5 replies to this topic

[Pablo]

Just when I thought I had found and discarded all my bad lengths of wire, I found another bad batch.

1/16 K & S piano wire, 12" lengths, and the entire bundle was bad.

Same markings as before - barber-pole-like dark striations, and it's bent through and through.

 

The reason I bring it up again is because I found a short cut to check entire batches as opposed to checking each piece with my dial indicator.

 

Simply lay the rods, or wires, together, and roll them together on a flat surface.

Any, or all, bad ones will be readily apparent. The ends must be either cut flush, or champhered.

 

 

In this case, the entire batch of 1/16 rods was good, but one piece had one bad spot.

[Bill from NH]

That's the way we used to check for bent axles. Roll them down an inclined piece of glass.The bent ones make quite a racket.

[Pablo]

Did you do them five at a time?

[Bill from NH]

It depends upon the size of the pane of glass used.

[Dave Crevie]

The spiral marks are from the straightening machine used to straighten the wire when it is uncoiled from

the spool it is shipped on. It is common for wire to take on a slight curve as it relaxes after straightening.

This can happen over time, so chances are if you buy hobby rod, it will have a bend. The exception is rod

that is drawn and then cut to length at the machine, not coiled on spools. You can find rod made that way

at commercial suppliers, but is more expensive and there usually is a minimum quantity order. I made a

straightener out of a length of brass tubing with an inside diameter slightly larger than the rod being

straightened, and put a slight S bend in it. When the rod is pulled through the tube, it will usually come

out straight. 

[Pablo]

That sounds like a nice trick for wire with a slight bend, Dave.

 

But let's be clear, I'm talking about entire batches of it that's bent like a snake every couple inches.

K & S denies it comes that way from the factory. All my bad wire is the 12" lengths but others say they have had bad batches of 36" lengths. All my 36" lengths of it have been perfect.

 

It's a mystery. But my batch roll method sure saves a lot of time identifying the bad stuff.