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a heavy duty bending aid for thick piano wire

auxiliary sprung vise jaws

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kenking-King Design08/06/2016 23:52:35
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237 forum posts
723 photos

A client recently asked me to groove the serrated jaws of his 6" vise, as he was having trouble keeping 8g piano wire firmly clamped whilst thumping it with a big hammer. Unfortunately, as the jaws are hardened, I couldn't do as he asked. I did, however, knock up a pair of auxiliary jaws, suitably grooved and connected by simple springs, which self-locate within his vise. Apparently the arrangement works very well, and so I show it here in case the idea is of use to anyone else.

Milling is involved, but if you can't get that done locally by all means give me a call.

The auxiliary jaws are made from 7/8" x 1/2" steel which I had in my stockrack. One longitudinal groove and two vertical grooves were requested, as shown.

100_5037.jpg

The two 'staples' are brass rod, about 3mm dia., which I used as fairly rigid springs to hold the jaws apart. The back of each jaw is relieved to provide a locating ledge which keeps them in place in the vise. The staple springs simply plug into holes in the underside of the auxiliary jaws, and are locked in place with grubscrews in the end faces. The following two views should make all the features clear .....

100_5042.jpg

100_5044.jpg

In use, the assembly is dropped into the vise and rests in place as you can see, allowing 'hands-free' operation, meaning you don't have to juggle blocks, spacers and clamps as well as position a piece of unco-operative wire, whilst trying to tighten the vice with one knee. We've all done it.

100_5038.jpg

Now you can approximately position the wire, then do up the vise until the wire is gently trapped within a vee-groove.

100_5040.jpg

When happy, fully tighten the vise and apply bending force by whatever means you prefer. Open the vise wide, and the staple springs keep the new jaws in location whilst the wire is removed. Tsimples !!

Hope you find this useful,

Ken.

Dave Hopkin09/06/2016 05:58:17
3672 forum posts
294 photos

Great idea BUT the end of the device (where the bend is to happen) should really be radiused to prevent concentration of stress in the wire

kenking-King Design09/06/2016 11:11:11
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237 forum posts
723 photos

Thanks for your observation Dave. I did consider radiusing but decided to first wait and see how the device performed. Naturally I have removed all sharp edges as per usual good practice, so there is a small chamfer on each edge anyway. The action of bending wires may itself slightly deform the vee edges to give a radiused effect, and in that respect the process is self-adjusting. In the fullness of time these areas could be case-hardened. Client feedback so far is that it all works to his complete satisfaction.

kenking-King Design09/06/2016 14:27:26
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237 forum posts
723 photos

Hello again Dave, I've just heard that there is now some bruising evident at ther end of the vees in use, and so these zones will be cleaned up and case-hardened. I'll put similar a similar radius on each vee of course. This is what I meant by the process being self-adjusting, i.e. the wire produces a radius at which it is happy to bend. Hopefully the case-hardening will help hold that permanently. Failing that we will have to move up to tool-steel.

I'lll let you know how we progress,

Ken

kc09/06/2016 18:48:25
5872 forum posts
168 photos

Wouldn't it be easier and better to make a proper wire bender for bending 8SWG piano wire? Hitting with a hammer is a crude and risky business! A proper bender is simpler to fabricate than the vice jaws and is much more precise in use.

kenking-King Design09/06/2016 19:55:49
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237 forum posts
723 photos

Well kc, you may be right, but this is what my client asked for and so this was the starting point. Would you care to supply an illustration of what you consider to be a 'proper' wire bender ? That would be most helpful,

Ken.

Tom Sharp 209/06/2016 20:28:36
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3352 forum posts
17 photos

I've got a proper tool to bend piano wire. It's called a Mighty Wire Bender made by K&S Engineering. Does bends and coils without effort, is totally efficient. The big shops stock it.

kenking-King Design10/06/2016 10:17:11
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237 forum posts
723 photos

Hello Tom, I've looked at the wire bender you mentioned, and although it undoubtedly produces beautifully curved or coilled wire, that isn't what my client wants. He is looking for a means to make the sharpest bends possible without cracking the wire, and we're close to achieving that in a sustainable tool. If it involves using a hammer to persuade the wire, then so be it. As for 'crudeness' remarked on by kc it doesn't offend my sensibilities in the least - humans have used hammers throughout history; probably the first tool ever picked up was a hammering stone. As a means of delivering high force to a small area it's hard to beat. That's not to say that some variation on the commercial bender might not be developed to do what is desired - the game is not yet over.

All your comments are appreciated and taken into consideration, so I thank you for them,

Ken.

Dave Hopkin10/06/2016 11:16:45
3672 forum posts
294 photos

The trouble with hammering sharp bends on piano wire is that you are focusing all the stress in one very small area and under load its very likely to fail - if your client wants this "feature" in his bends or is not using the wire in a load bearing role then its probably fine - but if its for Undercarriage you should warn him of the fatigue these bends will induce - There is probably a very good metalurgical formula that will confirm this......

kc10/06/2016 16:34:33
5872 forum posts
168 photos

Somebody on the forum put a design for a wire bender into one of the items but I could not find it yesterday. Eventually I found it here  and the previous  page.  I  would suggest that it's easier to make that than the vice jaws and that it will bend piano wire better. A homemade version of the quite expensive commercial item would also be worthwhile.

Hitting piano wire with a hammer is crude & often causes the wire to fracture into very sharp shards. Piano wire sometimes almost explodes if you hit it enough - quite dangerous to the eyes. Of course in the right hands a hammer is a precision instrument - I am not joking. I have seen a skilled panel beater hammer a dent out of a car bonnet without even marking the paint. Skilled stuff. And of course blacksmithing can be precise too.

Edited By kc on 10/06/2016 16:38:04

Edited By kc on 10/06/2016 16:42:35

kenking-King Design12/06/2016 00:10:09
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237 forum posts
723 photos

Well, I got the bending aid back from my client and I'm pleased to say that the 'bruising' he'd mentioned was barely visible; it was just where the wire O/D was impinging on the very shallow bevel I'd applied to the vee end. I did as Dave suggestd earlier; I filed a slight radius on each edge, then emeried it, and finally I took a piece of 4mm silver steel and bent it 90 degrees with heavy hammering, repeating in both directions in all four operational vee ends. This last imparted a nice polished finish.

After that the jaw ends were case-hardened, and the whole lot wire brushed before re-assembly. Another sil. stl. bending session showed all to be fine,with the previously seen straight-edged notching inside the bend now being much less severe and more rounded, so less of a stress-raiser.

The following photo shows the radiused vees.

100_5054.jpg

Thanks again for all the enlightened opinions given, they're much appreciated,

Ken.

Luther Oswalt17/06/2016 20:02:36
137 forum posts

Ken,

Here are three URL's for some small tools. Harry Higley is very good and has some great instructions on his pages. I have included Sullivan Products as they now own Higely's operation. Micro mark has loads of small tools.

1. **LINK**

2. **LINK**

3. http://www.micromark.com/

Leo

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