Newbie and Tear out

[GC171]

Hey this is my first post so this question probably has already been answered but I can't find an answer

I have been attempting to cut some basic animal puzzles out of some regular pine and some clear pine, when I cut them using an 18TPI and an 22 TPI (Teeth Per Inch) blade I'm getting a lot of tear out on the boards, I use the same type of blades and have cut 3/4 Walnut and Oak just fine with no tear out,
I run my saw about 900-1,100 strokes a minute.

If any one has any idea on how to solve my problem I would be greatly appreciative

Thanks again
~Grant

[USMC1126]

You could try to make a table insert that has a smaller hole, or you could try placing your piece on top of some 1/8 or 1/4" ply and then cutting both together. I guess you just need more support under the piece, you dont want to cut it over a hole. This stuff helped me out.

King

[GrayBeard Phil]

Not sure what you mean by tear out that occurs only with solid pine but not solid hardwoods. I am going to presume your complaint is not just a dull blade or low tension problem.

The problem I am going to answer occurs with others, which may or may not be what you are asking about. You may be using pinned blades since anyone talking about blades having Teeth Per Inch (TPI) is usually using pinned blades. Due of the low percentage of scroll saw users who use pinned blades, the selection of pinned blades is not very large.

A lot of people using pin-less blades would opt for a skip tooth design blade (every other tooth is missing) for 3/4 inch Pine. You don't really need bigger teeth (lower TPI), just more room for saw dust to escape from the cut. This design may not be available with pinned blades.

Usually when some asks about tear out, they are talking about on the underside of the wood. As King mentioned, a zero clearance table insert can be used. Other options include a 1/8 to 1/4 inch sacrificial piece of plywood attached to the underside. The point being to give support all across the bottom of the project so when the teeth cuts the wood, the wood is cut, not pulled out (ripped out.) Sort of like using a backer board when drilling a hole in pine wood. There is a popular aid using a business card taped to the table insert as a zero clearance insert, but the card needs to be replaced often.

With Pin-Less blades, there is another option (I don't have knowledge of pinned blades since I use pin-less) with blade design. On the bottom of the blade, the bottom 8 teeth are set reverse, pointing up. These few reverse teeth cut the wood from the bottom, but only a minute distance into the kerf. So called fuzzes, or tear-outs, is drastically reduced (reduced, not perfectly eliminated.)

Reverse tooth blade geometry has a draw-back. It is more critical that you do not apply sideways pressure on the project, and you must apply more hold down force with your fingers. As you spin the wood, it will be more likely that the lower reversed teeth can "catch" the wood and force it up. The wood will start to POP up and down as the wood is caught in the blade.
Your fingers are to prevent the POP from starting, you fingers generally cannot overcome the power of the saw motor once the POPing starts. Use of reverse tooth blade geometry takes more time to develop sawing skill.

There is also crown tooth design (each tooth has two edges, a down facing and an up facing tooth.) I find a lot more sawdust ends up on top covering the pattern and my dust blower cannot keep up. Again I don't know if crown tooth geometry is available in pinned blades.

Phil

[minowevie]

Originally Posted by GC171

Hey this is my first post so this question probably has already been answered but I can't find an answer

I have been attempting to cut some basic animal puzzles out of some regular pine and some clear pine, when I cut them using an 18TPI and an 22 TPI (Teeth Per Inch) blade I'm getting a lot of tear out on the boards, I use the same type of blades and have cut 3/4 Walnut and Oak just fine with no tear out,
I run my saw about 900-1,100 strokes a minute.

If any one has any idea on how to solve my problem I would be greatly appreciative

Thanks again
~Grant

Hi Grant, I am wondering what you mean buy tear out. do you mean, that there is lots of hairs or frezzys on the bottom of the work. or are you meaning that the wood blows out the bottom. or splitting off the grain??. I know for me. pine, and cheap pine, can be pretty gummy. shreading like cole slaw. also gummying up your blade. making lots of hair like thingeys on the bottome of your work. no matter what blade you use, that will happen with this wood. it just takes some sanding to get rid of it. a revears tooth can help. but pine is easy to cut. but also a bother. if it is not dry enouph. also the grain of it. can make the wood snap in small areas. if you are used to the hard woods. this can be a mistry for you. pine is very fradgil. and breaks easyley. and gummy. I am not sure how to help hear. but hope this helped some. your friend Evie

[JROSE]

Hey Grant.....welcome aboard.....I'm the new guy from Cordelia and although I use a hand-saw, I too have similar problems with tear out. After trial and error with various size blades, I found that a 2/0 reverse blade is the way to go. And, I'm also limited to the size wood I can easily saw. The "Max" for me is 1/4" stuff, and usually a good grade of birch or oak plywood...
good luck on your scroll sawing endeavors....and once again, welcome aboard...

[Dragon]

Pine will dull your blade faster than the hard wood. What I do sometimes is to put a pieces of cardboard at the bottom of my wood. I use pieces from the cereal box. They are usually large enough to cover what I cut.
Diane

[HAMMER]

Don't Use Pine Unless You Can With Out Exception Verify That It Is Not Wet....pine Sap Will Dull The Blade, Create Exccessive Heat And Break The Blade As Well As Cause The Wood To Tear Out Instead Of Cut.....

If You Must Use Pine Try White Not Yellow And Use The Back Up Board As The Others Suggest.... If It Feels Waxie Dont Uwse It.

[mdvt]

The only pine I have ever had success with, is the kind the home improvement stores have that is made into "panels" for shelving. The ones that are glued together side by side. All other types of pine I avoid. I never know what the project will start to look like (usually very messy). I stick strictly to hardwoods.............

[sawdustus]

Grant, most pine is very soft and has long wood fibers, that are not held together tightly, so that almost any type of blade will cause fuzzies on the bottom, and sometimes even on the top of a piece. That is why you are seeing them in the pine but not the walnut or oak which have shorter and more tightly held wood fibers. The fuzzies will be more noticible in the wider growth rings of summer wood which are even softer than the narrow winter rings wood. Rings around the collar don't count. Reverse tooth blades help reduce them but are very slow in thick wood, even pine. A backer does help but make sure that it is tightly held to the piece you are cutting just as you would if stack cutting something. If you can, try to increase your speed to perhaps 1400-1500spm, I find that it helps to reduce the number of fuzzies on the back and makes it easier to cut thicker wood.

sawdustus

[rayzir]

I use blue painters tape on the back of my wood if I have trouble with tearout. The extra support the tape offers will sometimes make a difference. Might be worth a try.