Sharpening blades ..."sharper than new"??

[Michael Donahue]

I've heard these claims in magazine ads that some sharpening services will make your blade sharper than it was off the shelf. I'm a bit skeptical of claims like this so that's why I wanted to make this post.

I have a Freud dado set (SD208 I believe) that is works pretty well in solid wood but still tears out some on crosscuts, and it's not very impressive when cutting plywood. I could tape all my cuts and what not, but I would ideally like a set that I can throw in my saw and make clean, accurate dadoes regardless of the material I'm using. I also don't have $200+ drop on a better dado set right now, so that's why I'm wondering about sharpening services. Could I have this set sharpened by a top-notch service and expect it to perform like a better set of blades or will I be disappointed after spending $50+ just on sharpening?

I really appreciate the advice. Thanks guys.

[Dewey Torres]

If it is dull, than yes it will improve your cuts, if it is "off the self" or hasn't seen enough use to be dull, I seriously doubt it.

I have the SD508 and it cuts everything I have put through it including all the materials you mentioned here. As long as the feed rate is good and consistent, it is close to flawless for me.

I do however think you are correct in being skeptical of the "better than new" claims. Hand plans are one thing, but off the self saw blades by manufactures such as Freud and Forrest are very sharp "off the self" and precision ground to a perfect bevel per their designs.

[Brad Shipton]

Michael, I agree with Dewey. Freud specializes in quality cutters, so I would not bother. High end cutter manufacturers such as Freud, Forrest, Garniga, Ghudo,... and so many other have strict quality control that must be met before it is packaged. Some of the foreign bits on the market, well thats another story.

Brad

[Bruce Wrenn]

A well respected sharpener once said, "most blades cut very well after you get, rid of the "factory dull" and have them sharpened. I sent some blades to Dynamic Saw in Buffalo, and they came back sharper than when new. Before shipping your blades to one of two companies in NJ, visit Dynamic Saw's web site and compare prices. You will be pleasantly surprised.

[Dave Falkenstein]

If your dado set is an SD208, then it has 12 tooth outer blades and 2 tooth chippers. I would not expect really good results from this set in plywood or in crosscuts of hardwoods that have a strong tendency to chip. Check the price to sharpen the set with a good quality shop, like Scott Whiting who is a member here. Then make a decision whether to invest in sharpening or put that money toward a higher tooth count dado set, like the Freud SD508.

[Mark Rios]

Another vote for the 508. Clean dados in all types of material. The 208 wasn't made to be as good a quality as the 508, hence the increase in price. Quality cuts are a question of money, how good a quality dado cut do you want? :D

[Martin Shupe]

I am no expert, but maybe it is not a good idea to use the same blade on plywood that you use on hardwood. I am thinking the plywood glue might dull the blades faster? I may be off base, and if I am, feel free to set me straight.

[Tom Walz]

First off carbide tools are like stock cars.

There are stock cars that race on TV and stock cars you see in a dealer’s showroom.

Figure maybe a commercial dado set is ground with a combination grit wheel where the finest grit is 400. A pro shop may run a 200 grit wheel followed by a 600 grit.

A manufacturer will sharpen until sharp is determined by final dimensions. However carbide is funny in that it is actually cemented grains of tungsten carbide cemented with a (usually) cobalt binder. To make tungsten carbide you use a lot of heat and pressure to distort the tungsten grain structure and pack carbon inside.

You can sharpen it until the dimensions are right but it moves after that. Not much but it does. There is a very complex tension / compression cycle that is best relieved by making several passes where the wheel just kisses the carbide.

There is a man named Al Bouchard, Head Filer at the Weyerhaeuser mill in Warrenton, Oregon who takes about 20 “kiss” passes after the saw is sharp. This is something you don’t really need to do except Mr. Bouchard’s saws run better. (Don’t bother Al. He is purely Weyerhaeuser. He is just one of the very best there is at tools.)

A manufacturer typically uses a centrifuge to filter his grinding coolant, which works well down to maybe 5 micron grit). A pro shop will add a post filter and get down to sub micron values.

So, yes it is entirely possible. Not sure what ad you saw but it can be done.

[Wilbur Pan]

Us hand tool users routinely sharpen our blades to a "sharper than new" state. ;)

[scott spencer]

If your dado set is an SD208, then it has 12 tooth outer blades and 2 tooth chippers. I would not expect really good results from this set in plywood or in crosscuts of hardwoods that have a strong tendency to chip. Check the price to sharpen the set with a good quality shop, like Scott Whiting who is a member here. Then make a decision whether to invest in sharpening or put that money toward a higher tooth count dado set, like the Freud SD508.

I think Dave's on the right track. What you're encountering is as likely to be due to the design of the cutters as it is their sharpness, though being sharp can help alot. The 208 is a nice set but 12T cutters with 2T chippers won't make an overly fine crosscut. A set with a higher tooth count and low to negative hook angle should have better tearout characteristics if all else is equal. The SD508 with 24T cutters and 4T chippers (or a set with higher tooth count) should improve tearout.

If you're not up to buying a new set, try a backer board at the exit of the cut, or cut the board wide and trim the tearout portion.