Re: CNC Knurling

Scott,

What diameters will you be knurling? The cut knurlers are good for
larger diameters, but not for small diameters. Cut knurls put side
pressure on the workpiece so deflection is a problem as diameters get
smaller.

For diameters in the 1" and smaller range I use an opposed knurling
tool. These will even work down as small 1/8" or less. All the
pressure from knurling is taken up in the holder, this is especially
good for light machines. Opposed holders are fairly reasonably
priced compared to the cut type. Check Ebay, opposed holders show up
all the time, most manufacturers of automatic screw machine tooling
have a couple of sizes in their product lines.

Once you get an appropriate knurl tool the problems aren't over.
Knurling is more of an art than science. It may take alot of
fiddling with various parameters until you can get a good looking
knurl. Workpiece diameter, speed and feed are some of the
parameters. The material makes a big difference, aluminum is
particularily hard to get clean knurls in, it flecks off and the
little flecks are beaten back into the knurled surface.
Whether to use coolant or knurl dry may depend on the job. We use
coolant on continuous production jobs to keep the knurl wheels clean
and lubricate the axle pins, for only a couple of parts those aren't
major issues so we run dry.

Generally, the knurl should be created in as few workpiece
revolutions as possible. This means a a fairly high rpm coupled with
a high feed rate. You NEVER want to idle the turning knurls on a
workpiece and if possible NEVER run the the knurls back over a
knurled area.

Doug

--- In CAD_CAM_EDM_DRO@y..., "fuddham" <fuddham@a...> wrote:
> I have a need to do some knurling. I have been told that cut
> knurling is what you want to do on a CMC machine. Looking at this
> the cost of the tool holder is very high. Is this what I need to
be
> able to do knurling on a CNC turret lathe? What holder should I
get
> or what other way should I do the knurling?
>
> Thanks
>
> Scott