Pocket Screws

The Gimlet Tool

When dating furniture it is essential to closely examine the clues left behind by the worker and his tools.  The process of shaping and joining wood will always result in some evidence of how it was done.  Over time, newer tools were introduced, and that provides a clear dating feature for students and conservators to understand.

Today I thought I would just show a simple example for collectors who may not have noticed it before.  To me this feature is obvious, but I have been doing this for so long I just take it for granted.  I take satisfaction in knowing that I am educating clients as I point out tool marks and dating methods so that they can gain a new appreciation of what they own.

Years ago I posted on the history of the screw (search: "Respect The Screw").  Today I want to continue that thought by discussing the gimlet.

The gimlet tool was a staple of every woodworker's tool box.  It looked rather like an old fashioned cork screw, in that it had a wood handle attached to a long metal shaft with a screw tip.  Since all the screws made before 1846 were blunt it was necessary to start the hole first with a gimlet.  This would create the screw tap for the blunt screw to get started.

When pointed screws became available the gimlet lost its function and sat abandoned in the bottom of the tool box.

However, something else happened at the same time.  The gimlet tip (a pointed screw) was added to the twist bit on the drill.  Instead of the blunt spoon bit or spur bit shape the gimlet pointed twist bit became quickly popular, since the gimlet actually helped to pull the twist bit into the wood.

Post 1850 Gimlet Tip Twist Bit

One application of this new twist bit was how it changed the method for installing "pocket screws."

I am using the term "pocket screw" here knowing it is a modern term.  Today a pocket screw device is rather common among modern cabinetmakers who use it to fasten face plates to kitchen cabinets, among other uses.  It is actually a continuation of the method developed centuries ago for installing a screw on a 90 degree joint.

Before 1850 the only way to install a screw on a corner was to use a gouge chisel and carve a "U" shaped entry.  First the proper distance from the edge of the wood was marked with a scribe, depending on the size of the screw.  That would allow a flat chisel to cut into the wood, leaving a surface for the screw head.  At the same time the gouge would be used to clean out the wood allowing for the "turn screw" (the traditional name for the "screw driver") to properly reach the screw.

This is what it looks like:

Before 1850

Many workers were quite careful to make this look clean and proper, even though it was never used on outside, finished show surfaces:

This Worker was Skilled and Proud of His Work

After the gimlet bit drill became popular the method of attaching screws changed.  The drill was used to create a hole in the wood and the screw was then introduced on the edge.  It was perhaps quicker, but it made it more difficult for the screw driver to properly approach the screw.  On this photo you can see the slight marks left on the edge of the hole by my screw driver as I removed and then re attached the screw:

Note the Center Mark left by the Gimlet Point

Normally, I find this feature common on furniture made around the time of the Civil War.  Old traditional workers did not abandon their methods over night and it is possible to find the chisel method used even after the Civil War.

This is an interesting example I found on an 18th century Philadelphia walnut drop leaf table.  Although the original screws were chiseled in as usual, some later repairs were made and the new screws were let in with a gimlet bit.  Perhaps not the best method for repairing pre industrial furniture, but still this photo provides a learning experience:

Don't Do This to Period Furniture, Please.