Hello. I’m in search of Screws/bolts for fixation of Kef B139. I bought the speakers (Kef Concerto) back in 1973. Recently I replaced the T27’s and then I noticed, 2 screws/bolts , of the B139 woofer were missing …
(please don’t ask me how this is possible..)
I searched the internet for days now, but I even can’t find which kind of screws this are.
I do know that the screws have withworth thread , but there seem to be 3 different kind of withworth-types..
The screws have a lenght of about 2cm and a diameter of approximately 5mm. (see pictures) .
The same screw is also used for top fixation of the crossover-filter SP1004.
Can anyone tell me more about these screws , or perhaps someone has a few spare or identical screws they want to sell to me?
Or someone can direct me (link) to a store where they sell such screws ?
Thank you very much.
Eric
(please don’t ask me how this is possible..)
I searched the internet for days now, but I even can’t find which kind of screws this are.
I do know that the screws have withworth thread , but there seem to be 3 different kind of withworth-types..
The screws have a lenght of about 2cm and a diameter of approximately 5mm. (see pictures) .
The same screw is also used for top fixation of the crossover-filter SP1004.
Can anyone tell me more about these screws , or perhaps someone has a few spare or identical screws they want to sell to me?
Or someone can direct me (link) to a store where they sell such screws ?
Thank you very much.
Eric
Attachments
So, You live in Europe like me and want Philips "round pan ?" imperial threaded screws.
Some Hardware stores have them available, but not all sizes.
Did You try Leroy Merlin or similar store ?
Chinese stores also have all things that we can think... I buy there black screws.
Try also a machinery store. Some carry a huge selection of screws.
I presume they attach to a T-Nut.
https://www.amazon.com/Bolt-Dropper-Pronged-Climbing-Cabinetry/dp/B01MSVU3WF
Change the nuts for 5 mm and use 5x20mm screws.
You can also get a larger Hex or Umbrako screw and screw it directly in the wood.
In this case make sure You don't overtight them or they loose grip.
Some Hardware stores have them available, but not all sizes.
Did You try Leroy Merlin or similar store ?
Chinese stores also have all things that we can think... I buy there black screws.
Try also a machinery store. Some carry a huge selection of screws.
I presume they attach to a T-Nut.
https://www.amazon.com/Bolt-Dropper-Pronged-Climbing-Cabinetry/dp/B01MSVU3WF
Change the nuts for 5 mm and use 5x20mm screws.
You can also get a larger Hex or Umbrako screw and screw it directly in the wood.
In this case make sure You don't overtight them or they loose grip.
There's no 5mm (0.197") British Standard Whitworth Screw (BSW).
It could be a 3/16" (0.188") BSW - you would need to measure the diameter accurately to confirm.
Fastenerdata - BSW Threads British Standard Whitworth fastener thread - Fastener Specifications
It could be a 3/16" (0.188") BSW - you would need to measure the diameter accurately to confirm.
Fastenerdata - BSW Threads British Standard Whitworth fastener thread - Fastener Specifications
I have a ton of them. You are welcome to them (but they are all destined for the metal scrap as that is their worth).
Get some good wood screws or use a bolt and threaded insert.
Only one of those T-Nuts need to come lose and it becomes very difficulat sometimes to get the driver out without damage to the baffle. Hard to drill the bolt out a sit is spinning.
dave
Get some good wood screws or use a bolt and threaded insert.
Only one of those T-Nuts need to come lose and it becomes very difficulat sometimes to get the driver out without damage to the baffle. Hard to drill the bolt out a sit is spinning.
dave
There's also a 3/16" British Standard Fine (BSF) screw which has 32 threads/inch compared to the BSW's 24 threads/inch.
Take the screw to a well stocked hardware store - find a nut that screws onto your screw, voila you now know the thread and can buy the right screws the same as your sample -easy.
The evidence points to it being a 3/16" BSW screw.
Readily available in the UK of course: BSW- Whitworth, 3/16", Cap Head, Socket Screw. – Fixaball
Readily available in the UK of course: BSW- Whitworth, 3/16", Cap Head, Socket Screw. – Fixaball
THANK TOU ALL FOR YOUR FEEDBACK. I will need tot think about all these reactions…
MAACO : “ I presume they attach to a T-bolt” @MAACO Correct. They attach to a T-bolt.
Galu :”It could be a 3/16” (0.188”) @Galu : I think you are right. The diameter is a little less than 5mm. And 0.188 inch = 4.8cm.
Planet10 : “Only one of those T-nuts need to come lose and it becomes very difficult to get the driver out without damage tot he baffle. Hard to drill the bolt out as it is spinning”. @Planet10 : Indeed, very good comment ; i’m well aware of this… But I don’t understand what you mean by ‘using a bolt and threaded insert’. I can’t visualise what you mean...
@Gary S : That idea also already crossed my mind. Only, to find such a shop in Belgium…
I still hope that someone might have two of these at his(or hers) home and want to sell and ship them to me… But now I know these are 3/16” BSW screws, I know exactly what to look for.
Using wood screws is also a good solution, but at first , I would like to try putting in the original screws.
THANK YOU ALL.
MAACO : “ I presume they attach to a T-bolt” @MAACO Correct. They attach to a T-bolt.
Galu :”It could be a 3/16” (0.188”) @Galu : I think you are right. The diameter is a little less than 5mm. And 0.188 inch = 4.8cm.
Planet10 : “Only one of those T-nuts need to come lose and it becomes very difficult to get the driver out without damage tot he baffle. Hard to drill the bolt out as it is spinning”. @Planet10 : Indeed, very good comment ; i’m well aware of this… But I don’t understand what you mean by ‘using a bolt and threaded insert’. I can’t visualise what you mean...
@Gary S : That idea also already crossed my mind. Only, to find such a shop in Belgium…
I still hope that someone might have two of these at his(or hers) home and want to sell and ship them to me… But now I know these are 3/16” BSW screws, I know exactly what to look for.
Using wood screws is also a good solution, but at first , I would like to try putting in the original screws.
THANK YOU ALL.
Eric, to be sure you really need to measure one of the existing screws with a thread gauge.
If they are the same, in the short term, why not take the two screws out of the filter and use them on the B139 and temporarily put some gaffer tape on the top of the filters.
Also, have you tried emailing KEP Support? Even if they don't have any screws left, they may be able to confirm what thread was used.
If they are the same, in the short term, why not take the two screws out of the filter and use them on the B139 and temporarily put some gaffer tape on the top of the filters.
Also, have you tried emailing KEP Support? Even if they don't have any screws left, they may be able to confirm what thread was used.
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This idea also already crossed my mind Levistubby.
For about €2 , I now ordered 5 screws in China.
When these arrive, I will use the original crossovers-screws for the B139 and use the Chinese screws for the crossover-filter.
I didn't know Kef support existed 😱
For about €2 , I now ordered 5 screws in China.
When these arrive, I will use the original crossovers-screws for the B139 and use the Chinese screws for the crossover-filter.
I didn't know Kef support existed 😱
Her eis an example of a threaded insert.
1/4-20 Quick-Connect Flanged Insert Nuts - Lee Valley Tools
dave
1/4-20 Quick-Connect Flanged Insert Nuts - Lee Valley Tools
dave
Only one of those T-Nuts need to come lose and it becomes very difficult sometimes to get the driver out.
Glue is Your friend. I usually staple a piece of leather on the back so they don't fall into the box.
Glue is Your friend. I usually staple a piece of leather on the back so they don't fall into the box.
Hello. I'm back again ...
I ordered the BSW's , probably the 24 threads/inch (3/16-24) , but they don't fit.
So I think I must look for 3/16-32 threads/inch screws.
Attachments
Try a 3/16" (0.188"), 32 tpi, BSF screw.
BSF, 3/16", Cap Head, Socket Screw (12.9). – Fixaball
It could even be a 2BA screw (BA = British Association) which has a diameter of 0.185" and 31.36 tpi.
The two are said to be interchangeable.
BSF, 3/16", Cap Head, Socket Screw (12.9). – Fixaball
It could even be a 2BA screw (BA = British Association) which has a diameter of 0.185" and 31.36 tpi.
The two are said to be interchangeable.
Hello Galu 
Thanks again for your answer 
I've found another seller on ebay and bought these screws :
3/16" BSF 1 1/2" Long Hex Bolt Grade R (Quantity 10) | eBay
To be 100% sure before I bought those, I asked the seller about these screws and he answered : "yes these will fit 3/16 bsf is 32 tpi will do the job. You could also use a 2BA thread which is the same thread type."
So
, but I'm very confident.
So thanks again, I'll keep you posted.
Have a nice day.
Eric
Thanks again for your answer I've found another seller on ebay and bought these screws :
3/16" BSF 1 1/2" Long Hex Bolt Grade R (Quantity 10) | eBay
To be 100% sure before I bought those, I asked the seller about these screws and he answered : "yes these will fit 3/16 bsf is 32 tpi will do the job. You could also use a 2BA thread which is the same thread type."
So
, but I'm very confident.So thanks again, I'll keep you posted.
Have a nice day.
Eric
