Cutting 2" hole in 1/4" SS plate

   / Cutting 2" hole in 1/4" SS plate #1  
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RichNJKubota

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I need to make a couple exhaust flanges to match up to the flanges on my car. The exhaust on the car is SS and would like to use SS for the repair parts.
I took my 1/4" SS 304 plate and put it into the vise on the drill press. Then used a 2" bi-metallic hole saw. Got 3/4 of the way thru and progress stopped. Used cutting fluid liberally. Tried a new hole saw but that does not cut either. Seems like the metal got real hard all of a sudden?
Anyone have any suggestions for getting thru this metal? Are there any better types of hole saws?
 
   / Cutting 2" hole in 1/4" SS plate #2  
Plasma cutter or have a machine shop with a water jet do it ?
 
   / Cutting 2" hole in 1/4" SS plate
  • Thread Starter
#3  
Yeah a water jet shop was going to do it but he never seems to get it done. I put the flanges into CAD so he could feed them right into his machine. Anyone know of a reliable water jet shop?
 
   / Cutting 2" hole in 1/4" SS plate #4  
RichNJKubota said:
I need to make a couple exhaust flanges to match up to the flanges on my car. The exhaust on the car is SS and would like to use SS for the repair parts.
I took my 1/4" SS 304 plate and put it into the vise on the drill press. Then used a 2" bi-metallic hole saw. Got 3/4 of the way thru and progress stopped. Used cutting fluid liberally. Tried a new hole saw but that does not cut either. Seems like the metal got real hard all of a sudden?
Anyone have any suggestions for getting thru this metal? Are there any better types of hole saws?
Click to expand...
You either ran the saw too fast or didn't use enough pressure or both. SS work hardens quickly which is what happened. The trick to drilling or sawing holes in SS is to use a slow speed and high feed. Make sure the cutting tool is constantly making a chip or chips. Don't let the cutting tool dwell in the cut. Either have the tool cutting or pull it away from the work. One thing you did right was to use plenty of cutting oil. BTW, motor oil is not cutting oil. I'm not implying you used motor oil but I have seen many people use it thinking it would be OK.
Eric
 
   / Cutting 2" hole in 1/4" SS plate #6  
   / Cutting 2" hole in 1/4" SS plate #7  
tomplum said:
I don't have any idea if these are good for stainless, but I just bought a basic set of them hoping that they would be. I have literally piles of stainless that I need to learn to work with. https://www.amazon.com/dp/B0B1ZCZJQZ?ref=ppx_yo2ov_dt_b_product_details&th=1
Click to expand...
Probably better than B-Metal. Remember that carbide is more brittle than steel and so will tend to chip if given the chance. When using carbide tipped hole saws the cutting pressure will start to lessen quite a bit when the saw is starting to break through the work. When you feel this back off on the pressure you are exerting on the cut so that the saw doesn't break through suddenly. This will help to prevent grabbing and tooth breakage.
Eric
 
   / Cutting 2" hole in 1/4" SS plate #8  
Seems like a lot of drill presses are geared more for wood than steel. Assuming 304 SS cutting speed is 100 surface ft/minute (I didn't look it up), that would only be 190 RPM with a 2" cutter.

And yes on the work hardening risk. Your hardened zone may not be deep. Can you start it again from the other side, and with more pressure?
 
   / Cutting 2" hole in 1/4" SS plate #9  
Could you anneal the area with a torch?
 
   / Cutting 2" hole in 1/4" SS plate #10  
Flip the plate over and use the same pilot hole to finish the hole. Go slow and use cutting oil -just make sure you are continuously generating chips. You should be at around 60sfm so around 100rpm for a 2"
 
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