Author Topic: Saw blade condition or is this normal?  (Read 3126 times)

Offline Gabby

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Saw blade condition or is this normal?
« on: February 06, 2011, 06:47:15 pm »
I decided to go out and make some practice cuts, and get a little time on the saw. It was overcast and chilly but I decided to tough it out. { For those who don't know I've set up in my carport open to the wind. I do have a shop / storage building but it is 300 ft. from power. I won't go into what all brought that situation into being. Suffice it to say lack of foresight. }
 About 10 minutes later the overcast was gone!
I had great lighting conditions and proceeded to practice making straight cuts and a few 90 degree turns, and checking to see how well the 2 pieces of wood matched up after the cut was complete. my wavy lines matched pretty good but the more angular cuts not so much. I decided to practice some straight lines on a piece of clear pine 1/2 x 3 x 4 inches. here is where my questions will start. I made a cut across the narrow part first cutting out a glue line just to see what would happen. that wasn't too bad, so I proceeded to do the same to the other end which had been broken of and was splintery. So I laid out a straight line to square up the end. Both of these cuts were rip cuts with the grain. I noticed the blade didn't really want to cut at the start going into end grain. I'd been noticing a little curl of wood in front of the blade and wondered if that is an indication that the blade may be getting dull??
After making the cut  which came out fairly straight.  :) I cut all but about an inch from one direction, and finished that up from the opposite just to see how close I could get doing it that way. The longer part of the cut was ragged on one side of the material as though it was tearing  the grain rather than a smooth cut, and the opposite sidewas relatively smooth, the short  part that I back cut was much smoother on one side  and the other not as badly torn as on the long part of the cut.
All this long winded dissertation is to set up to ask the question. Are all these signs  indications of a dull blade, a too loosely attached blade, or technique of feeding the material into the saw. I'm counting on you experienced people to set me straight. See what happens when a newbie O.F.gets a saw?   ::)
Last comment 2 hours vanished like smoke, I only quit because my fingers were getting a little numb!  ;D
Thanks in advance,
Gabby
MOLON LABE.
TRUST IN GOD!
 DON'T BELIEVE ALL YOU HEAR & DON'T SAY ALL THAT YOU THINK !

Offline dgman

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Re: Saw blade condition or is this normal?
« Reply #1 on: February 06, 2011, 07:58:21 pm »
Hey Gabby, First thing, Why aren't you watching the Super Bowl? Now for your question. If you where cutting for two hours with the same blade, Yes it is time to change the blade. As a scroll saw instructor I tell my students When the blade is not doing what it should be doing, it's time to change it. I don't set a time limit on the life of a blade, but after 30 minutes of continuous cutting it's probably time to chance it.
Just remember, blades are cheap if you buy them by the gross. So don't risk ruining your project because you didn't want to change your blade.
Dan In Southern California

tux_linux

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Re: Saw blade condition or is this normal?
« Reply #2 on: February 06, 2011, 08:09:58 pm »
Do not push the wood into the blade - the blade will do the cutting. You just have to "feed" it.

There are also some tricks to get the cut smoother:
First is to tape the wood. Seal it with some packing tape, the glue of the tape will lubricate the blade.
Sanding the wood before cutting seams to be also a good recommendation, at least fragile parts are better sanded first and easier finished after sawing.

Steve has some good patterns for practice in his catalog. The small shelf is one you should try - it's not too complicated/fragile and will look nice.

regards
Torsten

marmoh

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Re: Saw blade condition or is this normal?
« Reply #3 on: February 06, 2011, 10:20:41 pm »
Gabby, I noticed a big difference when I started using the FD blades...

Offline Gabby

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Re: Saw blade condition or is this normal?
« Reply #4 on: February 06, 2011, 11:11:00 pm »
OK Thanks folks, but I think what is being missed here is: The question..
Are the synptoms I have described indicators of a dull blade, or technique?
I was out there for 2 hours but  probably not cutting for half that time, due to examining the results and deciding what I would try next. I will replace the blade before I resume practice and will try to replicate the cuts I made and check the results.

Question:
How many times did you poke a hornet's nest before you learned NOT to?
LOL
Gabby
MOLON LABE.
TRUST IN GOD!
 DON'T BELIEVE ALL YOU HEAR & DON'T SAY ALL THAT YOU THINK !

Offline dgman

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Re: Saw blade condition or is this normal?
« Reply #5 on: February 06, 2011, 11:15:48 pm »

Question:
How many times did you poke a hornet's nest before you learned NOT to?
LOL
Gabby
Never!
Dan In Southern California

chief

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Re: Saw blade condition or is this normal?
« Reply #6 on: February 06, 2011, 11:53:32 pm »
Some blades ar precision ground, a little more expensive and cut better, and some blades are just ground blades.  The ground blades the teeth will have a set to one side which causes the blade to cut a little crooked and the teeth will leave on side smooth and one side a little rough.

Offline GrayBeard

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Re: Saw blade condition or is this normal?
« Reply #7 on: February 07, 2011, 12:03:19 am »
I was in a 'country tavern' once when a guy brought in a hornet nest he found...It was January and very cold...
Fortunately I left and went across the street to the hardware store just BEFORE the nest warmed up and the hornets WOKE UP!

You should have seen all the good ol' boys come flying out the door!
~~~~~~~~~~~~~~~~~~~~~~~~~~~
Now back to the question...I am getting the feeling that there are two things to be addressed...

1. Your Tension could be a bit loose. Make sure it is nice and tight and gives a 'pinging' sound when plucked
2. I also think you might be 'forcing' the feed as Torsten suggested. Take your time....slow and steady!

My $.02 worth!


~~~GB~~~
I never really wanted to grow up....All I wanted was to be able to reach the cookie jar...and play with my DW 788

Muzzlemike

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Re: Saw blade condition or is this normal?
« Reply #8 on: February 07, 2011, 03:49:58 am »
I would like to add to GB reply . Steve has a nice program on the left hand side of his blog to help with the sound of the blade when it has the right tension .

Mike

Offline Gabby

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Re: Saw blade condition or is this normal?
« Reply #9 on: February 07, 2011, 04:49:15 am »
Some blades ar precision ground, a little more expensive and cut better, and some blades are just ground blades.  The ground blades the teeth will have a set to one side which causes the blade to cut a little crooked and the teeth will leave on side smooth and one side a little rough.

OK now that makes sense to me, If anything I'm probably not feeding fast enough. I'm a little tentative, not wanting to break the blade by forceing it. I did notice that it took more pressure than I anticipated in order to get it to cut. Sort of like trying to turn a piece on the lathe with a dull tool. you end up burning or getting a catch. The sharp gouge cuts like butter.
I want to thank everyone who responded to my questions. I did see Steve's tightening advice and follow it.
Thanks Chief.
Mmike that was probably one of the best trips to the hardware store you ever made!  ;D I have to admit i never felt the urge to poke a nest either.
Gabby
MOLON LABE.
TRUST IN GOD!
 DON'T BELIEVE ALL YOU HEAR & DON'T SAY ALL THAT YOU THINK !

Offline julief

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Re: Saw blade condition or is this normal?
« Reply #10 on: February 07, 2011, 06:29:40 am »
The quality of your blade will make a difference.  You said you had a smoother cut on one side of the board.  If you are using a "hardware  store" blade, they are stamped and have little burrs on them so one side will be smoother than the other.  As far as entering from the opposite side to meet a line, well that just takes some practice.  If you feel you are going too slow - speed up.  You will find what feels right to you.  I was used to cutting pretty fast and after reading some entries on this forum, I tried to slow down and it did take some practice.  It is all about what works for you.

Offline Gabby

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Re: Saw blade condition or is this normal?
« Reply #11 on: February 07, 2011, 11:27:31 pm »
OK Today I changed out the blade and tried to replicate some of the cuts done yesterday. On 1/4" ply it worked great for a while. I don't remember the exact progression of test cuts, but when I tried to rip the 1/2" pine one side of the cut was definitely smoother than the other, the tear out wasn't as bad as with the old blade.
 I was trying some gentle curving cuts on the ply when it suddenly stuck fast bouncing up and down stuck to the blade. After shutting it down I had to spring open the cut with a screwdriver, actually breaking the wood away from the blade. I couldn't find a visible cause for the blade to stick. Putting that aside, Chief's response was verified as far as I'm concerned. I'm going to have to change blades more often than I thought at least if I use Olson blades in the future. My mentor included 6 with the saw we'll see if I have better luck with the FD blades when they get here. Thanks for all the responses.

As for the Super Bowl I watched parts of it and most of the final quarter. I've never been a big sports fan, I lean more to Rodeo and Bull Riding, that's what gets my juices flowing. Takes a special kind of man to be successful at that kind of sport. When they get it right it looks easy but it only takes a split second of inattention to be thrown. Or worse.
Gabby
MOLON LABE.
TRUST IN GOD!
 DON'T BELIEVE ALL YOU HEAR & DON'T SAY ALL THAT YOU THINK !

Offline mrsn

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Re: Saw blade condition or is this normal?
« Reply #12 on: February 08, 2011, 12:15:32 am »
I don't think this is exactly what happened when your blade got stuck, but it is interesting and the shop teacher part of me wants to share :)
when ripping wood the internal stresses can be released causing the two remaining pieces to do different things. Sometimes they can pull apart like a banana peel, other times they will tighen back on themselves. If they go back together they can tighten on the blade and cause all sorts of problems (kickback). It is why a splitter is so important on the table saw. I think pine is good prone to this. I once ripped a piece off a 2x4 and it ended up looking like a corkscrew.
lecture over, test tuesday ;)
Mrs.N

Muzzlemike

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Re: Saw blade condition or is this normal?
« Reply #13 on: February 08, 2011, 12:47:00 am »
I did not know that there was going to be TEST ! I would have studied a lot harder !

Mike

Offline dgman

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Re: Saw blade condition or is this normal?
« Reply #14 on: February 08, 2011, 12:54:40 am »
lecture over, test tuesday ;)
Mrs.N
OK teacher, I'm ready for my test! ::)
Dan In Southern California

 

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