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David Hart

Odd bow screw thread

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Hey fellas,

 

It's been a (very!) long time! Very sorry i missed the opportunity to meet my favorite violin maker in Australia last week, maybe one day I'll meet the legendary sawzall fiddler. I trust much hillarity was had over the week!

 

I have a french bow being restored atm and the eyelet is well and truly busted (along with the slide which was warped and had paper stuffed underneath for some reason)。

 

Unfortunately the thread is neither metric nor imperial, which is the only two eyelets I have. The bow itself isn't ridiculously old so I'm guessing the thread may be what I've found referred to as 'french’, but I'm wondering if anyone has an idea either where I can find this type of eyelet or an alternative solution  that doesn't involve an entirely new screw.

 

 

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I'm not a bow expert but I'm thinking that just because your screw doesn't fit the one imperial and one metric eyelets that you have doesn't necessarily prove that it's not some other imperial or metric size/pitch. I'd get out my screw thread pitch gages and try to find a match, and my calipers to look for a rationale for the screw diameter. That would be a start, at least.

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I'm keeping a heap of maybe 100 or more junk bows just for the reason that I'll need to look for different eyelets or screws.:)

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In the past, threads were much less standardized than they are now.

I buy eyelets with untapped holes.  Even with my collection of about half a dozen different taps I can't always find one that matches the threads of some screws.

Some bow restorers have taps custom made for uncommon threads.

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We had this problem recently with a lovely Simon. The 2 options that we ended with were:1-conserve the original eyelet and screw and replace them,and 2-someone in NYC who will analyze the metal in the eyelet,  fill the hole with the appropriate alloy, analyze the screw and fabricate a tap and  thread the eyelet. We chose 1. The bow works well and we have the original parts to go with the bow for the next owner.

On lesser bows, I have no problem with replacing the screw and eyelet. 

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I just had two taps made to fit the coarse threads on many of the old German trade bows. Taylor tools manufactured them, a M3x80 and a 5x30. They weren't cheap but I seem to run into a lot of these threads enough to warrent the expense.

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10 hours ago, Brad Dorsey said:

In the past, threads were much less standardized than they are now.

I buy eyelets with untapped holes.  Even with my collection of about half a dozen different taps I can't always find one that matches the threads of some screws.

Some bow restorers have taps custom made for uncommon threads.

This might be the long term solution. 

It doesn't help that the only eyelets you can buy are simply sold as "metric" or "imperial", which doesn't narrow much down.

If this bow didn't have an unusual end on the screw (using pernambuco instead of ebony) I would probably just replace the whole assembly. 

 

There was a second bow in the case which also seems unusual. Metal tip and small metal pins in the frog for eyes. Unmarked. No metal slide. Workshop marks (XVI) on both bow and frog. Workmanship is rough, but it plays really well. 

I'm curious about it's maker, but I'd like to know if anyone knows who was putting metal pins for eyes.

 

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