A discussion of 7 1/2" thin TS blades

Re: A discussion of 7 1/2" thin TS blades

William Duffield

Let go?!? I've seen the Forrest rep. do that with a WWII, but I surely wouldn't do it with any 10" blade, Forrest or Freud or otherwise. He had super tuned the table saw before he started the demo, and started with a pristine blade, knowing it had not been abused in any way. He also knew the wood he was working with didn't have any internal stresses, because he was also demo'ing the blade for lack of burning. Of course he chose cherry for the demo.

At the other end of the spectrum, I've also watched my brother saw up some crooked, bark-on branches of hickory for smoking BBQ on a cheap job site table saw handheld, without a fence or push stick. That was probably the most cringe-worthy woodworking I've ever seen. Very surprisingly, he survived it unscathed.

One more data point, which I've mentioned before: SawStop does not make a brake that works with a Diablo 7-1/2" blade, and the saw won't even start with one installed. But, there are work-arounds.

Re: A discussion of 7 1/2" thin TS blades

Bill Tindall, E.Tn.

Forest blades are for people that never want to change a blade till it is dull and don't mind using a $100 blade for a task a $10 will do as well.

The blades have little side clearance, This attribute would enable them to do the test you reported. It also make them dull quicker and build up pitch faster.

Re: A discussion of 7 1/2" thin TS blades

jessecloud

A few years ago when Bill first reported using a 7 1/2 inch blade on his tables, I gave it a try. Now its my go-to blade for cutting all but very thick wood. Never had a kickback or anything close to it.

Having a tracksaw and a bandsaw, I never felt the need to use a TS freehand. So no experience or opinion one way or the other on that.

The thin blade cuts well, doesn't build up crud like my idled Forrest used to, and lasts a very long time. Probably the best money I ever spent in the shop.

Thanks, Bill, for a very useful tip.

Re: A discussion of 7 1/2" thin TS blades

Paul grover

What brand and type of blades are you using. Thanks Bill

Blade possibilities

Bill Tindall, E.Tn.

I hope others will offer suggestions.

Reasons to not use a small blade-

1. you regard blade changing as an intolerable inconvenience. These small blades don't do everything so blade changes to deal with special situations are a must.

2. You deal mostly with 8/4 lumber

3. You need splinter-free cross cuts and glue line rips.

My first blade was a German blade given to me by the manufacturer, Stehle. It cut as smooth as a high quality 10" blade.

Almost as good is this CMT industrial blade.

I have just started evaluating this blade. It is thicker kerf

For routine work where cut quality is not critical this blade is dandy. It's few teeth mean almost no cut resistance. It rips fairly smooth and splinters a bit cross cutting.

Re: Dovetails

William Duffield

Another use of the 7-1/4 Diablo blade is for cutting of dovetails: tails only, not pins. This one is often taught by Steve Latta. I don't know if there are multiple Diablo grind styles; if so, you need to start with an ATB (alternate top bevel) pattern. Just remove every other tooth, and tilt the blade to match the angle of the grind of the teeth that remain.

I don't encourage anyone to use this suggestion

Bill Tindall, E.Tn.

One can get a dandy dovetail saw from LV for less than $100. Once started these not- much- set saws saw in a straight line and quickly. I would lay down a challenge that I could cut the tails in a drawer side in less total time than someone using a table saw. And, I am not particularly good at it.

This part of making a dovetail joint is only a tiny fraction of the total time involved. Not the place to focus effort.

Interesting thread but a question

Howard in Toronto

What do you get for a cutting height using 7.5" or 8" blade?

I'm asking because my Delta contractor saw provides a +/- 3.5" cutting height on a 10" blade.

Thanks.

Howard

About 1.5"

Re: A discussion of 7 1/2" thin TS blades

TomD

My first saw was my dad's 9" beaver with a 3/4hp motor. It was wired to a panels with fuses that if you just stood your ground, would blow. Next saw was a General 3hp 10". It like the Gorilla could sit wherever it wanted to. The point being it's mostly about power. You don't want to cross the wrong saw, but a lot of small saws from the olden days you could shoot wood through by hand, though generally I don't see the point to it.

but a question, and Inca

TomD

It is a 1.25" loss in radius, so if you got 3.5" actual with your saw, you should get 2.25" with a 7.5" saw. Saws vary quite a bit in how close the arbor can get to the underside of the saw, so people will get different results.

The cool thing about the 7.5" Skillsaw blades is that in a pinch they fit on the Inca large arbor saws if you break out the diamond. There is a little slop, but sometimes it spins out true, and at other times is out of true, but all that does is make the cut a little rougher, maybe like the old days before carbide. Because the saw is so solid, it does not cause vibration. Has saved me a few times when my other blades were dull. I need to make myself a nut that has the diamond milled into it, so that I can mount the diamond saw blades onto the Inca. With all the chop saws sizes, and Skillsaw sizes, there are a lot of cheap options for the Inca saws.

Re: but a question, and Inca

George Koch

Not that "size matters" but I believe they are talking about a blade that fits the most common circular saws which is 7 1/4" not 7 1/2". and doesn't a smaller blade have more ft/lbs of power at the tooth than a 10" blade on the same saw would have? Or am I thinking wrong! George

Re: A discussion of 7 1/2" thin TS blades

Pete in Holland MI

I've used some thin cut blades in the past (7-1/4" Skilsaw style). They do cut, but there are compromises.

Surface speed of the tooth is slower. Generally, surface speed on any woodworking operation yields a better cut.

Number of teeth per second hitting wood is less, because of generally fewer teeth per radius of the saw.

Any friction caused by wood closing up on itself during a rip can heat the blade, and have it temporarily warp, wrecking a nice rip cut.

They DO require less horse power to plow thru wood, due to less wood being moved.

For general rougher carpentry, they are not a bad choice, but I'll stick with my heavier 10" blades, as most of my cutting is precision cuts, looking for straight cuts and clean cuts. These are also being used on a well maintained & tuned Jet tablesaw.

To each their own......

Interesting information and perspective

Bill Tindall, E.Tn.

While the inexpensive framing blades produce a rough rip and splintery cross cut the cut from a fresh "industrial" quality 7 1/4" blade rivals a quality 10".

Interesting that most of your sawing requires finished cuts from the table saw. In making furniture few cuts from the table saw wind up showing or are used without further refinement, jointing on the jointer to prepare glued panels for example.

Re: Interesting information and perspective

Barry Irby

I rarely if ever get a glue line rip off my Freud Glue line rip blade, at least not one I would trust in a glue up that would show. I rip stock and seldom glue it up immediately. Depending on the amount ripped the wood sometimes warps and needs jointing to get a good glue line. I know I can pull it into submission with clamps but I would rather not introduce that stress into a table top or whatever. I might glue up a drawer bottom or back of a piece of furniture straight off the blade.

It seems to me that the smaller diameter Improves the power of the saw. A 10" blade has a longer lever arm for the motor to overcome.

My saw will cut something like 3 1/4" deep with a 10" blade. The 7 1/2" blade "costs" me 1 1/4", leaving me the ability to rip 2" stock. I have ripped heavy stock and it cut's like butter.

Years ago, I needed stickers for some lumber I had milled. Bought a pile of reject lumber from Lowe's and a carbide tipped skilsaw rip blade. Did not want to use my good blades. Literally ripped a mile of lumber.

It never occurred to me to get a glue line rip off a 7 1/2" blade. Wonder if you could do it with a good one?

I also use them on trash lumber and salvaged stuff. Would not hesitate to toss one if I mangled it.

Re: Interesting information and perspective

Walt

I bought a couple Irwin 7 1/4" blades to cut some 1/4" aluminum plate. $2 each figured I wouldn't be out much. It turned out I only needed one blade and it was still in good condition after I was finished.