On Mon, Jul 6, 2009 at 3:27 PM, Martin
Klingensmith<
[hidden email]> wrote:
> Does anyone make their own pattern and have it waterjet or CNCed from
> someone like at
http://rfqwork.com/ ? I've gotten some good quotes
> from people there. Same disclaimer applies.
Sure, you can do that, but the hard part is the measurement. Ideally
the shafts must be within about 3/1000th inch concertric to avoid
premature bearing wear.
You need to align the motor and transmission alignment system (usually
pins) pretty closely. This is easy if you have access to a coordinate
measurement machine. If you have access to a CNC machine you can
sometimes use it for measuring. Or you can use the tried and true
"cones and calipers" method. Once you get the center of the shaft and
the pins well aligned the other bolt holes are not as critical.
Waterjet is fast and easy, but can be expensive if you're doing only
one. A skilled machinist can drill the holes using a digital read out
equipped milling machine in a few minutes. The transmission can then
be laid on the plate, traced and cut out with a bandsaw or even a
jigsaw.
The hub is a little more time consuming. It takes care on the lathe
to get everything just right, and a little forethought to make sure
everything is precise and concentric. A little error here gets
multiplied by the width of the flywheel and can be a real vibration
problem. Broaching the keyway requires specialized cutters.
All this is within the range of most people with machining skills and
access to the tools. The rest of us will need to find an experienced
machinist.
REVOLT now has the tools and skills to do many adapter plates, but
we're struggling to find an affordable yet skilled machinist. When
EVCC was in operation Larry Foster was happy if he was collecting
$30/hr for his work. Today it is nearly impossible to find a
machinist that will work for that amount. So REVOLT has to charge
more, or we have to find retired machinists that are willing to work
for less, but they tend not to be very "schedule oriented".. I think
this is the cause of most of the lead time issues seen in getting
adapter plates.
Mark Farver
REVOLT Custom Electric Vehicles
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