Friday, July 23, 2010

making keystones for the window arches

There are nine arched windows in the tower on the front of our house.  Each of these arches will require eleven stones, so I have 99 stones to cut for the window arches.  Yes, that's my youngest daughter playing in the masonry sand near the front of the house.  Here's the step-by-step process of how I have been carving the stones for these windows...



The first thing I do is to score (cut a groove into) a large piece of stone with my chop saw.  Then I drive chisels into the groove until the stone splits off.  Now I have a 9" deep piece of stone.  This dimension is important.  I wish to end up with window stones that are 3.5" deep (give or take 1/2").  Further along in the process, I will split the stone in the 9" dimension to get two stones that are 4.5" deep.  Then I can face each of these stones with a chisel to achieve stones that are 3.5" deep.

Next, I score the long rectangular stone at 5" intervals.  The height of the finished stones will be 5", so this process defines the top and bottom of each finished stone.  I'm careful not to score too deeply, because I don't want saw marks showing on the bottom (visible) side of my window stones.  Looking at the giant stone from which this stone is cut, I can see fault lines, and I suspect the cut off stone will not yield as many high quality finished stones as I would have hoped for.


Driving a chisel into the grooves separates the large stone into smaller pieces of stone that will each yield two window stones.  A fault lines runs completely through one of these small stones, rendering it useless.  This stone is in the picture below the other stones.  You can see that it has split in two already.  The four stones in the top of the picture should yield a total of eight window stones.  I will lay out my cut marks so that only the split (rough) texture is showing on the bottom of the finished stone.

Now I get real busy with the chop saw.  I cut the stones in the previous step into double-thick keystones.  At this point, they have the shape of gold bars.  In this picture, you are looking at the bottom of a stone that will become two finished window stones.  To the right and left of the "keeper" piece in this picture are the tapered scrap cut-offs.  The bottom of these keystone shaped pieces is 4.5" inches wide, while the tops are 6" wide.  The bottom of this piece (facing up in this picture) is finished and requires no chiseling.

 The next step is probably the funnest and requires no noisy saw.  I take a hammer and chisel and tap the stone on all four sides in a line that circumscribes the stone at its mid point.  Eventually, the stone breaks in half, exactly on this line.  It almost always works like a dream!  The picture at the right shows the result - two stones that are almost ready to lay in the arch.  I picked this particular picture though because one of these stones has a fault.  The finished depth of these stones should be 3.5" which allows me 1" on each of the 4.5" stones to chisel a rough face that will be seen.  The stone on the left has a fault (see the iron deposits?) that impinges into, but does not traverse the stone.  I was able to use the chop saw to cut this flaw out of the stone, barely leaving enough material for me to chisel a rough face on the front of the stone.

Here are a bunch of finished stones, after I've chiseled a rough face on the fronts and in the process trimmed their depths to 3.5".  It's really hard for me to make more than eleven stones in a day.  Distractions, exhaustion, or something else always comes into play.  Oh well, I tell myself, this will last hundreds of years... so what if it takes a few weeks to cut these stones.

9 Comments:

Blogger brad_bb said...

Is this method(except for the chop saw), what would have been done 200 years ago?
Definitely labor intensive, but I'm sure you, like me, have learned patience, and to just keep plugging away at it. You know I discovered Timber Framing before I found your blog, but your blog was inspiring and your project a shining example. I discovered slate through your blog, and now I'll have to lean that was well. And now you're going to force me to learn to work stone! What's next Thomas Massie?!

July 23, 2010 at 10:41 PM  
Blogger Thomas Massie said...

The keystones can be cut with a chisel... but wow... it's slower... and unfortunately easier to go backwards.

If you want to try a little of everything... my advice would be build in small finish-able stages! I doubt I'll ever be done with this house.

July 24, 2010 at 12:04 AM  
Blogger D. B. Day IV said...

I really enjoyed your blog. I'm going to dig deeper into it. I am a Austin, Texas atty, way open minded but old school and conservative as well. I dig the fact you are a-in-the- establishment and building this labor-of-love house--with your hands. Old school with extraordinary refinement. Well played, Sir.

With highest regard,
D. B. Day IV

July 25, 2010 at 11:07 AM  
Blogger Raphael said...

just one concern: how are you going to get all these stone chips out of your yard??

July 30, 2010 at 10:48 AM  
Blogger Thomas Massie said...

ha ha Raphael. good point. I have to raise that part of the another foot or two by adding dirt. So one day the little chips will be underground. The big chips, we throw behind a retaining wall that also gets back-filled. (if we didn't get rid of some of the chips, there would be no room to walk!)

July 30, 2010 at 11:48 AM  
Blogger rhot8 said...

Looks Good! Thomas!
Just wear a mask, gloves and hearing protecting!
I can't help it, it's the ER nurse in me that needs all that stuff!
Just to up date ya' headed to Cadiz, KY for the class with Scott from GrandOaks in Oct. Can't wait to get an edgimikashun!
T8
n "Louaval", KY

August 6, 2010 at 7:34 PM  
Blogger Marvin said...

This comment has been removed by the author.

September 29, 2010 at 1:27 AM  
Blogger Marvin said...

Haha. I'm just wondering where did you get all those stones, anyway? I commend your patience there. A DIY build your own home is a really personal project that requires strong perseverance. Are you also planning a DIY dream house for your daughter there? I'm sure she's gonna love it! I've built a small tree house for my kids too.

September 29, 2010 at 1:32 AM  
Blogger Richard Boles said...

The house on the hill looks lovely, even though it's not yet finished. The first thing that I noticed is the roof of the attic. I've seen the progress of the tower stones, and they look like a part of a castle. Why did you pause in building it?

Richard Boles

November 23, 2011 at 1:36 PM  

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