A friend of mine has a problem with his mini-excavator. It is a
"Nagano" NS-15. The problem is in the unit that rotates the cab and
bucket arm. After disassembly we found the pinion that mates with a
large ring gear is broken.

My friend was told that the pinion was not available, and he would
need to buy the whole new rotator unit for something north of 5 grand.


At this point we are looking for a source for a used part. After a
web search I was not able to locate a used part of even a used rotator
unit.

Any help in finding this part would be appreciated.

John Normile
camperkn_at_yahoo_dot_com

John Normile wrote:
A friend of mine has a problem with his mini-excavator. It is a
"Nagano" NS-15. The problem is in the unit that rotates the cab and
bucket arm. After disassembly we found the pinion that mates with a
large ring gear is broken.

My friend was told that the pinion was not available, and he would
need to buy the whole new rotator unit for something north of 5 grand.


At this point we are looking for a source for a used part. After a
web search I was not able to locate a used part of even a used rotator
unit.

Any help in finding this part would be appreciated.

Could you just make one?

--
John R. Carroll

"John Normile" wrote in message
...
A friend of mine has a problem with his mini-excavator. It is a
"Nagano" NS-15. The problem is in the unit that rotates the cab and
bucket arm. After disassembly we found the pinion that mates with a
large ring gear is broken.

My friend was told that the pinion was not available, and he would
need to buy the whole new rotator unit for something north of 5 grand.


At this point we are looking for a source for a used part. After a
web search I was not able to locate a used part of even a used rotator
unit.

Any help in finding this part would be appreciated.

John Normile
camperkn_at_yahoo_dot_com


How about taking the pieces of the pinion to a machine shop and see if
they can repair it for you? If not, maybe they can make you a new one?
Art

On Feb 5, 10:43*pm, (John Normile) wrote:
...
My friend was told that the pinion was not available, and he would
need to buy the whole new rotator unit for something north of 5 grand.
...
John Normile
camperkn_at_yahoo_dot_com

Making an unavailable gear::
http://picasaweb.google.com/KB1DAL/H...10370886636434

The cutter was shaped to fit an undamaged tooth space in the broken
original.

That one is aluminum. How about Stressproof or 4140 Prehardened?

jsw

Jim Wilkins wrote:
On Feb 5, 10:43 pm, (John Normile) wrote:
...
My friend was told that the pinion was not available, and he would
need to buy the whole new rotator unit for something north of 5
grand. ...
John Normile
camperkn_at_yahoo_dot_com

Making an unavailable gear::
http://picasaweb.google.com/KB1DAL/H...10370886636434

The cutter was shaped to fit an undamaged tooth space in the broken
original.

That one is aluminum. How about Stressproof or 4140 Prehardened?

Better to break the pinion than the ring for one thing.
Make two and have an available spare.

--
John R. Carroll

"John R. Carroll" wrote in message
...
Jim Wilkins wrote:
On Feb 5, 10:43 pm, (John Normile) wrote:
...
My friend was told that the pinion was not available, and he would
need to buy the whole new rotator unit for something north of 5
grand. ...
John Normile
camperkn_at_yahoo_dot_com

Making an unavailable gear::
http://picasaweb.google.com/KB1DAL/H...10370886636434

The cutter was shaped to fit an undamaged tooth space in the broken
original.

That one is aluminum. How about Stressproof or 4140 Prehardened?

Better to break the pinion than the ring for one thing.
Make two and have an available spare.

--
John R. Carroll

But neither Stressproof nor a machineable hardness of 4140 is going to make
much of a pinion. Those things typically are loaded like crazy. If they're
through-hardened (the weakest heat treatment for a highly loaded gear, but
the most common), they're generally too hard to machine with ordinary tools
and machines.

Is this a straight-tooth pinion, or a spiral or hypoid? If it's one of the
latter, there aren't many shops that could make it, without a Gleason or
Liebherr gear generator, which means a custom gear maker. Not cheap. Even if
it's straight, it's not a heck of a lot easier. The teeth and the gullets
are tapered from one end to the other.

I'm wondering if the size of the set is close enough to that of a truck ring
and pinion that you could make that fit, or machine either one a bit to fit.

--
Ed Huntress

On Sat, 06 Feb 2010 07:00:12 GMT, (John
Normile) wrote:


The pinion has two ground bearing surfaces plus a spline on one end
and the gear on the other end. Being of Japanese manufacture, I
assume both the gear and spline are metric. I am looking at reparing
the existing pinion shaft, but want to explore finding a replacement
first.


Perhaps a last resort, but I just had a couple gears that need to be
duplicated quoted by these folks.
http://www.wgear.com/

One part was a non-standard (extended pitch) 8DP pinion on the end of
a shaft, with two bearing seats and a locknut thread, made from 4150
with induction hardened teeth. The price was about $900 for two
pieces, including an engineering charge to measure and document the
original gears.

By no means cheap, but it didn't seem unreasonable to me.

--
Ned Simmons

On Feb 5, 9:43*pm, (John Normile) wrote:
A friend of mine has a problem with his mini-excavator. * It is a
"Nagano" NS-15. * The problem is in the unit that rotates the cab and
bucket arm. * After disassembly we found the pinion that mates with a
large ring gear is broken. *

My friend was told that the pinion was not available, and he would
need to buy the whole new rotator unit for something north of 5 grand.

At this point we are looking for a source for a used part. * After a
web search I was not able to locate a used part of even a used rotator
unit. *

Any help in finding this part would be appreciated.

John Normile
camperkn_at_yahoo_dot_com

Sounds like he has a problem.

http://www.machinerytrader.com/list/...33&Manu=NAGANO

Better start checking the junkyards.

TMT