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Circle Cutting Jig ( for the bandsaw) #1: The urge for greater accuracy

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Blog entry by BritBoxmaker posted 1291 days ago 1668 reads 7 times favorited 7 comments Add to Favorites Watch
no previous part Part 1 of Circle Cutting Jig ( for the bandsaw) series Part 2: Of slidey things »

This is my second attempt at this blog after loosing the first two thirds last time, whilst blogging. Is there a size limit on blogs I wonder (Martin)?

I digress. My first circle jig (Version 1.0) worked fine but lacked positioning accuracy. So on to version 2.

The materials for this jig were pretty much what I had on hand. Chipboard (they throw away half sheets of 10mm stuff that comes in with deliveries where I work), Beech, 8mm threaded rod, nuts, washers etc. The idea for the jig is based around three layers of chipboard with Beech for anything doing any hard or accurate work and trim.

First thing to do was cut a sheet of 10mm chipboard into three identical 800mm x 380mm boards.
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One of theses boards, the base board, will have other layers, or parts of layers, attached to it or resting/sliding on it. I next cut a 9mm x 4,5mm slot in the middle and top boards so
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When glued and screwed together this makes a channel for an 8mm threaded rod to run through.
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In order to keep the boards properly aligned during the glue-up I made a 9mm square waxed hardwood (in this case Purpleheart) stick .
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When the glue was dry I cut the laminated board into two.
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The left hand half (to be called the left fixed table from now on) is approx’ 300mm wide.
I then glued a 30mm x 20mm strip of Beech between them.
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This forms the jaws of the two halves when cut through.
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The left fixed table was glued and screwed to the base board.
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I marked out waste areas on the bottom of the right hand half. Cut these out and replaced them with 50mm x 20mm strips of Beech
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When this assembly was dry I set the tablesaw blade to 15° and cut it into three pieces.
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The left side strip of Beech and the right side Beech/Chipboard piece become the runners which the centre piece (now to be called the sliding table) will slide within. The 15° angles holding the sliding table down to the base board.With the 9mm square stick threaded through the sliding table and two side pieces were butted up to the jaw of the left fixed table.
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The two side pieces were glued and screwed to the base board. Now, with the threaded rod installed, the sliding table runs freely between its runners.
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Right I’m trimming the blog off at this point so I don’t loose anything.

Be seeing you.

-- Martyn -- Boxologist, Pattern Juggler and Candyman of the visually challenging. http://www.theartofboxes.com



7 comments so far

View SASmith               's profile

SASmith

1565 posts in 1612 days


#1 posted 1291 days ago

Thank you sir. This is just what I wanted to see. Now if I can adapt it for use on my scroll saw bowls. This looks much easier than my current way: http://lumberjocks.com/SASmith/blog/20704
Ill be looking for the next in the series.

Thanks
Scott

-- Scott Smith, Southern Illinois

View BritBoxmaker's profile

BritBoxmaker

4354 posts in 1661 days


#2 posted 1291 days ago

Scott, I’d be interested in seeing that as I was going to adapt it for the scroll saw at a later date. You could save me some work!

-- Martyn -- Boxologist, Pattern Juggler and Candyman of the visually challenging. http://www.theartofboxes.com

View Dez's profile

Dez

1113 posts in 2702 days


#3 posted 1291 days ago

Thanks Martyn, I always appreciate folks sharing their jigs, especially the how to!

-- Folly ever comes cloaked in opportunity!

View moshel's profile

moshel

864 posts in 2309 days


#4 posted 1291 days ago

looks like a heavy duty jig… and heavy…

i usually write my stuff on word/openoffice writer and then cut and paste it into the net. this way i am sure it will not be lost and i can save and resume the writing in another day.

how did tyou fix the end of the threaded rod? epoxy?

-- The woods are lovely, dark and deep, but I have promises to keep...

View BritBoxmaker's profile

BritBoxmaker

4354 posts in 1661 days


#5 posted 1291 days ago

Moshel, Thanks for the tip on cut and paste.

As for fixing the rod, all is revealed in part 2, Of slidey things.

As for the weight. Yes its sturdy and no my bandsaw hasn’t collapsed or toppled over, yet.

-- Martyn -- Boxologist, Pattern Juggler and Candyman of the visually challenging. http://www.theartofboxes.com

View rsladdwoodworks's profile

rsladdwoodworks

311 posts in 1794 days


#6 posted 1291 days ago

his is ajig I need thank for sharing

-- Robert Laddusaw and no I am not smarter then a fifth grader ( and no I canot spell so if it is a problem don't read it ))

View mafe's profile

mafe

9483 posts in 1714 days


#7 posted 1290 days ago

Looking good Martyn.
Best thoughts,
Mads

-- Mad F, the fanatical rhykenologist and vintage architect. Democraticwoodworking.

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