Koken Zeal Sockets v. Snap-on Sockets: A snugness comparison

AnonymousToolGuy · Jan 20, 2015

Background on Koken stuff if you want the long version: http://www.garagejournal.com/forum/showthread.php?t=212739

Short version: japanese made sockets and socket accessories

Back Story:

I figured I'd break out into a separate thread to make anyone searching for a direct comparison have an easier task.

My toolbox mainly has usa-made CM sockets currently. However, I wanted sockets that would fit a bit more snug over bolts and not have so much play that I'm damaging/gouging fastener heads. I don't turn wrenches for a living, just work on my own car and other stuff around the house. So I came to a crossroads: Koken or Snap On with a student discount. In either case I won't have any warranty support, so that's something to keep in mind, but I've never broken a tool that was used properly (and I always try to use the proper tool for a job). Both are priced roughly the same (SO is probably a bit more expensive).

So on to the comparison.

The fasteners:

Brand new 17mm drain bolt that I had on my workbench. I also selected a couple 10mm power steering pump hose bolt, 12mm intake manifold nut, and 14mm strut mounting nut. All of these bolts are in good condition and not excessively dirty or rusted.

The sockets:

-Snap-On Semi-Deep Metric
-Koken Z-eal Deep Metric
(Z-eal is Koken's low profile and tight tolerance line of sockets, their regular line may be worse)
-Craftsman sockets deep. USA made. ~3 years old.

The results:

First off, my SO sockets came coated with oil. I don't know if this is laziness on the part of their manufacturing or anti-rusting, but I would hope chrome sockets aren't rusting on the shelves without being coated with oil.

The order of testing in all the videos is Craftsman -> Koken -> Snap-On. I tried to face the stampings on the sockets towards the camera so you can see movement. All videos are in 1080p, so you should probably watch them in that resolution instead of the default 360p.

10mm bolt head - Koken won. I found a 10mm bolt that was very snug fitting for both the SO and the Koken, and it had nearly 0 play with the Koken socket. There's was just a hair's play with SO, so it's a close second. Craftsman had the most play.

Video: Link

12mm bolt head - Koken won. Almost no play. SO and CM were about even.

Video: Link

14mm bolt head - Koken won, but not by a huge margin. All 3 had similar play.

Video: Link

17mm bolt head - Koken won...clearly. Because this was a loose fastener I was able to mark how much play there was (turn bolt to the right, mark it, turn to the left, mark it). The SO socket had more play than the CM socket! (*this is a newer laser engraved made in USA CM socket). Koken socket had barely markable play.

Conclusion:

Cutting straight to the point - Koken Z-eal won over Snap-On in this informal test on a few nuts and bolts. Snap-On comes in second place. CM comes in third. I'd like to test how well Koken's regular non-Z-eal sockets do. I will say that aside from the oil coating, the SO sockets are the nicest looking. Polished to a mirror finish, and the reliefs in the socket end for fastener corners are well defined semi-circles. The Koken sockets look like they get left with a slightly rougher finish and coated with hard chrome.

General Geoff · Jan 20, 2015

Out of all the various brands of sockets I own, Ko-ken are indeed the tightest fitting. They truly are top notch.

Just wait till you try their Wobble+ extensions!

Mohawk Dave · Jan 20, 2015

Only thing I can say is: snug doesn't necessarily mean better.

Off corner engagement will be strip less than corner engagement. Not saying the Kokens are corner engagement.

Also, if you look at Snap on Spline drive, they have more play than a regular 6pt flank drive, but grab further back on the flat, thus making them even less likely to strip. (and you don't get that nut or bolt stuck in the socket which we all hate.)

General Geoff · Jan 20, 2015

Mohawk Dave said:
Only thing I can say is: snug doesn't necessarily mean better.

It does when you're dealing with fasteners which are so tight that they deform under breaking torque. The more snug the socket, the less they are able to deform. Particularly important with aluminum, lead or brass fasteners, as well as fasteners which are literally flaking apart from rust.

dede2897234 · Jan 20, 2015

AnonymousToolGuy,

Thanks for this informative post! The videos were great! :thumbup:

I own a regular Ko-ken mid-depth, metric, 3/8" drive socket set. Like "General Geoff" mentioned above, the high tolerances associated with the socket design allowed the loosening last spring of all 4-8mm brake bleeder valves after 100,000 miles have accumulated between brake fluid changes on my 2003 Subaru Forester.

In the next couple years, I plan on purchasing Ko-ken Z-eal sockets to add to my collection.

Dave

AnonymousToolGuy · Jan 20, 2015

Mohawk Dave said:
Only thing I can say is: snug doesn't necessarily mean better.

Off corner engagement will be strip less than corner engagement. Not saying the Kokens are corner engagement.

Also, if you look at Snap on Spline drive, they have more play than a regular 6pt flank drive, but grab further back on the flat, thus making them even less likely to strip. (and you don't get that nut or bolt stuck in the socket which we all hate.)

I understand. The Koken sockets do have radius corners, and my main concern with the CM sockets was that they're so loose that when being torqued the "corners" of the socket that make contact with the fastener were gouging it. On my oil drain bolt I'm starting to get worried It's going to get rounded off because of how "abused" it looks (thus why I have another 17mm drain bolt on hand

) On other bolts I frown a bit when I see vertical lines where the sockets made contact. I like leaving things better than when I started working on them.

Looking at the end of the Koken socket, the catalog doesn't lie. The real thing looks exactly like the diagram does.

The SO sockets have a much more pronounced cutout for fastener corners.

EDIT: Actual pic (SO on right):

T45 · Jan 20, 2015

If you have complete sets would be inetersting to see the results accross the board.

T45 · Jan 20, 2015

The axial slop is also more important than the radia slop

Mohawk Dave · Jan 20, 2015

I agree with all these posts. I see how my earlier post may come across as saying "snug don't mean shiola". Didn't mean it that way.

We all know Koken is a master at socketry. (<-is that a word?) Anyways, like mentioned, a snug fitting ****** socket will round a fastener while a snug fitting quality socket, with cut out corners, will work the right way.

There's some back-peddalling for ya! lol.

T45 · Jan 20, 2015

The thread where the fasteners were coated in blue ink was a good one to reference

maybe someone can post it up, had alot of brands and showed precisely the engagements

AnonymousToolGuy · Jan 20, 2015

T45 said:
The axial slop is also more important than the radia slop

And in words you would use with a child this means?

TheRobotCow · Jan 20, 2015

Thanks for the post! I've been looking for a great quality Japanese tool brand. And I could use more sockets lol.

Sent from my iPhone using Tapatalk

AnonymousToolGuy · Jan 20, 2015

T45 said:
If you have complete sets would be inetersting to see the results accross the board.

All the sets I have 8-19mm. I have the Z-eal ones in both standard and deep, although standard is a bit of a misnomer since it's more like "low profile" and they won't fit over studs with nuts on them. The 14mm strut mounting bolt they weren't making complete engagement because the nut is extra-tall.

I'm game if someone wants to mail me a bag of metric bolts

I'm limited to what I could find poking around in my engine bay. Honda tends to use 10,12, and some 14 in most places. There's bigger stuff in the brake assembly and chassis assembly, but they're immediately accessible.

T45 · Jan 21, 2015

AnonymousToolGuy said:
And in words you would use with a child this means?

The slop you get when you rock the square-drive end back and forth (horizontally)

In picture terms \\ -> // vs ||

so in other words the socket is not fully squared up on on the fastener

AnonymousToolGuy · Jan 21, 2015

T45 said:
The slop you get when you rock the square-drive end back and forth (horizontally)

In picture terms \\ -> // vs ||

so in other words the socket is not fully squared up on on the fastener

OK I did this test as well. I moved the sockets around as though they were mini joysticks, and the SO 10 and 14mm had a lot more play in this direction as well. The Koken sockets seemed to mostly maintain full contact with the nut head, but the SO ones I could feel slipping off and exposing some of the head of the nut.

XxToolAholicxX · Jan 21, 2015

Oh man now I am tempted to add KoKen sockets to my collection. I might need them to work on my wife's Toyota. Good excuse. Now where can I buy these at a fair price?
---------------------------------------------------------------------------------------------------------------
I am a Toolaholic,Sometimes I regret it,Especially when the Toolman wont give me no credit

AnonymousToolGuy · Jan 21, 2015

XxToolAholicxX said:
Oh man now I am tempted to add KoKen sockets to my collection. I might need them to work on my wife's Toyota. Good excuse. Now where can I buy these at a fair price?

That's the tricky part. You basically have to get them direct from Japan, but shipping isn't outrageous. LevelChrome and FranksTools are supposedly US distributors, but I bought my shallow set from FT and he shipped from Japan so it was a waste of money buying from him. The deep set I bought through Rakuten from a seller called i-Tools. They seem to stock a huge amount of the Koken catalog. You search by the model number you're looking for. It's a bit interesting getting emails in half-Japanese, but Google Translate has it covered.

Don't give Rakuten a real credit card number - they've had issues with security. They ask for one even if you use Paypal to pay the merchant, so use a temporary credit card number if possible. I ended up paying i-Tools directly with a Paypal payment once they quoted me how much shipping would be (about $20).

Total I paid for the deep socket 8-19mm set was 14391 yen (incl. shipping), which is about $122 in current exchange rates. EDIT: Here's the exact listing I bought from: http://global.rakuten.com/en/store/i-tools/item/4991644219445/ (ignore the pic of 8 sockets. Z/12 means it's the 12 socket rail)

nicksnothereman · Jan 21, 2015

I would assume most import will win in metric fitment anyway. Japanese like koken? Forget about it, those guys don't mess around with tolerances. Problem is that I don't think koken is much if any cheaper than snap on and warranty would be an issue. Still dependable stuff...snap on ain't the only dependable brand in the world. I do wonder what most of the Japanese mechanics use in Japan though...they got some magicians there for sure. I knew a Japanese mechanic in Queens who was also a master magician and he used the junkiest **** imaginable...crappier than my stuff. The reputation he had didn't lie, true ninja with a ratchet. Also not a wrench guy. Hehehe.

n8n · Jan 21, 2015

This is what I get for reading threads at 3 AM. (just got to sleep and the GF's damned dog started going ******* for reasons unknown.) I originally read the thread title as "smugness comparison" and thought this was going a whole different direction...

ADSR · Jan 21, 2015

man those sockets are tight!

Adam.C · Jan 21, 2015

Play between the head and the socket is not a good indicator of socket effectiveness.

1) All sockets have zero play in use. They free rotate (play) until contact is made. A socket that does this will be easier to fit than a tighter fitting tool. We could argue that the looser fitting sockets are better because they are easier to install and remove. The problem with sloppy sockets is that they often contact the corner of the fastener which can round it off.

2) What is most important to the successful use of the socket is the exact location of the contact point between the socket and the bolt head.

View media item 47436The red arrows indicate the location of the normal force that helps rotate the fastener. For any given torque applied or (as in the picture) torque required to break the fastener loose, the closer to the corner the force is applied, the greater the mechanical advantage and the lower the force required is.

Lower contact force means less wear to fastener and socket. Keep in mind that this same force is reacted by the thin socket wall. If this force is small, the sockets can be thinner.

Obviously, contact too near the corner, can result in rounding the fastener off. Slop between the socket and the fastener was therefore more critical before Snap On's patented "flank drive" design. Flank drive sockets featured underr cuts (material removed) from the corners of the hex shape. This resulted in "off corner engagement" of the fastener-i.e. the relief cut prevented contact at the corner of the fastener.

The picture below shows (un-quantitatively) how the internal shape of the socket can affect the location of the contact location.

View media item 47437In this case, the tight fit of the Koken socket (left) could be detrimental to its ability to drive contact close to the corner of the fastener. The Snap On (right) clearly shows a sharpish corner adjacent to the corner relief. Tho we can't tell for sure from this picture, the tightness of the fit of the Koken, combined with this shape, probably indicate a closer-to-center contact location.

The resulting higher load may be the reason why the Koken appears larger (outer diameter) than the Snap On. Also note the rougher surface of the Koken. Roughed metallic surfaces generally result in weaker objects (shot peening excepted).

3) Other aspects of a high quality socket include high strength and highly wear resistant material. The latter helps react the friction between the socket and the fastener.

View media item 47438
Friction is a bigger issue for open end wrenches and likely the reason for Snap On's sharp fins inside their Flank Drive Plus wrenches.

Conclusion:
As a serious shade tree mechanic, I worked for 30 years with plain-jane craftsman sockets and broke only a few in that time. But socket failure is not a good indicator of the quality of the socket. A better indicator may be how often they round or slip off bolt heads.

Having tight fitting sockets may be alright for assembly work, provided they don't scratch off the finish putting them on. Otherwise, I see no particular benefit of a slop-free socket and several possible disadvantages. Chiefly, fitting them to dirty fasteners.

Contact location IS a good way to predict whether a socket will remove bolts without rounding or slipping off. But contact location alone is not enough. A combination of material, heat treatment, surface finish, design, and general manufacturing quality together will differentiate a good sockets from bad sockets. That's difficult for us to do here.

I am happy to consider some amount of anecdotal evidence (from pro mechanics who have used several different manufacturers' sockets) to help me choose quality tools. Based on this, I have no question about the excellent quality of Koken sockets. But I do not believe the tightness of their fit is a suitable indicator of socket effectiveness.

JDSV · Jan 21, 2015

Great review! I love my Koken Zeal sockets as well. Granted I paid a little bit more buying in country.

nicksnothereman said:
...Problem is that I don't think koken is much if any cheaper than snap on and warranty would be an issue. Still dependable stuff...snap on ain't the only dependable brand in the world.

If you buy the way the OP did the Koken sockets are much cheaper than SO, unless you are always using the student discount or your driver is always giving you at least 50% off, then Koken is only a bit cheaper. A 12 piece 3/8 deep SO socket set online is about $269. But I understand people may get discounts from their driver, or buy used from ebay and other such means.

Now in a professional environment I would go SO just for the warranty. I've never warrantied a Koken socket yet but I imagine it would be a pain as I would most likely have to mail it back to Japan. I would have to mail back a 10MM Anex nutdriver I have, but instead I am just going to bring it with me when I go back to Japan this Spring and warranty it then. Talking with Anex they are totally alright with me doing it that way.

nicksnothereman said:
I do wonder what most of the Japanese mechanics use in Japan though...they got some magicians there for sure. I knew a Japanese mechanic in Queens who was also a master magician and he used the junkiest **** imaginable...crappier than my stuff. The reputation he had didn't lie, true ninja with a ratchet. Also not a wrench guy. Hehehe.

My wife has a good friend whose brother is a mechanic in Hamamatsu and I asked her to ask her friend what her brother uses. He uses mostly KTC. In a Factory Gear magazine I bought last year they had an article interviewing some mechanics and asked them all their preferred brand of tool. Many had KTC, but some also had Nepros, Hazet, and many had Snap-on! And of course a few also had Deen which is Factory Gear's house brand.

bonneyman · Jan 21, 2015

Dang those Koken's are something! :rocker:

There was a 13mm socket test a while back, where the guy tested contact width and placement with a ton of different brands of sockets. IIRC, the Koken's came out #1 in that test.

M1TCH · Jan 21, 2015

Here in the UK we have an outlet called Halfords they have there own brand called pro series i have a full set of metric deep reach sockets and a torque wrench, at first glance they look like Snap-on except for the name etching but do have a life time Guarantee (which is only good as long as the company dont go bump) now i love my Snap-on been collecting it for 30 odd years but the Halfords stuff in my mind is as good but a third of the price, ive only been on here a few weeks and im amazed at the choices you have over there to here from tools to storage boxes to flooring very envious + the price you pay for stuff we get ripped off over here anyway thought i would chip in thanks for a great forum Gray. :rocker:

AnonymousToolGuy · Jan 21, 2015

Adam.C said:
Play between the head and the socket is not a good indicator of socket effectiveness.

1) All sockets have zero play in use. They free rotate (play) until contact is made. A socket that does this will be easier to fit than a tighter fitting tool. We could argue that the looser fitting sockets are better because they are easier to install and remove. The problem with sloppy sockets is that they often contact the corner of the fastener which can round it off.

2) What is most important to the successful use of the socket is the exact location of the contact point between the socket and the bolt head.

View media item 47436The red arrows indicate the location of the normal force that helps rotate the fastener. For any given torque applied or (as in the picture) torque required to break the fastener loose, the closer to the corner the force is applied, the greater the mechanical advantage and the lower the force required is.

Lower contact force means less wear to fastener and socket. Keep in mind that this same force is reacted by the thin socket wall. If this force is small, the sockets can be thinner.

Obviously, contact too near the corner, can result in rounding the fastener off. Slop between the socket and the fastener was therefore more critical before Snap On's patented "flank drive" design. Flank drive sockets featured underr cuts (material removed) from the corners of the hex shape. This resulted in "off corner engagement" of the fastener-i.e. the relief cut prevented contact at the corner of the fastener.

The picture below shows (un-quantitatively) how the internal shape of the socket can affect the location of the contact location.

View media item 47437In this case, the tight fit of the Koken socket (left) could be detrimental to its ability to drive contact close to the corner of the fastener. The Snap On (right) clearly shows a sharpish corner adjacent to the corner relief. Tho we can't tell for sure from this picture, the tightness of the fit of the Koken, combined with this shape, probably indicate a closer-to-center contact location.

The resulting higher load may be the reason why the Koken appears larger (outer diameter) than the Snap On. Also note the rougher surface of the Koken. Roughed metallic surfaces generally result in weaker objects (shot peening excepted).

3) Other aspects of a high quality socket include high strength and highly wear resistant material. The latter helps react the friction between the socket and the fastener.

View media item 47438
Friction is a bigger issue for open end wrenches and likely the reason for Snap On's sharp fins inside their Flank Drive Plus wrenches.

Conclusion:
As a serious shade tree mechanic, I worked for 30 years with plain-jane craftsman sockets and broke only a few in that time. But socket failure is not a good indicator of the quality of the socket. A better indicator may be how often they round or slip off bolt heads.

Having tight fitting sockets may be alright for assembly work, provided they don't scratch off the finish putting them on. Otherwise, I see no particular benefit of a slop-free socket and several possible disadvantages. Chiefly, fitting them to dirty fasteners.

Contact location IS a good way to predict whether a socket will remove bolts without rounding or slipping off. But contact location alone is not enough. A combination of material, heat treatment, surface finish, design, and general manufacturing quality together will differentiate a good sockets from bad sockets. That's difficult for us to do here.

I am happy to consider some amount of anecdotal evidence (from pro mechanics who have used several different manufacturers' sockets) to help me choose quality tools. Based on this, I have no question about the excellent quality of Koken sockets. But I do not believe the tightness of their fit is a suitable indicator of socket effectiveness.

You raise several excellent points. Particularly I agree that for dirty / rusty / grimy fasteners, really tight sockets can be a problem. Some additional points:

The Koken literature indicates that their sockets are meant to create a flat-surface contact patch between the socket and the fastener. What you'll notice from the diagram and picture of their sockets, they're not hexagonal with flat sides that are parallel to the opposite side (as it is with the SO sockets). Rather they're roughly hexagonal with radiused flats. This design, on its face (no pun), would become a flat surface when the torque is applied against a fastener head. Compared to the SO design where torque can only be applied in a vertical-line contact patch, which can dig into the corner area of a fastener.

Here's a exaggerated + simplified diagram of this. Simple shapes and only considering a single edge of the socket. The top would be the Koken method, the botton would be the SO method. The right side is if torque is applied and the socket rotates:

Also on tolerance, as you say in your first point a sloppy socket is going to round fasteners easier. This is because the effective diameter of the socket becomes greater.

Tolerance and consistency between the manufacturing process of sockets is also important. The best designs in the world are worthless if they can't be manufactured as drawn. So Koken for example, might have a great "radiused flats" design that applies a surface of torque instead of a line of torque to the fastener head, but if their tolerances are all over the place between different sockets that are supposed to be the same then the "good design" becomes a liability. The SO design seems like it would be less sensitive to manufacturing variations - as long as the socket isn't grossly oversized, the line of contact between the socket and the fastener just moves around a bit - either further away or towards the corners of the fastener.

Hopefully all this makes sense.

Adam.C · Jan 21, 2015

AnonymousToolGuy said:
The Koken literature indicates that their sockets are meant to create a flat-surface contact patch between the socket and the fastener.

A rounded surface can never touch a flat surface and result in a flat surface contact patch. But I believe this is exactly what happens. The reaction force inside these sockets may get fairly high and elastic yielding may take place. Keep in mind, that even if the force isn't super high, line contact would result in a very low contact area (A) in the compression stress equation s=P/A. So for very small contact patches, the contact stress (s) could be astoundingly high. (P=the force or "load").

AnonymousToolGuy said:
Tolerance and consistency between the manufacturing process of sockets is also important. The best designs in the world are worthless if they can't be manufactured as drawn.

The SO design seems like it would be less sensitive to manufacturing variations - as long as the socket isn't grossly oversized, the line of contact between the socket and the fastener just moves around a bit - either further away or towards the corners of the fastener.

I suspect both Koken and Snap On are using some form of broach or stamping die that produces fairly consistent sockets. The problem is the bolt head. The current Japanese std, which reflects all the other stds, permits bolt head dimensions to vary. An M6 bolt with a 10mm head can vary (IIRC don't have the std in front of me) 9.8-10mm. That's a pretty big variation.

I carry no water for the Snap On corporation. But I think their design is advantageous. It is designed to hit in roughly the same location regardless of the size of the bolt head. The stress the bolt head sees is likely high due to the small contact patch but the load will be smaller. This means less friction which can wear the sockets contact areas.

The Koken design, with that long radius likely won't touch near the corner for full sized fastener heads. This produces more load on the socket (requiring thicker socket or possibly leading to failures sooner), and more friction. But the contact pressure will be lower and will be less likely to damage fastener finishes.

Conclusion- It might make sense to choose the Snap On design for general vehicle maintenance. The design is permissive of variation in the fastener head and I suspect the sockets will remain in good shape for a long time. But they may damage the finish on high torque bolts.

For initial assembly, the lower contact pressure of the Koken sockets may preserve fastener finishes.

All said, the differences I see may be "in the noise" for 99% of GJ readers. As always, buy what you want, buy whosever snake oil sales pitch touches your heart. Just please keep in mind my perspective: If you are working on your daily driver, life is too short to use cheap sockets. One failure can cost you way more than a brand new set from a truck. DAMHIKT!

AnonymousToolGuy · Jan 21, 2015

Adam.C said:
A rounded surface can never touch a flat surface and result in a flat surface contact patch. But I believe this is exactly what happens. The reaction force inside these sockets may get fairly high and elastic yielding may take place. Keep in mind, that even if the force isn't super high, line contact would result in a very low contact area (A) in the compression stress equation s=P/A. So for very small contact patches, the contact stress (s) could be astoundingly high. (P=the force or "load").

I suspect both Koken and Snap On are using some form of broach or stamping die that produces fairly consistent sockets. The problem is the bolt head. The current Japanese std, which reflects all the other stds, permits bolt head dimensions to vary. An M6 bolt with a 10mm head can vary (IIRC don't have the std in front of me) 9.8-10mm. That's a pretty big variation.

I carry no water for the Snap On corporation. But I think their design is advantageous. It is designed to hit in roughly the same location regardless of the size of the bolt head. The stress the bolt head sees is likely high due to the small contact patch but the load will be smaller. This means less friction which can wear the sockets contact areas.

The Koken design, with that long radius likely won't touch near the corner for full sized fastener heads. This produces more load on the socket (requiring thicker socket or possibly leading to failures sooner), and more friction. But the contact pressure will be lower and will be less likely to damage fastener finishes.

Conclusion- It might make sense to choose the Snap On design for general vehicle maintenance. The design is permissive of variation in the fastener head and I suspect the sockets will remain in good shape for a long time. But they may damage the finish on high torque bolts.

For initial assembly, the lower contact pressure of the Koken sockets may preserve fastener finishes.

All said, the differences I see may be "in the noise" for 99% of GJ readers. As always, buy what you want, buy whosever snake oil sales pitch touches your heart. Just please keep in mind my perspective: If you are working on your daily driver, life is too short to use cheap sockets. One failure can cost you way more than a brand new set from a truck. DAMHIKT!

I agree with everything here. My OP wasn't meant to be a condemnation that Koken is better than SO, just that one is snugger than the other. People can make a determination how that jives with what they want in a socket. Some people are all about the chrome

I also remembered another issue I've had with loose CM sockets - when using a deep socket on some fasteners, the loose sockets have a tendency to "unsquare" themselves so I end up applying torque with the socket 80 degrees (for ex) from the fastener head instead of the ideal 90 degrees. I think this was also cause for a lot of gouging in fastener heads because my torque is being applied more to a few edges of the fastener than all of them equally. Snugness in theory should keep sockets seated better (although I'm sure there's other socket design considerations that can help sockets seat better too)

EDIT: And also to expand on your conclusion about low pressure / high contact surface area being better for assembly work where you don't want to damage fastener heads, I think it'd also be helpful for bolts that are repetitively being taken off and put back on as well. My oil drain bolt, for ex, is looking pretty trashy because I change my oil so frequently.

ncfh · Jan 21, 2015

These do look nice for initial assembly/production. Just what I need.

Thanks guys!

Now to find a low hassle supplier...

AnonymousToolGuy · Jan 21, 2015

ncfh said:
These do look nice for initial assembly/production. Just what I need.

Thanks guys!

Now to find a low hassle supplier...

Lowest hassle is one of the "english" sellers that koken lists on their website. But you're paying a premium, and in my case the only advantage was I didn't have to deal with a bit of japanese text and waiting to get an international shipping quote. I'm going to start ordering "accessories" like extensions, and I'm for sure going to be going to Rakuten to get them.

abvw · Jan 21, 2015

My observation:

North American tools seem to have looser tolerances, to accommodate the rust (and ****** grade 5 and 8 fasteners) we have to deal with. The worst offender is Allen screws, when will these brainless North American engineers start using Torx and e-Torx in their designs?

The free wrenches found in the trunks of Euro and Japanese vehicle fits fasteners more snugly, maybe because they don't see rust like this:

Whatever the European are doing with their nuts and bolts, they're doing it right!

Koken Zeal Sockets v. Snap-on Sockets: A snugness comparison

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