I haven't run one of the 12x36 China imports, but I've read numerous owners'
comments which were favorable about those lathes.
You received some excellent suggestions concerning chatter, which you can
usually count on when you ask questions in the RCM forum.
For the 2 Asian machines that I have (bought 1 new, 1 used), both of them
produced less chatter after I checked that the spindle bearings were fully
seated, and had adjusted them for a little preload.
The correct preload is especially important when turning parts that are only
supported by the chuck, IMO.
I dunno what the 12x36 model's bearing preload should be, and maybe it's OK.
Adjustment might require some experimentation, and I suppose the best
guideline is that the bearings shouldn't get hot when the spindle is test
run at one of the higher speeds.
On the loose end of the spectrum, the chuck shouldn't coast excessively when
spun by hand (with everything else disengaged from the spindle).
If I were trying to groove a 3" diameter piece, I'd try to cut the groove
with a thinner cutting tool.. a 3/8 radius groove is a lot of tool edge
contact.
I've roughed out grooves as big as 1/2" radius (and depth) with a smaller
cutting tool (although I use HSS), and finished the groove with files to get
a smooth radius (for tubing bending dies, for example).
For cutting a pulley groove for a V-belt, the same rough turning is SOP,
then the sides of the V are finish turned 1 at a time by advancing the
compound feed set to an appropriate angle.
I also use the Lenox Pro Tool Lube applied with a dispenser bottle or brush,
and find it to be a good all-around cutting lube for machining small parts.
I particularly like that it rinses off with water, and that steel parts
aren't especially susceptable to rusting even after water rinsing.
WB
..............
"Dennis Shinn" wrote in message
...
Totally new to metal turning on an engine lathe. Bought an inexpensive
(read cheap Chinese) Grizzly machine which is about all I really need
for my hobby type projects but - seems to me I'm getting way more
chatter trying to turn stuff than even this machine should produce.
I'm trying to turn a grooved disk, 3" in diameter. I faced off a piece
of stock (in a three jaw) and turned about 2" reasonably true. Then
took an old carbide cutter my brother gave me, looked something like a
thread cutting tool, and ground the end to about a 3/8" radius. On a
green wheel, of course.
If I 'touch up' the tool on the ginder, go back to the lathe, I'll get
a really nice curly chip off the stock at first then the tool will
start to chatter and I'll get a whole mess of little semi-circular
shavings, if you will.
I've checked and rechecked the tool for center and it's as close as I
can get. This chatter occurs with or without lube. (Using Lennox
ProLube applied manually).
Am I just asking more of this lathe than it can produce? It's the
12x36 Grizzly gear head model.
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