"Harold & Susan Vordos" wrote: (clip)The normal practice is to chuck a piece of stock and turn the center using your compound rest to create the angle. (clip) ^^^^^^^^^^^^ How about turning an "onsert" to fit over something you already have?
So long as the item you select can be turned after installing, and can't move about, it might work fine. Keep in mind that the reason for turning the center in place is so it will be dead concentric with the spindle. .
While Jim's point about concentricity and roundness are correct, working between centers that do NOT run properly is not a good idea. Often the reason for installing centers is for second operations. Centers are typically used for grinding, for example. If the centers are not concentric with the part (such as when the one in the headstock runs out), when the part is placed in either dead centers, such as are normally found in grinder headstocks, or in centers that run properly, the amount of error is now present. Assuming one has left .010" for grinding, and the headstock center was not concentric by a like amount, there would be no material for cleanup.
Harold
Hey GWE, I called and left a message but posting is also a good idea. Use a drill chuck arbor for your center. You can buy an import 2MT for
4 bucks and 14 bucks for one made by Jacobs. I dunno if the Jacobs branded ones are made in the USA. Later, ERS
catalog page: "Precision hardened & ground to closest tolerances" ..
Tougher to do than one might think. Centers are hard all the way through, and a torch would take a while to soak the entire part. It may cool too fast to fully anneal - I would think a charcoal fire and then leave it to cool in the ashes.
But a soft arbor (like for a drill chuck) comes annealed.
Jim
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.