Saws, saw blades and cut quality..

[ian maybury]

Judging by the cluster of recent threads on the topic this isn't a 100% straight forward deal. Personal experience and reading between the lines in what you guys report suggests that not everybody experiences the same outcomes, or that what works for one on sensitive materials like melamine coated particle board doesn't necessarily work for another.

Just thought i'd communicate what i've found, and try to kick off some discussion of the underlying issues.

For sure a good quality saw with an accurately running spindle makes a big difference, as do precise alignment (toe out versus the slider or fence) and stepping up to a premium/top quality/industrial quality blade. The latter means one with an accurately flat and stable saw plate/disc, plus precisely and correctly ground teeth. They typically use a finer carbide too, and hence can be sharper and some are definitely longer lasting.

Zero clearance inserts can perhaps be a bit of a catch 22 depending on what's going on. For sure they can add something to even very good set ups, but if all is not in order as above then there has to be a risk of hoping to solve a problem using a plate in circumstances which must to a fair degree kill its effectiveness. (by opening up the clearance) Against that (as in the recent melamine thread) it's often feasible to get perfectly clean cuts without one - using a good quality set up.

I'm not sure for example what the practice is in commercial scenarios in the US, but suspect that most rely primarily on quality hardware to get clean cuts?

[Bill Orbine]

Yes........ I do keep the Unisaw tuned. It helps. I also use appropriate blade for the type of materials I'm cutting. Takes a moment to change the blade. I don't use a ZC, though I wish I did....particularly to prevent narrow strips of cut offs from falling into the saw cabinet but not so much to enhance the quality of cuts which is really REALLY good, anyway.

[Lee Schierer]

Probably the single most important thing to achieve a good cut is saw alignment. Even a superior blade that is on a poorly aligned saw will give poor quality cuts and cause burning and tooth marks.

Combination blades no matter who made them are a compromise. A dedicated blade will give superior performance over a combination blade. For cross cuts, the more theeth the smoother the cut. For faster ripping you want fewer teeth and large gullets to handle the larger chips.

Where the zero clearance insert comes in it that it supports the piece being cut within a few thousandths of the teeth which prevents the wood fibers from tearing back along the piece of wood.

Blade height above the work piece also plays a role. The gullets need to clear the top of the piece being cut so that the teeth hit the wood at a good angle to shear the wood rather than pushing it. You also need to create a certain amount of down force so the wood doesn't want to come back at you. The higher the blade the shorter the cut is for the blade (fewer teeth in the wood). The same is true for a hand saw. If you hold a hand saw at a 15 degree angle to the wood it will take forever to cut a couple of inches. Raise the angle to 45 degrees or more and the cut goes much faster.

Technique is also important, you have to let the blade make the cut. Forcing the wood into the blade will slow it down and produce a poor quality cut. Feeding too slow allows heat to build up which may cause burning. Hard wood cuts differently than soft wood.

[Art Mann]

I put masking tape over the cut line on both sides and that seems to help a lot. I also use a 90 tooth trim blade and a ZCI.

[Ken Kortge]

One of the benefits of Eurekazone's track saw system is that their base inserts and anti-chip track edges provide VERY clean cuts on all four edges (both sides top and bottom) using just a common construction grade saw blade. I'm think some (??) of the other track saw systems out there have similar features.

I'm assuming a zero clearance insert for a table saw will do similarly clean cuts.

I am NOT trying to advertise Eurekazone products here (I'm just a user) - more talking about the benefits of zero clearance, but to see what I'm talking about take a look at this video by them that shows the cut quality differences pretty well:

https://www.youtube.com/watch?v=sSGkG17sNE8

[ian maybury]

For sure there's multiple ways to get there. Guess what i was hoping to bring out since there seemed to be a few experiencing problems (especially when sawing melamine) and perhaps feeling it was the norm is that it isn't necessarily the case - and that there are various factors that contribute to success. (blade flatness and sharpness/saw runout/saw set set up/zero clearance if needed, technique etc)

It's one of those scenarios in woodworking where high levels of precision do count. There's lots of saws and blades that can do the business, which is why i was purposely trying to focus on the aspects of set up that matter, but there are equipment quality levels below which problems becomes much more likely. There's when close also ways of heading the bandits off at the pass like tape etc….

The Festool track saw uses a plastic strip under the track that acts much like a zero clearance plate too, but it also runs very true and is fitted with a high quality, stable running and sharp blade...