CNC table saw problems and fix

pescadoman

pescadoman

Randy
Silver Member
The following shows, from left(ferrule end) to right(joint end) an issue that came up while I was trying to tune in my machine. The cut was OK for the first 22 inches or so, then THAT happened. A drop in diameter and then machine marks and barberpoling for the remainder of the cut.

I think I have it figured out, but I'm looking for opinions. I did just about everything I could think of, so I can tell you if your guess is wrong:thumbup:.

I'll tell you that it wasn't a software or Gcode issue.
 

Attachments

  • shaft.jpg
    shaft.jpg
    49.8 KB · Views: 489
Last edited:
It's not traveling straight ?
When it gets to that area, the blade is hitting wood way off-center ?


PS
I hate seeing that shaft getting wasted.
 
Wrong speed, dull blade or wrong blade, too much or not enough pressure holding material. Any of these can cause that problem.
 
It looks to me Randy, that you are conventional cutting and the cut is pulling the piece into the saw as the depth of cut increases. This can happen at about 2/3 rds from the tip, or 1/3rd out from the joint.
Let me know if I am wrong.
 
conetip said:
It looks to me Randy, that you are conventional cutting and the cut is pulling the piece into the saw as the depth of cut increases. This can happen at about 2/3 rds from the tip, or 1/3rd out from the joint.
Let me know if I am wrong.
Click to expand...

I'm climb cutting
 
Brickcues said:
Wrong speed, dull blade or wrong blade, too much or not enough pressure holding material. Any of these can cause that problem.
Click to expand...

You missed the part where all was good throughout the first 22inches, including the thinnest part of the shaft.

It happened on numerous test pieces in a row.
 
JoeyInCali said:
It's not traveling straight ?
When it gets to that area, the blade is hitting wood way off-center ?


PS
I hate seeing that shaft getting wasted.
Click to expand...

I think this is as close to the correct answer as possible. I took the table off to replace the arbor bearings and didn't get in on perfectly straight. When a reassembled everything it cut fine on several passes and then I was going to turn the cnc around. Decided not to and when I remounted the trouble started. First thing I tried was jockying the cnc around a bit and when that didn't work I looked at the rails, steppers, stepper screws.

Then the obvious happened and I loosened and realigned the table...

Seems to be working fine now...
 
Forgot to mention that the table had been taken off to replace bearing and then put back on. That would have been a dead give away as to the problem. Joey had already mentioned cutting off center, I just added a few other things that will cause the same problem.

I used to have a machine like that and used for years. I had a DC motor for a speed control and if the speed was not correct it would cut fine for 20 or so inches and when you got to the small end it would start to oscillate as yours did. It would also do it if you had the wrong kerf blade for the finished cut. Seemed to like the straight cut blades the best for finish cut.

pescadoman said:
I think this is as close to the correct answer as possible. I took the table off to replace the arbor bearings and didn't get in on perfectly straight. When a reassembled everything it cut fine on several passes and then I was going to turn the cnc around. Decided not to and when I remounted the trouble started. First thing I tried was jockying the cnc around a bit and when that didn't work I looked at the rails, steppers, stepper screws.

Then the obvious happened and I loosened and realigned the table...

Seems to be working fine now...
Click to expand...
 
pescadoman said:
I think this is as close to the correct answer as possible. I took the table off to replace the arbor bearings and didn't get in on perfectly straight. When a reassembled everything it cut fine on several passes and then I was going to turn the cnc around. Decided not to and when I remounted the trouble started. First thing I tried was jockying the cnc around a bit and when that didn't work I looked at the rails, steppers, stepper screws.

Then the obvious happened and I loosened and realigned the table...

Seems to be working fine now...
Click to expand...

Do you see any difference when climb cutting versus conventional cutting ?
Neil
 
Brickcues said:
Forgot to mention that the table had been taken off to replace bearing and then put back on. That would have been a dead give away as to the problem. Joey had already mentioned cutting off center, I just added a few other things that will cause the same problem.

I used to have a machine like that and used for years. I had a DC motor for a speed control and if the speed was not correct it would cut fine for 20 or so inches and when you got to the small end it would start to oscillate as yours did. It would also do it if you had the wrong kerf blade for the finished cut. Seemed to like the straight cut blades the best for finish cut.
Click to expand...

Yah I know, but it cut fine at first. That is why I didn't think of it immediately.
 
You must log in or register to reply here.
Back
Top