# Taper jig for long cuts



## pete lynch (Aug 10, 2008)

Hi, everybody.
This is my 1st post here. I have been doing carpentry for over 30 years but I’m always looking for new ideas.

Has anyone ever come up with an idea for a taper jig that will work with longer pieces of window jamb stock, like 60” or more? I don’t have a home shop (so no place to plan out a proper jig) and I use a piece of plywood and screw the jamb piece to plywood to get the taper I need. This does the job but leaves holes to fill and takes time to set up.

The reason I need to cut window jamb extensions on a taper is that my company has been using the Tyvek window wrap system and it leaves the window out a little bit farther on the bottom than the top, thus creating the need for a tapered jamb ext.

I have seen some good shop-built jigs on the web but they are mostly for table legs and furniture pieces.

I welcome any ideas and will share any I come up with.
TIA
pete lynch

FYI: I recently posted the above at lumberjocks.com forum. Just asking as many knowledgeable folks as I can.:smile:


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## pianoman (Jan 16, 2008)

I once modifyed a router base to flush trim the jamb in place (on the wall). Put a 3/4" rabbiting bit (without bearing) in the router... make a cleat 3/4 X 3/4" X 4"s long. Fix this cleat to a wooden router base plate so the bit is just slightly cutting a cove in the cleat. The bit depth should be set flush with the drywall. This will cut the jamb flush with the drywall. I recall having to cut the corners with a flex hand saw. Maybe a 3/8ths dowel in the base would be better...or a shorter cleat. At anyrate...this helped speed-up the trim job. All the jambs in this house were proud of the drywall. Another way to taper a jamb (a single board) is to make a sled for the radial arm saw. Scribe the taper...then pin the board to the sled. First, saw a shallow curf in the sled...then align the taper cut to the shallow curf. I guess that could also be done on the table saw. Hope this helps Rick


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## pete lynch (Aug 10, 2008)

pianoman said:


> ....Another way to taper a jamb (a single board) is to make a sled for the radial arm saw. Scribe the taper...then pin the board to the sled. First, saw a shallow curf in the sled...then align the taper cut to the shallow curf. I guess that could also be done on the table saw. Hope this helps Rick


 Hi, Rick. Thanks for the ideas. All this work is done on-site so we don't have the luxury of having a radial saw ( loading/unloading). It has to be done with a table saw for reasons of production time, etc.
pete lynch


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## joesdad (Nov 1, 2007)

Hey Pete, If it's just a few here and there that need to be ripped, I just draw the line on both sides of the jamb and freehand (no fence) rip it halfway then flip the board towards me and finish the rip leaving the pencil line on the board, then clean it up to the pencil line with a stiff sanding block and some heavy grit sandpaper. They come out perfect and only take a few minutes to do. Of course it takes a steady hand and an awareness of the safety risk involved, but we've done it this way for years and the it's the fastest easiest way. I won't do this with anything shorter than 36" because of the lack of material to hold onto. If you need this done to all of the jambs then I could see your need for something more on-site production oriented.

I can feel the safety police shaking their finger at me already.
Truth is on a house trim job, I work a bit differently than I do when I'm in my shop, but still apply the same basic rule...if it doesn't feel comfortable, I don't do it.


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## firehawkmph (Apr 26, 2008)

I will admit I have done something similar to Petesdad. I have cut the taper freehand on a portable dewalt table saw, then followed up with a power planer (makita hand model) to clean up the cut and straighten it out. I have also cut tapers with a hand jig saw and then followed with the power plane. Works well. One of the old black and decker workmates works well for holding the jamb piece while planing.
Mike Hawkins


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## mlightfoot (May 13, 2008)

Pete, The plywood method is the way I have been doing them. It is quick and safer (I feel) than the freehand method which I have also done. I use 1/4" luan (sp.?) plywood because it is cheap. If I am ripping 1x stock, then I use 1/2" drywall scews and make sure I screw to the backside so there are no holes to fill. I have ripped tapers up to 8 feet.


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## pete lynch (Aug 10, 2008)

mlightfoot said:


> Pete, The plywood method is the way I have been doing them. It is quick and safer (I feel) than the freehand method which I have also done. I use 1/4" luan (sp.?) plywood because it is cheap. If I am ripping 1x stock, then I use 1/2" drywall scews and make sure I screw to the backside so there are no holes to fill. I have ripped tapers up to 8 feet.


mlightfoot, I have done it exactly the way you describe when doing extension jambs on exterior doors. I have made a short taper jig with 1/2" ac plywood and toggle clamps on 3/4" ply' blocks. It works well for most of my needs. :yes:


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