Shopsmith Forums

Just saw this page and video at woodgears about how to reduce (or eliminate?) tearout in plywood. I thought it was interesting enough to share.

http://woodgears.ca/shop-tricks/tearout.html

Or you can buy a quality plywood only blade and get almost 0 tearout. I personally would never attempt to cut a piece of wood on my saw by pulling it across the blade backwards, even if it was on my sled.

bucksaw wrote:Or you can buy a quality plywood only blade and get almost 0 tearout. I personally would never attempt to cut a piece of wood on my saw by pulling it across the blade backwards, even if it was on my sled.

Since I have just done that, please explain to me why you think I should refrain in the future. Before you have to tell me, it did feel weird because it works against many of your nature instincts; those developed by standing on the other side.

Hi,

Scoring cuts can be done with out the extra blade. Just adjust your blade to just touch make a pass then repeat the cut at full depth. This is commonly done when routing so you don't get chip out. Control is of course essential so think how you are going to make sure the two cuts are the same.

Lots of ways to do this, taping the cut area is also common as well as cutting through some sacrificial material or using zci's.

Lots of ways for lots of folks, different methods for different projects, keep watching and learning and saving some of these ideas for future projects. I like to try things out and sometimes I find a way I like better and sometimes I don't.

Ed

bucksaw wrote:Or you can buy a quality plywood only blade and get almost 0 tearout. I personally would never attempt to cut a piece of wood on my saw by pulling it across the blade backwards, even if it was on my sled.

Even a little skim cut like that shown in the video? I have Dusty's question too.....how come you wouldn't.

mickyd wrote:Even a little skim cut like that shown in the video? I have Dusty's question too.....how come you wouldn't.

1. I have multiple plywood blades and have no reason to attempt the described scoring operation.

2. I don't feel that I would have safe control of the workpiece.

3. On a longer scoring operation I would probably have to be moving away from the saw. Could step on something or loose my balance and fall. Bad idea for me.

This months issue of WOOD Magazine has an article on how to deal with wood tearout on ply when it occurs. They offer three work arounds.

Not a tease my not listing the work-arounds. They were really just common sense. "Molding, chamfer a profile, recut and edge with solid material."
It was the type of article that is written when the editor has two extra pages and can't find anything worthwhile.
They forgot some of the best fixes: Lots of Durham's filler, A thick coat of paint, beat wood with hammer and call it distressed.
Did I forget anything?
I do read Wood Magazine. Not only is it a decent publication, but I need to order something every year from the grandkid's magazine sales.

Like any other potentially hazardous endeavor, it is not so much what you do as how careful you are and are you recognizing the hazard(s) and watching for/minimizing/eliminating it.

The 'problem' with a 'reverse' cut is the old climb vs plow cutting phenomenom. When you cut with a saw in the reverse direction, you are climb cutting(the cutting blade is climbing into the workpiece[i.e. pulling the workpiece towards the blade]). IF the workpiece is held adequately so that the workpiece is NOT pulled by the blade, it can be done with desired results. However if it is NOT held adequately, all hell breaks loose.

Therefore proceed only with caution and with sufficient confidence that if it does break loose, no damage will be done(to either the workpiece or the 'operator' or the equipment).

BTW Do we all understand why reverse/shallow cuts reduce tearout?