Mitre Template Casting

This page attempts to explain the steps in casting a Preston like mitre gauge. Just the pattern, core box and casting are shown on page 63 of Jim Kingshott's Making and Modifying Woodworking Tools. How it all fits together at the foundry is left to the readers imagination- unless the reader knows about pattern making or this page.

Pattern placed in the drag (bottom half) of the flask The pattern was dusted with parting compound.
Molding sand was then dumped in and rammed
around the pattern.

The drag was then turned upside down.
You are looking at the bottom of the pattern.
The white stuff is the parting compound. The cope (top half) of the flask is placed over the
drag and filled with molding sand. A sprew pin
(a dowel rod) is put in place. The pin will be
withdrawn later and eventually molten metal will be
poured down the hole left behind.

The flask halves are separated. Here is the
drag half with the pattern still embedded in the sand.
(picture repeated for clarity) The pattern is then withdrawn, leaving a void that
matches the patterns shape. We wouldn't want to
pour in the molten metal yet. If we did
the casting could come out exactly like
the pattern- which isn't what we want. We will add
a sand core to reduce the volume of molten metal
the mold will hold- giving us the casting we want.

Here's a picture of the empty core box. It's job
is to produce the prism shaped lump of sand
to fill the portion of the mold we don't want solid. Here's the pattern with some blue tape applied.
This area is referred to as the core print.
It creates a shelf to support the core.
If the core was the same width as the mitre
gauge casting, the core would fall in too far.

From left to right: the core box, pattern and casting. The core box has the same blue tape to hopefully
tie this all together. The pattern and its core print create a void that is partially cancelled out by the core.
The moldten metal can flow into the the area that's left - which gives us the casting we want.

The core box is filled with molding sand to which
a small amount of molasses and water has been added The core is removed from the core box
and baked for an hour at 350°F

The core is carefully dropped into place. The lighter
color is the bottom of the cooked core The sprew pin is removed from the cope and then
placed over the drag. Molten brass is then poured
into the mold

What appeared after opening the flask. The
lighter colored area is the baked core The casting remains after chiseling out the core.
Something that with a little cleanup will look
like a Preston mitre gauge!

The gauge is for laying out 45 degree mitres and
transferring marks from a boards edge to its face etc.
At Tiller's (where the casting class was held)
they said it would be a handy thing to have
when timber framing!

From the 1909 Preston Catalogue:
Improved Square and Mitre Templet.
For Mitreing and Squaring up the Ends of Wood.

Click here to read my oldtools post about this. (note that the links in the post are no longer valid.)

A few months after casting this gauge I found one for $5 at a tool meet. Pretty funny since the one I cast cost a few hundred dollars (transportation, tuition and lodging). The decal says "Smallwood Birmingham England". The opposite side has this stamped into the aluminum: "Makers Smallwood England"

Back to the Kingshott Shrine.
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Casting links - links to burner plans etc.


Pattern placed in the drag (bottom half) of the flask	The pattern was dusted with parting compound. Molding sand was then dumped in and rammed around the pattern.

The drag was then turned upside down. You are looking at the bottom of the pattern. The white stuff is the parting compound.	The cope (top half) of the flask is placed over the drag and filled with molding sand. A sprew pin (a dowel rod) is put in place. The pin will be withdrawn later and eventually molten metal will be poured down the hole left behind.

The flask halves are separated. Here is the drag half with the pattern still embedded in the sand. (picture repeated for clarity)	The pattern is then withdrawn, leaving a void that matches the patterns shape. We wouldn't want to pour in the molten metal yet. If we did the casting could come out exactly like the pattern- which isn't what we want. We will add a sand core to reduce the volume of molten metal the mold will hold- giving us the casting we want.

Here's a picture of the empty core box. It's job is to produce the prism shaped lump of sand to fill the portion of the mold we don't want solid.	Here's the pattern with some blue tape applied. This area is referred to as the core print. It creates a shelf to support the core. If the core was the same width as the mitre gauge casting, the core would fall in too far.

From left to right: the core box, pattern and casting. The core box has the same blue tape to hopefully tie this all together. The pattern and its core print create a void that is partially cancelled out by the core. The moldten metal can flow into the the area that's left - which gives us the casting we want.

The core box is filled with molding sand to which a small amount of molasses and water has been added	The core is removed from the core box and baked for an hour at 350°F

The core is carefully dropped into place. The lighter color is the bottom of the cooked core	The sprew pin is removed from the cope and then placed over the drag. Molten brass is then poured into the mold

What appeared after opening the flask. The lighter colored area is the baked core	The casting remains after chiseling out the core. Something that with a little cleanup will look like a Preston mitre gauge!
	The gauge is for laying out 45 degree mitres and transferring marks from a boards edge to its face etc. At Tiller's (where the casting class was held) they said it would be a handy thing to have when timber framing!
From the 1909 Preston Catalogue: Improved Square and Mitre Templet. For Mitreing and Squaring up the Ends of Wood.