Thread used for feet ESL57

[AdVis]

I've unscrewed the feet of my ESL57's so they can sit comfortably on top of my DIY Ripoles and they do sit there comfortably but I would like to have it all a little bit more secure. It seems quite feasible to bolt them to the Ripoles. And it seems like a good idea to use the thread already there for the rear foot.

Except, I can't seem to find what kind of thread it is! Because I am pretty sure it is an English thread, which is rare over here.

Can anyone tell me what thread I should use for a bolt that fits in place of the rear foot of an ESL57?

Thanks in advance!

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[JonSnell Electronic]

If original, they will be 2BA.

 

[rayma]

They should be vertical if significantly off the floor. About 18" is best.

 

[AdVis]

This is how they are sitting now, and it's surprisingly stable and indeed they do come into the right angle. I just want to add a bolt so it's a little less easy to "walk them off" the ripoles. I'll probably add a shim or so so I can tighten the bolt a bit more.

@JonSnell Electronic Is it possible that should be 0BA? The outside diameter of the thread is about 6 mm, but I do think they're original. (if I've understood correctly 2BA would be 4.7 mm)

 

[rayma]

Take the old feet to the hardware store and try to fit the threads of the new bolts into the old threads.
If they fit well, that should be right.

 

[AdVis]

That's the problem, that was my first thought. But the Dutch hardware stores don't carry anything but metric screws.

And the one I tried that was more specialized didn't recognise it either.

I may think of another solution but this just seemed so nice, also because I don't have to change anything on the ESL.

 

[rayma]

Appears there is no shortage of 2BA bolts on eBay in the EU. You do have to decide the proper length.

 

[JonSnell Electronic]

British Association threads are finer than BSF threads. It may well be OBA as it is a long time ago the last time I worked on one.
You may find the attached useful.

https://www.ebay.co.uk/itm/255049117681?_nkw=0BA+screws&itmmeta=01J591YDR7BVQ7FCYS4WJ4PWXD&hash=item3b621caff1:g:ziIAAOSwu0Zg6d4m&itmprp=enc:AQAJAAAA4HoV3kP08IDx+KZ9MfhVJKldsLUBWzIBUtOqwTxWkKYDG5iqgLIhatSXbWlgFf7JUJX5Z927GNMfZhrQcouIaTNB6ZyfLGd/GyQQMNTqZWy7ahJjMTKTB7CrD5t7YEzDQdYqqDCKDnexYNjw0dSw+VSbIq5jiENuWnI46bXrKLNXxsP+zSUwx0NtUrIhUBfH1xzJ9xEnoAqwvqG10Yg8oIW47ahPaRauxlsYMbQVgqkjo55h6iEgoMlzimsvWpZZZkiJzrInoifZUbUEE3xA4tfoA9uPvGudBy78c1BbCKVG|tkp:Bk9SR57c-aGqZA

If you draw a blank, you could always drill and re tap it to M8 or even M10.

 

[rayma]

If you drill, just make a through hole and use whatever bolt, washer, and nut you wish.
Large washers are best to avoid cracking the wood.

 

[wout31]

Thread type?
The original feet are fitted with wood screws to the bottom.

 

[lcsaszar]

I made it like this. 25x25 mm steel profile, sand filled.