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  • tension of blade

    I have be playing with my saw for a few months now and still can't figure out how tight to make the blade.. I thought it was good and went to work on my lizard puzzle and ended up wide at the top and narrow at the bottom. Very frustrating. I am working with poplar 1.5" by 1.5". Please help!

  • #2
    The tighter the better for the blade . Way better than too loose and for cutting 1.5" stock your blade has to be dead on 90 degrees to the table. take your time and let the blade do its job to prevent cupping of the cut.With everything set like that the pieces will slide in and out from top or bottom.
    Fred

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    • #3
      Little Twig:

      1st, and most important, a BIG Welcome to the forum. I hope you enjoy your visits.

      (I am normally long winded, but I will try to keep it short.)

      I presume you are using 3/4 inch thick wood that is a 1.5 inches square. And by wide at the top and narrow at the bottom means that the kerf made by the saw is wider at the top of the cut than at the bottom. This has lead you to belive that the blade is wobbling (vibrating) left-right due to tension (lack of).

      Is this correct??

      If my presumtion of your question is correct, it cannot happen. There should be almost no movement or wobble left-right of the blade. The blade would break. My guess is that your saw's table is not at right angle to blade (90 degrees.) The kerf is the same width, but the kerf has been shifted over a slight amount.

      take some scrape wood and make a cut on one side. Turn off the saw. Now flip the wood over so that you can feed the wood back into the same cut as before, but with the top now on the bottom. If, and only if, you table is exactly 90 degrees to the blade will the blade fit in the previous cut. Try it and let us know the results.

      There are some other problems that could be masking themselves by your description. One of them is the error of sideways pressure new scroll sawyer's always have. Scroll sawing is an easy skill to learn, but it is still a skill that you have to practice. This has to do with physical eye-hand stuff and training you arms and hands to work togeather. Comes with practice.

      There is also the speed of the saw (strokes per minute), your feed rate of the stock into the blade, your blade selection, and what you are doing. And the make of the saw could be important for us to solve your problem.

      So, talk to us.

      {Oh well, there goes my attempt at a short reply down the drain.}

      Phil

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      • #4
        little twig, I believe Phil has hit the nail on the head. Proper tension comes with practice. Tension the blade then pluck it with your finger like a guitar string, you should get a nice "ting" sound. Make sure you are pushing the wood straight into the teeth, not from the side. Good luck. Mick.
        Mick, - Delta P-20

        A smile is a small curve that straightens everything out.

        Comment


        • #5
          Little Twig

          You have gotten some good advice and I would like to add some and ask some questions. First you do not mention what saw you are using and what type of blade or size of blade you are using. You do not mention the speed at which you have your saw set on. You do not mention the thickness of wood you are cutting. These are all important factors that needed to be known in order to help you properly. Phil mentioned the table being 90 degrees to the blade that is a great place to start. unless you are making relief cuts which you do not mention. Second the tension is something you will learn but a good starting point as was mentioned is to hear a sharp ping when plucked like a guitar string. If you have a starter's book this should be explained in it. As with all beginners it is a gtood idea to get hold of a beginner's book because they all have basically the sdame info and good starting practices in there. There is a learning curve with a scrollsaw as with any tool but is easy to learn.


          The problem as you stated with a difference in the top and bottom of you pieces leads me to believe a few things. As mentioned the table and blade must be 90 degrees. The right blade must be used for the job the right amount of tension at least not too little. and you must let the saw do the cutting. Scrollsawing is a slow artform. The blades are small so they will cut slow. You must not over push or you will find yourself pushing sideways and that will contribute to your problem. A good thing to do as your cutting if you get a clear moment and not in the middle odf a step curve let the wood relax and see if it springs back. If it does this tells you you were pushing sideways too much. This all come with practice so do not fret. Would appreciate it if you could answer the questions and maybe we can be of more help.
          John T.

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          • #6
            I am using a 16 inch Dremel, The speed dial just has + or -. The blade I was using is a no.5 crown. The wood is 2x2x18" poplar for the lizard puzzle in the fall issue of ssw. when I did the first cut for the puzzle portion I worked very slowly at it, letting go frequently to make sure I wasn't pushing to hard or sideways. The top view of the cut looked good but when I was finished the cut was not so wonderful on the bottom.
            I have made one lizard already but I used a pin end blade and the gaps in the puzzle pieces are too big. So I tried the smaller blade with poor results.

            I will check the table for level. The blade is quite tight (pinging). the speed I tried was 3/4 speed.

            Comment


            • #7
              Originally posted by little twig
              I am using a 16 inch Dremel, The speed dial just has + or -. The blade I was using is a no.5 crown. The wood is 2x2x18" poplar for the lizard puzzle in the fall issue of ssw. when I did the first cut for the puzzle portion I worked very slowly at it, letting go frequently to make sure I wasn't pushing to hard or sideways. The top view of the cut looked good but when I was finished the cut was not so wonderful on the bottom.
              I have made one lizard already but I used a pin end blade and the gaps in the puzzle pieces are too big. So I tried the smaller blade with poor results.

              I will check the table for level. The blade is quite tight (pinging). the speed I tried was 3/4 speed.
              When I am cutting puzzles like the lizzard I use #5 reverse skip tooth.
              I have noticed that FD blades are thinner than some others I have used and you could even get by with a #7 of that brand.
              I probably cut about 1/4 of the speed and push at the stock at the rate of a glacier.
              2" is really thick wood for that saw, thick for any saw, you must go slow.
              I do like crown teeth for some cutting but I think you will get better results with the reverse skip tooth. The gullet between the teeth will allow the sawdust to fall through.
              CAЯL HIRD-RUTTEЯ
              "proud member of the best scroll sawing forum on the net."
              Ryobi SC180VS scroll saw EX21

              Comment


              • #8
                I see you have put up some answers to the questions I posed. The foremost thing is to check for 90 degree blade and table relationship. The next thing is I would use a # 7 skip tooth blade non reverse for cutting wood I bet is 1 and 1/2" thick not 2" Third I would increase the speed to full out if you do mot get too much vibration. You must let the saw do the cutting and must not push sideways. Other than that you can try a prcision ground blade of that size. They are extremely sharp but I found hard to control but in wodd that thick it would help in that area. Good luck and let us know how you make out. These are strickly my opinions.
                John T.

                Comment


                • #9
                  John is right about a precision ground blade for what you are doing as well as a very tight blade which is 90 degrees to the table. Here is specs on precision ground blades
                  http://www.sloanswoodshop.com/scroll_saw_blades.htm
                  Fred

                  Comment


                  • #10
                    Actually,

                    I have to disagree with some of the advice on blades...Use the biggest blade you can find for this puzzle! I used a #7 because that's what I had on hand. The author, Len Wardle, cuts his out on a bandsaw. If you've got a #9, use it! You want the kerf to be as big as you can--that's what gives the lizard the flexibility to bend into the "realistic" lizard poses!

                    I'd use a #7 or #9 skip tooth blade of some sort. Also, be sure to take your time and let the blade do the work. If you force it, it will also bend the blade.

                    Bob
                    Scroll Saw Workshop
                    www.GrobetUSA.com

                    Comment


                    • #11
                      Little Twig,
                      I agree on the #7 or even #9 blade, but more than that, I use a mediium speed and really concentrate on putting absolutely no side pressure on the blade - for me it was that fairly minor side pressure that caused the top to look good, but the bottom to be all over the place. I even did some pressure thing that caused a "barrel cut" - where the top and bottom looked good, but the pieces were pot-bellied! That really plays heck with getting them apart, to say nothing of actually using them for a puzzle. The answers for me were that side pressure - you cannot have any!
                      As for cutting 1 1/2 x 1 1/2 - that seems perfectly OK for most saws - I often cut 2 to 2 5/8 inch thick stuff - you just have to not rush - and a new, sharp blade does wonders. They're cheap - use a new one for each thick project you cut. You could probably then use those used blades for thin stuff, but I usually just throw them away.
                      Good luck on your next attempt.
                      Sandy

                      Comment


                      • #12
                        Keeping the blade at 90 degrees goes without saying--oops, I said it. I used a #5 PGT skip tooth for the lizard and it worked just fine. I did, however, cheat a bit on the instructions by cutting the pieces out before doing any shaping like rounding over the edges, tapering, etc. It is a whole lot easier to get good, straight cuts when the wood is not trying to roll or without having to use huge clamps on the table top.

                        Moon
                        Old Mooner

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