Re: Productivity in 1/2 in aluminum, tessellation
>My simplest answer is 'not a chance in hell' I wouldn't cut 1/2" deep
> Does it seem practical that an 1/8" endmill would be able to
> do full depth cuts in 1/2" aluminum?
with a 1/8" mill on my knee mill. Usual advice is to cut one diameter,
or less with an end mill, so a 1/8" cut MIGHT be possible on a big
machine. Not a chance it would even work on a Sherline. Far to much flex
in the machine.
Your part size is reasonable on a Sherline, but not your 8-12" square
stock. Maybe the long stock would fit, but your length of travel on a
Sherline wont make more than 2 or 3 parts without resetting.
Sherlines are great LITTLE machines, but I dont think this planned job
If you make a jig and use bushings to locate the drill, the amount of
variance part to part can only be the clearance of the drill bit in
the bushing. Obviously you want the minimum clearance here but
whatever it is will determine the variance. Hardened bushings will
probably have little to no wear in a run of 2000 parts but if it is a
concern you would probably need to replace the bushings along the way.
Note that what is involved here is variance rather than error. After
all the jig may be off in it's manufacture.
Hand locating CNC spotted holes has more potential for error since
for any kind of reasonable production speed the drill bit will not be
lined up true to the spot by some amount. Certainly a jig will do
I assumed that you would use a Sherline mill to produce the jig;
although the bushings could be bought rather than made at home.
As far as watching the CNC mill do the work goes, that could be fun
for 1, 5, even 10 or more pieces. But 2000? I'd rather read a book
--- In SherlineCNC@yahoogroups.com, "joel.graber1" <joel.graber1@...>
> A previous poster suggested that even with a jig, the drill bit
> would skate around on the face, which reduces the precision of the
> location of the holes. Hardened bushings would help keep the jig
> from wearing during the skating.
> Do you have any personal experience to share about the accuracy
> of drilling through a jig?
> Another poster suggested that hand locating cnc spotted holes
> would run faster on the drill press than using a jig on each block.
> The tradeoff is that contracting out the jig means I don't
> have to buy the CNC in the first place, which also means I dont
> get to watch it work....