[Reuben Hoff III]

I am looking at adding some more straight edges to my shop. I curently have 3 sizes of Penske. I have seen the phenolic ones that can tap together to mke different combos. Was curious what others thought is best to use?

Reuben

[Norm Walters]

Rueben, I use phenolic straight edges by Perfect Edge. There have been some complaints about them not being machined smooth on the edge. Mine are fine, if you order them and they are not right, send them back. You can also have someone with a CNC make you some, and I believe Joe Corlett has a way to make them without a CNC if I recall. Joe???

[Joe Corlett]

Norm:

I have made some straightedges, but nothing I’d like to brag about.

I did some work for a guy who used plywood with a plastic laminate edge on it and they worked as well as any. Maybe better, they were lighter and wider than the Pinskes and therefore easier to clamp.

Joe

[John Cristina]

If you have the means to make cheap ones that are fairly easy such as the ones Joe explained, I would. Even though my guys are usually on the ball, sometimes a bearing goes, or someone tips a router and they destroy or damage an edge which could get costly. A good cut of plywood with a laminated edge works real well.

John

[Tom M]

I’m with Joe and John.
Do you know anyone with a Streibig? It will cut your template board it straight and true, as far as I can see.
And get your thick phenolic soon. There are fewer manufacturers making it now, unless it’s volume.

Tom

[Andy Graves]

We just use pieces of solid surface cut on the panel saw. Worked great for years. Plus you can make one that is 12′ long.

[Wade Stein]

I HAVE A SET AND WOULD NEVER BUY ANOTHER. THEY ARE NOT SMOOTH AND THE 12′ ONE HAS A WARP. I JUMPED THEM AND THEY SENT ME ANOTHER AND IT WASN’T ANY BETTER. I JUST GAVE UP .

WADE

[Amir Azami]

I bought the the Perfect seam edges and they were far from perfect. I got po’d and bought the Pinske Edges and they are great.

[John Christensen]

The Pinske straight edges that I bought over ten years ago were not straight enough to use with the wavy edge bit. I gave up on the perfect straight edges and wavy bit technique. I always use a mirror cut for seams and it doesn’t even matter if the straight edges are perfect. The seam always turns out.
Johnny C

[Norm Walters]

Johnny, someone on a forum once said they free hand the mirror edge route, I thought that was kinda scary but, to each his own.

[Seth Emery]

Looking at the drawing (in BMP format) that I am attaching, mirror edge routing doesn’t seem to work very well to me unless it is in a straight line. The lines in white represent a sheet with a 1/2″ router bit cutting through it. The red and green (I guess I’m finally getting in the Christmas spirit) lines represent how the resulting pieces would not line up. I know the arcs are exaggerated, but any arc in mirror routing an edge will end up like this to a degree unless you have a jig made especially for that type of seam. VIEW PICTURE

Have a good evening,
Seth

[Seth Emery]

Duplicate Post

[Tom M]

Seth,
I would think you’re correct. It is possibly worse the larger the diameter of the bit. Remember, though, you’re only going to sway on mirror cuts the diameter of the bit (actually, a little less than that), unless you average a curve in the sheet to allow more.

Maybe that small a variation doesn’t visually make much of a difference. Your example is perfect if tried using a clean, balanced bit and you are routing overlapping laminate sheets.

Tom

[John Christensen]

Seth,
You are right in your depiction. However what I have found in practice is that normally the mirror cut seam is very near straight and the amount of arc that may result is very small. For instance maybe a 144″ radius or even greater. That would make one side of the cut 144″ and the other side of the cut 144 1/2″. In a short distance of say two or three inches of the total cut, this would still seam together very well.

I often will make a mirror cut and not even use a straight edge. To do this place both pieces 3/8″ apart and clamp in place so that they cannot move in relation to each other. Use a 1/2″ bit and pull it through the seam with a continuous speed single motion. Do not stop. The router will follow the path of least resistance and cut about the same amount off of both pieces. This seam will pull together beautifully. Sometimes if the need dictates, I will run the router against a straight edge. But not necessarily a certified straight edge, just a piece of phenolic that I have straightened on the table saw and sanded the saw marks off.
Johnny C

[Steve Lefebvre]

I have a few customers that use their parallign clamps for mirror cutting. They suck them to the bottom of the sheets and use the closing cam to adjust the gap between the sheets. This keeps the sheets on the same plane and makes the job easier for them.

We have also repaired one or two clamps that got hit with the router bit.

[Author]

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