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V shaped open end (like Bonney)

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matthew

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So I'm curious - at one time a bunch of wrench brands used a V-shaped open end design, notably Bonney, and also a mix of other brands (some of which were made by Bonney) including John Deere, Herbrand, Matco, Mac, Wright, IH, etc.
bonney_c26_1167a_wrench_combo_polish_f_cropped_inset.jpg




Today, however, it seems like just about everyone uses a round shaped open end.
bonney_c26_1167a_wrench_combo_outline_f_cropped_inset.jpg
.



The question is why would everyone change to the rounded profile? At a glance it would seem to me the fit of a V shaped open end should give a better fit on a nut. And although I haven't done any stress analysis on it, it would appear stronger. So why does everyone seem to use the rounded open-end design?
 
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caper

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The v shaped open creates a stress riser that is prone to cracking.I've seen several of the Herbrand ones crack there.
 
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Rnz520

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I still prefer the V shaped open end to a circular style, thats why I buy MAC Knuckle Savers and Cornwells over Snap Ons and Matcos, except old bonney Matcos
 
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senlow

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The V shaped notch creates three stress risers - one at each corner. This makes the wrench weaker.

The usual justification for a wrench with the V shaped notch is that contact on four sides of a fastener is better than two. That is true. However, when force is applied, the wrench tends to push away from the fastener leaving only two surfaces exerting force on the fastener. This means that the V shape is not any better at preventing fasteners from being rounded off.
 
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back2class

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Yeah, my concern would be jaw spread because of the extra depth of the V. My guess and it is only a guess is that they do the same job the same.
 
OP
M

matthew

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Interesting, I had just thought there might be some other reason - like how well the wrench would fit on shafts that have two sides machined flat. I guess my question was also why those manufacturers went from a curved, switched to a vee, and ended up changing back...

I understand stress concentrations quite well, and there's no doubt the V-notch will have a concentration where the vee meets the flat side. Some of the older round-end designs also had a very abrupt transition, which would probably act similarly. In fact, they may have been worse than the vee design, because there would be an increased bending moment (torque) from the edge of the fastener to the edge of the broaching compared to the vee design fitting closer to the fastener.

Having looked again at some of my wrenches, and a few on AlloyArtifiacts, and the interesting thing is looking at the curved end profiles, it has evolved over the years to become stronger - I had never noticed that before. I guess in summary, it looks like the design of that shape has evolved, which would be why the old curves to vee to modern curved wrenches would be a progression.



Nonetheless, I like the look of that Stahlwille.:thumbup: Know where I can get a set???
 
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sk farmer

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Rnz520 said:
I still prefer the V shaped open end to a circular style, thats why I buy MAC Knuckle Savers and Cornwells over Snap Ons and Matcos, except old bonney Matcos
Click to expand...

i would think those that love the v opening would be all over the knucklesavers i have listed here for sale. :headscrat.
 

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Monte

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matthew said:
Nonetheless, I like the look of that Stahlwille.:thumbup: Know where I can get a set???
Click to expand...

good question...
You can try it to search for "Stahlwille open box 15" or "Stahlwille 15/10KT" which is a 10 piece set in a plastic tray. http://mdmetric.com/ probably have this set in stock. The best is if you call the US distributor http://www.stahlwilleaerospace.com/ and ask for the "open box 15" series with the "softgrip" open end.

1510kt_fot_011.jpg


scottmlew said:
+1

Monte, do you know why they stopped making these?
Click to expand...

just called Stahlwille, and the lady said that the market didn`t accept them so they are phased out. They still have some of the sets pictured above in stock and also individual wrenches. Sizes can be seen here: click
 
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TwoInch

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i like the looks of them stahlwille soft grips. cant imagine why the market didnt accept them, they look primo!

mdmetrics.com has the set for $170
 
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Wakefield

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Newer WrightGrips have sort of that V shape in the base of the open end but it is a little bit blended or smoothed out. I think I see a slight curve in the (straight?) side of the jaw also like the Stahlwille but very subtle.

Doesn't look like she'd break very easily!
 
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K

kc-steve

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Wakefield said:
Newer WrightGrips have sort of that V shape in the base of the open end but it is a little bit blended or smoothed out. I think I see a slight curve in the (straight?) side of the jaw also like the Stahlwille but very subtle.

Doesn't look like she'd break very easily!
Click to expand...

I had to double check that and you're right! (see photo)

Steve
 

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otis66

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I had set of Bonney's with the "V" and I loved them. The Wright wrench is nice too.
 

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otis66

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Lets not forget Cornwell wrenches. These wrenches feel realy nice in the hand and when being used. since I bought these three years ago they are my go to wrenches. I like these beter than my Snap On's.
 

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B

barcalo

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matthew said:
So I'm curious - at one time a bunch of wrench brands used a V-shaped open end design, notably Bonney, and also a mix of other brands (some of which were made by Bonney) including John Deere, Herbrand, Matco, Mac, Wright, IH, etc.
bonney_c26_1167a_wrench_combo_polish_f_cropped_inset.jpg




Today, however, it seems like just about everyone uses a round shaped open end.
bonney_c26_1167a_wrench_combo_outline_f_cropped_inset.jpg
.



The question is why would everyone change to the rounded profile? At a glance it would seem to me the fit of a V shaped open end should give a better fit on a nut. And although I haven't done any stress analysis on it, it would appear stronger. So why does everyone seem to use the rounded open-end design?
Click to expand...

I am actually trying to build a set of the Bonney at the top. If anybody has any they want to trade I have TONS of tools, all top US brands.
 
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