Shopsmith Forums

Okay I got the difference between a jig and scroll saw, is the advantage to one over the other?

Smoothness of cut. The jig saw blade "flops" during the up stroke causing kerf disturbance in the wood. The scroll saw stays "rigid" during the full up and down stroke.

At least that is what I read ....

A conventional jigsaw powers the blade down through the cut and uses a spring to pull it back up. Since the spring is seldom fast enough to keep pace with the lower power cylinder, the blade tends to bend in the middle which produces a rough cut and leads to premature blade breakage.

With the scroll saw, however, the blade is suspended between two parallel arms. These arms move up and down with the blade, so the blade is under constant tension during both the up and down stroke. This reduces blade bending and breakage-and the slight forward and backward motion of the blade allows the teeth to cut smoothly, so sanding is often completely unnecessary.

http://www.shopsmith.com/academy/scrollsaw/

Thanks Dick, learned a bunch here in the last day or 2.

rjent wrote:Smoothness of cut. The jig saw blade "flops" during the up stroke causing kerf disturbance in the wood. The scroll saw stays "rigid" during the full up and down stroke.

At least that is what I read ....

A conventional jigsaw powers the blade down through the cut and uses a spring to pull it back up. Since the spring is seldom fast enough to keep pace with the lower power cylinder, the blade tends to bend in the middle which produces a rough cut and leads to premature blade breakage.

With the scroll saw, however, the blade is suspended between two parallel arms. These arms move up and down with the blade, so the blade is under constant tension during both the up and down stroke. This reduces blade bending and breakage-and the slight forward and backward motion of the blade allows the teeth to cut smoothly, so sanding is often completely unnecessary.

http://www.shopsmith.com/academy/scrollsaw/

Ya notice that John?

BuckeyeDennis wrote:

rjent wrote:Mine is just amazing. Works great

One bolt attaches it. I am concerned about the presserfoot being made of pot metal, but I have seen replacements made of aluminum.

Top half comes off (with a spacer for the bolt) and turns into a saber saw using standard hand jig saw blades.

Very impressive operation for something 60 years old. Took mine apart (like I did the rest of the machine), cleaned it up, painted it Verde Green and carried on. Not much to it ....

Where did you see those aluminum replacement feet? Mine was badly cracked/crazed when I got it, and then a minor accidental drop broke it in half.

I know this is kind of a dead thread, but Dennis, here is a picture of the aluminum replacement foot ....

Old threads never die!

They get found and posted to.

Top hole threaded?


I can see one being made up in Ohio.

JPG wrote:

rjent wrote:Smoothness of cut. The jig saw blade "flops" during the up stroke causing kerf disturbance in the wood. The scroll saw stays "rigid" during the full up and down stroke.

At least that is what I read ....

A conventional jigsaw powers the blade down through the cut and uses a spring to pull it back up. Since the spring is seldom fast enough to keep pace with the lower power cylinder, the blade tends to bend in the middle which produces a rough cut and leads to premature blade breakage.

With the scroll saw, however, the blade is suspended between two parallel arms. These arms move up and down with the blade, so the blade is under constant tension during both the up and down stroke. This reduces blade bending and breakage-and the slight forward and backward motion of the blade allows the teeth to cut smoothly, so sanding is often completely unnecessary.

http://www.shopsmith.com/academy/scrollsaw/

Ya notice that John?

Yes. Your use of the words elliptical motion threw me. After thinking about the geometry and actually taking a close look at the scroll saw I think it is probably closer to an elliptical motion than a forward and backward motion as SS claims. It is a tilting of the blade front to back. Since we are moving a rectangle formed by the arms, blade and rear tension post up and down on a pivot point the top of the blade tilts toward the operator on the down stroke and away from the operator on the up stroke. At the same time the blade is moving up and down. I guess that would describe an ellipse. However, the blade chucks also pivot front to back at the same time as the arms move. I would think that would eliminate the tilting of the blade since the blade is not held rigid in that plane. It would be very interesting to see an actual plot of what the blade is doing with no load. Never the less there is some kind of blade movement front to back.

Weather or not that motion contributes to smoothness of the cut a SS claims I am not sure. That motion is certainly not unique to the SS scroll saw. The blade movement is a result of the design not because of the design. Feed pressure more than likely eliminates any "forward and back" movement of the blade on the wood. I believe the smoother cut with a scroll saw comes from constant tension on the blade on both the up and down stroke and the ability to achieve greater blade tension than a jig saw. The maximum blade tension on a jig saw is determined by the return spring. On a scroll saw I can tension the blade until it either pops out of the blade chuck or the blade breaks.

I referred to the frame as a parallelogram since the 'corners' angles changes through the cycle. The tension end also pivots like the blade holders.

The 'forward/back' is a fluctuating/rocking motion that like the bandsaw cuts the lower portion of the workpiece first then advances into the upper portion.

I think this provides room for the debris to exit out the bottom more easily.

rjent wrote:

BuckeyeDennis wrote:

rjent wrote:Mine is just amazing. Works great

One bolt attaches it. I am concerned about the presserfoot being made of pot metal, but I have seen replacements made of aluminum.

Top half comes off (with a spacer for the bolt) and turns into a saber saw using standard hand jig saw blades.

Very impressive operation for something 60 years old. Took mine apart (like I did the rest of the machine), cleaned it up, painted it Verde Green and carried on. Not much to it ....

Where did you see those aluminum replacement feet? Mine was badly cracked/crazed when I got it, and then a minor accidental drop broke it in half.

I know this is kind of a dead thread, but Dennis, here is a picture of the aluminum replacement foot ....

Thanks Dick. That photo is going in my Model A-34 jigsaw file. I don't have the equipment to mill aluminum myself, but maybe I can get a blank of the right size, and just drill & tap it. I'd bet that even hardwood would suffice in a pinch.

BuckeyeDennis wrote: Thanks Dick. That photo is going in my Model A-34 jigsaw file. I don't have the equipment to mill aluminum myself, but maybe I can get a blank of the right size, and just drill & tap it. I'd bet that even hardwood would suffice in a pinch.

I found the image in the Yahoo 10ER site. The description says that the block was totally made by the 10ER. I think drilling the holes should be easy in aluminum and tapping them for the set screw(s) should be pretty easy. I can't figure out how the block attaches at the top. Since you broke yours, how does it attach?

BTW, when you make yours, make a second .....