How to Measure for 8pt Socket

[CHI_Tool&Die]

I’m trying to figure out what I am doing wrong. I have this square stock, for lack of a better term, that protrudes from the milling vises. It’s used to clamp/unclamp my work. I’ve been using the cheap wheel that came with it but I want to have something that allows me to apply better force. I’m trying to measure for an 8pt socket but what I’m measuring and what sockets fit are not adding up. I’m measuring across the two flats and getting a reading of ~.555 but the only sockets that want to fit are my 12pt 17mm and my 12pt 11/16”. Neither fits perfectly but anything smaller doesn’t fit at all which doesn’t make sense because I’m measuring just over half an inch. Anyone know what I’m screwing up? It’s early and there’s no coffee in the shop so I’m kinda off my game.

 

[BrandonV]

Wouldn't that be a 14mm 8 point?

I don't think you'll find a lot of 12 point sockets fit square fasteners as well as you'd expect. The angles I think are a little off for that.

 

[CHI_Tool&Die]

Wouldn't that be a 14mm 8 point?

I don't think you'll find a lot of 12 point sockets fit square fasteners as well as you'd expect. The angles I think are a little off for that.

That’s what is confusing me. I’m assuming it’s metric because it’s made in Japan. So am I off because 12pt will not match the angles? I cannot even get a 16mm on, much less a 14mm. I’m going nuts overthinking it. 17mm and 11/16” are the first 12pt socket sizes that fit.

 

[BrandonV]

That’s what is confusing me. I’m assuming it’s metric because it’s made in Japan. So am I off because 12pt will not match the angles? I cannot even get a 16mm on, much less a 14mm. I’m going nuts overthinking it. 17mm and 11/16” are the first 12pt socket sizes that fit.

Yup. Usually I find you have to bump up the size to use a 12 point. Not to mention you're banking on the geometry and angle of the 12 point to be comparable between makers.

I'm guessing if you had an assortment of 12 point sockets, you'd probably have conflicting results using the same size socket on the same square fastener from different makers.

 

[CHI_Tool&Die]

Yup. Usually I find you have to bump up the size to use a 12 point. Not to mention you're banking on the geometry and angle of the 12 point to be comparable between makers.

I'm guessing if you had an assortment of 12 point sockets, you'd probably have conflicting results using the same size socket on the same square fastener from different makers.

Ok that makes sense. I’ve been plugging around with 12pts and it was driving me nuts. I was measuring .555” and could get a 14mm or 9/16” open end wrench on it but then the 12pt stuff didn’t match. So much for being able to use 12pts on square stock.

 

[Hakeem]

12pt sockets have 60deg angles, not the 90deg angles you’ll find on 8pt sockets (or square stock).

For all the hate spline drive gets, it works well on square drive. I carry a set of splined sockets for work as there are still a fair amount of square-headed fasteners in legacy electrical installations.

I’d probably just use an open ended wrench over getting 8-point sockets.

 

[cherrybomb]

I'm not exactly sure but I think you measure from point to point.12 point sockets aren't the correct tool,I got my 8 points from Williams.not sure if their catalog can help you tho!I'll check my catalog and sockets later.Post your diagonal point to pont and I will attempt a correct reply.Ill draw a square at .555 and measure diagonally,see what I can figure out.Their is so much knowledge on this site,you've come to the right place

 

[mike93lx]

I'm not exactly sure but I think you measure from point to point.12 point sockets aren't the correct tool,I got my 8 points from Williams.not sure if their catalog can help you tho!I'll check my catalog and sockets later.Post your diagonal point to pont and I will attempt a correct reply

If it's really square, it should be 0.785" on the diagonal

 

[KnurledNut]

14mm 8-point would be a close fit, but could even be a bit snug. Since I already have 9/16, thats what I would try.

 

[KnurledNut]

If it's really square, it should be 0.785" on the diagonal

The corners are chamfered so that measurement would read less.

 

[mike93lx]

The corners are chamfered so that measurement would read less.

Fair. That chamfer looks about 1mm wide? If so, that would take a total of about 1mm off the diagonal measurement, putting it at a hair under 19mm, or 0.745"

 

[kjbenner]

A 12 point socket is two hexagons offset by 15°. If those two hexagons are inscribed in a circle, a square also inscribed in that circle will fit in the 12-point shape.

Neglecting rounded corners and whatnot, a hexagon inscribed in a circle with diameter D will have a distance across flats of D*cos(30°). A square inscribed in that circle will have a side length of D*sqrt(2)/2. So to fit a 12-point socket over a square, you'll need a socket sized for a hexagon of 2*cos(30°)/sqrt(2) times the size of your square. This works out to a factor of 1.22, or about 17.1 mm for a 14 mm square.

 

[Jeeper99]

https://sunextools.com/products/1-2-dr-9-16-female-plug-socket

4 point socket work? I have 3/8 and 1/2" drive sets for pipe plugs, it should work for your application as well.

edit looks like koken has a 14mm 4 point https://kokenusa.com/products/weld-...OaQ_44WMOH8LO_ZJ7euG76YWTcdmspeY98AU2KwMvmLVK

 

[CHI_Tool&Die]

https://sunextools.com/products/1-2-dr-9-16-female-plug-socket

4 point socket work? I have 3/8 and 1/2" drive sets for pipe plugs, it should work for your application as well.

edit looks like koken has a 14mm 4 point https://kokenusa.com/products/weld-...OaQ_44WMOH8LO_ZJ7euG76YWTcdmspeY98AU2KwMvmLVK

I didn’t even know 4pt was a thing. Thanks!

 

[CHI_Tool&Die]

A 12 point socket is two hexagons offset by 15°. If those two hexagons are inscribed in a circle, a square also inscribed in that circle will fit in the 12-point shape.

Neglecting rounded corners and whatnot, a hexagon inscribed in a circle with diameter D will have a distance across flats of D*cos(30°). A square inscribed in that circle will have a side length of D*sqrt(2)/2. So to fit a 12-point socket over a square, you'll need a socket sized for a hexagon of 2*cos(30°)/sqrt(2) times the size of your square. This works out to a factor of 1.22, or about 17.1 mm for a 14 mm square.

And this is why I love GJ. Thank you for the explanation. It completely corroborates what I am seeing. I ordered a couple of 8pt sockets and I’ll see what happens.

 

[cherrybomb]

If you ever get to a flea market,look for a machine shop vendor,sometimes many different tools ,as liked we know,fasteners and wrenches are always changing