Screws for Mission 760 speakers?

[BrendanC]

Hi all,

I have a pair of venerable Mission 760 speakers which I'm trying to spruce up a bit. I've had them for 30 years - they were from the very first incarnation of this model, bought after a launch review in What Hifi back in the day. They still sound great so I'd like to keep them going if possible, but they're a bit aesthetically challenged.

The problem I'm having is that a couple of the screws retaining the woofers and tweeters are missing, and some of the remaining ones are a bit loose, and if I try to tighten them they're just turning in the wood and not really getting any purchase. However, having bought some replacements speculatively online which don't fit, I just cannot find a way of figuring out what screws I need, or where to get them from.

I've attached two photos showing the width and length of screw. They're about 4mm wide and 23mm wide. The same ones are used for securing the woofers and tweeters. I don't know the thread size nor would I know how to calculate this.





I don't think the length is important as I've tried longer screws and there doesn't seem to be anything inside that impinges on them. However, I would maybe want to try something very slightly wider, as that might help get more purchase and hold the screws (and units) more tightly. Also it would be nice to have Allen-key type hex ends because, well, they look cooler.

Any ideas?

Thanks, Brendan

 

[BrendanC]

Hey, nice idea, thanks! Thing is, I have a couple of screws missing so I'd still need to identify them. But thanks for the suggestion for getting the others to fit better (and if I get replacements for the missing ones that could still work with them).

 

[twinkletoes]

Unsrew them all and renew the hole with a wood glue and saw dust mix, fill the holes till level and repeat if shrinkage happens, once truly filled drill pilot holes just slightly smaller than the screw. Will be good as new in 48hr.

 

[My2Cents]

There are many ways to repair the holes required for the screws.
The 'paper' idea is not the best and not going to work very well.
From the type of screw used, it looks like these screws are basically going into the plastic baffle material.
Unfortunately, it sounds like you may have screwed some 'longer than original' screws into the holes, which may have gone all the way through the baffle and created a 'thru' hole.
Anyway.
1) Try to find the matching screws, it shouldn't be difficult at a good hardware store... if not call Mission and see if they have any.
2) If the screw is not too loose, wrap plumbers tape around the thread and screw it in (much better than paper idea and easier too).
Best option:
3) After finding the correct screws, remove all the screws (and the drivers) and fill the original holes with either screwable wood filler or epoxy. When dry, use a Bradawl or a screw starter tool to 'start' the hole and then screw the drivers back in.
When done correctly they will last another 30 years.
Do not over tighten. Check the tightness after a few hours of using the speakers.

 

[My2Cents]

PS epoxy would be best as the baffle is made from a composite plastic material.

 

[BrendanC]

Excellent reply, thank you. I just tried the paper method and it didn't work unfortunately, but before even reading this I hit on the idea of putting wood glue in the holes, which I'll leave to dry then hopefully the screws will purchase. I've contacted a couple of hifi repair places for the replacement screws. Funnily enough I didn't even consider contacting Mission but will do now!

 

[My2Cents]

Wood glue does not really bond to plastic or composite materials. It's designed for wood to wood. If you fill the holes with wood glue it may just start to spin around in the hole when you screw the screws back in.

 

[BrendanC]

Ah well, I'll leave it to dry and see what happens. If no joy I'll try the epoxy glue. Thanks anyway.

 

[Gray]

If I all ready had holes right through the front baffle, I'd be making them wide enough to take some of those spiked, metal threaded inserts (with spikes into the rear side).

Then you could have your choice of Allen bolts with matched metal threads.

I'd go straight to doing it that way, but maybe you can do it only if your repairs fail.

 

[Vincent Kars]

Have a look at "Impact and screw-in nuts for wood"

or hollow wall plugs

 

[Stuart83]

Have a look at "Impact and screw-in nuts for wood"

or hollow wall plugs

Yep clip a wall plug off the right depth.
"Job done" as they say, done it loads of times over the yrs with all sorts.

Coincidentally the 760i was my first ever self bought speakers at 12yrs old.
I'd saved 1.40 pocket money up for ages with my birthday monies etc to get to purchasing them with my father's advice.

I fondly remember them coming and hooking them up to a sansui au-505 and Philips CD player.
I was in love 😘 my little feet tapping away to every CD I could find out of my dad's cd wall (started of as a small rack)

They had me fall in love with mission as a brand and not much later I moved up to the 763i a relative heavyweight floorstander.

The little 760i lasted 12yrs or more.
All through my bedroom yrs to my first flat.
They would of went longer but they were simply never off.
They were used as djay monitors for yrs after moving out of the tiny bedroom I grew up in.

You'd be hard pushed to better them now regardless of modern claims in advancement.

I recently had the 763i fail causing a huge hunt to find something similar ending up with fyne audio f502's and a few others 🤔
The hifi bug caught on whilst I was looking again 😂
I was modernising my main hifi to streaming etc in my defence.

What fond memories ensue when thinking about those little speakers.

I even remember the picture in the what hifi magazine when the 760i won best book shelf speaker.
(A photo of the speaker with a red rose on top of it)

If I remember it tipped the wharfdale diamond off it's top spot prior that yr.

 

[BrendanC]

Ha, my fond memory is of having a demo pair of JPW Sonatas, and while testing them I read up about these amazing new speakers from Mission. I remember the phrase "how did they shoe-horn such a huge performance from such small speakers" but I have't been able to find the article online sadly.

Anyway, when I took the Sonatas back, I showed the guys at the shop the review of the Missions and asked if they had any in. They'd literally taken delivery the day before and hadn't read the What Hifi review, so were intrigued. Me too - I asked if I could take them instead of the Sonatas, and was blown away when I got them home and hooked them up.

They still sound incredible to me, all I've had to do is patch one small part of a woofer. Still paired with a Rotel RA820AX amp and RCD 865 CD, plus now with a Chromecast Audio going into an Arcam Delta Black Box with some tasty audiophile upgrades for streaming. I can't recall if they won a What Hifi award that year but I'd be surprised if not because they caused quite a stir.

 

[nopiano]

I’ve still got my 760i, the ones made a bit like a shoebox, with an awful plastic clip on grille. Are they yours?

They are very bouncy and ‘free’ sounding, though a bit quacky on some vocals, but very enjoyable. Worked brilliantly on contemporary Marantz amp and CD player in a studio flat I occupied while seconded to work in London.

 

[BrendanC]

Mine aren't even the 760i model! Straight 760s, but yes, with the clip-on grilles which I discarded almost immediately. Woofer on the top, tweeter below, front-facing bass port.