Bolt through garage door

[OldKettle]

Hi,
I am currently installing some locks on a garage door. The instructions say to drill an 8mm hole for the securing bolts, which I have done.

However, the tops of the bolts have a square section which is just over 8mm side to side and 10.5mm corner to corner. It fits into a square section on the lock body.

What is the best way to get the bolts flush to the door?

Any advice would be much appreciated.

 

[rsgaz]

A square file.

Also, where you have drilled is now bare steel which will rust. A smear of vaseline or grease will do, if you have something like Kurust, that would be even better.

 

[OldKettle]

Thanks! Would this do the trick?

https://www.amazon.co.uk/Draper-449...F8&qid=1532189230&sr=8-4&keywords=square+file

 

[JohnD]

if the steel is very thin (probable) then tightening a nut on the other side of the bolt will likely cause it to pull the square shank of the coach bolt through the steel door. It will work better if you have the square hole in the fitting pressed against the sheet steel on the other side. Turn the nut only.

If not satisfactory, you can tidy the edges of the hole with your file afterwards.

I can't see the dimensions of the file in the ad. You need one no wider than the square shank of the coach bolt. It shoulf be about 8mm. You want the bolt to be a tight fit.

I'd use gloss oil paint on the rough edges to resist future rust.

edit
The Q&A suggest it's the right size
https://www.amazon.co.uk/ask/questions/Tx1PUVXPPYQ1X87/ref=ask_dp_dpmw_al_hza

 

[OldKettle]

if the steel is very thin (probable) then tightening a nut on the other side of the bolt will likely cause it to pull the square shank of the coach bolt through the steel door. It will work better if you have the square hole in the fitting pressed against the sheet steel on the other side. Turn the nut only.

Yep, that did the trick! Thanks very much.