Reliable, long straight edge

[Marton Czebe]

I bumped into a problem this weekend. I needed a straight fence of above 2.3 metres in length to do some edge routing. I couldn't find anything in my small and basic shop that I knew was TRULY straight across this length. (found some particleboard scraps about 2 metres, but as I sighted down the long edge, I could see some dents, as well as a small curve in it.

What do you people use as a reference straight edge? (preferably something that stays straight for a while...iron, aluminium?)

thanks for your advice...

Marton Czebe

[Charlie Self]

Marton Czebe asks:

Usually, wood, but it tends to require some preparation as most commercial boards aren't straight enough.

Failing that, iron or aluminum is useful. Aluminum is more easily dented, but is easier to handle. Some say angle iron (or aluminum), but I tend to prefer bar stock, as there's less likelihood of the angle piece interfering with whatever you're trying to do (by catching on a low handle or a cord).

Charlie Self "Half of the American people have never read a newspaper. Half never voted for President. One hopes it is the same half." Gore Vidal

[Mortimer Schnerd, RN]

Do a google search on "cutting guides". A cursory look shows most of them seem to run about $50 or so. I've been using an aluminum extruded guide for about 25 years that I paid considerably less for. I just clamp it to the panel and run the circular saw (or router) against it.

[bugbear]

How straight do you need - what deviation ("tolerance") from mathemical straightness would affect your project?

BugBear

[JGS]

[Andy Dingley]

For that size, I use a piece of box section aluminium extrusion. I think it was meant to become door or windo frames, but I got it cheap from a scrapyard.

[Jim & Sharon]

my brother works in a medal working shop he got me a piece of 1/4 scrap aluminum 8' long by 4"wide. he said it was cut off and would be trash anyway.

[mac davis]

i hate to admit this, but I use an old garage door part... not sure what you call it, but it's a 2x3" aluminum channel about 8' long that the chain used to run through..

I used to use a 2 piece aluminum cutting guide called "the edge" or something, but it was pretty flexible and hard to store..

Mac

[Pat Barber]

A sheet of carefully selected MDF is gonna be VERY straight. 1/2" or 3/4"... Rip a piece to the size you wish making note of factory edge.

You "might" f> I bumped into a problem this weekend. I needed a straight fence of

[GerryG]

[Lew Hodgett]

"Marton Czebe" > I bumped into a problem this weekend. I needed a straight fence of

My preference is a 2" x 2" x 1/8" x 96" long aluminum angle which translates arrroximately as follows:

50mm x 50mm x 3mm x 2.44 m.

Add a couple of C-Clamps and you are in business.

HTH

Lew

[Dan Cullimore]

If you go this route, I'd recommend the heavier gauge metal--it won't flex in the middle.

Dan

[Ba r r y]

I do the same, but my chunk of aluminum is a channel. It's not straight in the checking jointer tables for co-planar sense, but it makes a great tool guide.

Barry

[mac davis]

or the high tech method... I finally found a use for that $9.99 laser line projector I bought at HF.. lol

Mac

[Adrian Mariano]

I have a phenolic straight edge that I got because I was concerned about the durability of aluminum (and the phenolic was affordable, though not as cheap as other things discussed in this thread). Subsequently the place I got it from (McMaster-Carr) has quit selling phenolic straight edges. I wonder why?

[Gary DeWitt]

Here is another time-tested solution:

have two I made from 1x3" auuminum box glued to 1/4" hardboard. One other mod - leave an inch or two of hardboard on the "back" side for clamping, so your clamps don't interfere with the saw or router. Better yet, leave enough hardboard on each side so you can use one side for your saw and one for your most common router setup. Trim the guide with the tool you will be using it with, and the edge can be used to set the position to your marks.