Question about blade

[EZ]

Can a 7 1/4 circular saw blade cut both direction.
I know of at least one of the swing blade mills do this, but I dont know if its the way the teeth are angle or set or something, that makes it saw both ways.
EZ

[Ianab]

Basically.. No
you have to avoid 'climb' cutting.. the blade will try to climb out of the cut and everything just turns to custard real fast.
What the swingblade mills do is cut like a conventional circle saw going foward, then the blade pivots 90 deg and returns. You are effectively using the other side of the blade, so the rotation /  teeth are correct for the return cut. Likewise doing  a double width horizontal cut, the second 1/2 is made from the other side of the log, using the other side of the blade, and sawing in the reverse direction. Again the blade rotation is correct. Making a cardboard saw blade on a pencil may help visualise the rotation involved. The saw allways rotates the same way, and the teeth always enter the wood in the correct direction.

Cheers

Ian

[sawguy21]

This raises an interesting point. A carbide tipped circular blade will cut aluminum very well when reversed but definately not wood.

[Tom]

There is a big difference in turning the blade around as opposed to its entering the medium from the "wrong" side.

If you turn the blade around, you're cutting with the back of the tooth.  I don't know of any situation where this is correct on wood.  If you did it on aluminum, wouldn't it knock the carbide tips off of the blade?

[Ianab]

This raises an interesting point. A carbide tipped circular blade will cut aluminum very well when reversed but definately not wood.

To clarify, you mean moving the saw the reverse direction, or running the blade backwards ???

[Larry]

Picture a radial arm saw.  Usual method to make a cut is to pull the head towards you through the material.  On the other side of the pond them guys put the wood between the fence and the head and use a pushing stroke.  Much more control with a pushing stroke on a RAS.

Run a blade backwards on a circular saw and it won't cut wood at all.  A method to cut building steel is to run the blade backwards.  It is called cutting but actually the blade is burning its way through the steel by friction cutting.  

[SasquatchMan]

The reversed blade thing works well for cutting vinyl siding and thin metals - as pointed out, it is a bit hard on the carbide teeth.  

Cutting "backward", which is rightfully called climb cutting, is absolutely stupid with a hand held circular saw.  The tendency to bite in and run is really high.  I've done it a few times, but you have to go incredibly slow, and conditions have to be perfect, and you have to be *DanG good with the saw, to be perfectly honest.  I have 1000's of hours on my circ saw, so I tend to be a bit of a hotshot with it - use it for planing surfaces, too, but I don't recommend that either!

A "pocket" cut can be done, where you plunge the moving blade into a surface, but this takes steady nerves and some experience.

Larry, your "usual" method gives a smoother finish, but is much more dangerous, as you point out.  Most shops around here would fire someone for using a RAS that way.

[EZ]

Well I guess I didnt word this correctly.
What I'm trying to do is build an edger on my mill. I want to saw one of the edges by running the mill down and saw the other side on the way back.
EZ

[Fla._Deadheader]

  EZ, that's gonna take some fanciful injunearen : ??? ???

[SasquatchMan]

To mill like that, "with the rotation" you'll need two things - one is something to control feed rate, and I mean ABSOLUETLY control it - something that the wood really can't get out of.  The other thing is a riving knife after the cut, to keep green or case-hardened wood from pressing on the blade, stalling and frying the saw, or dragging the material in and THEN stalling and frying the saw.  

If you make this work, all power to you.  It sounds hellish to me.

[Percy]

Hey EZ
Before I had an edger, I was concockting a plan as to where I had a couple of skilsaws following behind the band and cutting at the correct depth so I could make a board in one pass. (mill-edging aint one of my favorite things to do). Biggest problem I came up with was power for the saws. It got soooo complicated that I gave up and bought an edger. ;D

[EZ]

I figure on making it work some thing like the bandsaw head, except it will be on the back side of the carriage. The blade or blades will be powered by a 11 hp briggs.
Percy, I know what you mean about edging, aint my favorite job either. An edger wood be nice but 90% of my sawing is away from home and pulling an edger with me wouldnt be worth it. ;D
SasquatchMan, I cant see know different in a factory built edger and with my home built one as far as the blade gummimg up and stuff.
FD, where theres a will theres a way.. ;D :D
EZ

[Fla._Deadheader]

  EZ, Even I know when to quit. : : ;D :D :D

[EZ]

 :D :D :D :D ;D
EZ

[Percy]

Actually EZ, You might be able to pull this off. THe 11 horse would have plenty of hormones for a couple of Skilsaw blades. If they were on a common shaft, there would need to be  a way for them to slide back n forth but once you got that beat, youd be "One Pass Producin" :D  With crooked logs, youd have to place them carfully for maximum yield but production would increase bigtime if you got it tweeked and performin like it otta. Heck, yuod have enuff power left over for a debarker as well.....Im getting carried away here, some body slap me :D :D :D :D

[ARKANSAWYER]

Depth of cut.  This is your greatest problem.  You have to know how deep you are cutting or you will cut into the (soon to be board under) next face.  It may in fact trim out to be a wider board.  You will have to be able to not only space the blades apart but also silde the whole thing to center it over the logs as not all logs are in the same place.
  There are ways to cut down on edging.  Most depends on what you are sawing.  I saw differently when I have my edger handy then when not.  It is easier to edge when one edge is trimed some.  So if you will saw one slab then rotate 90 degrees (without a debarker put the cut face the way the blade enters) take a slab and then fletching (s).  It may have a barky edge but it will sit more flat on the deck and be easier to edge and guess where to cut.  On manual mills it may mean more turning and the effort will cut down or productivity.  
  On large mobile jobs I just save the fletchings from the frist day and bring the edger the second day and trim them when we get done sawing the logs.  It may mean a extra trip to get "Egor" home but it saves a lot of time and blade life on the mill.   The edger alone ups production by 500 bdft a day and saves at least one blade change on the mill.  If you saw much that $120 a day will make an edger payment as your labor and fuel cost will remain the same if you edge on the mill or on the edger but the time savings is where you make money.  But you need the logs and amount of sawing to justify the edger.
   EZ   just think how much time you would have saved had you bought the mill you needed instead of taking one and building on it for years. ;D  The time you take to build is time you could be sawing or deer hunting and time is money no matter how little you pay yourself.
ARKANSAWYER

[Jeff]

Arky, some folks have the same feelings of accomplishment after building something as they do shooting a deer or counting money.  I remember spending several saturdays creating a ice fishing tip up out of an old toy ray gun  that had flashing lights and a siren when a fish hit it. I fiddled with all kinds of things to make it work. learned about mercury switches and things like that in its creation.  I could have spent a whole lot of time fishing with my perfectly good tip ups rather then mess with the idea of one with a siren, but you should have seen the attention it got the first time it went off in a group of fishermen and I pulled in a 24 inch Northern.

[Bibbyman]

To extend on what Arky said –

If all logs were perfect mounting edger blades on the sawhead may work. But often times a log will not lay parallel with the length of the mill.  That is in the case with a butt cut log with a lot of taper or a crooked log or one with some kind of ugly bump will push one end or the other out.  Thus, if the edger blades are running inline with the mill,  you'll not get a good edged board out of the process.  

[MULE_MAN]

I guess that's why they have that saying  ( Different strokes for Different  Folks )  :D  :D :D  ;D

[Swede]

 

Before I had an edger, I was concockting a plan as to where I had a couple of skilsaws following behind the band and cutting at the correct depth so I could make a board in one pass  

 >:( Thats MY Idea!!!!!! >:(  

 :D :D :D Still thinking about that angular gear and other stuff.

There was a photo on an other site, a cirkular mill sawing in both directions. Feeding forwards the shaft was low, cuting with center "under" the log. Before feeding "home" they lifted the shaft and blade up and sawed normal.

Looked realy dangerous, nothing for protection around the big blade.  

Swede.

[Fla._Deadheader]

  I MOSTLY agree with Arky. BUT, He saws full time, so, had no desire to build a mill.  Besides, He's got COIN. ;) ;D ;D :D :D

[EZ]

Dont know how long it will take me to try and build this, I guess it dont really matter cause I have the old carriage to rig it on. Between working at the shop and sawing and what ever else, it wont be built in a week or two. All I know is I really want to try and make this work.
The reason I ask about if I could saw both ways is it would be easyer to use one blade for this. I want to have it to where the blade and motor will move or slide back and forth so I can adjust it for whereever I need to.
Arky, I already know about the right depth thing, that should'nt be to much trouble, as the blade will have fine adjustments on it. I will have a scale just like the bandsaw scale. On the smaller logs edging aint to bad, we put the boards that need edge besides the log and when the cant is small enough they get edge. But when I have to drag a 28 inch board off and put it on the ground and turn around later and there's 20 0r 30 of these puppys laying there, then that when its a pain in the butt.
Buying a mill would have been alot easyer, but I still save alot of money building my own and I know what I can do with it. ;D Building an edger on my mill would be like hitting two birds with one stone,( not that I throw stones at birds) if it works, I wont have to drag a porable edger around with me and it will be something I made.
EZ

[Fla._Deadheader]

  If you would edge the boards when you have 4 or 5, it would not be nearly as bad as waiting for 20 boards to edge. :

  Have you looked at how an edger is designed  ???  If not, I would strongly suggest that, before making the first cut of Steel.

  Determination is a good thing. : ;D ;D ;D

  Yesterday, we made 1 X 6's, by sawing the cant to 12" and then taking off boards. Re stack 6-8 at a time, and split at 6". Goes pretty fast with 2 people. : ;D ;D  Cut 500' in 3 hours, including washing the logs. ;D ;) ;)

[J_T]

Why couldn't you desine it where it lowered with the saw head ??? And use adj. blades and rig a electric or hyd adj. for them 8) If no one had ever took time to invent things we would prpbly all still be using an ax and livung in a hand hewed log cabin . So full speed ahead . You know I think an acuwaiter off an old big dish would move them blades ???

[Furby]

JT,
It would work great until you got down to a cant, then ya would have to get the thing out of the way. If It would swing and have a locking pin that would stay accurate, that would be one way. Having a seperate head to edge with, would just mean more work then just useing the mill to edge.

What ya need to do is take something like a 1 1/2" - 2" machined stainless steel pipe, with some sliding collars. The pipe would be mounted to the head in a fixed postion. Then build a frame that mounts on the collars. The frame holds the motor, two blades, and drive shaft. The frame and collars would both pivot and slide side to side on the SS pipe, but would have a stop and lock for the correct depth as that would only change if you were to realign the blade guides. There would also be a locking mechanism of some kind so that the frame could slide sideways to align to the log, say a T bolt with a pad against the SS . The blades would have to move sideways on the shaft via some kinda adjustable screws.

As long as the whole thing can flip up and out of the way easy, be adjusted easy and fast, it would probly work pretty good. Might have to worry about throwing the mill head off balance with the extra weight, though. For this to be fast and worthwile, you would HAVE to use two blades, and simply edge as you cut. Would also have to figure out wich way the blades need to spin so as not to mess up the travel of the mill head. The blades would probly slow down the feed speed of the mill. That would get worse as the thickness of the board increased. Might be possible to edge BEFORE cutting the board free from the log. Would have to play around with that idea though. :

I would probly look into building a small edger that I could simply mount onto the mill bed when needed. All one unit that the boards would pass through just like a bigger edger or planner. Just my 2 cents. :