CNC tight fit sockets idea

[noid]

I've been considering CNC machining 'tight fit' 6 point sockets in the more common sizes to bridge the tolerance gap found between the socket and bolt ISO standards.

I consider material displacement to be the major factors behind why bolts strip. This is particularly evident when comparing 6 point to 12 points wrenches/sockets.

Notice the open space between the bolt on the 12 point; as the bolt rounds, it 'mushes' into those voids. If the bolt has nowhere to displace, its much less likely to round; and that's why 6 point > 12 point on rusted or questionable bolts.



The torque test channel actually ran a comparison here validating:

For an average 13mm socket, between the two ISO tolerances, there is a minimum of 0.04mm and a maximum of 0.57mm between bolt and socket.

In practice this falls somewhere in the middle; most bolts average ~12.92mm and most sockets will measure ~13.18mm; a ~0.26mm gap.

Flank drive is a mitigation to this gap because with an excess gap the first thing that interact are the corners. If the fit was exceptional, the void made by rounding the corner is best eliminated.

Another problem is that the bevel on the edge of the socket that aids in quicker socket to bolt mounting loses 36% of the engagement (approx. 1.8mm of the 5mm height of the bolt head).

All to say these sockets would not be for daily use; because their tight fit, and lack of bevel would require extra fiddling to mount.

Where it would be useful is on those very questionable bolts that are likely to round or are corroded heavily (rust belt).

Thinking about making two levels; eg. 13mm +0 - 0.02mm and another that is 12.9 + 0.02mm - 0 to get the tightest fit possible.


Sockets: ISO 691:2005



Bolts: ISO 4759

 

[Xcursion88]

Snap-on Store

shop.snapon.com

I believe this is what you're talking about. You don't use these every day as they're a real ***** to remove from the fastener

 

[JradM]

Interesting idea. My presumption is that flank drive and spline socket designs are alternate ways to skin the same cat. E.g. rather than make the sockets tighter and risk having them not fit some fasteners, these designs promote off-corner engagement to avoid rounding.

A really super-tight socket seems like it would achieve the same goal. Although it would engage on the corners first as things start to round, conceptually that would be mitigated by the small amount of movement before the flats make contact further away from the corner.

That is assuming you will machine flat six-point sockets matching the profile of bolts rather than making a tighter-fitting version of a modern socket design.

Maybe you could make an impact cap for the sockets too? I.e. like a ratchet spinner but just flat across the top (i.e. no female square recess).



Since you'd be designing them for your very precise sockets, you could make the impact cap fit tightly. Then use it when you want to pound the socket onto a bolt.

I thought something like that might prove necessary because the times when you most want a tight-fit socket include rusty bolts that may have swollen slightly and have a softer rust covering.

 

[noid]

Snap-on Store

shop.snapon.com

I believe this is what you're talking about. You don't use these every day as they're a real ***** to remove from the fastener

Not really; the extra flank just makes the flats convex. This design still leaves substantial gaps for bolt material displacement.

Interesting idea. My presumption is that flank drive and spline socket designs are alternate ways to skin the same cat. E.g. rather than make the sockets tighter and risk having them not fit some fasteners, these designs promote off-corner engagement to avoid rounding.

You're exactly right, its about compromise. The ISO standards ensure that the socket is a one size fits all; and with that companies have to work to mitigate (imperfectly) the consequences of 'one size fits all'.

A really super-tight socket seems like it would achieve the same goal. Although it would engage on the corners first as things start to round, conceptually that would be mitigated by the small amount of movement before the flats make contact further away from the corner.

If there is no gap between the socket and bolt head; where would the material displace (strip)?

Any corner relief would add unwanted voids. They are 100% necessary when we are talking about looser fitting sockets, but when the fit is tight, its a detriment.

That is assuming you will machine flat six-point sockets matching the profile of bolts rather than making a tighter-fitting version of a modern socket design.

Exactly right.

Maybe you could make an impact cap for the sockets too? I.e. like a ratchet spinner but just flat across the top (i.e. no female square recess).

Since you'd be designing them for your very precise sockets, you could make the impact cap fit tightly. Then use it when you want to pound the socket onto a bolt.

I thought something like that might prove necessary because the times when you most want a tight-fit socket include rusty bolts that may have swollen slightly and have a softer rust covering.

Could you expand on this further?

Why not pound directly on the socket or use an extension?

 

[dnschmidt]

Unless you live where I do, in the Desert Southwest, this idea is a dead end street. As many know I shipped a lot of TOPTUL wrenches to Eric O. up in Avoca, NY which apparently is the salt capitol of the United States. TOPTUL has very tight tolerances on their wrenches with respect to fit on fasteners. Eric's only complaint with the TOPTUL wrenches was that they didn't fit the swollen rusty nuts that he deals with on a daily basis. So, short form answer: You can't win.

 

[vjquan]

It's ridiculous that a wrench has a slight oversize tolerance and a fastener has an undersize tolerance. In my mind, a wrench should be dead on accurate and exact and let the slop be in the fastener alone.

 

[JradM]

if there is no gap between the socket and bolt head; where would the material displace (strip)?

I'm imagining there must be some gap - just a really really small one. When the gap is taken up, it's the corners that would touch first.

However, if the socket is very tight-fitting, it might well be that the slight elasticity of the metal would allow the flats of the fastener to make contact with the walls of the socket long before any damage could occur to the corners.

E.g. to use your numbers, if a ~0.26mm gap is too large and sockets work better with the off-corner relief cuts at that point, how small does the gap need to be before a tight-fitting socket works better?

I bet an engineer could calculate a pretty good estimate depending on the fastener and socket material, size and engagement (though I wonder if given the variability of fastener material, size and condition, how useful the answer would be versus testing).

If most bolts are 12.92mm and you plan to make a socket 13mm to 13.02mm, the gap is 0.08mm to 0.1mm. That's tiny, so I can totally accept that it would work just as you say. The corners might contact first as the socket turns, but the corners likely have a tiny amount of flex and the sides of the socket would make contact before damage could occur.

This might all be moot in real-world use anyway. E.g. if you're pounding the socket on, then some material is likely being displaced to fill up the 0.08-0.1mmm gap.

 

[JradM]

Could you expand on this further?

Why not pound directly on the socket or use an extension?

You totally could pound on the socket directly. I just figured that if you spent a bunch of time and money making these very precise sockets, you might not want to risk marring the top with hammer strikes. An extension would work too.

If you made an impact cap yourself, you could also ensure the drive square and top cap both make contact with the socket at the same time - spreading the impact load on the socket compared to using and extension that only contacts the middle. It might not matter of course - depends how hard you're hitting!

You also wouldn't want a ball detent in the impact cap because removing the cap from the socket might pull it off the fastener somewhat.

None of that is something you need - but you're the one making low-tolerance sockets from scratch!

As much as your design would benefit damaged, rusty and stuck fasteners, it might be useful when you're working on new stuff too. E.g. did you see the thread where the fellow wanted sockets that wouldn't damage the fasteners on the motorcycle being restored for a museum? I imagine very tight tolerance sockets would be just the thing for that application.

 

[Xcursion88]

I am right smack in the middle of the rust belt and let me tell yeah...
It's very easy to put the wrong size tool on the fastener. Standard practice has become shooting fastener with air ti rid loose scale and road debris... and even then there are times we also need to wire wheel them.

You can easily put the one up sized fastener on by accident, hit it with the Impact gun and let me tell ya.....
The hot feeling that comes over you as you watch the socket turn right around the fastener while it stays put. I don't recommend such feelings unless your life is boring.


That said your idea might be great and may work well in Florida or Arizona...etc. i.e. no rust areas.
But around here too tight is a real thing.
Those flank drive extra sockets are not for everyday use. They are way too tight as you have to **** around removing the fastener afterward...(even in no rust areas)
Those are more for distorted fasteners than anything else.

I appreciate your motivation for innovation but in a professional environment time is money and if we have to piss around removing a fastener we just removed from said motorcar...that's not good.

See the problem I see is this...You're making a tighter spec socket and you will have great tolerances I'm sure but....
We deal with fasteners that all have differing tolerances....yet all fall within an acceptable engineering standard. In other words you will be making a socket to fit an 18mm as example but the range of 18mm fasteners has an acceptable window of tolerances yet all conventional 18mm tools fit that (provided it's not insanely rusty like we deal with)

That said I think some fasteners your isea will work great but others not so much. Then you have to beat it out (time away from making money)

 

[JradM]

See the problem I see is this...You're making a tighter spec socket and you will have great tolerances I'm sure but....
We deal with fasteners that all have differing tolerances....yet all fall within an acceptable engineering standard. In other words you will be making a socket to fit an 18mm as example but the range of 18mm fasteners has an acceptable window of tolerances yet all conventional 18mm tools fit that (provided it's not insanely rusty like we deal with)

That said I think some fasteners your isea will work great but others not so much. Then you have to beat it out (time away from making money)

I don't think that undermines the utility of the OP's idea. These tight-fit sockets wouldn't be the best choice for some fasteners, but might still be useful for others.

It would be handy to have a quick way to remove bolts stuck in sockets though... That comes up even with regular sockets. I usually just spread my vise jaws to line up with the edge of the socket and then knock a pin punch through the center. If there was a tool for use out-in-the-field, that would be handy.

Maybe if the sockets are all the same height, you could design/find an appropriately-sized non-adjustable puller with a pin matching the drive size?

Please accept this miserable drawing I made in Paint as an illustration:

 

[Cruzan80]

Not sure rusty/swollen/rounded sockets are the best idea for tight tolerances...

Unless ypu make 2-3 for each size in steps of .1"

 

[Xcursion88]

I don't think that undermines the utility of the OP's idea. These tight-fit sockets wouldn't be the best choice for some fasteners, but might still be useful for others.

It would be handy to have a quick way to remove bolts stuck in sockets though... That comes up even with regular sockets. I usually just spread my vise jaws to line up with the edge of the socket and then knock a pin punch through the center. If there was a tool for use out-in-the-field, that would be handy.

Maybe if the sockets are all the same height, you could design/find an appropriately-sized non-adjustable puller with a pin matching the drive size?

Please accept this miserable drawing I made in Paint as an illustration:

But that's just it...

And while the world can always use more than one mfg...

Snap On FD "xtra" are made with what the OP has in mind.

It's a much tighter fit on fasteners that are distorted. That's the company purpose of those....and not meant for daily use.

 

[RoninB4]

Interesting notion and not unworthy of making some for personal use, I've made many tools for similar reasons. For commercial purposes there are several considerations others have already posted. Further, what happens when you're approaching a fastener of unknown origin, is it SAE or metric? Some sizes (8mm or 5/16, 19mm or 3/4 come to mind) are within .002 of each other. There's even the less common but still used 5mm (.009 from 3/16) or 5.5mm (.002 from 7/32) that come up now and then. Sure it doesn't happen very often but I've worked on injection molds made in Canada that some goof repaired here in the US and replaced a metric with an SAE fastener.

I still think your notion is worthy of making a set for yourself, a few others might want one also. But as a full commercial venture I'd question the size of the market for these. There are also economic considerations about material, heat treating, finishing, etc. that can/will affect this. I routinely make special tools that nobody in their right mind would pay for the time/materials in them. Also curious how you intend to machine an internal hex unless you relieve the corners, broach, or use an electrode for conventional EDM. Show me what you got, I may even contact you for work I don't have the machines for. Good luck.

 

[Showkey]

It's ridiculous that a wrench has a slight oversize tolerance and a fastener has an undersize tolerance. In my mind, a wrench should be dead on accurate and exact and let the slop be in the fastener alone.

You can’t depend on manufacturer tolerances on just one side of the equation when two parts are involved. Then add that tolerances or +/-. (If they are not +/- that adds substantial cost)

Then add corrosion as mentioned in several posts.

 

[noid]

Unless you live where I do, in the Desert Southwest, this idea is a dead end street. As many know I shipped a lot of TOPTUL wrenches to Eric O. up in Avoca, NY which apparently is the salt capitol of the United States. TOPTUL has very tight tolerances on their wrenches with respect to fit on fasteners. Eric's only complaint with the TOPTUL wrenches was that they didn't fix the swollen rusty nuts that he deals with on a daily basis. So, short form answer: You can't win.

I can relate well to Eric O; I live within 3 hours of Avoca NY.

The TOPTUL just like every brand would be speced to the ISO standard with all the aforementioned tolerances.

However, if the socket is very tight-fitting, it might well be that the slight elasticity of the metal would allow the flats of the fastener to make contact with the walls of the socket long before any damage could occur to the corners.

If most bolts are 12.92mm and you plan to make a socket 13mm to 13.02mm, the gap is 0.08mm to 0.1mm. That's tiny, so I can totally accept that it would work just as you say. The corners might contact first as the socket turns, but the corners likely have a tiny amount of flex and the sides of the socket would make contact before damage could occur.

The plan would be to make two increments one socket thats 13 -0.02mm and another that is 12.9 +0.02mm, as some 13mm fasteners measure out sub 12.9mm (still considered within tolerance).

I am right smack in the middle of the rust belt and let me tell yeah...

Welcome fellow rust belter; where it takes but 1 bolt to make a 1hr job into a 4hr job.

Not sure rusty/swollen/rounded sockets are the best idea for tight tolerances...

Unless ypu make 2-3 for each size in steps of .1"

That's the idea; have 13, 12.9, etc.

But that's just it...

And while the world can always use more than one mfg...

Snap On FD "xtra" are made with what the OP has in mind.

It's a much tighter fit on fasteners that are distorted. That's the company purpose of those....and not meant for daily use.

But it really isn't because tighter fit =/= voidless.

At the extreme; you could make a 12 point fit exceptionally tight, but it would still be far more prone to stripping over a 6 point. Why? voids.

Interesting notion and not unworthy of making some for personal use, I've made many tools for similar reasons. For commercial purposes there are several considerations others have already posted. Further, what happens when you're approaching a fastener of unknown origin, is it SAE or metric? Some sizes (8mm or 5/16, 19mm or 3/4 come to mind) are within .002 of each other. There's even the less common but still used 5mm (.009 from 3/16) or 5.5mm (.002 from 7/32) that come up now and then. Sure it doesn't happen very often but I've worked on injection molds made in Canada that some goof repaired here in the US and replaced a metric with an SAE fastener.

For Metric or SAE I normally just reference the head bolt stamp. If its a number like 4.8, 8.8, 10.9 its metric, if its lines its SAE. When no stamps present, I break out the digital caliper.

I still think your notion is worthy of making a set for yourself, a few others might want one also. But as a full commercial venture I'd question the size of the market for these. There are also economic considerations about material, heat treating, finishing, etc. that can/will affect this. I routinely make special tools that nobody in their right mind would pay for the time/materials in them. Also curious how you intend to machine an internal hex unless you relieve the corners, broach, or use an electrode for conventional EDM. Show me what you got, I may even contact you for work I don't have the machines for. Good luck.

I'm at that stage now; trying to conclude if I should just make myself a set or make a run of 50 for those niche freaks like me. Going full commercial is a different proposition all together.

I just do the CAD/Drawing sheet; I'm fortunate to have access to facilities that run 5-axis, DMLS, you name it.

No conclusion yet on how the internal hex will be machined, broached or otherwise; given the capabilities, it should be no problem to solve.

Always happy to help if you have a need that exceeds your machines.

 

[vjquan]

You can’t depend on manufacturer tolerances on just one side of the equation when two parts are involved. Then add that tolerances or +/-. (If they are not +/- that adds substantial cost)

Then add corrosion as mentioned in several posts.

I've never seen a wrench with a - tolerance, smaller than its stated size, nor a fastener with a + tolerance and bigger than its stated hex size. If you do, you have a unicorn. I also don't think corrosion is a factor when it comes to defining said tolerances.

 

[noid]

I've never seen a wrench with a - tolerance, smaller than its stated size, nor a fastener with a + tolerance and bigger than its stated hex size. If you do, you have a unicorn. I also don't think corrosion is a factor when it comes to defining said tolerances.

Agreed.

Something doesn't come from nothing when it relates to corrosion; at best any additional material is either rust scale or a deeper form of oxide jacking. All to say, it can either be cleaned off, or it will collapse to its original (likely smaller) size as socket pressure increases.

Its underappreciated that nearly every brand makes their tools to the tolerances in the ISO standard. Tool truck brands, lesser name brands, etc all work to the same tolerance bounds. Anything outside of those ISO tolerances is (or should be) flagged as a QA problem during production.

 

[Showkey]

I've never seen a wrench with a - tolerance, smaller than its stated size, nor a fastener with a + tolerance and bigger than its stated hex size. If you do, you have a unicorn. I also don't think corrosion is a factor when it comes to defining said tolerances.

Need to get out more ……..southern Californium, I can understand your lack of experience with rust and corrosion causing fasteners to subst bigger or smaller than their orginal sizes.

Guess your not catching the concept that too tight of tolerances makes using the tool a PIA when fasteners must be extracted or driven from the tool.

The perfect example of fasteners changing size is the swollen capped lug nuts.

 

[545_days]

I guess with a tighter fitting socket I could break off the bolt head quicker...

 

[Buckgnarly]

If removing the faster from the socket AFTER you get it off is the biggest worry you have, that's first world problems. I sometimes wonder if people really understand what the rust belt is.

 

[Kscardsfan]

If the fastener is that bad, rusted, soft, damaged etc I just use whatever wrench fits best or cut the rotten SOB off entirely since I’m going to replace it. But the weird OCD streak I have in me really does appreciate and like your idea, I just can’t see it being super practical for most users outside of maybe specialized restoration shops etc.

 

[vjquan]

Need to get out more ……..southern Californium, I can understand your lack of experience with rust and corrosion causing fasteners to subst bigger or smaller than their orginal sizes.

Guess your not catching the concept that too tight of tolerances makes using the tool a PIA when fasteners must be extracted or driven from the tool.

The perfect example of fasteners changing size is the swollen capped lug nuts.

Like I said Wisconsian, tools are designed for the new fastener, not rust nor corrosion. I get that a perfect or too tight wrench is frustrating, but the slop seen with todays wrenches can be a lot better and still not be too tight to be unusable. If wrenches came with a measured spec, I'd choose the tightest one. Regarding capped lug nuts - that's what the **.5 sockets are for. Don't tell me, you want wrenches with +/- 0.5mm tolerance?

 

[matthew]

Filling in the corners on flank drive, even with a perfect fit, won’t be an improvement.

The tools are not perfectly rigid, and there is such a thing as a stress concentrations. The relief not only puts the force on a stronger part of the fastener, but it helps spread out the forces in the wrench, just like drilling a hole at the end of a crack may stop it from propagating. Don’t think about the fastener in static condition - think about how things start to stretch and flex when a large torque is applied. Even a box end wrench has some elastic deformation. Which is why sometimes when you round off a fastener, you’ll find it still doesn’t freely spin in the wrench you just used - the wrench has flexed back to its unloaded condition. 6 point tools don’t have as much flex in those areas when loaded.

 

[dnschmidt]

If removing the faster from the socket AFTER you get it off is the biggest worry you have, that's first world problems. I sometimes wonder if people really understand what the rust belt is.

I lived in Pittsburgh for 41 years. Yes, I know what the rust belt is. That's why I got the hell out of there and moved to Phoenix. It's hilarious to me when I watch YouTube videos from Eric O. Customer States What and several other northern channels. Between the rats nests, corroded wires and rusted bolts it seems that if these guys lived out here they would be penniless from lack of work as such things don’t exist here. The rattlesnakes eat the varmints and nothing rusts. It never snows and it hasn’t even rained in the last six months. The guys that clean up out here are the car painters as the sun eats the paint right off of the cars. That’s why you buy white or silver cars out here.

 

[Xcursion88]

This whole topic is about an item that is so specialized.....how often do you even need it.

I'm in the heart of the rust belt and corrosion takes it toll no doubt but there are many hacksaw artists in my business and they take just as much a toll on fasteners. They might call themselves mechanics..just not good ones. .
Lug nuts are a great example. Capped lugnuts absolutely mangled because someone was too lazy too use a properly sized socket. After a few loosening and tightenings that lugnut now looks like chewed bubble gum. Hence why I have 18.5mm, 19.5mm 21.5mm etc etc.

That's just an exanple of other oeople using "kinda close " tools instead of the proper one.


I use two things if the fasteners are in sorry shape. Matco no slip sockets.
If thats not a candidate then Mac twist sockets.
The Mac versions come with handy bolts to push the ignorant fastener out.

I might need those once a couple weeks.

I never use 12 point unless it's sonething I need a box end wrench on or 12 point fasteners.

6 point only and as long as I clean the fastener and make damn sure I'm using the proper size. No problems.

 

[ChevyEFI]

Before you go custom, try existing tooling.

22mm socket on a 7/8 bolt. (Or size mixes you can find that closely match your theoretically tighter fasteners.)

Does it work better to have a 22.053mm socket on a normal, undersized 7/8 bolt? Do your testing.

Does a true hex tool work better than a traditional 6 sided surface drive socket? In either case? I would say no.

Sometimes, when things are done one way after decades, questioning it is fun, but not necessarily beneficial in the end.

 

[tarbellb]

Have you checked specialty industries for these yet? Does aerospace or ??? already make a set

Also, what environment are you using these in?



I feel like there should be a flow chart for removing stubborn fasteners

 

[American Locomotive]

I don't think they round off because material is displacing. I think the material is displacing because the head has already failed in shear, due to high stress on the corners. Even if you stop the material from displacing - it can still shear. Think of how you can break the shear pins on a snowblower, or break the key on a piece of shaft-driven machinery. Nothing is getting displaced in those two circumstances - the material literally just shears and cuts.

All material is elastic, and the moment you start applying force to a perfectly fitted socket, it's going to distort. The faces are going to pull away from each other, and the corners are going to start engaging and carrying the marjority of the load. I'm pretty sure the only way you can have a precision-fit socket not have corner engagement, is to make it a literal press fit onto the bolt, which just isn't practical. This is why all of the tool manufacturers have gravitated towards the extreme "off-corner-engagement" designs, where they purposely make the tool avoid the corners all together. Even as the tool distorts under load, it doesn't get anywhere near the corners of the fastener.

Secondly, bolts in good condition don't have a problem. You can basically break any bolt with the right sized socket, 12 or 6 point, if it's in good condition. So that means you're left with rusty, bad condition bolts. The bolt heads will likely be asymmetric at that point, and the sizing will be so variable, you'd need like 10 variants of every "size" just to get something that fits. As mentioned earlier, unless it's a press fit, you're still going to have off-corner engagement and stress concentration in the corners.

Finally, how do you plan to machine these?

• You say you don't want any gaps in the corners, but the traditional way to machine an internal hex on a CNC with an endmill inherently results in large corner radii. Do you have a way to overcome this?
• You could rotary broach it to get sharp corners, but rotary broaches don't make geometrically correct hexes (by their nature), so there goes your really tight "gap-less" fit.
• You could maybe water jet/plasma cut/laser it, but you're going to have serious tolerance control issues.
• You can manually broach it with a press-through hex broach, but this is a very labor intensive and expensive proposition. I'm not sure you'd be able to acquire the different broaches in the different tolerances you'd need, either.
• Even if you did manage to machine it, are you still going to be able to hold tolerance after heat treat? You can't just machine a piece of 4140 and call it good - it'd be a terrible socket. You're going to need to heat treat it and get the hardness up. Dimensional accuracy suffers after heat treat unless you compensate before hand.

I personally think you could have something with "short chamfer" or "unchamfered" sockets, as I ran into an issue recently with a particularly shallow bolt head, and sockets with a particularly deep chamfer. But I think the "precision fit" socket is a non-starter.

 

[tarbellb]

All of this ^^^

I just didn't want to type it

Especially this
"Secondly, bolts in good condition don't have a problem. You can basically break any bolt with the right sized socket, 12 or 6 point, if it's in good condition. So that means you're left with rusty, bad condition bolts. The bolt heads will likely be asymmetric at that point, and the sizing will be so variable, you'd need like 10 variants of every "size" just to get something that fits. As mentioned earlier, unless it's a press fit, you're still going to have off-corner engagement and stress concentration in the corners."

 

[Zewnten]

"Turbo" sockets were invented for this problem as I understand your position Noid. Lots of room between the socket walls and bolt. Snap On offers(ed) extra tight fittings sockets but I seem to remember most people not finding them particularly useful.

 

[gigamel]

Maybe you already have some of these tools in your tool box?
1/2" (12.7mm) tools are between 12.80 - 12.95mm ANSI.
I have found 1/2" sockets and wrenches around 12.94mm and they give you a very tight and snug fit on almost all 13 mm bolts/nuts - the ones < 12.90mm never fit 13mm bolts.
I simply keep these "oversize" 1/2" tools together with my 13mm - the fit on regular 1/2" bolts is very sloppy so I only use them on 13mm anyways.
Same for "oversized" 14mm that gives you a snug fit on 9/16" bolts.

 

[dchawk81]

In my limited experience, if a normal 6 point won't do it I need bolt extractors.

Just bring back affordable 6 point wrenches. My Craftsman set is incomplete.

 

[PoorUB]

I have been bending wrenches for over 40 years and as long as you have a quality tool the rounding off heads of stuck bolt heads is pretty much a non-issue.
I have rounded heads with a Craftsman wrench, then grabbed a SnapOn and broke it loose. Pretty much why you don't see Craftsman in my shop.

 

[4 FN 27]

The plan would be to make two increments one socket thats 13 -0.02mm and another that is 12.9 +0.02mm, as some 13mm fasteners measure out sub 12.9mm (still considered within tolerance).

At what temp will you plan on doing the work? Coefficient of Thermal Expansion is going to come into play.

Secondary to that, wear will be an issue. In our QC Lab and throughout the Plant all tools have the be calibrated per our ISO Standard. Frequency of calibration is based on a number factors. Currently excluded list includes Mechanics Tools and anything tagged "For Reference Only".

Cool idea. A bit of overkill...and I am the master of overkill.

I like your research and math. If you do move forward with this project which I think would be cool you will need to consider what post manufacturing treatment, ie: Chrome/Black Oxide you want to use. You will need to plan accordingly and oversize your manufactured sizes by 2X the plating thickness and specify the the plating thickness to the Plating Company. You will need to do a bit more math based on what tolerance the Plater can hold.

I use to design side plates for Drive Rollers in Printers. We would Hot Upset Precision Pins on to the Plates. We had to make all the Pins under size so when they were nickel plated they would "grow" back into spec. We were dealing with +.001/-.000 on the OD. Groves for snap rings or stepped pins added a whole new set of issues.

 

[zendriver]

I have been bending wrenches for over 40 years and as long as you have a quality tool the rounding off heads of stuck bolt heads is pretty much a non-issue.
I have rounded heads with a Craftsman wrench, then grabbed a SnapOn and broke it loose. Pretty much why you don't see Craftsman in my shop.

Was the Snap On a 6 point and the Cman a 12?

Seems to be the usual config for both Mfgs, so it might be hard to point to "quality".

 

[bwringer]

I have a couple of compact motorcycle axle nut wrenches that are basically steel sheet (1/8" I think) with a hex cut in with a laser.

They fit VERY tightly, and you have to get the tool lined up exactly. You also have to make sure the axle nut hasn't been banged up by some monkey with pliers, and even clean up any dirt or the wrench won't go on.

In this use case, the added precision makes the tool harder to use, but I think it mainly prevents marring the nut (a thin wrench made from sheet that didn't fit closely would absolutely displace or round over part of each corner) and helps prevent side-loading the steel sheet, since you are forced to line it up straight.

Anyway, I think all this is a very interesting idea, and you'll need to make some and experiment with them a while to see what the best use cases are.



I think one fairly obvious use case is not really stuck or rusty fasteners, but the opposite; keeping the socket from marring the fasteners on valuable rare oddball machinery.

I could see some sort of custom machined precision socket service; maybe you're working on your beloved Hupmobile or whatever, and you don't want to chowder up the priceless, irreplaceable Hupolater frammis bolt or something. The custom socket service sends out a kit with modeling clay or whatever to get a precise impression, and a week later the owner gets a socket with a superb close fit that won't gouge up the soft prewar steel used to make the frammis bolt. In some cases, you'd probably need to mark the socket for orientation, since plenty of fasteners, especially on older machines, are not precisely symmetric, or they've been chowdered up in the past.

I've actually made "custom" sockets a few times for super-weird nuts and bolts (for example, pentagons) using JB Weld inside a sacrificial conventional socket. Apply mold release (wax or petroleum jelly, IIRC), squish a blob of mixed JB over the fastener, squish the socket on top, trim excess, clean out any excess from the square drive, and wait.

 

[PoorUB]

Was the Snap On a 6 point and the Cman a 12?

Seems to be the usual config for both Mfgs, so it might be hard to point to "quality".

Both 12 point.

Another thing, A buddy was in my shop working on his car. There was a bolt we wanted to remove and could not use a socket because of room. He had a Craftsman wrench and broke it while standing on the wrench trying to loosen the bolt, then he took my Craftsman and broke it. I dug out the SnapOn combination wrench and he stood on that wrench and bounced for what seemed like a minute or two and the bolt came loose.

 

[dchawk81]

Both 12 point.

My 6 point Craftsman are quite good. I wouldn't try any brand of 12 point on a sketchy fastener if I had a choice.

 

[dnschmidt]

I think you're thinking in reverse. Rusty **** expands so very well fitting sockets aren't the answer to that question. Where you will find more of a market is the OCD motorcycle crowd that would cry a river if their beloved Harley bolt loses some chrome.

 

[Jtels85]

The only bolt I’ve ever rounded was a 13mm oil drain plug on a 2013 Challenger SXT, using a 3/8” drive 13mm, 12 point Craftsman USA socket. The drain plug metal must have been soft, because I’ve never see anything like that before. Replaced it with a brand new OEM drain plug socket from Chrysler and used a 6 point going forward, no further issues.