I had a shaft to rework yesterday in the shop. It is for a walk-behind
concrete saw. I had to build up a worn spot with weld and turn it back
down. The shaft was 1-1/4" and shouldered to 1" for a few inches on each
end. I removed all the parts (washers, spacers, pillowblocks, nuts, etc),
but could not get the pulley off to save my life.

The customer brought his own replacement pillow blocks. He said he tried to
order a new shaft, too, but is no longer available. The new pillow blocks
were 30mm, so I had to turn the whole shaft down in order to slide the new
pillow blocks on from one side.

I have the "non-pulley" end in a 1" 5c collet in the spindle, and the pulley
end on a live center in the tailstock. The lathe is an 11" Logan model
955. The shaft turned just fine until the few inches before the pulley. I
got some pretty rough chatter when I was turning the part that goes inside
the pillow block. It shook the entire machine. I tried different speeds
(270-500 something), different tool height, different feed speeds, but
still the chatter. I also tried a center rest. I could not used the
follower rest because of the proximity to the pulley on the tailstock side.

The thing just barely fit in the lathe. I couldn't put the part in the
other way because the pulley assy. extended over the 1" part, so it
wouldn't slide all the way into the collet.

Any ideas why the chatter?

Thanks!
--
John L. Weatherly
MacGyver Industrial Technologies
Nashville, Tennessee

Could that end have been welded before?

"John L. Weatherly" wrote in message
.. .
I had a shaft to rework yesterday in the shop. It is for a walk-behind
concrete saw. I had to build up a worn spot with weld and turn it back
down. The shaft was 1-1/4" and shouldered to 1" for a few inches on each
end. I removed all the parts (washers, spacers, pillowblocks, nuts, etc),
but could not get the pulley off to save my life.

The customer brought his own replacement pillow blocks. He said he tried
to
order a new shaft, too, but is no longer available. The new pillow blocks
were 30mm, so I had to turn the whole shaft down in order to slide the new
pillow blocks on from one side.

I have the "non-pulley" end in a 1" 5c collet in the spindle, and the
pulley
end on a live center in the tailstock. The lathe is an 11" Logan model
955. The shaft turned just fine until the few inches before the pulley.
I
got some pretty rough chatter when I was turning the part that goes inside
the pillow block. It shook the entire machine. I tried different speeds
(270-500 something), different tool height, different feed speeds, but
still the chatter. I also tried a center rest. I could not used the
follower rest because of the proximity to the pulley on the tailstock
side.

The thing just barely fit in the lathe. I couldn't put the part in the
other way because the pulley assy. extended over the 1" part, so it
wouldn't slide all the way into the collet.

Any ideas why the chatter?

Thanks!
--
John L. Weatherly
MacGyver Industrial Technologies
Nashville, Tennessee

John L. Weatherly wrote:
I had a shaft to rework yesterday in the shop. It is for a walk-behind
concrete saw. I had to build up a worn spot with weld and turn it back
down. The shaft was 1-1/4" and shouldered to 1" for a few inches on each
end. I removed all the parts (washers, spacers, pillowblocks, nuts, etc),
but could not get the pulley off to save my life.

The customer brought his own replacement pillow blocks. He said he tried to
order a new shaft, too, but is no longer available. The new pillow blocks
were 30mm, so I had to turn the whole shaft down in order to slide the new
pillow blocks on from one side.

I have the "non-pulley" end in a 1" 5c collet in the spindle, and the pulley
end on a live center in the tailstock. The lathe is an 11" Logan model
955. The shaft turned just fine until the few inches before the pulley. I
got some pretty rough chatter when I was turning the part that goes inside
the pillow block. It shook the entire machine. I tried different speeds
(270-500 something), different tool height, different feed speeds, but
still the chatter. I also tried a center rest. I could not used the
follower rest because of the proximity to the pulley on the tailstock side.

The thing just barely fit in the lathe. I couldn't put the part in the
other way because the pulley assy. extended over the 1" part, so it
wouldn't slide all the way into the collet.

Any ideas why the chatter?

Thanks!
Tool post grinder?

On Wed, 26 Jan 2005 08:19:55 -0600, "John L. Weatherly"
wrote:

Snip

Any ideas why the chatter?

Thanks!

Well, a long shaft can act like a tuning fork and vibrate. It must be
just the right length to produce some serious harmonics.

I have some 3/8-inch lead wire, here, that could probably help you if
only there were not the problem of distance.

If I had a chattering problem with a shaft I'd try putting a steady
rest, somewhere, and wrapping my lead wire around it in an attempt to
cut down on the harmonics.

Are you using carbide or HSS? If you're using HSS, use as small a
radius as you can on the tip of your cutting tool.

Let us know how things turn out.

Orrin

On Wed, 26 Jan 2005 08:19:55 -0600, "John L. Weatherly"
wrote:

I had a shaft to rework yesterday in the shop. It is for a walk-behind
concrete saw. I had to build up a worn spot with weld and turn it back
down. The shaft was 1-1/4" and shouldered to 1" for a few inches on each
end. I removed all the parts (washers, spacers, pillowblocks, nuts, etc),
but could not get the pulley off to save my life.

The customer brought his own replacement pillow blocks. He said he tried to
order a new shaft, too, but is no longer available. The new pillow blocks
were 30mm, so I had to turn the whole shaft down in order to slide the new
pillow blocks on from one side.

I have the "non-pulley" end in a 1" 5c collet in the spindle, and the pulley
end on a live center in the tailstock. The lathe is an 11" Logan model
955. The shaft turned just fine until the few inches before the pulley. I
got some pretty rough chatter when I was turning the part that goes inside
the pillow block. It shook the entire machine. I tried different speeds
(270-500 something), different tool height, different feed speeds, but
still the chatter. I also tried a center rest. I could not used the
follower rest because of the proximity to the pulley on the tailstock side.

The thing just barely fit in the lathe. I couldn't put the part in the
other way because the pulley assy. extended over the 1" part, so it
wouldn't slide all the way into the collet.

Any ideas why the chatter?


Any time there's a heavy weight on a relatively thin shaft it will
be more prone to chatter. The weight will cause any small vibrations
to increase dramatically as you found out. A really sharp tool and
very slow speed is sometimes the only way to get around this. A steady
rest can help if you can get it in the right place but that's not
always possible. In this case I would of slowed down to 100 rpm or
slower and used a extremely sharp pointed HSS tool. Grind the tool
with lots of top, and end rake to help.

I'm not real sure that makes sense but I'm rather pooped from moving
several thousand pounds of steel for the last two days.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook

Wayne Cook wrote:


Any time there's a heavy weight on a relatively thin shaft it will
be more prone to chatter. The weight will cause any small vibrations
to increase dramatically as you found out. A really sharp tool and
very slow speed is sometimes the only way to get around this. A steady
rest can help if you can get it in the right place but that's not
always possible. In this case I would of slowed down to 100 rpm or
slower and used a extremely sharp pointed HSS tool. Grind the tool
with lots of top, and end rake to help.

That makes perfect sense. I turned it down within 10 thou, & took it the
rest of the way with a file. I spent extra time on it, but the customer
was happy. Thanks to all for the replies.

--
John L. Weatherly
MacGyver Industrial Technologies
Nashville, Tennessee

Tom Gardner wrote:

Could that end have been welded before?

It was chattering near and on the weld that I laid. I would have thought
that it was the weld but the chatter started about an inch before. My
money is on harmonics. I wonder what steel these things are made from.
Seemed a bit harder than regular mild steel.

--
John L. Weatherly
MacGyver Industrial Technologies
Nashville, Tennessee

On Wed, 26 Jan 2005 17:29:47 -0600, "John L. Weatherly"
wrote:

Tom Gardner wrote:

Could that end have been welded before?

It was chattering near and on the weld that I laid. I would have thought
that it was the weld but the chatter started about an inch before. My
money is on harmonics. I wonder what steel these things are made from.
Seemed a bit harder than regular mild steel.
Having turned lots of long shafts over the years as a lathe man
chatter sometimes responds to increased tool pressure and sometimes to
decreased too pressure. It seems odd I know. I see you have finished
the shaft so maybe this will help another day. If the shaft is stout
enough, and your setup rigid enough, using a negative rake tool can
work very well. A fairly high feed is also usually needed with the
negative rake tool. On the other hand, a limber shaft, especially if
it's a tube, can benefit from very sharp tools, and a finer feed.
However, you must be careful to grind the tool such the shaft will not
tend to ride up on the tool. One job in particular that I used to run
were tubular drive shafts for turbine engined light planes. These
shafts were made from 4340 and were heat treated to about 38 Rc. The
wall thickness was about .100 and the O.D, about 1,75 in the middle.
They were about 44 inches long. Using a sharp carbide tool with a ,004
or .005 radius on the tip and spinning about 700 rpm worked the best.
I had to use enough cutting oil to keep the shaft lubed enough that I
could wrap my hand around and gently squeeze the shaft while turning.
ERS

In article , "Tom
Gardner" says...
Could that end have been welded before?

"John L. Weatherly" wrote in message
.. .
I had a shaft to rework yesterday in the shop. It is for a walk-behind
concrete saw. I had to build up a worn spot with weld and turn it back
down. The shaft was 1-1/4" and shouldered to 1" for a few inches on each
end. I removed all the parts (washers, spacers, pillowblocks, nuts, etc),
but could not get the pulley off to save my life.

The customer brought his own replacement pillow blocks. He said he tried
to
order a new shaft, too, but is no longer available. The new pillow blocks
were 30mm, so I had to turn the whole shaft down in order to slide the new
pillow blocks on from one side.

I have the "non-pulley" end in a 1" 5c collet in the spindle, and the
pulley
end on a live center in the tailstock. The lathe is an 11" Logan model
955. The shaft turned just fine until the few inches before the pulley.
I
got some pretty rough chatter when I was turning the part that goes inside
the pillow block. It shook the entire machine. I tried different speeds
(270-500 something), different tool height, different feed speeds, but
still the chatter. I also tried a center rest. I could not used the
follower rest because of the proximity to the pulley on the tailstock
side.

The thing just barely fit in the lathe. I couldn't put the part in the
other way because the pulley assy. extended over the 1" part, so it
wouldn't slide all the way into the collet.

Any ideas why the chatter?


Charge extra for the decoration.
Paul Powell




Thanks!
--
John L. Weatherly
MacGyver Industrial Technologies
Nashville, Tennessee




--
The older I get, the better I used to be.