Flat saw blades.

[Brian Runau]

I have a good forest blade. I've used it for a while, but still sharp and cuts fine. I reset the blade to the slot this morning using a calibration disc and I-gage digital unit. I'm within 1/2 thou; which tickles me pink.

Put the Forest blade on and it is showing .003 out. I unaware of any problems while using it where I would have caused this. Is this normal over time?

Thanks.

Brian

[Brian Gumpper]

Seems like acceptable flatness to me, wish my WW skills were that tight. Forrest doesn't tension their blades, they put a straight edge across them. Good ones get braised tips and bad ones go in the trash.

[Jacques Gagnon]

Brian,

Have you noticed any problem when cutting wood after you installed your blade? If so, what did you notice?

If not.. go have fun with your saw and forget about the never ending chase for the elusive fraction of millimeter that your measurement apparatus throws at you. 🤓

Regards,

Jacques

[Mel Fulks]

Probably heat from some recalcitrant pinching wood. We had a sharpener who always checked flatness of blades, He would turn over his egg
timer when he started to true up the blade. If he fixed saw before timer stopped there was no additional charge.

[Robert Hazelwood]

Are you checking the blade from one side to the other, or rotating it so the same spot on the blade is measured when you check front and back distances? The second technique will account for arbor runout (and blade wobble). You should do the same thing when you use your calibration disc.

You can make a test cut and measure the kerf left by the Forrest blade and compare it to either the manufacturer's spec or the measured tooth thickness. The amount by which the actual kerf exceeds the spec is due to arbor runout and/or blade wobble.

[Richard Coers]

There seems to be a whole new concern about perfection in tooling on here lately. You guys don't really expect .0005" on everything you use, do you? What says this blade doesn't flatten out more when running? A properly hammer tensioned saw blade is a work of art, NOT part of the Hadron Collidor.

[James Pallas]

Turn the blade 180* on the arbor after marking carefully on the arbor flange the blade and the washer. Re-torq the nut to the same as it was when you last installed it. Re-check your measurements and report back.

[Brian Runau]

Thanks everyone. I was checking a point in front and rotating theb blade 180 degrees. It cuts square though, good to go. Thanks brian

[Bruce Wrenn]

Measure with a micrometer, mark it with a piece of chalk, and cut it with an axe. Precision woodworking, to the ten thousandth!!

[Darrell Bade]

As an engineer that has designed, drawn and dimensioned his share of widgets over the years .003 is pretty tight, more than I would expect everytime with a saw blade and arbor. Most sheet tolerances on engineering drawings are plus or minus .01 and you make an individual tolerance tighter if needed. Use you saw and be happy, I guarantee you move that wood more than that pushing a rip cut through it.

[Brian Tymchak]

I have a good forest blade. I've used it for a while, but still sharp and cuts fine. I reset the blade to the slot this morning using a calibration disc and I-gage digital unit. I'm within 1/2 thou; which tickles me pink.

Put the Forest blade on and it is showing .003 out. I unaware of any problems while using it where I would have caused this. Is this normal over time?

Thanks.

Brian

Those digital gauges have at least +/- .001 tolerance on accuracy. I think you are good to go.

[glenn bradley]

Thanks everyone. I was checking a point in front and rotating theb blade 180 degrees. It cuts square though, good to go. Thanks brian

Kudos on going with the "how does it perform?" test as the final word. I am a stickler for specs but we can get lost in the measurements and forget that what really matters is how a tool performs. I do know the heartbreak of getting in a hurry and tilting the saw without removing the ZCI. This can make your blade (and your RK) a potato chip in short order :eek:.

[Tom M King]

I thought Forrest blades were hammer tensioned. I wouldn't expect one to be flat. The important thing for a circular saw blade is that the edge runs true at speed. It doesn't matter if the plate is a little out of flat.

https://carbideprocessors.com/pages/saw-blades/hammering-saw-blades.html

If one doesn't want to read the whole thing, I pulled this out of it:

This is why the body must be stretched slightly so the rim has this stretch to compensate for. Thermal expansion of the rim or hub and cutting strain need to be compensated for by tension.