Blade angle

[Jim-78028]

I See on the net most everyone says 90 degrees, left to right and front to back.
And then there are some that like a forward lean to the blade too.

So after finally modifying a real square to work in that small space, I find out that I have been working with a forward lean, not much but some.

Using credit cards, and blocks of wood just did not show the forward cant to the blade

Any reasons for one way or the other?  Or any reason why one is not the best choice even though it works?

[Bill Wilson]

Checking the forward lean of the blade in a fixed position, may not be an indicator of how square it actually cuts.  Depending on the design of the saw, there can be a slight rocking motion to the blade as it moves up & down.  It's inherent to the geometry of how the upper & lower arms are designed and where the pivot points are on the saw.  If testing, by making a shallow kerf in the (square) edge of a thick piece of wood, indicates that the kerf is the same depth on top and bottom, then you are good to go.  The fact that your blade is canted forward, while in a static position, just means that it may have a  little more aggressive cutting motion than one that maintains a more straight up and down motion througout the cut.  If the forward lean revealed itself in the cut, this would be a problem, because as you cut to the line on the top of the piece, the bottom would not be cutting as far and the waste pieces wouldn't release without overcutting on the top.  This would be especially problematic when stack cutting. 

[Jim Finn]

My saws run the blade straight up and down.  No movement fore and aft.  I think that if this were not so I would have trouble making tight turns in thicker stock.  I cut a lot of 3/4" stack to do my inlays and can cut pretty sharp angles with a #5 blade.  That is how I cut this:

[Rapid Roger]

Jim,
What kind of saw do you have? All of the current saws that I've seen have two arms on them one upper arm and one lower arm which causes an arc at the blade. With blade installed there is about 5" of difference between the upper clamp and lower clamp so, the arc is very slight but, it is still there.
I think that more than likely your saw is set up very well but still, the blade doesn't run in a true straight up and down movement. I have cut 1-1/2" thick wood on my De Walt  saw and don't really see any difference from the top of the cut to the bottom but, I'm sure there is some difference. If I check for square with the arms at the upper limit and compare to arms at the lower limit, there is a slight difference.
Ideally. the area just above the table should be a true 90 degrees with the arms in a center position but, sometimes that is difficult to achieve.

[sawdust703]

Regardless of the type of your saw, it will be set up with just a touch of forward lean. This is for many reasons, one in particular is for fretwork. The blade leans forward to cut into the material cleaner, straighter, & keep a more accurate cut. It is necessary to check your upper & lower cutting arms for alignment occasionally. Otherwise, as long as your blade is square w/the table, & straight up & down, your saw should cut well.

[Dan26]

This is an interesting topic. I've heard a number of reasons for the blade leaning but have never seen anything from a manufacturer which has me wondering where everyone gets their information from. I know there are some folks who have been around a while so I'm just asking if any of the manuals for your scroll saw have information about the forward to aft movement of the blade?

Another one that I heard was as the scroll saw evolved the geometry of the blade movement allowed for sawdust to be removed from the kerf and allow the blade to cut cleaner with less heat buildup.

[Jim Finn]

I have two Hegners 20" and 25" and a  15"Jet.  the arc is slight because much of the whole arm swings up and down not just the front few inches like a DeWalt or Excalibur.

[dirtrider73068]

Depends on the saw, my old craftsman had alot of forward bite when running made cutting fretwork a challange, but would chew though thick stock with the aggressive cut. My EX can be changed by rotating the motor can make it aggressive or not, I have mine set at a non-agressive cut for control and fretwork cuts slower this way but get better cuts.

Also depends on the saws arm there are two types I forget what they are called, take teh craftsman, ryobi cheaper saws have parrell arms that move up and down at same time in the same motion, this creates a agressive forward bite. EX, Dewalt don't really have this, the arms stay put but a rod moves to and fro hooked to camber arms that move up and down allowing the blade to cycle more straight up and down rather like a craftsman to move up down but also forward.

When I check my blade movement on my EX I turn it by hand or set on lowest motor setting and run it and take a piece of wood and come in from the back or front slowly and just kiss the blade and listen to hear how its cutting, I can also draw a straight line and line it up with the blade run saw at slowest setting or by hand and watch how the blade runs to the line you will be able to see it move to and fro of the line. If that makes sense.

[Jim-78028]

Thanks to all for the replies, sorry I should have mentioned I just picked up a used ex-21.  It appears to be set up fine, the left to right 90 degree aspect for the blade is right on, and I have no problem with tight turns (well no machine problem anyway, I am still getting my hands trained)

I will try that cutting a thick piece and comparing the top depth of cut to the bottom, great idea.

After I posted this, I checked my starter saw, porter cable, and there is no back to front cant to the blade at all.  I thought it interesting that neither the porter cable nor the ex owners manual talks about back to font blade alignment/setting, only left to right perpendicular blade setting.  Of course then again I am a guy and I generally flip through the owners manual ... quickly.
:-)

[dirtrider73068]

Thanks to all for the replies, sorry I should have mentioned I just picked up a used ex-21.  It appears to be set up fine, the left to right 90 degree aspect for the blade is right on, and I have no problem with tight turns (well no machine problem anyway, I am still getting my hands trained)

I will try that cutting a thick piece and comparing the top depth of cut to the bottom, great idea.

After I posted this, I checked my starter saw, porter cable, and there is no back to front cant to the blade at all.  I thought it interesting that neither the porter cable nor the ex owners manual talks about back to font blade alignment/setting, only left to right perpendicular blade setting.  Of course then again I am a guy and I generally flip through the owners manual ... quickly.
:-)

I think the EX manual explains it and how to adjust the motor to get a more agressive cut. I have my EX book somewhere would have to find it and flip through it and see if they explain it.

[Jim-78028]

@ dirt rider

You are right, the manual does talk about moving the motor to adjust forward lean, I found it last night during commercials.

[dirtrider73068]

I thought it did, just didn't remember if I saw it or not, its been a long time since I looked at it when I first got my saw.

I always look at the owners manual when I get any new tool or machine and make sure to look iver the adjustments page and mantaince page before even touching it unless I take it out the box to look at it.

[Jim-78028]

I thought it did, just didn't remember if I saw it or not, its been a long time since I looked at it when I first got my saw.

I always look at the owners manual when I get any new tool or machine and make sure to look iver the adjustments page and mantaince page before even touching it unless I take it out the box to look at it.

That is  a good habit, I should, I know I should, but ....

[Bill Wilson]

This is an interesting topic. I've heard a number of reasons for the blade leaning but have never seen anything from a manufacturer which has me wondering where everyone gets their information from. I know there are some folks who have been around a while so I'm just asking if any of the manuals for your scroll saw have information about the forward to aft movement of the blade?

Another one that I heard was as the scroll saw evolved the geometry of the blade movement allowed for sawdust to be removed from the kerf and allow the blade to cut cleaner with less heat buildup.

Rick Hutcheson has some information on his website about the general physics of how different saw designs cut.  Check out pages in the "About Saws" section, listed in the left margin of the screen.

http://www.scrollsaws.com/

[Jim-78028]

Bill, thanks, what a complete site!