Fixing a floating mantle-shelf

[Nathan]

I'm fitting a woodstove in the dining-room, and want to fit a mantle above the opening.

I've got a chunk of elm (about 60mm by 1540 by 300) and I want to attach it floating (i.e. bracklet-less).

So far I've used 4 expansion bolts to fasten threaded rod (M10) into the stone behind the mantle-shelf; these are rock solid.

My plan was to drill (with a pillar-drill) into the elm, ending up about 30mm short of the outer edge, then slot the shelf onto the supports.

I was thinking of drilling 10mm holes in the shelf, then whacking the shelf on, but would I be better with 12mm, and podging car-body filler in around the rods?

Haven't drilled the holes yet, but just resting the shelf on the rods and it "bounces" - it won't fall down, but there is movement in it.

So, any ideas on how to improve this without any visible supports? It won't be holding a huge weight other than the shelf itself (vase, pictures etc.), but I'd rather it didn't flex!

The rods are being plastered around tomorrow, but I could remove them and re-drill with more substantial bolts, and M12 rod?

thanks, Nathan

[Mike Clarke]

So that's 4 rods about 290mm long engaging with deep holes in the shelf. You'd need to have the rods all perfectly aligned parallel with each other to slide the shelf on using 10mm dia holes. I expect you'll need quite generous clearance.

[JimK]

hi

yeah I'd drill holes however big they need to be to fit it on how you want it "dry" - then splodge a bit of body filler on rods and plant it on - support it if it won't naturally "sit" at the correct angle(s) whilst the filler sets. Sure you know but bear in mind the filler sets fast from 1st mixing and that the mantle won't be coming off easily again :>)))

Cheers JimK