Factory cut edge identification

[Jeff H Lee]

This is a silly question from a newbie . How does one identify factory cut edges besides visual inspection ? Do manufacturers of the ply or mdf sheets mark them in same way ? Tks

[Roy Harding]

Factory cut edges are not marked in any way - but they are usually beat up and dirty from shipping and handling. I'm assuming you're looking at a partial sheet of plywood that's been hanging around your shop for a while. Even if the edge you're looking at is, in fact, an edge you previously cut yourself, the same issues apply - IE, dirty, dinged up edges happen when moving partial sheets around your shop. If in doubt - trim the edge on the table saw, that way you'll know you have a true edge to work from (actually - I always start with a fresh cut when pulling a partial sheet out of the rack - even when I know which edge is shop cut).

[Jeff H Lee]

Factory cut edges are not marked in any way - but they are usually beat up and dirty from shipping and handling. I'm assuming you're looking at a partial sheet of plywood that's been hanging around your shop for a while. Even if the edge you're looking at is, in fact, an edge you previously cut yourself, the same issues apply - IE, dirty, dinged up edges happen when moving partial sheets around your shop. If in doubt - trim the edge on the table saw, that way you'll know you have a true edge to work from (actually - I always start with a fresh cut when pulling a partial sheet out of the rack - even when I know which edge is shop cut).

No. I mean when I buy a new piece of 8x4 from lumber yard.

[Kent A Bathurst]

No. I mean when I buy a new piece of 8x4 from lumber yard.

The sheets came from the factory in that form - so seems to me all 4 sides are factory cut by definition.

Am I missing something here?

[Peter Kelly]

Factory edges on hardwood ply from mills in North America are typically sanded after cutting.

[Rich Engelhardt]

I usually pull out the track saw and recut one long and one short factory edge so I'm sure everything is nice and straight and square.
Basically, I make my own.
It only adds seconds to the job to recut the factory edge with a track saw & I find it's worth it.

[Jerome Stanek]

I usually pull out the track saw and recut one long and one short factory edge so I'm sure everything is nice and straight and square.
Basically, I make my own.
It only adds seconds to the job to recut the factory edge with a track saw & I find it's worth it.

And how do you determine that your cut is square.

[Roger Pozzi]

This is a silly question from a newbie . How does one identify factory cut edges besides visual inspection ? Do manufacturers of the ply or mdf sheets mark them in same way ? Tks
I think that is your answer,,,, look at it.

[Roy Harding]

No. I mean when I buy a new piece of 8x4 from lumber yard.

In that case - they're ALL factory cut.

[Jim Dwight]

While there may be markings it is not consistent. Once you start cutting the sheet goods up, I don't think there is a fool proof way to tell which is the factory cut edge. Factory edges are pretty reliably straight and corners square. But tracksaw cut edges are just as straight and haven't been dinged up by handling.

[Kent A Bathurst]

I pick what looks to be the cleanest long side, and measure & cut everything from there. That makes the parts square, regardless of the other 3 factory sides.