly straight line. If you tear it at right angles to that alignment, it tears crookedly.

Twisting steel also twists the grain flow pattern.

http://www.turleyforge.com Granddaddy of Blacksmith Schools

[evfreek]

Thanks, Francis and Frank. I looked at the anvilfire iforge twist method tongs drawings. In the middle drawing, it shows the notch being twisted around, and it is pretty clear how the metal is becoming forced down in the transition. Frank, that word "cheesy" is the one I was searching for. They do look cheesy. They seem to work fine, though, as long as you don't abuse that transition. As for welding on reins, that has always given me trouble, but it seems to be slowly getting better.

[Francis Trez Cole]

bill robertson do a great video on tongs and he uses a twist on the ends of his gooseheck tongs. The twist method is good for someone just starting out. once you get some hammering under your belt then tongs fall in place the ones that clicked for me was the scrolling tongs made from RR spikes that Bill Erapp did a BP on. Making a hores's head has alot of the same elements used in making tongs.

[HWooldridge]

I've made about 15-20 tong pairs using the 'flat stock and twist' method and the secret is to make the transition area smooth without any sharp corners. The cross section needs to be as close to round as possible or you will experience the problems described herein.

[evfreek]

Hi Hollis. Thanks for the reply. It is pretty clear how to manage the transition.

I was thinking about the problem a bit this morning, and I finally figured out why the process makes me uneasy. This operation reminds me of Brian Brazeal's bar shear, which I think was posted here. This tool consists of two pieces. A slotted block that is fixed to the acorn table that the flat stock is slid into. And, a handled tool with another slot in it matching the thickness of the flat stock. There is no pivot. The handled tool is slid over the protruding end of the flat stock and twisted. The flat will shear. This tool provides a simple and effective means of quickly cutting same length pieces for collars.

It can probably also be repurposed for making twist method flat stock tongs. Just leave a little clearance for the transition

The problem about this process is that if you are not twisting a round cross-section, the wide edge is undergoing extension. Unless the metal is hot, extension tends to rip it. Many materials are much stronger in compression than they are in extension. Again, credit to Brian, from his excellent demo of hitting cold steel at a CBA conference.

[thingmaker3]

Here is a link that will help you the size of the tongs should be made in relation to the size of stock you are working with. For twist I use a pipe wench with the teeth ground off and a bar welded to the head the jaws are adjustable and the frame is strong. http://www.anvilfire.com/bookrev/ind_pres/tongs_chart.htm

I've seen that Machinery's chart (or variants thereof) a few times. What I don't understand is why the chart goes by diameter or side length of the stock instead of by mass of the stock. Can someone explain the theory at work here?

[evfreek]

OK, I understand what is going on. Someone just posted the answer on another thread. It is that little diagonal step that is created by the 3 turn method that is missing from the twist method. It is so obvious now. Thanks.

[double_edge2]

OK, I understand what is going on. Someone just posted the answer on another thread. It is that little diagonal step that is created by the 3 turn method that is missing from the twist method. It is so obvious now. Thanks.

where abouts was it posted please?

[HWooldridge]

Finally got around to taking a pic. These were all made from flat material and the twist method. The bottom pair was cut from 3/8"x1" mild steel; the rest started life as 1/4"x1". I used to do a lot of production forging for the craft business and would always make at least two sets of tongs for most any job so I always had an iron in the fire...

Starting at the top: A pair made expressly for making S and J hooks in 1/4 or 5/16 stock; the jaws have grooves along the length and across the width to hold either end. The ring allows your left hand to get a little rest. The next two pairs were forged in a swage to get the round transition between boss and jaws; the top pair holds 1/4x1 and the next one holds 3/4 round or 5/8 square. The last pair was also made specially for S and J hooks in 1/4 stock and has a ring to lock the reins.

[John B]

I've seen that Machinery's chart (or variants thereof) a few times. What I don't understand is why the chart goes by diameter or side length of the stock instead of by mass of the stock. Can someone explain the theory at work here?

Tongs need to fit properly to secure the workpiece, that is why sizes (diameter, square or height and width) are specified.

Mass as I understand it is the total volume/weight of an item, not relating to its linear dimensions (ie, width, breadth, length)

What do you understand as to the meaning or definition of "mass" ?

[thingmaker3]

Tongs need to fit properly to secure the workpiece, that is why sizes (diameter, square or height and width) are specified.

Mass as I understand it is the total volume/weight of an item, not relating to its linear dimensions (ie, width, breadth, length)

What do you understand as to the meaning or definition of "mass" ?

I define mass the same as they taught in high-school: height x width x lenght x density. But why do I need longer reigns for a larger diameter piece? I could understand more stout reigns for a heavier piece.

For example, if I'm handling a 2" diameter by 5" long pipe versus a 3/4" diameter 5" bar, why do I need beefier tongs for the tube? Why can I get away with 15" reigns holding a knife blank flat, but have to switch to 22" when dressing the profile?

How come the overall mass of the workpiece has less influence on the size of tong than a single dimension of said workpiece's cross-section?

Am I thinking about this backward?

[LDW]

Here are the two videos Brian has made on forging tongs. This way will create the hinge without twisting. There is a standard for tong reins and rivet sizes for tongs. Once you are efficient in making tongs you can make tongs the way you like them. I like light weight tongs myself. Brian has shown me that as long as your reigns are tapered nicely they will be flexible without bending even when made from mild steel. Your left hand gets as much work or more from holding tongs than your right hand. ( If you hammer right handed) Therefore I like to work with light weight tongs as much as possible. After working with Brian I have learned tong clips are a neccessity as well. The smooth taper allows the tong clip to do a better job. Maybe we can get Brian to put his 2 cents in.



http://picasaweb.google.com/brianbrazealblacksmith/TongBlank#5444538182975584098

http://picasaweb.google.com/brianbrazealblacksmith/TongBlankInClay#5444814678944207826

[double_edge2]

ive done a sample for this post, this is how they look after the twist and bed down. I try to be pretty neat with the jaw bit thingy on my twist tongs, that and enough stock,....and since only a quarter turn, and hot enough, i would have thought the tortion/stress on the amount would not weaken it by much. dont get me wrong i love normal (made from solid stock) if there is a normal, and for larger tongs i would go from solid stock...but my consistency is ....well...not the best, unless a jig is employed...lol.
the twist tongs, and hammer down from notch, are the best for me for batches of consistency in general tongs.

[evfreek]

where abouts was it posted please?

Thanks to the poster for clearing this up.

[double_edge2]

Thanks to the poster for clearing this up.

thankyou, i saw this die,...how does it relate to strength in twisted tongs?

[evfreek]

thankyou, i saw this die,...how does it relate to strength in twisted tongs?

"This almost doubles the cross section at the root of the jaw, one of the places where I have seen many tongs broken."

Simple, direct, and to the point. And the mental picture really pops out.

[John B]

I define mass the same as they taught in high-school: height x width x lenght x density. But why do I need longer reigns for a larger diameter piece? I could understand more stout reigns for a heavier piece.

For example, if I'm handling a 2" diameter by 5" long pipe versus a 3/4" diameter 5" bar, why do I need beefier tongs for the tube? Why can I get away with 15" reigns holding a knife blank flat, but have to switch to 22" when dressing the profile?

How come the overall mass of the workpiece has less influence on the size of tong than a single dimension of said workpiece's cross-section?

Am I thinking about this backward?

I don't think you are thinking this backwards,

These charts were universal commercial specifications for tongs that were on sale to the general trade so that when they were purchased the customer knew what they were getting, or if you were going to produce them commercially, this was the standard expected. I think it is fair to assume they were expected to be used for holding solid bars. The blademakers and other trades such as cutlers and surgical implement makers had their own styles and types of tongs that were totally away from these recommendations.

I didn't go to high school, but Mass is still total weight which then agrees basically with your understanding of stout reigns for heavier pieces

The holding range and component weight (mass) is more important than the length of reins, 2" diameter by 5" tube is a lot lighter than solid, and can be handled with shorter reins, so in essence you don't need "beefier tongs" its just that by reading the charts and adhering to them, that is what is probably confusing you. You are comparing a 2" capacity with 3/4" capacity,

The charts are guidelines from a previous era, but still valid, and were used for industrial 'smithing suppliers, most 'smiths make their own tongs that suit their needs and applications.


Quote
Why can I get away with 15" reigns holding a knife blank flat, but have to switch to 22" when dressing the profile

There is no reason why you have to switch to 22" reins, I can only think you are switching to a different type of tong to hold the blade whilst dressing it, personally for small work my tong reins are round about 10" long for working on the anvil, but I also use a pair of a similar capacity jaw wise with 20" reins to remove the piece from a gas forge, before transferring it to the shorter pair to work on the anvil.

I don't make many blades, but for the ones I do make, I make my own tongs or adjust previously made ones to hold them securely,

I hope this helps, going by the book is not the only way, do what you have to do, and use what works best for you (Safely)

[thingmaker3]

These charts were universal commercial specifications for tongs that were on sale to the general trade so that when they were purchased the customer knew what they were getting, or if you were going to produce them commercially, this was the standard expected.

Thank you, John. That makes a whole lot more sense.