On Tue, 15 Dec 2009 04:24:06 GMT, "Ray Field"
wrote:

Have the need for a low cost CMM or equivalent.
The requirement is to measure bagpipe chanter reed blades (made with metal
machinery!). Reeds are of shaped bamboo slips one and one half inches long
by three quarter inches wide and sixty thou thick (that is the envelope
dimensions). Accuracy plus/minus half a thou. Blades are tapered in length
and width, variably.
Have considered a micrometer stage microscope, my eyes are getting weaker
but could probably manage with average of several readings. This method
would be OK for X & Y axes but what about Z? Could the focussing mechanism
provide accurate measurement?
Ideal would be a computerized laser measuring machine but definitely far too
costly.
Micrometers although very accurate are difficult to apply to the varying
thickness of the blades and angular geometry.
Anyone with experience measuring small parts in a quality control
environment. Any suggestions on suitable and available tools? (A hammer to
smash the reed and render the pipes inoperable is not an acceptable reply!)
Has anyone homebuilt a CMM equivalent?
Any leads on cheap components and plans for building one?
All help appreciated, and I promise that the reeds produced will make 'pipe
music better.
Ray


A toolmaker's microscope would work. The limit on resolution would be
the surface finish on the bamboo, especially when using the focus to
take Z dimensions. Presumably you could avoid taking depth
measurements with the focus by using the fat end as the X dimension
zero and rotating the reed on edge in a fixture to take Z dimensions.

An optical comparator might also work and give you a larger working
field, but would require using surface illumination in the Z
direction, but I don't think would be as sensitive as a microscope in
that axis.

If you send me a reject reed and a table of the dimensions you're
interested in, I'll measure it for you and take a few photos thru my
toolmaker's 'scope.

--
Ned Simmons