Warburton top and backbore!

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TrombVB
Posts: 129
Joined: Oct 11, 2021

by TrombVB »

Hi to all.

I have such a question. I purchased a top 7ST and a backbore ST1 from two different sellers. But for some reason they do not fit together.

I used to have a ST2 backbore and used it with this top.

Can you please help me in this matter?

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Slidehamilton
Posts: 176
Joined: May 05, 2018

by Slidehamilton »

You might just need to clean the threads. Might be a little excess plating in the threads. Try some kind of oil, and slowly work the backbore into the top a little at a time. Something like key oil.
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TrombVB
Posts: 129
Joined: Oct 11, 2021

by TrombVB »

[quote="Slidehamilton"]You might just need to clean the threads. Might be a little excess plating in the threads. Try some kind of oil, and slowly work the backbore into the top a little at a time. Something like key oil.[/quote]

Thanks, but that's probably not the problem. For some reason, the thread on the backbore is larger by 0.2 mm than on the top.<EMOJI seq="1f937-2642" tseq="1f937-200d-2642-fe0f">🤷‍♂️</EMOJI>
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ithinknot
Posts: 1339
Joined: Jul 24, 2020

by ithinknot »

3/8" x 40 tpi if you need a die...
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Slidennis
Posts: 100
Joined: Jan 08, 2019

by Slidennis »

Warburton changed the diameter of the thread many years ago.

I had him make backbores with the old thread diameter for some bass cups I purchased...
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MTbassbone
Posts: 558
Joined: Apr 21, 2018

by MTbassbone »

Contact Warburton
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TrombVB
Posts: 129
Joined: Oct 11, 2021

by TrombVB »

[quote="MTbassbone"]Contact Warburton[/quote]

I'm waiting for an answer from them<EMOJI seq="1f609" tseq="1f609">😉</EMOJI>
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Kevbach33
Posts: 295
Joined: May 29, 2018

by Kevbach33 »

I was wondering about this myself, but reversed: on my ST9 top and ST2 backbore they're a little wobbly threading on, as if the tolerances were too loose. Looking at the threads it appears the top had lost it's plating, which might account for the wobble (threads on the backbore are fine). But it threads and is tight once on.

I should note that I bought my setup from the same place.

To the OP: How did your prior ST2 thread on? And what are the threads like on the top? You may be surprised at how little it takes to fill the grooves, especially with such fine threads, with gunk.

Here are a few photos of my set up. You can see where the plating has been lost on the top's threads.

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