Proper Rpm For A Plain Slitting Cutter

tackit

tackit

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I hope to cut one side of a .0900thick plain steel 3" X 1 1/2" rectangular tubing off to make a tray from it, but I can't find the proper RPM for the cutter... It's a 3" X 1/8" X 30 tooth plain slitting cutter. I find formulas but they don't give the RPM just the SFPM. Could someone please help me? Thanks.
 
You did not mention the wall thickness of the tube, or material.
If your dimensions on the saw are correct, 3" Dia. X 3.141 = 9.432" / 30 teeth = .314" tooth pitch, this is a very course saw.

As a rule of thumb, especially with band saws try to keep 3 teeth in the material, for instance a band saw cutting 1/4" wall tubing one would chose a minimum .083" tooth pitch or a 12 tooth per inch blade, a 3" slitting saw would have 100+ teeth.

I have no idea of how many parts you require but this is doable just pay careful attention to the feed rate, start with a very slow spindle speed and increase from there. The sound will tell you when it gets too fast. Either way that is likely to be a noisy operation. As a side note some tubing will close up when cut through one side jamming the saw.

Good Luck
 
tackit said:
Clueless, I don't know how to use the formula, it wants me to enter numbers I don't have and don't know how to find.
Click to expand...
100 RPM's with a 3" tool = 79 SFM

Morse Tools recommends 110 SFM for low carbon steels, 79 SFM would be a good place to start, increase it until the tools begin to fail quickly then back off.

This also somewhat depends on the machine used, a chattery machine will increase tool wear. Also flood coolant will be required for decent tool life, do not slit the welded side if possible as the weld may sometimes cause anomalous behavior.
 
tackit said:
Clueless, I don't know how to use the formula, it wants me to enter numbers I don't have and don't know how to find.
Click to expand...

You want to calculate RPM so use the second calculator on the page. For example lets say you want 100 SFPM, and your cutter is 3 inches in diameter. Plugging those numbers in and hit calculate you get 127 RPM.

SFPMCALC.PNG
 
Very informative and helpful, thank you all for taking the time to help me out. Those speeds seem slower than my round column 31 F Rong Fu mill can go. I'll have to go to the shop and check it out, I haven't used if for this purpose before so I could be very wrong. Thanks again everyone.

I just checked, it's speed range is 150-3000 RPM. I'll set it for 150 RPM and go slow with blade lubrication.
 
Last edited:
Rather than use the online calculator, this formula will give you the same result:

RPM = SFPM X 3.82 / Diameter.

100 X 3.82 / 3 = 127
 
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