Resolving Crooked Cuts Lesson #5

Larry Anderson
Technical Advisor

In Lessons 1 through 4 we have examined the saw.

Now we should make a trial cut with very conservative settings to see if the crooked cut can be duplicated. A two inch (2”) round cold roll would be perfect, but then again a four inch (4”) square tube is easier to measure for squareness.

Test cut settings

A 2" round solid cold roll bar should be able to be cut in 15 seconds or less. The saw should be set at 300 sfpm and rate adjusted after cut is begun to achieve a 15 second or better time. Cut two pieces and measure the second cut for equal thickness. If you cut a 4" square tube with 4-6 tooth blade the cut time will probably be a minute.

Check squareness

Check the base piece after one cut for squareness left to right and up and down. If it is out of square left to right it generally means that the vising is off or the head is mis-aligned with the bed of the saw. If it is off top to bottom the problem is about everything we have been checking.

So, let’s say the cut was perfect left to right but was off 1/8” top to bottom. The customer buying this piece cannot tolerate 1/8" from square What to do? Call the manufacture and ask them what is tolerance when cutting a 4" 1/4” wall square A36 tube. If they say 1/16" per inch travel you have done better than what the saw calls for so you have to live with it.

Another approach is to cut slower. Leave the speed high but slow the cut time to 3 minutes and then check for accuracy. Sometimes the cut will be perfect. But, that brings up another problem: Can you live with that extended time?

So, we'll say after lesson number 5 we still have not solved the problem.