SCMS and Dimensional Lumber

[Mike Goetzke]

I have a question about the subject matter. Once in a while I have a project requiring dimensional lumber. This time I'm building a floating deck at my wife's request. For the framing I purchased a bunch of 2x8's it 8' & 10' lengths.

I set up my miter saw to cut these to length and had several cuts that had the blade start to bind and try to push the saw back at me a bit. I ended up using a circular saw.

In years past I have used a SCMS for these kinds of cuts and didn't remember this happening, but, I have changed something. I had a Makita corded SCMS for years and recently (maybe year ago) replaced it with a cordless Makita (36V).

Wondering:

1) I'm thinking that the boards aren't perfectly flat/square so at the end of the cut it causes the blade to bind?
2) Corded saw has more power and doesn't slow down as much when it starts to bind?
3) I have the OEM blade on the saw. Maybe blade is causing the issue?

Input appreciated.

Thanks
Mike

[Chris Schoenthal]

Mike, you're probably right on all three.
1) Dimensional lumber can be warped and pinch the blade
2) May not have the "umph" to get through sometimes, especially after a lot of cuts
3) A negative rake tooth blade will help a lot

[Mark Katz]

Check your support situation on both sides of the blade. If the board is bowed (or if the outer supports are too high) such that the board is not flat on the table, then the board will flex downward as the cut is made and pinch the blade.

One thing that might help a lot is to clamp the board down within a few inches of the cut. My old Makita LS1013 SCMS has a clamp the mounts to a post behind the fence and can be swiveled into position when needed. I use this a lot, especially with long boards.

[Jim Becker]

You may need to resort to clamping the material when using construction grade lumber as it often has "features" that don't play nice with CMS or SCMS cuts.

[Mike Goetzke]

You may need to resort to clamping the material when using construction grade lumber as it often has "features" that don't play nice with CMS or SCMS cuts.

Is it just me or do others find it difficult to work with dimensional lumber after being use to milling lumber yourself?

[Rod Sheridan]

Is it just me or do others find it difficult to work with dimensional lumber after being use to milling lumber yourself?

Mike, I was going to be a smartass and say that I find that dimensional lumber makes great firewood, just doesn't make anything straight.

Then I realized it makes far worse firewood than the hardwood scraps from stuff I've milled myself.

Now I'm thinking maybe the only thing dimensional lumber is good at making is profits for Home Depot........Regards, Rod.

[Matt Day]

Is it just me or do others find it difficult to work with dimensional lumber after being use to milling lumber yourself?

Completely agree. These are facts I have to consider whenever using the stuff:
1) boards are never straight
2) boards are never the same length
3) boards are never the same height
4) boards are never the same width (thickness)
5) 2x material is not meant to be used by a furniture maker that’s used to precision!! Especially PT lumber!!

[David Kumm]

Even when making jigs and forms, I mill dimensional stuff to 1.25". Makes me feel a little better about using it. My SCMS will also get pinched with Hickory or Hard Maple unless I take shallow cuts. I assume the design of a moving blade causes some vibration under heavy load that pinches the plate. Most SCMS blades have a heavy plate very little distance from the edge of the tooth to that plate. Dave

[Prashun Patel]

I also think it's all 3.

I switched from a corded circular saw to the makita 36v cordless, and I also notice some binding.

These weaker saws (but oh how convenient!!!!) probably can't forgive anything out of perfectly true.

[Lee Schierer]

One thing that has changed is that dimensional lumber is now generally at 14% moisture or even a bit higher and is made from the center cuts of the logs. The rpms of your battery powered saw are probably slower than the corded saws.

[Jim Becker]

Is it just me or do others find it difficult to work with dimensional lumber after being use to milling lumber yourself?

Honestly...yes. I don't particularly enjoy working with any kind of "construction" lumber at this point. I like flat and straight and that's what I get when I process my own. But alas...sometimes one must do what one must do... ;)

[Tom M King]

Were you pushing, or pulling for the cut?

[Jeff Bartley]

Mike,
If you can find where you live try Weyerhaeuser framer series lumber. It's southern yellow pine, a little more expensive, but it's straight and dried properly.

[Tom M King]

I'll agree with that. Framer series lumber is Yellow Pine framing lumber like it used to be. I used it building these trusses in an 1850 attic to fix a terribly sagging roof. I haven't seen YP framing lumber that nice, and stable since the last local mill went under in 1992. The access opening we had into that attic is the white lined squarish opening near the junction box, on the other side of the light. Main chords are 2x12x16's.

http://historic-house-restoration.com/images/biggertrussview1.JPG

[Jeff Bartley]

That's a nice looking truss Tom!

[johnny means]

I make a habit of cutting with any bow up and out. That way it tends to open up as i cut, instead of binding.

[Tom M King]

That's a nice looking truss Tom!
Thanks. They're not quite four feet tall. The rafters were about 3x3's 20 feet long, and had sagged about 5 inches in the middle. Some had split. With opposing wedges over those trusses, also tied to the ceiling joists, the rafters went right back up to being nice, and straight, for a flat roof. That house also had some other trouble with long spans for ceiling joists, and the trusses solved that problem too. There is another one under the other half of that roof.