slide in steel bar for garage doors

[Horse]

googling a bit, now I am confused, ill need to drill holes in the wood for the M8 coach bolts what size drill bit will I need, I think 8.2mm will be too big

Assuming your meaning M8 machine thread on the coach bolts then 8.2 mm will be fine.
Theres usually a domed head which should always go to the burgler side, thats so they can't get a grip on it with a spanner.
Its usually got a square section under the domed head which stops it from rotating when you tighten the nut on the other (nside the shed) end.

yeah they are those.

when you say fine, should I go 8 or 9, how do you work out the correct size???

IIRC an 8mm thread (if you were cutting one from scratch, you would start with an 8mm diameter bar, no bigger. If you use an 8mm, expect to use 'encouragement' to get bolts into place. As said, the head end of the bolt being square, it won't want to go into the hole. You need that to stop it rotating when you tighten the nut.

[David]

The brackets have a square hole.

[demographic]

The brackets have a square hole.

Yeahbut it depends on if you want the locking system on the inside like maybe a garage door or on the outside like a shed where you have no access from the inside.
Put the system on the outside of the door and use the square holes in the locking bar and the nuts are safely on the inside.
Put the locking bar system in the inside like a garage where theres another door in from perhaps a utility room and if you put the domes and square ends on the inside and then the nuts can be removed from the outside. Fail.

If you see what I mean.

[demographic]

Forgot about this vid.
It's about a way to remove the weld bead from the inside of square section tubing.
Having two sections of square secion tubing that slide in inside another is pretty much one way to make a large sliding garage door bolt. The vid starts out kind of slow and he's not making a lockbar but the principle is the same.

[formula400]

Right can't use that security from the 1st listing as the brackets are 100mm wide, I was going to mount them on the wooden door frame, they have 45mm for mounting.

I could how ever drill through the brick the brick is 210mm deep, but not 100% confident doing that.

https://www.ebay.co.uk/itm/BLACK-LOCKAB ... SwiI1eaOAw

this one does not use coach bolts, its uses 8 x 2 clutch security screws. are they good??? should I just buy longer coach bolts and use them instead???

[demographic]

I've used clutch head security bolts on a line of toilet cubicles somewhere, might have been in a school or a pub, can't remember for sure.
Anyway, I found them to be a "right bastard" because if they slip while tightening sometimes you can't get them in fully nor get them out without a lot of faff.

They had a head like this but went into what I'd call a female Chicago nut (more or less an internally threaded tube).


I've also used another type which shear the hex head off when a certain torque is reached, that was for the vandal protection for security lights round a castle.
Err, they worked ok but if it snapped off too soon it could also have been a "Right Bastard" to sort.
Looked like these.

[formula400]

right ignore me, the bracket is 50mm wide and 100mm high so they will fit. ill stick with my original plan.