2002 Unisaw

[Bill]

Consider a 72" long beam consisting of 2" by 2" square steel tubing,

1/8" thick, fixed at each end. Assume I attach a 3' beam right in the middle, perhaps cantilevered, to which my blade guard is affixed. How much "rigidness" have I bought myself, as far as the beam is concerned? I believe we are talking about the "strength" of the steel tubing. I realize that if I shorten the 72" beam, the rigidness will improve, but how is it doing so far? By comparison, lesser material options that are available would probably seem flimsy, no? To provide a more complete picture, I intend that this beam will span an outfeed table.

Thanks! Bill

[Bill]

A related question is "Will it sag with time?" (like a 2by4 hanging in the same manner would?) Maybe I need to use an I-beam (that's a joke!) Maybe a small I-beam (that's not a joke!)

Bill

[jloomis]

Consider a 72" long beam consisting of 2" by 2" square steel tubing,

1/8" thick, fixed at each end. Assume I attach a 3' beam right in the middle, perhaps cantilevered, to which my blade guard is affixed. How much "rigidness" have I bought myself, as far as the beam is concerned? I believe we are talking about the "strength" of the steel tubing. I realize that if I shorten the 72" beam, the rigidness will improve, but how is it doing so far? By comparison, lesser material options that are available would probably seem flimsy, no? To provide a more complete picture, I intend that this beam will span an outfeed table.

Thanks! Bill

[Bill]

Thank you for extending my "universe" of materials (and building techniques)! Where I grew up, an I-beam really looked like an I-beam. I see that things are more complicated now!

Bill

[Lew Hodgett]

------------------------------------------------------- Dig out a strength of materials text, learn and understand the following:

I^3 = (bh^3)/12 + 1/2(Ad^2)

It's the basis of all beam design and application.

Lew

[Bill]

So are you saying that you didn't need to look it up??? : ) I trust you, I'm just curious.

I was doing okay on Wikipedia, until I ran into the units MPa.

I spent the whole evening learning more about steel. %-) As every Wrecker is surely aware, steel has lots of recipes and is comes is sold in a variety of molecular patterns. I doubt you can get square tube that is not annealed (A) in retail. Online, all I can do is "go bigger". I'm up to 1/4" thick now, I just don't want it to flex...lol I'm going to physically visit Lowes and actually hold some in my hand, so I can get a better feeling for wall thicknesses.

If I was clever enough, I could probably back up a few steps and build a wooden truss instead (and have fun doing it). I didn't know what a "truss" was until John Loomis mentioned the term in an earlier post yesterday. That is a great word for me to know for what I wish to accomplish. Even if the tubing did flex, I truss could be use to firm it up (as he suggested), which is reassuring, and reminds me of the nature of all of our woodworking experiments.

I have no reason to rush this purchase. I tried to resolve it, but it can wait. I think I'll take a break, and do some of my work for work!

Cheers, Bill

>

[Lew Hodgett]

Lew Hodgett wrote> :

-------------------------------------------------------- "Bill" wrote:

----------------------------------------------------- Alzheimers may be in my future but doesn't seem to have arrived yet.

Anyway, that formula was beat into me more than 50 years ago by my structural prof who would begin his homework assignments with "Gentlemen, put on your coolie hats and have fun tonight".

You don't forget that experience.

Have fun.

Lew

[Bill]

Here's a link in case anybody doesn't know what a coolie hat is:

[Bill]

This Uni-T-fence is sold in 43" and 36". When ripping a large piece do you slide your fence forward a bit (toward you), so that you can get more of the edge of the stuff you are cutting against the fence before it reaches the blade? Otherwise, I don't understand why one would be concerned about the additional length here.

Question: If you were trimming a 40" piece of plywood using the fence (I hesitate to call it "ripping"), would you stand right behind it and hold it down real well near the blade and hold it real well against the fence? It seems what is really called for here is a good sled (that may be supported in part by the extension table as well as the miter slots). But if that were really true then the fence wouldn't be able to travel so far away from the blade (50"). I haven't yet really made sense of this. If I "knew absolutely nothing" this would make more sense to me...

Ah, my recollection had been that you liked the board buddies. Jim Tolpin, the author of "Table Saw Secrets" certainly likes them for dados, and especially for stopped dados. That was what got me thinking about the Uni-T-fence again. The Woodworking Show is coming to town this weekend.

You surely already know that dado blades are not allowed in some countries (I just mentioned that for a little "woodworking trivia"). Be careful when you travel abroad... ; )

Bill

>

[Leon]

Sliding the fence out toward you to give you more of a guide before reaching the blade would be a definite advantage. If you check into most Euro style table saws most all use this type fence. The big advantage would be when cutting sheets of plywood and you are about 7' back from the front of the saw. It is tough to keep the panel parallel along a 12" section of fence before a blade than a much longer section before the blade.

Secondly you can use the fence to cross cut shore pieces more safely. The end of the fence can be slid to the front of the blade so that short pieces will not be trapped between the fence and the blade.

That would depend on the other dimension of the 40" piece of plywood. Consider that the heavier the piece of panel the less likely that the blade will throw the panel any appreciable distance. ;~)

If I am trimming a few inches off of a 40 x40 panel I stand in the middle of the panel pushing with my right hand and using my left hand to gently push the panel up against the fence. Basically I give most of the push towards the blade with my right hand and a little bit of push, just enough to keep the panel flat against the fence, with my left hand.

Actually I believe it is the "stacked" dado blades that are frowned upon. There are however dado blades, they call them something else. that will cut wide slots. These are typically more like a sharper cutter as they are wide and fixed in width IIRC.

[Swingman]

Bill wrote: If I "knew absolutely nothing" this would make more sense to me...

At this point, nothing will answer your questions better than a good deal more up close and personal experience using your table saw.

[Bill]

I just don't want it to throw anything at me (and I don't want to be in the line of fire if it tries....) And I don't want to have to explain that I didn't know I was doing something in a "stupid" way. As you suggested, Leon provided me with good answers to my questions.

Bill

[Leon]

All in all you can't foresee what is going to be best for you. You cannot foresee all possible problems. You cannot foresee any gotcha's.

Like Swingman indicated, until you actually start using the saw, shop, over blade guard/dust collector you have no clue what you are going to actually want to end up with.

You can way over think all of this, and possibly put a lot of work into something that you may end up not liking. Better to make a decision from actual experience vs. a preconceived notion of something you have read or think you wold prefer.

[Bill]

Okay. But having said that, what do you think of this choice of blades:

(Freud) LU74R (30-tooth, "glue-line rip") LU-85R (80-tooth, "ultimate cut-off")

and possibly LU80R ("Ultimate plywood"--so that LU85R above, doesn't get "abused").

I know there are a lot of Forrest WW-II fans, but the reviews were not very overwhelming, so it's sort of a tough call (but you can see which way I'm leaning).

According to my measurements, my Biesemeyer Blade spreader is .105-.107 inches. I'm not sure how small of a kerf I can go down to (and was not able to find further direction). Two of the blades above have kerfs of .116 and .118. We talking about a 1/100" of an inch, and "blade runout" (however much there is) is on my side here, so it doesn't seem like a problem. FWIW, I have no plan to cut anything thicker than 3/4" for now.

As Jeff suggested, I'll surely buy a lesser blade (if I can find any full kerf ones) to practice on. The Freud-Diablo's, IIRC, seem to have kerf around .91.

Bill

[Lew Hodgett]

------------------------------------------------------------- Freud once offered a set of blades consisting of a 24T rip, a 50T General purpose, and an 80T cross cut ply.

That set met all my needs when I added the 8" Freud stacked dado set.

Might want to check if the set is still offered at a set price.

-------------------------------------------------------------------- "Bill" wrote:

--------------------------------------------------------------- Pardon my French, but after Leon signs off on a blade, who gives a f*ck what the rest of the world has to say?

Time to spend some money.

Lew

[Bill]

Yes, that set has been on my Amazon wish list ever since you mentioned it, and I even searched the Internet for it (for hours, at first), but Freud apparent has not chosen to sell that set ("PGM 1060") since. The salesperson at Rockler remembered it too, but he didn't know whether it would be offered again either. Studying the details of the set did however improve my knowledge about blades at the time.

I sort of created my own "1060" set above. I'll see if I can get abbreviated-pricing at the woodworking show.

I picked up the same dado set a few months ago when I had a Rockler

20%-off coupon burning a hole in my pocket.

Bill

[woodchucker]

What reviews were not very good. WWII is generally the best blade in reviews.

Get yourself a 40T 1/8 kerf blade. You can't use a thin kerf blade with the Bies splitter.

Just a good way of getting used to the saw before you do something dumb.. we all do dumb shit when we are learning. If you are not pushing the envelope you are not learning.

[Swingman]

It is a no brainer call.

Buying a Forrest WW-II is not something you will ever regret. If there was a better 'bang for the buck' blade out there trust me, I'd own it. It's all I use except on the rare occasion when I rip 8/4 + hardwoods with a Freud Glueline Rip, but one of the three WW II's I own is really all that is necessary at that.

[Bill]

Thank you.

1. With regard to the WW-II, a number of folks were complaining about their Cherry wood getting burnt. Have you observed any special issues with Cherry (need to cut it faster?)

1. I assume any blade that is used to cut plywood is going to dull much faster than one used for ordinary wood. Does it make sense then to have a separate blade for plywood, so you can always have a "nice, sharp" one available for cross-cutting wood? And besides those 2, I'd expect to use an extra-cheap blade for rough-cutting plywood.

Bill

[Swingman]

While that is a risk working with cherry to some extent, If the blade is sharp and the feed rate is even, and the cherry still burns, IME most of the time it is something other than the blade. Poorly setup tool, reaction wood, etc.

Does it make sense then to have a separate blade for plywood, so you can always have a "nice, sharp" one available for cross-cutting wood? And besides those 2, I'd expect to use an extra-cheap blade for rough-cutting plywood.

Use a WW-II and forget about all that. (I have more than one WW-II just so I can rotate one to Forrest for sharpening when needed). I've used the same (high quality) Festool blade to both rough and finish cut more plywood in the past three years than the average woodworker will cut in 20.

Cheap blades are a waste of time/money.