Sawblade Error?

[projectnut]

As many of you know I have been in the process of refreshing a Delta 14" long arm radial saw. I've also been looking for moderately priced blades for the machine. It was suggested by members here I look for ones with a negative relief (hook), and either a triple chip grind or an alternative top bevel. I came across a couple Guhdo Gmaxx blades last week with 100 teeth, a triple chip grind, and a 2* negative rake. The pictures were a bit blurry, so I contacted the seller and asked for some clarification. They answered all my questions satisfactorily and I thought they met all the criteria, so I ordered them.

They arrived today and I was a bit shocked. The one picture I didn't get was the one with the UPC label. That picture describes the blade as being one for non-ferrous metals and aluminum. To further complicate things there are reputable blade vendors that also recommend this tooth grind for laminates, plastics, and even precision cuts for picture and door frames. These vendors stated that a blade with a triple chip grind, and 80 or more teeth should be used for cutting across the grain. They excel in making crisp miter cuts.

I would like some input and opinions as to whether the blades I purchased will be adequate for general use. The first job on the list is to finish cutting the boards for the pier decking.

 

[ddillman]

100 tooth is kind of fine for general work especially on thicker stock

 

[ARC-170]

It is my understanding that negative rake blades are generally for non-ferrous material. Use wood-cutting blades for wood; they have a positive rake for biting into the wood. Forrest Woodworker 2 blades are often recommended. I used Tenryu blades when I taught woodshop. I use the Diablo ones from HD at home.

 

[projectnut]

There appears to be considerable differences in opinions as to what style blade is preferred for radial arm saws. The saw came with a Diablo 14" 70 tooth combination blade with an ATB grind, and a +10* hook. I did use it for a few dozen cuts, and it seemed to work fine other than a small amount of blow out. When I started looking for blades almost everything I read recommended a neutral or negative hook blade to minimize the possibility of the blade self-feeding.

Trooper27 also recommended Tenryu blades. His recommendation was IW-35560AB2, which has a -3 rake and 60 teeth with an ATBR grind. Tenryu does make a number of industrial blades for radial arm and table saws. All the blades they recommend for radial arm and miter saws have a negative hook of either 3 or 5 degrees. Those they recommend for table saws have a positive hook anywhere from -5* to +20*.

I guess I need to learn a lot more about which blade configuration to use in different materials. Tenryu recommends both ATB and TCG tooth grinds for "general applications in wood with a table saw" and "smooth cuts in wood with a table saw". However, they recommend the ATBR grind for "general applications in wood with a radial arm/miter saw".

Here's a Tenryu blade chart from Amazon

 

[toprecyler]

In theory, the blade should work good. Even though it says it is meant for metal. As long as the carbide is ground sharp.

Being negative rake, it will have to be pulled thru the wood, and not self feed like you want on a radial arm saw.

The 100 tooth should mean a cleaner cut. But will also be slower. There is not as much gullet for sawdust to fill while in the cut. So a slower feed will be needed. As long as you are not burning the wood by too slow of a feed.

If you ever do cut metal with it, it may not ever cut wood as well again, due to microscopic rounding of the cutting edges.

Probably the best way you will know how it works, is to try it. It probably will also depend on the type of wood you are cutting. Hard wood, or soft wood.

 

[cathead]

I like lesser numbers of teeth for several reasons.

They rip without a blade change out.
There are less teeth to sharpen.
They seem to be smooth enough for my glue ups and general work.

 

[MikeInOr]

I have had a few radial arm saws over the years. My fathers Delta 10" turret arm RAS that I have been working on since I was 10yo has a slight bit of self feed with a positive rake blade. My first RAS was a Craftsman that came with the fire damaged house I purchased when I was 22 would wasn't to self feed with any blade... there was no internet back then and no information about blades on radial arm saws so it probably had a positive rake blade on it.

35 years ago I purchased my 16" 7.5hp 1947 Redstar radial arm saw. It came with a 16" positive rake combination blade that I still have and use. It has never shown ANY signs of wanting to self feed with that blade. I bought a pair of new 15" Freud ultimate cut off blades off ebay about 30 years ago for something like $40 each. These are positive rack and my woodworking blades. I use the combination for stuff like PVC pipe and framing lumber. About 3 years ago I unpackaged the second 15" ultimate cut off blade because the first was starting to show signs of getting dull. These ultimate cut off blades have never shown the slightest propensity to want to self feed.

My new Delta 16" turret arm RAS has a touch more resistance to the carriage. It has also shown no propensity to want to self feed in test cuts with the Ultimate cut off blade or 16" combination blade. (Test cuts revealed noisy motor bearings. Replacements are supposed to arrive this Tuesday.)

I think you are taking negative rake blade advise aimed at loose, flexible and often improperly aligned Craftsman radial arm saws and applying it to your heavy, tight and ridged 14" Delta turret arm radial arm saw and the advise isn't really pertinent. If your saw is well aligned with no heal in (the blade is parallel to the arm) I would highly recommend a Freud ultimate cut off blade for glass smooth cross cuts. No matter how perfect the blade alignment on a Craftsman mine would always flex, always want to self feed and frequently leave burn marks on the wood. Large turret arm Redstar / Rockwell / Delta turret arm saws shouldn't have these problems if properly aligned.

 

[MikeInOr]

Cross cut blades have a high tooth count and small gullet (gap / void between teeth). Rip blades have a lower tooth count with a larger gullet for clearing the saw dust when ripping. Crosscutting produces smaller chips because it is cutting across the grain. Ripping produces larger chips because it is cutting with the grain. If you use a high tooth count blade for ripping it won't be able to clear the larger ripping chips effectively enough and build up heat which can warp the blade (been there, done that, blade goes into the trash). When a blade cuts across the grain the chips are smaller and don't plug the gullets like the larger chips when ripping and the higher tooth count gives a smoother cut when cross cutting.

A combination blade is just a compromise which gives poorer quality of cuts when ripping and cross cutting. I have always used cross cutting blades for cross cutting and ripping blades for ripping. When I only had one saw I would change blades to suit the type of cut. My radial arm saws pretty much always wears a cross cutting blade. My table saws pretty much always wear ripping blades. If I cross cut on the table saw I will change to a cross cutting blade. I haven't ripped on my radial arm saw in over 30 years, since I bought my table saw.

Freud ultimate cut off blades have given my glass smooth cuts when cross cutting on every saw I have used them on (radial arm saws, table saws and miter saws). Freud hair line rip blades have always given me very smooth glue ready cuts when ripping.

 

[Eddyde]

IMHO, a negative rake, industrial quality blade is the best way to go. Such blades are better balanced, have thicker carbide and run truer with less vibration than consumer level blades. They make a big difference but only worth the investment if you resharpen them. Negative rake blades especially need to be sharpened regularly.

 

[MikeInOr]

IMHO, a negative rake, industrial quality blade is the best way to go. Such blades are better balanced, have thicker carbide and run truer with less vibration than consumer level blades. They make a big difference but only worth the investment if you resharpen them. Negative rake blades especially need to be sharpened regularly.

What do you consider an "industrial quality blade"? I have expensive negative rake blades that I use for plastics and composites. They are no better balanced, don't run truer and don't vibrate less than my go to positive rake Freud cross cutting and ripping blades. My experience is that the amount of carbide is more determined by the blade kerf, width of the tooth, than the the cost of the blade. There are different qualities of carbide and it has been my experience that Freud uses a high quality long lasting carbide.

Sorry to sound like a Freud blade commercial but they really are good blades. I have an Amana 16" combination blade and Amana 12" stacked dado blade set that have also been excellent long lasting blades.

I have also had excellent cut quality from cheap Harbor Freight 12" cross cut blades on miter saws for laying engineered flooring. The teeth do wear out from the silicone impregnated finish on the flooring so I consider these blades disposable.