What causes slitting blade mistracking?

[WobblyHand]

I was attempting to slit a piece of solid steel stock in half with a slitting saw. It appears the saw started mistracking and started cutting off at a downward angle. I was preoccupied with trying to feed the saw and didn't notice the mistrack until too late. Saw was 0.020" thick. Material was 1018 5/8" thick. Was the saw defective? Is the answer a thicker saw? What causes the mistracking? There was plenty of oil. Sierra American SA-1000 arbor.

 

[Cadillac]

Did the part move maybe?

 

[WobblyHand]

Did the part move maybe?

Don't think so. Actually, it's still in the 3" toolmakers vise. I could check if the parallels are still tight.

I thought I had read that this is a problem with thin blades, but didn't think 0.020" was very thin. I could see this happening with a 0.002" blade if it hit a hard spot?

 

[WobblyHand]

Don't think so. Actually, it's still in the 3" toolmakers vise. I could check if the parallels are still tight.

I thought I had read that this is a problem with thin blades, but didn't think 0.020" was very thin. I could see this happening with a 0.002" blade if it hit a hard spot?

edit: moveable jaw parallel has loosened, can move that parallel along the x-axis.

 

[FOMOGO]

Are your decimal points in the right place re blade thickness?

 

[Cadillac]

Yeah to me something has to move. Part quill not locked down, knee lock slips. If the saw is cutting on acouple teeth it can vibrate the part loose.

 

[Cadillac]

.002 slitting saw? ICan barely keep a .002 feeler gauge from bending

 

[Winegrower]

I just sawed some brass with a 0.020 slitting saw, after making an arbor for it. Worked perfectly. Must have been movement of some kind, or maybe the arbor screw loosened.

 

[Lo-Fi]

Feeding too fast is always the answer when I've had that problem with thin blades. Getting the saw to run true so most of the teeth work is the magic bullet, but it can be tricky!

 

[WobblyHand]

It was a 0.020" saw. You can see it in the picture in the first post. The marking is on the hub. As for feed rate, it took 20 minutes to go 1", so that is 0.05 ipm, hardly a fast feed. The quill didn't move. The z axis didn't move. I have dro's on both. The R8 collet was tightened. The arbor was tight.

I can try to measure the gap between work piece and the parallels. The movable jaw side parallel can slide side to side. It wasn't that way when I started, because I always test for that. So a small amount of jaw lift happened. I'm not expecting it is much lift. The last time I tested this vise for jaw lift it was under 0.0005". But I will check it.