Is it permissible to use galv bugle screws to secure a bearer to a post instead on galv bolts with washers and nuts
Welcome @cbenjamin. It's great to see you make your first post and we'd be happy to help.
Could you please share more about the deck you plan to build? What type of deck? How big will it be? What type of timber are you using and in what size?
Our resident D.I.Y. expert @MitchellMc will be happy to help when he's back on the site tomorrow. @Adam_W may also be able to share his thoughts.
@Adam_W has written these helpful guides How to build a low-level deck and How to select decking timber that may be of assistance depending on the type of deck you are building. You may also like to read through the discussions of deck projects by Workshop community members by checking out these inspiring low-level deck builds.
Hi @cbenjamin the only time I would consider doing that would be when the bearer is checked or rebated into the post so therefore has a degree of physical support to carry downward load. I would also be using probably at least 4 per post in such a situation.
It's worth getting in your mind the difference in how the 'load' or stresses are being transferred to your fixtures.
With M10 or M12 bolts and washers when there is strain or load it is transferred through the post as the bolt is pressing down with load inside the full thickness of the post and then the washer on the outside of the far side of the post takes load too as the bolt pulls. An M12 bolt is also around 4x thicker than a bugle batten screw so more resistant to bending forces from downward loading.
With unsupported bugle batten screws all of the load is being carried by the thinner screws and how well the thread is holding in the post.
That make sense?
It's great that you've received in-depth advice from @Adam_W. His recommendation is spot on. I personally prefer using hex head bolts as it allows you to put your shifter on its head and prevents the bolt from spinning while being tightened. I've seen cup heads tear through timber and become next to impossible to tighten.
It sounds like a fantastic decking project in the making. Would it be possible for you to post a photo of your project? I'm sure our members would be keen to see what your deck looks like.
Please keep us updated with your progress, we look forward to seeing your deck finished and ready for use.
If you need further assistance, please let us know.
I agree entirely with @Adam_W. It would be my recommendation to use bolts regardless of whether the joint is rebated or not. They'll add much more rigidity to the joints as they have a higher compressive force than the screws. Screws are great at holding things in place, but the bolts will pull the timber together into one solid joint.