Gear wear on my lathe
 

Some day I'll figure out how email works..
----------------

Thanks for much detail, Scott. I thought cone-pinion was a pretty
strange name for the gear. I'm talking to a guy named Chris, who goes
pretty much by the drawing and asking questions of someone else. I'll
check into this further.

The twins have differing numbers of teeth, 28 on the right, 32 on the
left. It looks likely this can be seen in the part numbers.

Much appreciated,
Steve

Scott S. Logan wrote:

On Thu, 06 Oct 2005 19:28:24 -0400, Steve Smith
wrote:


I clearly need to replace some gears on my lathe, the question is how
many? There are four gears showing signs of wear, one of them really
bad. Replacing all four gets pretty expensive. The lathe is a 14 1/2"
Southbend.

First, naming the gears. Here's a picture of the group:
http://users.frii.com/sos/Steve/Overall.jpg

Parts Works names them as follows:
top gear in picture (this gear is on the spindle): "cone-pinion"
two gears just below cone-pinion: "twin gears"
gear which right twin gear drives (below R twin gear): "reverse gear"


Usually, I would not contradict Rose, but at least one of the names is
incorrect. According to the SB manual, the upper gear in your pic is
the Spindle Gear (PT30F2).

The Cone Pinion is a different part, located partially within the Cone
Pulley (hence the name).

The "Twin Gears" are called that in the manual, although we call those
the Reverse Idler Gears. For your lathe, they are PT27K32F2 and
PT27K28F2. 'Course, if they are "twins", why different numbers?

The Reverse Gear is PT28F2.

As mentioned elsewhere, these may last a long time yet, but might also
fail during a critical operation tomorrow.

I agree that the Twin Gear needs replacement at least. I don't know
if you can swap them as mentioned by DoN, since they have different
part numbers, but if so, that may prolong the life.

I respectfully disagree with Harold, that if they fail, they will not
do other damage. I've seen it happen in Logan Lathes, and the tooth
that gets kicked out CAN wedge into another gear damaging it and even
the shaft or stud upon which it is mounted.

Of course, if you leave the Reverse Bracket in neutral, there is no
load at all on any of these gears, and they SHOULD last forever. Kinda
tough to thread that way, though.

Good luck!