I need to heat a 1" diameter piece of 360 brass that is .100" thick to
375 degrees F minimum. I need to slip fit a .09375" (3/32") shaft in a
..0906" hole. I calculated using thermal expansion that at 375 degrees F
the hole would expand by about .003". My problem is I of course need to
heat it up to a higher temp to keep it at 375 degrees after I remove it
from the oven to get the piece onto the shaft.

I am heating these in a toaster oven that will get to about 500 degrees
but is terrible in efficiency.

I am sure to calculate this you need the area and the volume so they
are below:

Area = .00785 in^2
Volume = .000785 in^3

I mainly need to know how long it will take to heat up a piece of brass
to around 500 degrees F with the below listed volume and area.

Any help will be greatly appreciated.

wrote:

I mainly need to know how long it will take to heat up a piece of brass
to around 500 degrees F with the below listed volume and area.

Until it is hot enough to fit.

Who cares how long it takes or the efficiency of a toaster oven, are you
trying to calculate the cost or something? Turn the darn thing up to
high for bit and see what happens. If you really need some feeling of
technical control go buy a tempstick for the temperature you want.

Rick

If you're that interested in precise temperature measurement,
electronic, optical pryometers (sp?) are sold in ever cooking store in
the country at low cost. (My daughter purchased on to measure the
temperature of here pizza stone!) Still, why bother?

For the shrink-fitting of metal parts, as other posters have suggested,
I simply eyeball it. Still, I usually work in the opposite direction,
by machining the insert to the dimensions for a shrink-fit, then
cooling it in either a dry-ice/alcohol mixture or (if available) liquid
nitrogen.

This method works much better than trying to heat something with a hole
in it, and hoping that the hole expands as predicted with heat.
(Usually it doesn't and you'll likely screw-up a dozen or so parts
before you get it right.)

Harry C.

wrote: (clip)I usually work in the opposite direction,
(clip)
^^^^^^^^^^^^^^^
Why not do both? A combination of heating and cooling doesn't require as
much of either.