# straight edge jig



## Skyewalker (Aug 30, 2012)

this has probably been answered before but I can't find the info so here goes.
I saw somewhere a method of attaching an aluminum angle to a board (permanently ?) to produce a portable straight edge for jointing long boards. not on a router table. It was a piece of 8 foot angle attached to backer of some kind and this was attached to the material to be jointed using a bottom bearing flush trim bit. 
It sounds easy but I can't figure out how to get the alum and the backer even so that the router doesn't tip.
From what I recall, it produced perfect joints.

Can anybody help with the design or a reference?
Many thanks.
David aka Skyewalker.


----------



## gwizz (Mar 3, 2012)

How about using the router to rout a shallow recess in the backing material the thickness of the aluminum then you will have a flat surface.


----------



## Skyewalker (Aug 30, 2012)

terrific idea!!!! Am going to try it.
Thanks.


----------



## Quillman (Aug 16, 2010)

And what makes the aluminum straight, flat & true?


----------



## kp91 (Sep 10, 2004)

There was a jig sold at woodworking shows a long time ago, kind of a neat idea as well.

WOODWORK MADE EASY EDGE PREP JOINT A BILITY JIG - YouTube

a review right here

http://www.duckworksmagazine.com/03/r/columns/cupp/04/index.htm


----------



## KennK (Mar 7, 2012)

Take a look here:

Eurekazone | Eurekazone

... and click on the EZ Routing link. This might be the kind of think you're thinking of.

This video shows how it works - it shows an older style EZ Routing device, but the idea with the newer style is the same. 

http://www.youtube.com/watch?v=IaXVrLHlt_8

BTW ... I'm NOT connected with this company other than being a user of their track saw.

Ken


----------



## MAFoElffen (Jun 8, 2012)

kp91 said:


> There was a jig sold at woodworking shows a long time ago, kind of a neat idea as well.
> 
> WOODWORK MADE EASY EDGE PREP JOINT A BILITY JIG - YouTube
> 
> ...


So the theory behind that jig is that it doesn't matter that you have a straight edge as long as the jig has "parallel" sides. You create one edge by butting against the start end of the jig, one edge of the jig, route towards that start end going towards the direction of travel of the router. Then you butt the other side of the joint with it's end towards the start end of the jig, the opposite parallel side of the jig, away from the start end going with the direction of travel of the router.

With that, even it the jig were not straight and had lots of curves to it, as long as the opposite edges were parallel, you end up with joining edges that line up.

As I follow that logic, the reality of that is if there is a curve in parallel surfaces, the inside edge has a tighter curve than the outside edge... Think of the shoulders of a road. The more distance between the edges, the greater the difference between. So if the jig has a narrow guide between the parallel edges, then it would be less noticeable.

Even though I just said that, I still think that jig is an elegant solution and a great idea. It seems like it would be easy to make and use.


----------



## MAFoElffen (Jun 8, 2012)

Quillman said:


> And what makes the aluminum straight, flat & true?


Pat-

Very good point. 

Seems like the jig the OP is describing is a variation of the table saw jointing / straightening jig I use.

I corner joint a piece of stock to create a piece about 3/4 x 3 inches wide, creating parallel surfaces of the 3", that I'll ID as piece A. I plane a piece about 3/4" x 3", to create parallel surfaces of the 3/4, that I'll ID as piece B. I rip a piece of 1/4 mdf the width that I need to support plus 3-3/4 inches, that I'll ID as piece C.

Lay piece A on top of piece C, lining up one edge. Screw & glue down one end. Take an engineers scale/straightedge and put against piece A. Screw piece A to piece C, while ensuring it is straight using the engineers scale/straightedge. When finished, with piece C laid down stand piece B on edge against the aligned edges of piece A and C, 90 degrees. Screwed and glued. I secure toggle clamps to ends of piece A towards the exposed area of piece C to hold the work securely together. 

So piece B of the jig slides against the TS rip fence. The work rests on top of piece C against piece A, secured by the toggle clamps. This is the jig I use for ripping glue edges.

In the OP's description, the aluminum angle would replace my jig's pieces A and B. Using an engineers straight edge when mounting, you secure it "while" you ensure it's straight when it is secured. Aluminum angle still has flex enough to do that. Right? Plausible?

On a sliding table I use a different jig... Jointed on one edge. I have slots routed at 90 degrees from the jointed edge. In the slots, I secure with knobs and t-nuts to the miter/t-slot. In the jig, I have a t-slot routed near the edge that I have 2 flip stops in. I have 2 toggle clamps in the same t-slot in the jig, between the flip stops. I can line up the jig parallel to the blade... or at an angle. The work goes against the jointed edge of the jig. The flip stops go on each end of the work. The toggle clamps secure the work. That way I can rip glue edges, straighten or create tapers. Currently rebuilding that jig, using extruded aluminum.


----------



## Harrison67 (May 30, 2012)

Quillman said:


> And what makes the aluminum straight, flat & true?



I don't ever remember seeing an 8 foot piece that was straight, flat, and true.


----------



## Quillman (Aug 16, 2010)

Moreover, the flatness, thickness, & straightness specs on unmachined extruded aluminum are about as abysmal has the Challenger Deep.


----------



## bobj3 (Jan 17, 2006)

I have one that's 8ft long ,I use it to rip up plywood I got it from HD,it's 1/4" thick in the shape of double angle iron (like a T ) and very true and flat I don't recall the cost ,I have had it forever...
I think I saw the same thing on the 80/20 site on ebay..
===


----------



## MAFoElffen (Jun 8, 2012)

Quillman said:


> Moreover, the flatness, thickness, & straightness specs on unmachined extruded aluminum are about as abysmal has the Challenger Deep.


After it's sudden premature landing or during it's descent?

Using that type of jig on a slider, doesn't matter if it is straight and true. 

On jointing and straighten- Distance from point A and point B (the ends) making sure they are the same distance from the blade. Slide the slider past the blade. Straight line cutting edge.

On tapering- Point A's distance from the blade, point B's distance from the blade minus the taper... Slide the slider to create the taper.

That can happen as long as the rise in the not-straight is away from the work, so the the ends of the work rest against the jig... just like when position your work on the jointer fence for your first cut.

Thickness as being flat doesn't matter as the work is against one edge, not laying on top of it. So on aluminum angle , the work rests against a face of the angle with the other edge away from the work, creating a straight edged fence extension. The base it's secured to "tries" to keep it straight. Hopefully the other edge of the angle is somewhat parallel to that other edge that is being used as a fence extension, as that edge is riding against the table saw rip fence. With that type of jig, you need straight and the edges parallel between the edge that rides against the rip fence and the face that creates the fence extension.

Piece B on my jig... is really not required, but I sometimes clamp it to my rip fence and use is like a long fence extension... sliding the work against the jig, instead of the fence against the rip fence.

I guess the idea to that is if your rip fence is not straight, or it is short, that a jig like that will give you more control for longer pieces or pieces that don't start out being straight. All I know, is it seems to work just fine for me and others.


----------



## Phil P (Jul 25, 2010)

Quillman said:


> Moreover, the flatness, thickness, & straightness specs on unmachined extruded aluminum are about as abysmal has the Challenger Deep.


Hi Pat

It seems fairly common practice amongst Corian (solid surface) fabricators to have one or more pieces of 10/12mm HPL (high pressure laminate - the same stuff they use to male bathroom/shower cubicles in public buildings) which has either been sawn on a sliding table carraige saw, or better still machined by a CNC router. I have a couple of pieces for the purposes of edge jointing (3ft and 6ft x 8in or so wide) and they work well. Nobody I've worked with uses aluminium profile for the reasons you've stated

Regards 

Phil


----------



## Skyewalker (Aug 30, 2012)

Many thanks for all the great ideas. 

Skyewalker


----------



## MAFoElffen (Jun 8, 2012)

As an afternote- 
The problem with cutting a long board that is non-straight on a short fence, you feed it along the rip fence, pushing it against the rig fence... as you push, the non-straight edge of the piece follows either against the rear and front of the fence -or- the crest of the non-straight pushes against the fence resulting in another panographed non-straight cut.

So you use a straight jig that goes off the fence and holds the non-straight piece as if it were straight..

Just 3 "_other_" ways around this:

1. Build your TS jig to move off the left miter slot as kind of sled. It would move past the blade similar to a sliding table, in a controlled constant distance from the cutting edge.

2. Build a TS jointing fence extension (sacrificial type) the secures to your rip fence. You make a 1/16" to 1/8" step at the rear of the blade (angled edge), where the left edge of the blade aligns with the left edge of the back step. (Blade cut into the sacrificial fence extension) The work feeds along the front half to the fence, contacts the cutting edge of the blade, then gets supported by the rear step.

3. Just use a jointing fence on a router table.

*** Like I've said many times before, there's usually over a hundred ways to end up at the same destination. Depends how you want to get there and the labor you see as acceptable on that journey.


----------



## waynecochran (Aug 2, 2011)

some people use metal studs with good luck. I guess there are two different gauges you can buy


----------



## jw2170 (Jan 24, 2008)

Phil P said:


> Hi Pat
> 
> It seems fairly common practice amongst Corian (solid surface) fabricators to have one or more pieces of 10/12mm HPL (high pressure laminate - the same stuff they use to male bathroom/shower cubicles in public buildings) which has either been sawn on a sliding table carraige saw, or better still machined by a CNC router. I have a couple of pieces for the purposes of edge jointing (3ft and 6ft x 8in or so wide) and they work well. Nobody I've worked with uses aluminium profile for the reasons you've stated
> 
> ...



I noticed, that was what my wood work teacher used, also.

I just went and bought a straight edge...

Veritas® Straightedges : CARBA-TEC


----------



## Phil P (Jul 25, 2010)

jw2170 said:


> I noticed, that was what my wood work teacher used, also.
> 
> I just went and bought a straight edge...
> 
> Veritas® Straightedges : CARBA-TEC


Ah yes, James, but mine came off a job and were the right price - FREE! They were only going to the skip if I hadn't had them (BTW they were trim cuts from a new installation)

Regards

Phil


----------



## jw2170 (Jan 24, 2008)

Skyewalker said:


> this has probably been answered before but I can't find the info so here goes.
> I saw somewhere a method of attaching an aluminum angle to a board (permanently ?) to produce a portable straight edge for jointing long boards. not on a router table. It was a piece of 8 foot angle attached to backer of some kind and this was attached to the material to be jointed using a bottom bearing flush trim bit.
> It sounds easy but I can't figure out how to get the alum and the backer even so that the router doesn't tip.
> From what I recall, it produced perfect joints.
> ...


I believe this is a very pertinent question, David.

I have seen so many projects which require some type of straight edge. If you look at the Ron Fox videos on youTube, he is emphatic that a good straight edge is the beginning of jig making.

I used to use a piece of aluminum angle as well.

And I for one, hope that the edge I have on my jigs is straight to start with, but without a true edge how can you check?


----------



## Bradleytavares (Feb 25, 2012)

Joint an edge of 3/4" thick hardwood that is wide enough to be held safely while jointing, approx. 8" longer than the piece you want to straight line. Rip this piece on the table saw, now you have two paralell edges approx. 3/4" wide. Dado a piece of 1/2" baltic birch (my choice for jigs) that is the same length as the hardwood, 1/4" deep and the dado wide enough to seat the parallell edge piece tightly, glue and pin nail it in place, let glue set. The dado should be set back an inch or so wider than the width of your router centerline to edge of the base. Run edge of router along the hardwood fence and the bit will cut off the plywood along the inside of the bit which will give you a zero clearance cut off jig. Place the zero clearance cut off jig on the line to be cut, run router base edge along the hardwood fence and you'll have a glue quality cut on the piece that's to be cut. The extra 8" will give you 4" on each end for clamping to your material. If necessary, use a long sanding block to remove any chatter marks left on the finish piece due to feeding the router to fast. This tecnique can also be used with a Skill saw for a door cut off jig or anything you'd like to have a zero clearance cut on. It works great as long as you remember to always use the same router bit or saw blade. Give it a try, it's a very old tecnique.


----------

