How can I produce a tapered piece of brass rod?

[billmart]

I'm trying to make a shift lever for a vintage automobile in 1:13.7 scale.  I'd like to produce a tapered shaft since such details are apparent in this large scale.  So, let's say I want to start with an 0.060" diameter brass rod, then have it taper down to 0.040 inches over a length of 2 inches.  I'd like some suggestions on how to do this.  I have few power tools so I'm probably stuck with manual methods.

Bill Martinsen

[Bexley]

I've done it by chucking the brass into a drill and using coarse files to get it close, then finer and finer grits of sandpaper to smooth it. I't's a lot easier on a lathe, but I don't have one at home. (Yet.)

[lab-dad]

I have a lathe but wouldn't do it on a lathe.
I would chuck it in a drill, then lay it against my belt sander.
A piece of sandpaper on a flat block would also work, just not as fast.
-Marty

[billmart]

Thanks for your ideas, Bexley and Martin.  In the past, I've chucked the wire (rod) in a drill and applied sandpaper as it rotated.  I'll probably resort to this brute force technique again.  I was hoping someone might have an easier and less time consuming method.  I might try dipping the wire into ferric chloride (used for etching brass) repeatedly, dipping it a little deeper into the etchant each time.  This should result in a rough taper that could be smoothed with some sandpaper.

I'll let you know what I do.

Bill Martinsen

[narrowgauger]

Hi Bill

I do this quite frequently using the lathe and standard Swiss files.

technique is to place the orinal rod material in the 3Jaw chuck; extend the material about 10mm in excess of the required final length; set the outer end in your tailstock chuck loosely tightning the chuch to the extent that the material will still rotate freely in the tailstock chuck. Small drop of oil at the tailstock end will help, but not essential

file the material (I assume you are using brass rod) using normal rotation of the lathe by moving the file diagonally accross the material towards the tailstock.

you will find that the workpiece will deflect under the file pressure,  this is not a problem providing you only apply light pressure.

simply continue to work the files towards the tailstock until you have the required taper and diameters.  remove from chuck and tailstock and cut-off the excess length from the end.

simple technique, takes only minutes.

hope this helps
Have fun
Bernard

[lab-dad]

Placing a tube of material the correct inside diameter in the tail-stock in a drill chuck
would also hold it from deflecting too much and allow it to spin.
-Marty

[billmart]

I finally got around to trying a couple of the suggested techniques.  I chucked a piece of 0.052" diameter brass rod in the 3-jaw chuck of my little OLD Unimat lathe.  I put a piece of styrene tubing in the tailstock to support the free end.

For attempt #1, I used a short strip of 80 grit emery cloth.  It was working, but very slowly.

For attempt #2, I used a small file.  Worked like a champ!  In just a few minutes I had reduced the diameter from 0.052" to 0.040" over a length of about 2 inches.

I am now a happy camper.  Thanks, guys.

Bill Martinsen