1.25" hole in 3mm stainless steel plate

Florin Andrei

Florin Andrei

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I'm making the face plate for a control panel. I was able to cut the SS plate pretty easily, following the advice given by many of you here on this forum - thank you.

Now I need to cut a 1.25" round hole in the 3mm SS plate, to install an emergency stop button. I'm pretty sure brute-force drilling with a 1.25" drill bit will not work - I've made much smaller holes and it's quite difficult. The material hardens very quickly. The only thing that worked well for a linear cut was milling it with a carbide mill at slow speed while constantly moving the work.

What are my best options to make that big hole? I've access to a mini-lathe, mini-mill, drill press, and various hand tools.

The plate size is 8.75" x 3.5". The big hole is not in the middle, but closer to one end.
 
My thought would be to drill hole out in steps to 1/2 inch then use the mill with a boring bar to take it the rest of the way out or if you have one a rotary table on a mill
just my thoughts
 
Florin Andrei said:
I'm making the face plate for a control panel. I was able to cut the SS plate pretty easily, following the advice given by many of you here on this forum - thank you.

Now I need to cut a 1.25" round hole in the 3mm SS plate, to install an emergency stop button. I'm pretty sure brute-force drilling with a 1.25" drill bit will not work - I've made much smaller holes and it's quite difficult. The material hardens very quickly. The only thing that worked well for a linear cut was milling it with a carbide mill at slow speed while constantly moving the work.

What are my best options to make that big hole? I've access to a mini-lathe, mini-mill, drill press, and various hand tools.

.
Click to expand...

Florin----I would use a dremmel type tool with a cutoff disc to cut a square 1 1/4" hole or a 1" carbide tipped cement drill bit for a hole-----then you can put a carbide burr in your mill and clean up the hole to size needed--the hole doesn't have to be perfectly exact cause the mounting ring will cover outside----if you are handy with a hand die grinder with a carbide burr you could clamp your piece in your vise and make quick work of it---carbide burrs are very durable and fast and you can save your expensive endmills for better projects------another better option is to use an electricians 1 1/4" knock out punch---- they work the best--- and buying a good set for your shop would be a continuous help--------Dave
 
Like Douglasr, Holesaw and a thick timber backup, (19mm ply or similar) will make short work of it

Cheers Phil
 
12bolts said:
Like Douglasr, Holesaw and a thick timber backup, (19mm ply or similar) will make short work of it

Cheers Phil
Click to expand...
I just drilled three holes that size in 1/8 stainless pipe using a regular hole saw and a 50/50 mix of antifreeze and water. I ran the Bridgeport at 200 RPM and squirted the anti freeze mix on the drill continously with a spray bottle. It worked like a charm and the bit cut right through with no problem.
Dale
 
yep - hole saw with tim:nuts:ber backing will do the job. Myself - I would use a step drill.
 
hotrod said:
I just drilled three holes that size in 1/8 stainless pipe using a regular hole saw and a 50/50 mix of antifreeze and water. I ran the Bridgeport at 200 RPM and squirted the anti freeze mix on the drill continously with a spray bottle. It worked like a charm and the bit cut right through with no problem.
Dale
Click to expand...

Be careful using antifreeze as a coolant.
If it contains ethylene glycol it can make you sick.
If you must use antifreeze as a coolant please use one that is made with propylene glycol, it is much safer.
 
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