TAPERING SPRING WIRE (Warning: No Political Content)

Sounds a bit like some items I made a few years ago but the taper was shallower and longer but the idea may apply. Details from the dropbox

I very reluctantly designed #0-80 fillister head screws 1.25" long into a set of narrow, tightly packed optical assemblies and had to make the first batch myself. They weren't as difficult as I had expected to turn and thread from stainless TIG rod, either 1/8" or

5/32", I don't remember and still have some of both. I reduced the rod from full to final size about 0.2" at a time, supported closely in a collet. I think I found that I could cut full depth in one pass.

Perhaps you could turn a series of 20 evenly spaced steps of 0.001" each and then file it with a fine single-cut "pillar" or "hand" file until the steps disappear. You could smooth them further with fine sandpaper backed by the file. jsw

If the 0.070" is at the end of the wire set up for electropolishing and repeatedly dip the wire into the solution and remove it. I've made needle points 1/8 to 3/8" long that way, you should be able to do 1.25" of taper. I was never successful just slowly removing the piece from the solution once, it was too irregular. Repeated dipping averages all of that out. With the tiny surface area you won't need much of a power supply, maybe 5-10 V and 1 amp.

I have an application where I need to make some small stainless steel core pins for a mold. I have some .090 spring wire that would probably work fairly well after I straighten it. Straightness does not have to be perfect, so I'll probably just do that part by hand. Then I run into my issue. I need to taper it from .090" down to about .070" over a reach of about 1.25 inches.

The only thing I could think of is to to a shallow v block and clamp that it the tool holder on the mini lathe. Then lay a file against one end of the V block and slowly bring it back until its just scuffing the wire at the 1.25 inch mark. The grove is to hold the wire from bending against the cutting force of the file. My concern is if I will be able to continue to cut the wire with the file as it work hardens from the action of the file. My other concerns are that I have my hands so close to the spinning lathe, and that this seems to be a very hand skilled approach to the problem.

No the pre tapered pins for sale from McMaster absolutely WILL NOT work for this application. Besides. I already have several hundred feet of .090"

316 spring wire left over from a past project.

I guess its time to go play with a file and see....

That's a way to do it. I had not really though of clamping a guide to the ways like that, but I think it might work if I can get a good cut on the wire.

I did consider some form of solvent forming, but I may need to make a bunch of these. Seems like it would be a little slower than I might like.

Oops. So much for the no political content warning. Good thing I'm not target shooting today. I'ld totally miss the target and break the support wire.

Do them in parallel, each with its own current-limiting resistor, to ensure that the current spreads evenly.

Joe Gwinn

A wet grinding wheel would work for this too. You can just hold stuff against those with your hands.

stuff like small shafts can be allowed to just spin on their own. Want a taper- press harder on one side.

I balled parked it. I found a piece of pre-straightened .094 and cut it into suitable lengths. Then I just chucked a piece up in the cordless drill and free handed them against sanding disc on the side of my benchtop sander. They went way faster than anything else I might have done. Amazingly when I checked it with a caliper it wasn't perfectly linear, but it was pretty darn close. I just spun the drill the opposite direction of the disc and it tapered very quickly and it was very easy to control.