DavidB
Well-known member
After reading Joe Mamma's excellent comparison of the open ends of a Wright and Snap On wrench I was curious what the contact points looked like for the box ends. Here is the link to his post: http://www.garagejournal.com/forum/showthread.php?t=40058&highlight=wright+grip
So, I decided to test my meager collection of regular sized 9/16" wrenches. I chose 9/16" because thats the only size Snap On wrench I have. (Its a mark against me I know.)
Here are the wrenches.
1. Craftsman Professional 45978 bought during the great sale on these wrenches last year.
2.Craftsman Raised Panel 12pt Date Code: -V(inverted V)- Purchased during the 90s some time I think.
3.Craftsman Raised Panel 6pt Date Code: -V(inverted V)- Purchased during the 90s some time I think.
4. Promark Taiwan made wrench received sometime in the 90s.
5. Snap On OEX18 No date code. Flank drive. Purchased used.
6. Craftsman Raised Panel Flare Nut Date Code: -V(inverted V)- Purchased during the 2000s some time I think.
7. Craftsman Raised Panel 12 pt Date Code -VV- From my grandfather.
Here are some close up views of the box ends of the wrenches.
Testing Method
Nuts were purchased from Lowes, colored on 3 sides with a black Sharpie, and numbered. I put a bolt in my vice upside down and then placed a washer on the bolt. I the finger tightened a nut on the bolt and tightened it with a wrench. Each nut was then loosened with the same wrench. A new nut was used for the next wrench and the process was repeated again.
Contact Points
All of the images tend to show a wider contact point near the top. I'm guessing this is due to the angled head on the wrenches. All of the wrenches were used "face up" so that the open end was higher than the box end.
1. Contact points are fairly even and away from the edge.
2. Contact points are missing from the center and away from the edge. It is possible that I didn't use as much force with this wrench and with more force a complete print would be seen.
3. Contact points are wider than the 12 pt wrenches. Points are also away from the edge.
4. Contact points are on the edge and even.
5. Contact points are fairly even and close to the edge but not on it.
Here is the same wrench but on different nut. This one was slightly larger (~0.005") than the rest of the nuts.
6. Contact points are even and very close to the edge. On the face to the left the contact point seems farther away from the edge.
7. Contact points are even and on the edges.
I won't offer much of an opinion since I'm no expert in this stuff. From what I've read to reduce the chance of rounding a fastener you want to move the contact point away from the edge of the face. This is the idea behind Snap On's Flank Drive and everyone who has copied it. This makes sense logically and is evidenced by the fact that the newer and more expensive wrenches do this. I'm pretty sure #4 and #7 would round a faster off before any of the others would. Also with a wrench that moves the contact point away from the edge you have a better chance at removing a fastener that has been rounded.
Anyways, I hope this is informative and I'd be happy to answer any questions. I'd like to test more wrenches and see how they turn out. If I do I'll add them to this post. What are your thoughts?
PS Yes, they did do a great job centering the box end on wrench #7
Update: Upon further review I think the Snap-On wrench is a Flank Drive. At first I thought the wrenches with the shown style of markings didn't have flank drive.
So, I decided to test my meager collection of regular sized 9/16" wrenches. I chose 9/16" because thats the only size Snap On wrench I have. (Its a mark against me I know.)
Here are the wrenches.
1. Craftsman Professional 45978 bought during the great sale on these wrenches last year.
2.Craftsman Raised Panel 12pt Date Code: -V(inverted V)- Purchased during the 90s some time I think.
3.Craftsman Raised Panel 6pt Date Code: -V(inverted V)- Purchased during the 90s some time I think.
4. Promark Taiwan made wrench received sometime in the 90s.
5. Snap On OEX18 No date code. Flank drive. Purchased used.
6. Craftsman Raised Panel Flare Nut Date Code: -V(inverted V)- Purchased during the 2000s some time I think.
7. Craftsman Raised Panel 12 pt Date Code -VV- From my grandfather.
Here are some close up views of the box ends of the wrenches.
Testing Method
Nuts were purchased from Lowes, colored on 3 sides with a black Sharpie, and numbered. I put a bolt in my vice upside down and then placed a washer on the bolt. I the finger tightened a nut on the bolt and tightened it with a wrench. Each nut was then loosened with the same wrench. A new nut was used for the next wrench and the process was repeated again.
Contact Points
All of the images tend to show a wider contact point near the top. I'm guessing this is due to the angled head on the wrenches. All of the wrenches were used "face up" so that the open end was higher than the box end.
1. Contact points are fairly even and away from the edge.
2. Contact points are missing from the center and away from the edge. It is possible that I didn't use as much force with this wrench and with more force a complete print would be seen.
3. Contact points are wider than the 12 pt wrenches. Points are also away from the edge.
4. Contact points are on the edge and even.
5. Contact points are fairly even and close to the edge but not on it.
Here is the same wrench but on different nut. This one was slightly larger (~0.005") than the rest of the nuts.
6. Contact points are even and very close to the edge. On the face to the left the contact point seems farther away from the edge.
7. Contact points are even and on the edges.
I won't offer much of an opinion since I'm no expert in this stuff. From what I've read to reduce the chance of rounding a fastener you want to move the contact point away from the edge of the face. This is the idea behind Snap On's Flank Drive and everyone who has copied it. This makes sense logically and is evidenced by the fact that the newer and more expensive wrenches do this. I'm pretty sure #4 and #7 would round a faster off before any of the others would. Also with a wrench that moves the contact point away from the edge you have a better chance at removing a fastener that has been rounded.
Anyways, I hope this is informative and I'd be happy to answer any questions. I'd like to test more wrenches and see how they turn out. If I do I'll add them to this post. What are your thoughts?
PS Yes, they did do a great job centering the box end on wrench #7
Update: Upon further review I think the Snap-On wrench is a Flank Drive. At first I thought the wrenches with the shown style of markings didn't have flank drive.
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