Securing hatched with internal latches, coach bolts or pop-rivets?

[spicemouse]

As title. I'm looking to switch from external padlocks to internal bolts. As I can't weld, my options are either coach bolts (not sure how the square section works with steel doors) or pop-rivets. 

As with most things on the boat, my initial ideas are often not the best and searching here has already yielded many opinions on this sort of thing. I don't expect anyone to tell me how exactly they secure their hatches, all I'm looking for is advice on the best way to secure latches to the inside of steel doors. 

Thanks! 

[David Mack]

Pop rivets are very soft and easily drilled out. Bolts would be better. For coach bolts drill round holes then file them out square to take the square section under the bolt head. A pain of a job for which you will need a small square or triangular file. That way nobody can undo them from the outside (but you can from the inside), and the domed heads will look like rivets!

[Tracy D'arth]

Dome head allen machine screws with nuts are neater and easier than coach bolts. Available in lots of sizes and gauges.

 

 Like these on ebay but engineers suppliers will stock. Stainless is nice, no need to paint!

 

  https://www.ebay.co.uk/itm/174774640276?_trkparms=ispr%3D1&hash=item28b1615e94:g:q2gAAOSwAIpgrj3V&amdata=enc%3AAQAGAAACkPYe5NmHp%2B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsSDAeS9EQtjPGVfKXTxF0%2BjpG2iWY5ohPQKW8Lw7w3NQJTAfG6a7O74yHtdRE%2FV9K%2FqoQZJoP3vEsm2AFsS2qOleKxEgA%2F%2FPnBdIhAO6mdSgzep4iVeO0hqcftxZMgbRHG%2BXNomKmtY9iz0VzreHl3Kh1iaGsVX0uYAcgbRLeLZM9aIZEAzinzk3H9%2B4M0Yjn7hAZlKeoDnO%2FOib08vZpUfqsTB3Y7go9ZaTfIVliOw2euwLBC%2F3wYS4TxFqlw4WJ2%2B%2FlZiC51P1V%2FmzORliPicdn%2F%2BXZ%2Fiu0qWhO904NZEAGdHNYRh1oATB2%2Blzcq%2FG9IMLDlFl28SZuB%2Bzw6PBkt8RZaETJw1NFZfXX8Ka6cNGSi4L3T4DMF7Sd42mUWtMTSsl2kSEFfuTHKgGX7JZuyfxDy6ua%2FS1kxTNcOlfZKawW62At6vKdnjCxm%2Bi0z3n9gwUfBwdJPMD9jTZwKfHHZuwlu%2BAL6hzTDiIOgCTBqo1tlvRms%2Fh27KXXo1WMW6NqZUvBpPg1i9ixfedXbMMDBvZCxHvJVY%2BC5enl2XdmVymOsCDULBfj9%2FxcTAU2qmAQPWpjvFMwl1%2BhJGh%2BqWjU2P6CREPHqAphR3x0t5%2FHxRZEI9Zj1bCEICr0WrVpdfl1Z%2BUyTEpKt6zhvd%2FIEuIYKXs2MWMeVkhZLttuim8zbEBLUjnttd%2BZHbYSGdpXtgoioNp0dFRI%2BqqTKPRJrR9npe%2BVpPmR4UigIcCa9TLw2TQ8fDcjf2u7hLurdJrj6ilPfD1m89FkCoJoLmtlYrABi2toncU2CgH5u9caHrAMLVtaaBB2%2B%2FiCAu3RKrlu2CuFV|ampid%3APL_CLK|clp%3A2334524

 

  

If the allen head is outside fill them with Araldite after tightening to render them difficult to remove.

[Detling]

If use cross head countersunk bolts use a drill to round the cross head after fitting.

[ditchcrawler]

4 minutes ago, Detling said:

If use cross head countersunk bolts use a drill to round the cross head after fitting.

I went with the coach bolts, handy if you need to remove them for any reason

[spicemouse]

Think I'll go return the coach bolts. Got files, fitting, drills & impact driver.. shouldn't be too hard. 

[FredDrift]

2 hours ago, Tracy D'arth said:

Dome head allen machine screws with nuts are neater and easier than coach bolts. Available in lots of sizes and gauges.

 

 Like these on ebay but engineers suppliers will stock. Stainless is nice, no need to paint!

 

  https://www.ebay.co.uk/itm/174774640276?_trkparms=ispr%3D1&hash=item28b1615e94:g:q2gAAOSwAIpgrj3V&amdata=enc%3AAQAGAAACkPYe5NmHp%2B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsSDAeS9EQtjPGVfKXTxF0%2BjpG2iWY5ohPQKW8Lw7w3NQJTAfG6a7O74yHtdRE%2FV9K%2FqoQZJoP3vEsm2AFsS2qOleKxEgA%2F%2FPnBdIhAO6mdSgzep4iVeO0hqcftxZMgbRHG%2BXNomKmtY9iz0VzreHl3Kh1iaGsVX0uYAcgbRLeLZM9aIZEAzinzk3H9%2B4M0Yjn7hAZlKeoDnO%2FOib08vZpUfqsTB3Y7go9ZaTfIVliOw2euwLBC%2F3wYS4TxFqlw4WJ2%2B%2FlZiC51P1V%2FmzORliPicdn%2F%2BXZ%2Fiu0qWhO904NZEAGdHNYRh1oATB2%2Blzcq%2FG9IMLDlFl28SZuB%2Bzw6PBkt8RZaETJw1NFZfXX8Ka6cNGSi4L3T4DMF7Sd42mUWtMTSsl2kSEFfuTHKgGX7JZuyfxDy6ua%2FS1kxTNcOlfZKawW62At6vKdnjCxm%2Bi0z3n9gwUfBwdJPMD9jTZwKfHHZuwlu%2BAL6hzTDiIOgCTBqo1tlvRms%2Fh27KXXo1WMW6NqZUvBpPg1i9ixfedXbMMDBvZCxHvJVY%2BC5enl2XdmVymOsCDULBfj9%2FxcTAU2qmAQPWpjvFMwl1%2BhJGh%2BqWjU2P6CREPHqAphR3x0t5%2FHxRZEI9Zj1bCEICr0WrVpdfl1Z%2BUyTEpKt6zhvd%2FIEuIYKXs2MWMeVkhZLttuim8zbEBLUjnttd%2BZHbYSGdpXtgoioNp0dFRI%2BqqTKPRJrR9npe%2BVpPmR4UigIcCa9TLw2TQ8fDcjf2u7hLurdJrj6ilPfD1m89FkCoJoLmtlYrABi2toncU2CgH5u9caHrAMLVtaaBB2%2B%2FiCAu3RKrlu2CuFV|ampid%3APL_CLK|clp%3A2334524

 

  

If the allen head is outside fill them with Araldite after tightening to render them difficult to remove.

Same theme but pin hex in a plethora of sizes…

 

https://www.tcfixings.co.uk/product/m10-x-30mm-h6-pin-hex-a2-button-head-security-screws/13201

 

 

[dmr]

Coach bolts are much more secure than button heads etc and look better. Making a round hole square is much quicker than it might sound.

Coach bolts are available in black stainless which is rather nice.