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questions about making tongues


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Paul, thanks for your helpful measurements.  

 

Alex, thanks for your detailed explanation.  I calculate that the average spread in all of Paul's measurement to be 0.0059 inch, or +/- 0.003 inch.  Can you estimate the average gap between tongue and slot that you get with your finished product?  

 

If I recall correctly, Dana once commented that his gaps are maximum about a half thousandths of an inch.  

 

Paul's measurements indicate that the slot inaccuracies don't follow the same trends among the different results, and that would perhaps make filing the tongue more tedious.  I'm curious how you visualize the gap in order to see  how your filing is going.  I once used an optical comparator, which, on an overhead screen, displayed a very magnified version (10x) of whatever you placed on the table, which had a glass surface that was backlit.  I'd think that such an apparatus could be very helpful for this kind of work.  

 

Regards,

Tom

 

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1 hour ago, ttonon said:

Alex, thanks for your detailed explanation.  I calculate that the average spread in all of Paul's measurement to be 0.0059 inch, or +/- 0.003 inch.  Can you estimate the average gap between tongue and slot that you get with your finished product?  

 

If I recall correctly, Dana once commented that his gaps are maximum about a half thousandths of an inch.  

 

Paul's measurements indicate that the slot inaccuracies don't follow the same trends among the different results, and that would perhaps make filing the tongue more tedious.  I'm curious how you visualize the gap in order to see  how your filing is going.  I once used an optical comparator, which, on an overhead screen, displayed a very magnified version (10x) of whatever you placed on the table, which had a glass surface that was backlit.  I'd think that such an apparatus could be very helpful for this kind of work.  

 

I don't have a good way of measuring it. Certainly less than 1 thou. I used to use a low power optical binocular microscope, but I've lately switched to a 1080p video microscope connected to a 22" monitor. I place the reed assembly on top of a lit stage to illuminate the gap.

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hello again. there are some suppliers that sell 1095 tempered steel in rolled strips like this:fleje.jpeg.dac304f2183f09fb1f057255b6a722e6.jpeg

would this work? I understand that if it works I should straighten the steel somehow

thanks for your help

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10 hours ago, lucayala said:

hello again. there are some suppliers that sell 1095 tempered steel in rolled strips like this:fleje.jpeg.dac304f2183f09fb1f057255b6a722e6.jpeg

would this work? I understand that if it works I should straighten the steel somehow

 

Can you get them to give/sell you a small sample that you can try first? A few years ago I bought a 10Kg roll of spring steel from a new supplier, cut 50mm off the end, and made a couple of test reeds from it. It was no good: much too soft. The supplier refused to take it back for a refund because I'd cut some off it. Expensive mistake.

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39 minutes ago, lucayala said:

oh, that's bad. I will try to get some samples

how did you straighten the steel?

 

It will probably already be reasonably straight once you've unrolled it. Beware it is likely to instantly and violently unroll itself if you simply cut the band that holds it together (and to make matters worse it may have razor sharp burrs on the edges). Once you've cut a piece off the roll and sheared it lengthwise into roughly reed-tongue-sized blanks, you can clamp one end of each blank in a vice and use pliers to grip the other end while manipulating it to take out any twist and bend it straight.

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Quote

Beware it is likely to instantly and violently unroll itself if you simply cut the band that holds it together (and to make matters worse it may have razor sharp burrs on the edges). 

Do not, under any circumstances, cut the external retaining band fitted to coils of spring steel.

Always cut pieces from the inner end of the coil using good substantial snips. 

 

Geoff 

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