Setting Lathe compound at precise angle, a Real Keeper!!!
 

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.

Setting Lathe compound at precise angle, a Real Keeper!!!
 

spaco wrote:

I just summarized a recent post for myself, so I can add it to my own
"machining hints" notebook.

While you are collecting taper-tips:

When taking off the taper from an existing one, it is important, that the
dial indicator's tip is at center height. If it is just off by 1%
(heightwise of the centerline, relative to the diameter), the error will be
about 3% in diameter.

When I had to make a collet holder for ER collets, I took off the taper from
a collet. Therefore, I turned some bar with two lands with exactly the same
diameter. Slipped the collet over it and took off the taper with a dial
indicator.
The bar looked like this (if my explanation was hard to understand) (only
one half shown):

######################## - collet
########################
+-----+ +-----+
| +------------+ |
| |
-- . --- . --- . --- . --- . --- CL

HTHL (hope that helps later),
Nick

Setting Lathe compound at precise angle, a Real Keeper!!!
 

On Aug 5, 12:50 pm, Nick Mueller wrote:
spaco wrote:
I just summarized a recent post for myself, so I can add it to my own
"machining hints" notebook.

While you are collecting taper-tips:

When taking off the taper from an existing one, it is important, that the
dial indicator's tip is at center height. If it is just off by 1%
(heightwise of the centerline, relative to the diameter), the error will be
about 3% in diameter.

When I had to make a collet holder for ER collets, I took off the taper from
a collet. Therefore, I turned some bar with two lands with exactly the same
diameter. Slipped the collet over it and took off the taper with a dial
indicator.
The bar looked like this (if my explanation was hard to understand) (only
one half shown):

######################## - collet
########################
+-----+ +-----+
| +------------+ |
| |
-- . --- . --- . --- . --- . --- CL

HTHL (hope that helps later),
Nick

Thank you both

I just printed this post to act as a simple quick reference for me.

Brent
Ottawa Canada

Setting Lathe compound at precise angle, a Real Keeper!!!
 

"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

Setting Lathe compound at precise angle, a Real Keeper!!!
 

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

Setting Lathe compound at precise angle, a Real Keeper!!!
 

"Tom" wrote in message
...
Harold and Susan Vordos wrote:
snip-----
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

Oh gawd! Did I type that? sigh!

OK----lets change that to a sine bar. :-)

Harold

Setting Lathe compound at precise angle, a Real Keeper!!!
 

Naw, Harold! You typed it right the first time. "Sing", is the sound all those little gage blocks
and that bar thingie made when I threw them on the concrete floor.

Bob Swinney

"Harold and Susan Vordos" wrote in message
. net...

"Tom" wrote in message
...
Harold and Susan Vordos wrote:
snip-----
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

Oh gawd! Did I type that? sigh!

OK----lets change that to a sine bar. :-)

Harold

RCM: Setting Lathe compound at precise angle, a Real Keeper!!!
 

Hi Guys:

I'm going through the current topics to hopefully suggest a way to tag
valid RCM traffic.


Add RCM: on the beginning of the title line - BEFORE the obligatory OT?

Hang tiugh - keep posting.

CaveLamb