Planning and Building a Jig #2: Definitions

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Blog entry by Peter Oxley posted 12-15-2007 09:01 PM 7078 reads 0 times favorited 11 comments Add to Favorites Watch
« Part 1: Introduction Part 2 of Planning and Building a Jig series Part 3: Safety »

The story is told that after the Great Fire of 1666, the architect Sir Christopher Wren was commissioned to rebuild St. Paul’s Cathedral in London.
St. Paul's Cathedral, London Upon the completion of this huge undertaking, Queen Anne reviewed the work and is said to have declared that it was, “Awful, amusing, and wholly artificial.” Wren was quite pleased to receive such a compliment from the Queen! The English language has a sneaky way of changing over time, and a lot of woodworking definitions have changed or been lost as the language changed. Many woodworkers can not explain the difference between a dado, a groove, a rabbet, and a fillister. “Mullion” and “muntin” have become virtually synonymous. Many professional woodworkers don’t know the difference between a smoothing plane and a jack plane. I don’t think the change of definitions is either good or bad – it just happens.
Well, a rabbet is like a bunny, dado is what some folks calls their dad, groove is kinda' like dancin',  and a fillister is where those senators just won't stop talkin'!

“Jig” and “fixture” are two more words that have become virtually synonymous. Even though most of the books I have on the topic use both words in their title, none of them even make an attempt at explaining the difference, and Webster’s definitions aren’t very helpful, either, so we are stuck with my definitions. In my mind, a “jig” holds or guides a tool and a “fixture” holds or guides a workpiece. Unfortunately, these definitions fly in the face of many common uses (whoever heard of a “honing fixture”?), and there are any number of devices that hold and guide both the tool and the workpiece! I will abandon my definitions without hesitation if I think the “correct” usage might cause confusion or seem redundant. Generically, I tend to refer to jigs and fixtures as “jigs”.

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11 comments so far

View Thos. Angle's profile

Thos. Angle

4444 posts in 5177 days

#1 posted 12-16-2007 01:08 AM

How about; a jig guides and a fixture holds. We could always go back to doo-hickey and thing-a-ma-jig.

-- Thos. Angle, Jordan Valley, Oregon

View dennis mitchell's profile

dennis mitchell

3994 posts in 5529 days

#2 posted 12-16-2007 02:51 AM lost me at “fillister”. Never heard of it.

View Peter Oxley's profile

Peter Oxley

1427 posts in 5089 days

#3 posted 12-16-2007 05:01 PM

Thos – that’s what the definitions boil down to, most of the time. Except when you have a doo-dad on the whatcha-ma-callit.

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View Peter Oxley's profile

Peter Oxley

1427 posts in 5089 days

#4 posted 12-16-2007 05:12 PM

Dennis – you can hold your mouse cursor over the president to get his definition, or …

A fillister is an old word which is almost never used anymore – which was the point of course. It’s basically the same thing as a rabbet, but a rabbet goes across the grain and a fillister goes along the grain. I learned the difference fairly recently when I was reading about old hand planes, and learned that different planes were used for making rabbets and fillisters. Now we generally use the same kind of tool to make both, so the distinction between the two becomes less important. It’s interesting that the cross grain words – dado and rabbet – have continued in common use, and the with-the-grain words – groove and fillister – are less used.

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View mrtrim's profile


1696 posts in 5095 days

#5 posted 12-16-2007 05:37 PM

im not sure if this is on topic or not . if not please excuse me and ignore it . two terms i see most commonly misused in my industry are window sill and window stool it would seem the definitions have been blured somewhere along the line my two scents ( assuming im tax exempt on lj if not 1 scent ! )

View mrtrim's profile


1696 posts in 5095 days

#6 posted 12-16-2007 05:40 PM

p s i think that very pic of bush might well end up on the one dollar bill one day !!lol

View SPalm's profile


5338 posts in 5097 days

#7 posted 12-16-2007 05:59 PM

I always like the term ‘awfully good’.
I guess it means it is so good that it makes you full of awe.
But the ‘amusing’ usage above has me baffled.

I want to go with Thos’ answer, but I tend to use ‘fixture’ only when holding the workpiece, not the tool. (?)

Thing-a-ma-bob is my preferred.

-- -- I'm no rocket surgeon

View GaryK's profile


10262 posts in 5203 days

#8 posted 12-17-2007 04:40 AM

I prefer the technical and proper term “Thingie”.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View Karson's profile


35278 posts in 5615 days

#9 posted 12-17-2007 04:54 AM

Now you know why I don’t use them. I do searching and never find what i want. So I do without.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Appomattox Virginia [email protected]

View MsDebbieP's profile


18619 posts in 5375 days

#10 posted 12-17-2007 04:12 PM

and now .. we know!
or do we?? “that’s some groovy dado” is probably a really confusing phrase.

-- ~ Debbie, Canada (, Young Living Wellness )

View Peter Oxley's profile

Peter Oxley

1427 posts in 5089 days

#11 posted 12-17-2007 04:18 PM

Apparently, in the late 17th century
  • “awful” meant something like our word “awesome” (SPalm – I like “wicked good” but I can’t pull it off!)
  • “amusing” mean something closer to “causing happiness” than “mildly funny”
  • “artificial” meant “artful” instead of “false”

Just think how people will be talking in another 300 years!

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