View Full Version : Scribing lines
05-28-2001, 01:46 PM
I want to scribe some degree marks on an IC engine pulley. I've got a rotary table, but what do I use to cut the lines? I've looked in a couple of catalogues and can't find a pointed end mill...
I believe Guy Lautard's "Machinist Bedside Reader #1" describes making a cutter for that purpose. You don't need one that turns. Make something about like a very pointed lathe tool (make it out of drill rod and harden), put it in a collet in your mill, set it a few thousandths lower than the work you want to scribe, and crank the work under the cutter by moving the mill table. (I'm assuming here you will be starting off the edge of the work and moving onto it.) You may want to lock the mill spindle against rotation; if that's necessary, I just tie a rope across the V-belt. You don't need absolute rigidity, as there is no particular inclination for the spindle to turn, anyway.
05-28-2001, 07:27 PM
Here are a few other options you may want to try...depending on how fine a line you want
to make. You could turn a point on a piece of drill rod and harden it. Also, you could turn a point on a dowel, though its not easy and will waste some carbide. You could hand grind a point on a broken end mill shank. I've seen a spring center used, and a # 0 center drill(spinning)also works. Good luck.
05-28-2001, 09:40 PM
I'll try a couple of of the techniques on a spare.
I checked the catalogues again. A side-'V' cutter looked good with a vertical set up, but they are short and the cutter diameters are smaller the the holder diameters.
05-29-2001, 11:34 PM
Hi. I have a broken tap that I ground a point on very simmiler to a threading tool for a lathe. It is chucked in a collect in the mill and the table is used to scribe the line after adjusting the depth of the mark.
05-30-2001, 08:28 PM
Now there's a hard piece of metal...
Somehow, I'd bet there's a broken tap around here, since I hardly ever throw anything out.
Steven L Jones
06-03-2001, 11:46 PM
many times I have used a center drill .to mill divisions marks with . touch the work .then lower the center drill .010-.015 and proceed .same as a milling cutter.gently.
06-08-2001, 08:10 PM
Ended up using an old tap I ground to a 60* V, held in a drill chuck. Kinda 'broached' the lines.
A .0075" deep cut (three passes @.0025") produced clear, easily visible lines.
I'll try a center drill for the heck of it.
Edit; 60*, not 69*; keys are kinda close
[This message has been edited by Ron LaDow (edited 06-08-2001).]