Cutting OSB am I doing something wrong?

[OutbackL130]

I'm a metal fabricator by trade and have less experience in wood working. Few weeks ago I was cutting OSB with a circ saw to put up in my shop and I had trouble with the OSB binding my saw blade. This does not happen everytime and I have cut plenty of osb in the past with ease.

When it starts binding if I slow down the saw wants to kick back or bind worse. If I would push harder then the saw kept going but made a wobbly cut. I thought the blade was bad so I picked up a new one for cuttin osb. Tonight I was cutting some to make shelving and the same thing happened as before even with a new blade. I had the scrap side hanging off my cutting table and a helper trying to hold it. Any help would be appreciated!

 

[yelbike]

Weird! Make sure the blades going through the cut straight. Ensure the front of the blade and the back of the blade line up in the cut. Also check the play in the bearings. Again weird.

 

[john40981]

this might sound dumb but what is OSB??

 

[Degolyerent]

Wobbly cuts come from blade getting to hot. It could be wrong type blade, bad cutting technique, or bad base plate on saw(bent). It is building to much heat on blade for some reason. Blade needs to protrude through the material by a full tooth.
John

 

[Harvey9]

this might sound dumb but what is OSB??

OSB = Oriented Strand Board, engineered wood.

 

[downsizingnow48]

Things to check for kickback and wobbly cut in more or less an order of likelihood to causing the problem. First, have a good quality carbide tooth blade. Bad blades warp. Second, adjust blade so it is just deep enough to cut the material with a tooth showing at the bottom. Too deep adjustment makes the blade work inefficiently (overheat=wobbly cut) and also causes binding and kickback. Third, arrange several 2x4s on each side of the cut so the sheet is well supported on both sides and can fall away just a bit from the blade as it is cut. OSB is floppy and easy to bind. On this item, unless the helper really knows what he/she is doing, can easily contribute to the problem of binding. The last thing to check is if the saw is worn out (blade should be rock solid). A worn out saw can not cut well.

 

[k0ua]

On this item, unless the helper really knows what he/she is doing, can easily contribute to the problem of binding

This has been the number one cause in my experience.

 

[Scooby074]

this might sound dumb but what is OSB??

Chipboard.

 

[LD1]

Ditto on the type of sawblade. Some sawblades have no set in the teeth. Made for cutting plastics and such. They dont work well with wood as they dont cut any wider than the blade, and will bind. A good carbide blade made for wood has set in the teeth, so it actually cuts a little wider than the width of the blade for relief.

Ditto on the helper making things worse too. Is this only happening once you have cut about 1/2 way or more through??

 

[ishiboo]

I used to look like an idiot cutting OSB/plywood - got a new saw and it's a world of difference. If the saw is not tracking straight, you end up trying to adjust it by "turning" the saw and that's where a lot of bindup occurs. Make sure you are going with the flow and not attempting to guide it all over - you have very minimal adjustment with 6.5" of a blade in the wood.

 

[Dr Dave]

I think the adhesive in OSB has something to do with it, they make a wax/ lube stick to coat the blade, it helps.

Dave

 

[joshuabardwell]

Set your saw height as high as possible. Makes for a shorter length of blade in the kerf, and less to bind up.

Make sure the OSB is supported on both sides. Once one end starts sagging, it binds terribly.

Lastly, if your blade is worn unevenly, it will want to cut in a curve, and will fight you if you try to cut straight--but it's probably one of the above two.

 

[Cord]

I have a ton of carpentry experience so I'll chime in on this one. I believe you were binding the saw because your cut wasn't straight. The kerf isn't much wider than the blade so it doesn't take much of a crooked cut to bind the blade. The give away are the rub marks on the side of the blade. Those only come from material blinding. Although you don't need full cutting depth, setting the blade to max depth makes a straight cut much easier to achieve. When you place the saw on the material, try to square it up the best you can. You are probably watching the alignment of the blade on the pencil line. This makes for a seemingly accurate cut, but it's very difficult to make a straight cut. Instead, look at the front edge of the shoe. You will probably notice there are a couple of marks on it. These are guide marks. Instead of watching the blade, watch the guide mark. With this technique you'll end up with a much straighter cut.

And I do agree with properly supporting the material. 4x8 sheets are tough to handle and safely cut. An extra saw horse or helper will go a long way. Just don't let them close your cut or the saw will bind.

 

[randy41]

you could set up a fence for your saw to ride along to make the cut straight. you still need to support the hanging side to prevent binding.

 

[nc redneck]

I had the exact same problem a year or so ago. Starred with a brand new Irwin plywood blade bought at Lowes. Went back bought another one ( only Irwin in stock ) Same problem. Ordered Fraud Diabloe from Amazon. Problem solved still using it today. I never new you could cut plywood or Osb so straight and easily.
No more Irwin blades for me.

 

[kw22614]

try shortening the depth of the cut to no more than about 1/4" deeper than the material thickness

 

[BukitCase]

Another vote for the Freud Diablo blades - but I would stay away from their cheaper, "avanti" series - 'bout the same as the stuff that used to be in the Sears catalog under "even at this low price"... Steve

 

[Budweiser John]

I recently retired from the carpentry trade and have cut thousands of sheets of OSB. As building materials go, OSB is easy to cut. First off, those "plywood blades" with umpteen hundred teeth are worthless. Even for plywood so throw them away. A good quality carbide blade with a positive hook will aggressively cut hundreds of sheets with out the need for anything other than a steady hand and adequate support for the sheet being cut. Depending on the size of the job, work off the bunk or for smaller projects, use saw horses in either case, use some sacrificial 2x4s to support the material being cut and send the helper to the coffee shop. For a really nice straight cut use a shooting board.

Just a word about portable circle saws "Skill Saws" These guys run the gamete from $19.95 at Horr Freight to well over $125.00 for a Milwaukee side winder or a Skill '77 worm drive. Bottom Line, ya get what ya pay for Period. East of the Mississippi side winders rule, West of the Mississippi, the worm drives rule so pick your poison and keep the **** blade SHARP.

Guess I really do miss the smell of concrete and sawdust on cool fall morning.
Budweiser John

 

[EddieWalker]

Set your saw height as high as possible. Makes for a shorter length of blade in the kerf, and less to bind up.

Make sure the OSB is supported on both sides. Once one end starts sagging, it binds terribly.

Lastly, if your blade is worn unevenly, it will want to cut in a curve, and will fight you if you try to cut straight--but it's probably one of the above two.

I agree with Joshua.

You need to keep the wood the same level. If it starts to sag or twist, it will bind up the blade. More power or a better blade wont fix this. The farther cut the wood, the more the weight of what you are cutting off puts pressure on the blade. I have four saw horses for this very reason. It's not just OSB, but any sheet material will do this to you.

Eddie

 

[downsizingnow48]

to me the bottom line here is several things need to be considered. because this is not a single factor solution. you need a saw with no runout in the arbor. if it has runout, it will run out. generally that means a good quality saw not too worn. you need a blade that will cut well. generally that means modern quality carbide. because a bad blade will wander and bind. you need to support both sides of the work so it doesnt sag and bind the blade. that means saw horses and 2x4s, or just cutting it flat on top of the stack. and it means not having a helper to hold the work cuz mostly that makes it worse. and if you want real straight you use an edge guide of some kind.