Full Chisel Blog

July 25, 2013

Philosophical Instruments: Drawing Machine

This one has been on the list for a long time, so it was nice to finally build this ancient, archaic and obscure ‘Drawing Machine’ as Leonardo named his drawing.  There are several woodcuts by Durer showing a similar device and this particular design comes from a British movie ‘The Draughtman’s Contract’, which I saw years ago and inspired me to build this one.  I can’t remember much of the movie but I do remember the instrument.

drawing machine

It is constructed of pine with waxed linen cordage, it is portable and comes apart for transportation.  It also has a threaded insert for attaching to a tripod.  I appologize for the modern tripod, a wooden one is also on my list, which doesn’t seem to be getting any shorter.

The framework is joined with open mortice and tenons at the corners, glued together with Fish Glue.  I carefully laid out where the cords whould be in 1″ grid based on an 8 1/2″ by 11″ piece of paper.  I drilled the holes from both sides to insure proper placement and knowing the small drill bit may wander.

The base holds the large frame and a holder for the small cross hair frame aperature, which is adjustable up and down depending on whether the large frame is ‘portrait’ or ‘landscape’.

drawing machine1

I also made a stencil using a ponce wheel, that matches the grid on the large frame.  A linen bag with some powdered charcoal leaves a grid on the paper when the bag is rubbed over the stencil, which can be used again and again.

My first attempt at using the drawing machine, it takes a little getting use to, but it gets easier.

drawing machine2

Fun project, I still have a bit more refining to do and a bit of embellishment, not sure when I will make the tripod.

Durer woodcut:

ALBREC~1

Stephen

July 17, 2013

Arts & Crafts, Craftsman, Gustav Stickley Lamp Shade

A client referred by a local Antique Store asked me if I could make a ‘wicker’ top for their Stickley style lamp.  I said sure and they came to my shop with a picture of what they wanted and the lamp shade over which the wicker covering would fit.  So not knowing any better I said sure.

Between the time I said ‘sure’ and the time they picked up the lampshade I learned how to make the cover.  I actually spent more time thinking about making the shade to the actual process of weaving.  It also had a snowshoe weave pattern with which I was familiar as they are the same as the rawhide seats on my Quebec/Virginia ladder back chairs I make.

I first measured the diameter of the top and bottom rings, divided by two and multiplied it by 2 pi [6.28\, that math I hated in high school comes in handy come to think of it.  I then cut a rather thick piece of maple veneer to 5/8″ wide and 40″+ for the top hoop or ring then not having veneer material long enough I used a rattan chair spline, for factory woven cane, I had left over from another job.  I cut it to 62″ long and put a scarf on each end so I could glue them together.  The maple was also slightly scarfed and roughened with a file to increase the surface area for the Fish Glue.

lampshade1

With some scrap aspen I made a framework to hold both hoops 11″ apart in such a manner as I could weave the cane material, while keeping the hoops in place.  I purchased chair caning, 250 feet of 3.5mm, just over 1/8″ wide, it was the widest they sold and the shortest length.  I figured I used about 60 feet to complete the shade.

lampshade2

I first did a test with some linen string to make sure everything worked out, the first attempt had too many purchases; so I reduced the number.  The number of runs needs to be odd for the weaving to work out.  It is also critical that the strands running diagonally to say the right must be on top while the strands running diagonally to the left need to run on the back to make the final horizontal weaving possible.

lampshade3

Instead of soaking the cane material in water, I only did that to take the folds and kinks out of the pieces then allowed them to dry completely.  For use I just got the parts wet where I was knotting them to the rims.  I did a test of a piece that was soaked and cut it 12″ long when wet, it shrank over 1/8 inch in length which would cause problems.  So I just got it wet where it was looped over the hoops.

lampshade4

When I was ready to match the ‘fumed’ stain on the lamp I had the client bring the lamp base over.  They asked if it fit and I said I have no idea if it will fit.  There was a pause then they said ‘you must be very confident that it will fit?’, to which I said yes, the diameters of the hoops did fit on the test fit and the height is right.

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The picture below is showing a couple of sticks and a holdfast to flatten out the upper hoop that got a bit of a dip in it during the process, it worked out fine.

lampshade6

Because the material will not fume evenly because of the different materials, so I used shellac with red iron oxide, burnt umber, yellow ocher, and a touch of black iron oxide to get a good pigmented stain/finish that matched the original.  I had help from my apprentice with staining the entire shade, the horizontal strands were stained before they were woven in place.  A bit of fish glue on the ends finished things up.

lampshade7

lampshade8

This is only the second Arts & Crafts period piece I have worked on,  I built a white oak bookcase for a friend.

Stephen

July 14, 2013

Map Glass leather and wood case, with copper tacks

I have wanted one of this type of magnifying glass stand for a long time.  I recently acquired this on a large trade for many other tools, etc.  I had my apprentice cut out the round pine disk with a coping saw then using a rip saw cut it in half leaving two pieces 5/16″ in thickness and 1 7/8″ in diameter.

map glass1

I made a paper pattern for the leather for the case as well as 3 pieces of round leather, the lower pine disk has leather on both sides and the upper disk has leather on the inside and walnut burl veneer on the top surface.  The leather and veneer were glued on with Lee Valley Fish Glue, I really like that stuff.  I put a French polish on the walnut burl, then a thin coat of Moses T’s Gunstocker’s Finish.  I punched my mark in the bottom before assembly.

map glass2

Using a bone folder I put some decorative line work around the leather including the tongue that secures the case shut when pushed through the retaining strap.  The strap also had decoration on the front, it passes through slits in the leather I made with a sharp chisel.  Using a Hudson Bay pattern stitching awl, I punched square shaped holes for the waxed [beeswax and tallow] linen thread, in line so the points of the square holes line up.  This allows the thread to lay flat along the seam.  I also pounded the thread flat into the leather to reduce wear.

map glass3

map glass4

Using #2 copper tacks I affixed the leather to the sides of the disk after having applied fish glue to the leather and edges of the top and bottom pieces.  Tiny little tacks, but just right for this small project.

map glass5

I then cut thin strips of leather to cover the exposed pine edge; I scarfed the ends of the leather to lay flat where the leather flap opening is not attached to the top and bottom.  Using even smaller #1 1/2 copper tacks to attach the exposed pine edges finishing off the case.

It was a fun project and took my mind off a truely challenging project that I will post soon.

Stephen

 

July 11, 2013

Sharpening a Gedge or Cooks Pattern Auger Bit

Filed under: Drilling,Historical Material,Of Interest,Proper Tools,Sharpening,Techniques — Stephen Shepherd @ 9:35 am

I received a request about how to sharpen a Gedge or Cook pattern auger bit from someone who follows my blog, and I realized I had never posted about how to sharpen this type of auger before.  This is a great bit because after the led screw engages the auger bit can be tilted to almost any angle and the unique nature of its engineering allows it to cut a perfectly clean entry hole with no tear out or chipping.  And the spelch looks unusual.

gedge1

gedge2

It is absolutely crucial that the top flat remains flat, no micro bevel devil or stupid tricks for getting this type of bit to cut properly.  Try any of those hair brained ideas on this bit and it will get stuck in the hole, if it can make a hole.

gedge3

gedge4

With a fine flat file gently get the top to a shiny edge keeping the file flat on the back.  It is just like a chisel or plane blade in that you want it flat.  You can also use a small whetstone to accomplish the same purpose but keep it flat.

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gedge6

Any chips or irregularities on the cutting edge is dealt with from the inside flat bevel.  The inside on my two bits are very flat as well with no improper filing of an additional small bevel, so keep it as flat as possible even on the inside.  The smaller bit [7/8″] made by Marples had what looked like a small chip perhaps made while hitting a nail?

gedge7

 

I corrected the problem by filing it from the inside.  I used two sizes or round chain saw files to work the inside, however a round slip whetstone would have worked.  I filed the inside curve from both the top and bottom, the sweep takes a little practice to follow.

gedge8

gedge9

Once I felt a slight burr on the top, I was finished sharpening.  I don’t bother removing the small burr as it will go away after the first few times I use the bit.  The larger bit [1 15/16″] is a Cooks Pattern Patent dated 1851.  Never improperly filed it sharpened up quickly.

Here is a link to a video of this bit in use.

Stephen

July 5, 2013

Carved Mirror Frame Restoration & Gold Leaf

carved frame1

This carved mirror frame is made of some sort of South American hardwood, the species of which I have no idea.  When it was brought to the shop the owner wanted the pretty lavender paint removed for some reason.  So I obliged and suggested maybe they want the sun gilted, to which they agreed.

carved frame2

I removed the paint one section at a time, using blue masking tape to isolate surrounding areas for better control of the stripping process.

carved frame3

carved frame4

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carved frame5

I worked my way around the frame again isolating areas with blue painters tape.

Once I had all of the paint removed, I used the slow acting citrus stripper, I cleaned up the surfaces with alcohol then added a thin coat of shellac.

Next I put a coat of gesso on the carving to fill the grain and smooth out the surface.  The gesso is hide glue size and marble dust with a bit of whiting and a touch of red iron oxide.  I lightly sanded between coats until the surface was smooth.

carved frame7

carved frame8

carved frame9

I then mixed up some bole using kaolin pipe clay, red iron oxide and hide glue size and painted it over the gesso.  I applied about 3 coats of the bole, smoothing them with a piece of coarse linen cloth between coats.

Next it was onto the gold size [a mixture of 10% hide glue and 90% distilled water.  I put a couple of coats on allowing them to dry between coats.

carved frame10

carved frame11

carved frame12

On to the gold leaf, because of the nature of the carving [not intended to be gilded] it required several applications to get it covered.  The gold size is made ready by applying gilder’s liquor a mixture of distilled water and alcohol to activate.

I got to use my gilder’s cush and gilder’s knife that I made, also my gilders tip, although I need to make another as the bugs did damage to the bristles.

After I finished I mixed up some shellac, red iron oxide, burnt umber and black iron oxide to cover a bit of gold that got on the side of the carving.  This worked better than trying to scrape off the little bits of leaf.  I also touched up the lighter area on the top right side of the frame.

carved frame13

And the customer was happy.

Stephen

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