On 2010-10-10, Michael Koblic wrote:

"DoN. Nichols" wrote in message
...

[ ... ]

I would suggest that you take a set of fine adjust inside and
outside calipers (spring hinge and a knurled nut on a fine screw) and
use that to transfer the fit from the workpiece pocket to the part which
it fits. It takes a bit of "feel" but that should be better than the
digital calipers overall. That is how machinists made things to fit in
the old days. If you have two pair of each style, you can set the
outside calipers to fit both dimensions on the thing you are fitting,
and then transfer to the inside calipers for both dimensions and use
those to check the fit.


Don, is there any place for using telescopic gauges in this instance?

If you have them -- and can get them to work well for you --
*and* if they fit where you need to measure -- sure.

Personally, I have had limited luck in transferring dimension from outside
to inside calipers and vice versa.

There are people who have trouble getting repeatable
measurements with telescoping gauge, too.

With both -- it is a matter of developing the right feel to get
repeatable measurements or dimension transfers.

Granted -- something which gives you numbers makes it easier to
figure out how much to advance the cutter for the next pass. (But with
the standard calipers, you can get similar information (in a
non-numeric form) by the angle of the clipers when you start feeling
contact with both sides. (Of course, this will change with the size of
the dimension you are measuring.)

I have taken to setting the dimension on
the micrometer (or use the micrometer to measure the male part of the
assembly), set my telescopic gauge to that dimension and then us it to check
the part being machined.

Hmm ... another way to do this is to use some adjustable
parallels -- find one which fits reasonably in the pocket, adjust it out
to make firm contact with the walls of the pocket, and measure the part
which is projecting from the pocket using your micrometer. (Do I
remember you asking what adjustable parallels are for in an earlier
exchange?)

Here is a web site showing the use of adjustable parallels to
measure an internal dimension:

http://www.wttool.com/product-exec/product_id/16863?utm_medium=cpc&utm_source=froog

Anyway -- there are always multiple ways to accomplish something
in machining -- and in many other things as well. The trick is to find
one which works for you.

Enjoy,
DoN.

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