Screws vs nuts for mounting speakers

[itsGiusto]

Silly question here: For all of my previous amp work, the cabs I bought always had bolts sticking out of the baffle into the cab, that I could mount the speakers on using nuts, and the nuts would go right up against the speaker frame. However, I just bought a used JCM900 1960a cab. This cab seems to use screws that you screw through the speaker into the baffle. In this, the screw head sits against the speaker frame.

Does this matter at all? For some reason, I'm more worried about overtightening and warping the speaker frame if I'm using screw heads. Or I'm also worried about stripping out the baffle socket that I'm screwing the screws into.

 

[_MementoMori_]

I wouldn't worry too much about it. If it really bothers you, get some felt washers to sit between the speaker frame and the screw head. Just don't torque everything down like He-Man.

 

[JRapp]

60s/70s Magnavox era Ampegs use the screws for front-loading and I usually swap them out for nuts and bolts rear loaded. Sounds better to me and prolly more durable.

 

[itsGiusto]

60s/70s Magnavox era Ampegs use the screws for front-loading and I usually swap them out for nuts and bolts rear loaded. Sounds better to me and prolly more durable.

This one is using screws, but it's not front-loaded, you screw the screws into the back of the speaker.

This guy shows it in this video:

 

[NoTeleBob]

Unless you plan to change them often, screws are fine. I like to have small washers on the to spread the load a bit like the bolt mount washers do.

 

[itsGiusto]

Unless you plan to change them often, screws are fine. I like to have small washers on the to spread the load a bit like the bolt mount washers do.

If that's the case, I'd probably rather use nuts instead of screw. I don't plan to change them, but I might end up doing that, and I don't want to preemptively wear out the speakers.

What size nuts, bolts, and washers should I get to mount Celestion Greenbacks? Should I get tee nuts?

Edit: Oh, I coudln't tell since it's behind the grill cloth, but I just checked, and there are tee nuts! So I guess I just need to get bolts to screw into them? I'm not 100% sure how you attach a bolt to the tee nut in-order to mount the speaker with nuts instead of screws. Maybe I could just get a very long screw and put it in from the front side, sticking through the t-nut to the back?

 

[Peegoo]

When I build cabs, I use T-nuts from the front of the baffle, and matching machine screws through the speaker frame on the back of the baffle into the T-nuts.

Studs (with mounting nuts) are a liability because you have to be careful not to poke a hole in the speaker cone when mounting the speaker.

 

[telemnemonics]

If that's the case, I'd probably rather use nuts instead of screw. I don't plan to change them, but I might end up doing that, and I don't want to preemptively wear out the speakers.

What size nuts, bolts, and washers should I get to mount Celestion Greenbacks? Should I get tee nuts?

Edit: Oh, I coudln't tell since it's behind the grill cloth, but I just checked, and there are tee nuts! So I guess I just need to get bolts to screw into them? I'm not 100% sure how you attach a bolt to the tee nut in-order to mount the speaker with nuts instead of screws. Maybe I could just get a very long screw and put it in from the front side, sticking through the t-nut to the back?

What you have in the Marshall cab is superior, modding it to have nuts would be a downgrade to satisfy a thinking problem.

The speaker mounting with machine screws into tee nuts is NOT a problem.

Are you saying all the machine screws have been lost?

 

[telemnemonics]

Unless you plan to change them often, screws are fine. I like to have small washers on the to spread the load a bit like the bolt mount washers do.

These are machine screws which are bolts but with the slot head so we call them screws, but they are not wood screws and they are really the exact same thing as Fender aside from which end has the nut on it.
Washers are certainly good and should be present in the Marshall cab.

Far better than the Fender system where a machine screw is driven through the baffle and can tear out.

Tee nuts have a bigger grasp on the wood, and you never puncture speaker cones when lining up the speaker.

 

[King Fan]

you never puncture speaker cones when lining up the speaker.

^^^ this is the important difference, not the nut v. bolt part, for internal mounting. Nuts go on threaded *studs*, which are like four big paper punches sticking up as you lower the cone into place. Bolts (machine screws) going into tee nuts are thus much safer.

FWIW you can get machine screws with broader heads. But as far as the original question, over-cranking, you’re much more likely to overdo a hex nut than any screw — wrench v. screwdriver torque is no contest.

Finally, even tee nuts aren’t 100% safe. Since all four speaker holes don’t always align *automatically*, it’s easy enough to crossthread a bolt, and then even with screwdriver torque, I’ve had the teenut 'teeth' rip/bend out of the front of the baffle. At which point it spins on the stuck bolt, and you’re moderately 'screwed.' If you build your own baffles out of hard ply, make sure the teeth are fully sunk — and in any case only finger tighten the bolt until you’re *sure* it spins easily.

 

[Peegoo]

This is what Fender used on their amps; many still have this mounting scheme.

These have a coarse (wood) reverse threaded collar that you screw in from the front of the baffle. You drive the screws into the baffle counterclockwise. Because they're reverse-threaded, it prevents them from unscrewing as you snug the speaker nuts in place.

They are conveniently pointy to make poking a hole in a speaker as easy as possible

When applying the speaker nuts, get them as tight as you can with your fingers, and then follow with a little socket or nut driver and rotate the nut no more than one full turn clockwise.

Apply a little dot of enamel paint or fingernail lacquer to the nut where the screw protrudes; that serves to lock the nut in place and prevent vibrations jarring it loose.

 

[NoTeleBob]

Tee nuts have a bigger grasp on the wood, and you never puncture speaker cones when lining up the speaker.

You mean the threaded collars that insert from the baffle side? Yes, those are best. Secure and puncture proof. Until someone overtightens one and it spins :- (

 

[telemnemonics]

^^^ this is the important difference, not the nut v. bolt part, for internal mounting. Nuts go on threaded *studs*, which are like four big paper punches sticking up as you lower the cone into place. Bolts (machine screws) going into tee nuts are thus much safer.

FWIW you can get machine screws with broader heads. But as far as the original question, over-cranking, you’re much more likely to overdo a hex nut than any screw — wrench v. screwdriver torque is no contest.

Finally, even tee nuts aren’t 100% safe. Since all four speaker holes don’t always align *automatically*, it’s easy enough to crossthread a bolt, and then even with screwdriver torque, I’ve had the teenut 'teeth' rip/bend out of the front of the baffle. At which point it spins on the stuck bolt, and you’re moderately 'screwed.' If you build your own baffles out of hard ply, make sure the teeth are fully sunk — and in any case only finger tighten the bolt until you’re *sure* it spins easily.

The small T nuts I see in cabs including Marshall are a little delicate, the US version is usually a #8 and the UK is similarly small but not even metric in the old Marshall cabs.

So when I build new cabs I use #10 24 which are bigger stronger teen nuts, bigger machine screws and have bigger heads.
My old Marshall cab came to me empty and with NO screws.

Those damn UK spec imperial screws are called "cheese head screws", and cost like a buck or two each.
So I changed my valuable vintage Marshall cab over to US specs before putting on new grille cloth.

 

[King Fan]

Good points. Couple items I couldn't resist, sorry:

bigger stronger teen nuts

No comment...

called "cheese head screws", and cost like a buck or two each.

Readily available in Wisconsin?

Seriously, 'cheesehead' just describes the head -- my Ace hardware has a few in inch and metric, and sometimes both slotted and Phillips.

But I dunno from Marshall. Did you ever decode British imperial size system? For curiosity's sake, I did find this. Also for Marshall types, not sure it helps, but here is a US source of British fasteners.

 

[telemnemonics]

Good points. Couple items I couldn't resist, sorry:



No comment...



Readily available in Wisconsin?

Seriously, 'cheesehead' just describes the head -- my Ace hardware has a few in inch and metric, and sometimes both slotted and Phillips.

View attachment 875255

But I dunno from Marshall. Did you ever decode British imperial size system? For curiosity's sake, I did find this. Also for Marshall types, not sure it helps, but here is a US source of British fasteners.

Hahahahahahaha oops!
Well cheese head Marshall is more specific than cheese head hardware store.
(Oh I see you searched and covered that!)

The little "teen" nuts (teen not tee and not teeny) in old Marshall cabs are neither SAE nor metric, so almost no hardware store has Marshall compatible "cheese head" machine screws.

While oval head or pan head would work if the thread fit, it seems the brits like their cheese?
Presumably better because it's one louder, innit?
Crisp edges like the union jack?
I dunno, but I was not buying no dang import screws for my import Marshalls!

At the time I was also buying brit style basketweave cloth, brit style handles and brit style caster cups.
Plus a Marshall logo which I forget the origin of.
Great vintage cab with that Brutish woody Baltic Birch tone.

Wait, the Baltics are not in Britain?
So, Baltic tone?
Or Baltics tone?
Big balls either way.

 

[itsGiusto]

What you have in the Marshall cab is superior, modding it to have nuts would be a downgrade to satisfy a thinking problem.

The speaker mounting with machine screws into tee nuts is NOT a problem.

Are you saying all the machine screws have been lost?

Thanks, that all makes sense. The original machine screws are still here, but maybe they're a little worn, so I bought new ones.

I the reason why I though the mounted studs is better than screw-head with tee nuts is:
1. all my previous cabs did the former, not the later
2. This marshall cab had no washers, and maybe the screws were tightened too hard, so the speakers that came stock seemed a little deformed at the screw heads

I can see, however, why screws are actually better than studs, though, like you say, so I'll just get some washers, and carefully tighten the screws when I mount my nice speakers into it, so as to not deform them.

 

[saltyseadog]

I use pronged t-nuts which dig into the baffle and keep them fixed. I also prefer to use allen bolts with them which have less chance of rounding out like most of the soft chinese steel philips/pozi heads do after a few ins and outs.

 

[schmee]

Silly question here: For all of my previous amp work, the cabs I bought always had bolts sticking out of the baffle into the cab, that I could mount the speakers on using nuts, and the nuts would go right up against the speaker frame. However, I just bought a used JCM900 1960a cab. This cab seems to use screws that you screw through the speaker into the baffle. In this, the screw head sits against the speaker frame.

Does this matter at all? For some reason, I'm more worried about overtightening and warping the speaker frame if I'm using screw heads. Or I'm also worried about stripping out the baffle socket that I'm screwing the screws into.

I assume there are threaded inserts or T nuts in the baffle. If so then it's fine.... and keeps you from poking a hole in your speaker!
If wood screws into the baffle...? Not acceptable and not a Marshall procedure that I have seen...

 

[muscmp]

i also add neoprene bonded washers to isolate the nut from the speaker frame. thus no metal to metal contact. i get them at home depot and they are pretty cheap.

play music!