A question for you engineers/stonemasons or general DIY folk.

[Dave7]

EDIT***
I am (thinking) of having some speaker stands made out of marble...........to match the new fire-place.
The base plate will be 20mm thick.
I want to mount the stands on 'spikes'. These spikes have 6mm** threaded male sections to insert them..........as this link.
http://www.ebay.co.uk/itm/4-x-Speak...ion-M6-thread-31mm-black-plated-/261977970572
The people who can make the stands do not think you can tap a thread into marble...............drilling is not a problem-its just the threading (they think it will crumble). I thought you could but don't know.
So my questions are..................
Does any-one KNOW if it will work OK ?
or........
What if they simply drill **8mm holes and resin a 6mm hex nut over it ?
Before people ask the obvious................
The speakers are old and I cannot get good ready made stands to suit.........without paying a kings ransom.
*** the guy is going to give me a piece so I can get a local fab' shop to experiment.

 

[numbnuts]

Plan "B" sounds better, but use threaded tube would be better, but you will have to go out to 10mm plus

 

[Milkfloat]

Why not just resin the spikes directly into marble - do they need to be removable?

 

[Profpointy]

I would not expect threading into rock will work, at least not in a small size like 6mm; certainly in caving we never do this. Admittedly, dangling over a 100m drop is a bit more critical than merely standing speakers on !

Have a look for "threaded inserts" and find some that can be araldited in.

All that said, I might question marble speaker stands. Might be worth doing some googling of hi-fi fora, even though there's a lot of bollocks talked on some of them.

Can't you get some generic metal framed speaker stands that would do ? I'm assuming marble blocks will cost you a couple of hundred, so it's not as if you're doing it for 50 pence.

 

[Profpointy]

Why not just resin the spikes directly into marble - do they need to be removable?

Probably need levelling - though could do the levelling at the speakers I guess

 

[Oldfentiger]

Why not just resin the spikes directly into marble - do they need to be removable?

Then you'd have a problem levelling the stands.
I think the threaded tube is the better method.

 

[Dave7]

Plan "B" sounds better, but use threaded tube would be better, but you will have to go out to 10mm plus

Yes.............I need them to be more 'discreet' than that though. My thinking is that hex nuts won't be visible.

 

[classic33]

Genuine marble, not a chance of cutting a thread.

 

[Dave7]

Why not just resin the spikes directly into marble - do they need to be removable?

The idea with spikes is (I think) to be finely adjustable.

 

[Dave7]

Genuine marble, not a chance of cutting a thread.

It is real genuine marble (as against the marble/resin types).
Why do you say "not a chance" ??

 

[Oldfentiger]

Yes.............I need them to be more 'discreet' than that though. My thinking is that hex nuts won't be visible.

The marble is 20mm thick, so get the holes drilled 15mm deep, araldite the threaded tubes in. You won't see them. Still have adjustability.

 

[Dave7]

The marble is 20mm thick, so get the holes drilled 15mm deep, araldite the threaded tubes in. You won't see them. Still have adjustability.

Now that seems a workable idea..........thanks.

 

[Profpointy]

Here's one

http://www.directindustry.com/prod/specialinsert-srl/product-58531-960945.html

Never used or seen them mind

That said, might be better to be araldited in, as that would be more rigid - which may or may not matter in hi-fi bollocks term

 

[raleighnut]

What you need are known as 'Nutserts', you want resin bonded ones and I'd only use 3 per stand (as opposed to 4)

https://www.google.co.uk/url?sa=t&r...co.uk/&usg=AFQjCNHdj_6bz0Hv8oe3pnjAZXQ5u1JbxQ

 

[classic33]

It is real genuine marble (as against the marble/resin types).
Why do you say "not a chance" ??

Cutting a thread in stone. The marble isn't exactly soft, nor the thread coarse.

What about a plan c. have them drill the holes, araldite the inside. Have a greased peg put in place in the holes whilst drying, then tap that. Small bolts could even be used saving on cutting a thread.