Keganthewhale

Anyone ever forge a vise screw?

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I searched but couldn't find anything on actually forging the threads for screw vices. I'm assuming this has been done at some point in the past so I assume there might be some book that has the info, if so, can anyone point me to that book (or books)? Or if anyone has experience forging one I'd love to hear about it. I was wondering if you has a top/bottom die for a single thread on a press, then work your way down till you had enough threads, could you effectively forge one out like that?

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Historically I know of no examples of forging a screwthread till we get to modern times with machine roll forming. They were filed, chiseled and cut on the lathe. (The history of cutting screwthreads on the lathe is fascinating BTW, especially the bootstrapping method used to make the first lead screws).

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Assume that was a case of the first one was completely by hand, which was then used as a lead screw for the next, and so on, improving the accuracy with each iteration?

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Actually one of the first ones was used to cut itself; why I used the term bootstrapping.

But you are right about using one to make a better one and using it to make an even better one.  The search for precision and accuracy in the industrial revolution is what gave us today's techno world.

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I have seen it done - using a hot cut, and holding the work piece at an angle to it, You hit and rotate it continualy. a helical groove is formed and "guides" itself on the hot cut. you must maintain a fixed angle, and you get a prety decent screw.

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Decent for use as a vice screw or decent for use as a wood screw?

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from the earliest days they were pretty much always cut.. Be it by hand with chisels or files or with metal lathe with bits.. 

One of the most interesting things about screw boxes on these vises is they use square threads vs acme..    Sq threads have a higher work load with less inherit binding vs acme or any other thread.. A sq thread only keeps the faces in line vs a taper of a thread which becomes tighter the more friction is applied.. 

The cutting of sq threads is considered by most machinist today to be nearly impossible (very problematic)  that 99.95% of them will tell you to just use acme vs the difficulty of producing Sq threads on the lathe..  

it might be different now with CNC but years back I wanted to get a screw newly threaded and out of 50 machinist not 1 of them would cut me a  2 thread per inch sq thread.. 

They said it was ludicrous.. the back spacing of the thread and the lead angle of the bit are paramount to get a good sq thread..      A 2 threads per inch uses 1/4" wire wrapped around and this is then placed into the box and fire brazed in place..   Technically making it a lifetime box as when worn it can just be bored out and done again.. 

Anyhow, I never did locate anybody and even a close friend of mine who worked at Wyman-Gordons told me it wouldn't be worth his time and just to do Acme.. 

I now own a lathe so at some point will take on the challenge of producing a thru square thread.. All the old machinist books show how to cut them but no modern guy wants to take on the job..   

I figure when I forge my 10" Super giant German Style vise I will take on the calling.. :)   

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JLP, the problem may have been not being able to get that feed rate on the lathes they had. I have a Monarch that will get down to 1.5 TPI and that is unusual for many manual lathes. With CNCs you can pretty much dial in what you want.  For square threads you usually do a vee thread first to remove some material, then come back in with a square toolbit.  Another option for easier cutting would be to do a buttress thread, and those are excellent for unidirectional application of force.

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On ‎10‎/‎04‎/‎2018 at 7:45 PM, ThomasPowers said:

Decent for use as a vice screw or decent for use as a wood screw?

I wasn"t refering specificaly to vice screw, but in general to historically forging screwthreads.

My blacksmithing teacher demonstrated forging a large screw, and explained how to forge a matching nut. He claimed this method was used pre-industrial revolution. This method makes triangle thread, but can easily be used to make square (by following the thread with a square fuller).

Filing will make a smoother and more accurate thread. But I think that for a rough work, like in a vice, this type of screw will do.

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Can you ask him for some documentation?  I don't recall reading that in any of the historical methods books and so must need more books!

Iron vises tended to be high end items historically and so tended to be much higher finish than other smiths tools---you don't expect a crude Mercedes.

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Mr Ralph does a lot of stuff on a powerhammer that lesser mortals can only dream of.  He did like the propane stove we made out of a HF ASO one quad-state.

If I had to manually make a largish screw thread I think I would rough forge, then chisel, then file and probably decide it would be an excellent task for a Journeyman smith in the shop to do.  (Some of the really fancy vises in the museums were Masterpieces.)

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You might be getting the concepts mixed up..

A vise screw needs to be highly accurate compared to nuts and bolts or screws.. (highly accurate for what it is) which is usually sloppy..

Hand made non cut bolts and screws can be pretty sloppy compared to modern equivalents depending on the item made..  (guns very accurate, wagons not so much)

Lag screws are a whole different ball game and if that is what you are referring to these are very low tech and easily forged, but even these were cut threads once screw machines came on the scene..

Before standardization each and every Smith (est) would generally use the size thier master used... this only changed if the Smith found a better way based on a lack..

Taps were always produced first and these were then driven into the die or plate..

Many a bolt was put over a plate then upset to take on the dies threads needing no cutting teeth at all..

Ive made screws and bolts using several different vintage methods for flint locks, wagons and such to match the custom threads in place..

One of the most wonderful and appealing things sbout real blacksmithing is the ability to make what ever it is one wants with only ones hands and a basic concept and understanding on how metal moves...

The forging by hand of threades faded out pretty quickly once travel and standardization came in...

With that said its possible to produce many things by different methods,  historically the variations were innumerable.. anything is possible with a concept..

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The screwplate was listed as one of the necessary tools for a smith in Moxon's Mechanick Exercises, pub 1703 a lot of it written in the previous century.

But as mentioned each one tended to be individual---or copied from the one in the shop you trained in.  Reading on how hard it was to get "interchangeable parts" reliably interchangeable is interesting if you are into the history of Technology. 

One Good Turn: A Natural History of the Screwdriver, Witold Rybczynski, has some information dealing with this topic. (I'd consider it quite readable rather than academic though.)

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