door hinge double hex socket
- Thread starter imp75
- Start date
I can't specifically answer your question as my car is still in storage, but I can help us all get on the same page regarding nomenclature. Aside from the familiar hex head bolts, most small fasteners on modern BMWs have internal Torx drive heads, where there is a 6 lobed star shaped recess in the head into which the Torx driver is inserted. Torx is a trademark name for this particular pattern. Sizes are designated T1-T100.
Larger bolts, particularly on engines, use the external variant, where the bolt head appears similar to a 12 pt hex head sometimes seen on sparkplugs. Closer inspection will reveal the head is nearly identical to the Torx internal driver tool. You should use an external Torx socket to drive these bolts. Their sizes are designated with an E instead of T, so E10, E16, etc. You could use a standard hex socket on some sizes of E Torx bolts, but this is a poor practices.
There is an internal double hex head fastener around, for which you can use a standard hex key to drive it, I don't think they are used on BMW cars. There is also a internal triple square head fastener which has 3 concentric square recesses cut, each 30 deg from the other, resulting in a 12 point star shape. The difference between this and the double hex is the star tip angles are 90 deg instead of 120 deg. While you could use a square driver on these, it's a bad idea because these are high torque bolts and square drivers don't have the precision needed and will only stress 1/3 of the pattern. This pattern is most easily seen in the assembly bolts around the rim of 108 style wheels. They are also used in Audi axle components.
There is also a spline drive which looks very similar to triple square, but is incompatible.
(I'm guessing the tool you are looking for is an external Torx, but my memory of that particular door fastener is fuzzy)
Larger bolts, particularly on engines, use the external variant, where the bolt head appears similar to a 12 pt hex head sometimes seen on sparkplugs. Closer inspection will reveal the head is nearly identical to the Torx internal driver tool. You should use an external Torx socket to drive these bolts. Their sizes are designated with an E instead of T, so E10, E16, etc. You could use a standard hex socket on some sizes of E Torx bolts, but this is a poor practices.
There is an internal double hex head fastener around, for which you can use a standard hex key to drive it, I don't think they are used on BMW cars. There is also a internal triple square head fastener which has 3 concentric square recesses cut, each 30 deg from the other, resulting in a 12 point star shape. The difference between this and the double hex is the star tip angles are 90 deg instead of 120 deg. While you could use a square driver on these, it's a bad idea because these are high torque bolts and square drivers don't have the precision needed and will only stress 1/3 of the pattern. This pattern is most easily seen in the assembly bolts around the rim of 108 style wheels. They are also used in Audi axle components.
There is also a spline drive which looks very similar to triple square, but is incompatible.
(I'm guessing the tool you are looking for is an external Torx, but my memory of that particular door fastener is fuzzy)
