Harold and Susan Vordos wrote:
"spaco" wrote in message
...

I just summarized a recent post for myself, so I can add it to my own
"machining hints" notebook. This one is one of those real keepers, as far
as I am concerned. Thanks to the original poster and the guys who answered
him.
Pete Stanaitis.


The Question:
I'd like to try to turn some short tapers with a lathe. I'd be interested
in suggestions on how to set a fairly precise angle.

Answers:

1. If you have a sample of the taper needed:
You start with a piece with that known taper mounted in the lathe and
centered. Then you mount a dial test indicator in the toolpost and crank
the compound rest back and forth watching the needle (indicating the
taper, obviously). When the needle doesn't move, you have matched the
taper.

2. If you don't have a sample of the taper needed:
Fairly precise? With the engraved numbers on the cross slide.
Preciser? With a cylindrical round in the chuck, a dial indicator on the
compound and feeding a known distance with the compound. The rest is math.

3. If you don't have a sample of the taper needed:
A guy I used to work with had a sine bar that had a base which was mounted
between centers. The actual sine bar was hinged. I think he held the gage
blocks and all together with rubber bands. I suppose he used a dead center
under pressure to keep everything from moving.


The harsh reality is that you have too many chances of introducing error by
the method described in example 1. Not only must the indicator be dead
on center, so , too, must the cutting tool.

If an angle is critical, the reliable way to check it is with a sing bar or
plate, and a proper setup.

Harold


What key would the sing bar been in, Harold? :-)

Tom