Plasma cutting 'thin' (3/16in) stainless steel wrenches

I run into this problem every so often where I get a piece of grinding media stuck in the angle grinder. Knowing this was a problem, after buying my first angle grinder, I put anti-sieze compound on all of those 5/8-11 threaded studs when each next grinder was new, and yet the grinders wind up with grinding media bound up tight and I’m always concerned I’m doing damage to the bearings or other components in the right-angle head give the measures I have to go through to break things free.

I primarily use Norton media. Most Norton media comes with a metal hex that if one only had a suitable wrench to grab hold of it, then the issues I am facing here would dissapear. None of my standard box end (or other) wrenches can reach down in there to grab it, so I decided to take matters into my own hands and quickly knock out a set of thing right-angle grinder wrenches. While I’m at it, I’ll make a set for my neighbor and a few friends…

I sketchedup a quick wrench profile in CAD and headed down to the plasma table side of the AVIDcnc. I missed the fact that I should have, kanted, the head by ~30deg, but these seem to wrok well beside the fact that I missed that detail.

I loaded up a plate of 3/16th-in stainless steel on the water table. It is a bit hard to see in the photo, but if you look close, along the back left edge, behind the spindle, there is a 3/4in thich chunk of 4in wide steel bar providing extra hold down force to this plate so that the ~85psi air pressure used in plasma cutting doesn’t blow it around.

After that, the lower left corner was dialed in with the lasers to locate “0,0” from the CAD, (Link Here for a write up on the laser alignment system) a G31 command was used on the MDI screen to find Z0 and it was ‘off to the races’ proverbially.

Cutting stainless can always be a crowd pleaser, and modern cameras with extermely fast shutter speeds capture some incrediable shots.)

I’ve got a much higher resolution photo of the picture ‘above’. I might just have to get a quality print made and frame it for the haldway between the studio and the garage.

The parts don’t look that impressive right off the plasma cutter. Just like welding, plasma cutting leaves a HAZ (Heat Affected Zone.) This shows up as a strong decolorization in photos and to the eye as well leading one to thing the resultant part is much worse off than it is. Checking with dial calipers however tells a different story and shows theyse parts are going to turn our just fine.

I did not capture the photo here, but the first step in cleaning these up was a good minute on the slack belt of the belt grinder. After the belt grinder these transitions over to the coars wheel on the buffer. The coars wheel will grind down mild steel, tears through poweder coat in nothing flat and will remove a good amount of steel if one is not careful, but in this case, it was the perfect tool to soften up the edges and make these wrenches comfortable to hold.

The image below shows how these will engage with the integral nut on the Norton grinding wheels. (This one is a thick cut-off wheel).

This last image is a closeup of two of the four ‘thin’-wrenches I made. These work great. I figured these would want to be 0.020in over-sized, so I cut them 0.005-in over sized on the plasma cutter and figured I’d use the filing machine to bring them into a “net fit”, however the 0.005in oversized came in spot on and they work prefectly, as-is.

-Just a fun quick weekend project I thought to share… This one came out of necesity in the middle of a bigger project (a side project) that I’ll share here soon.


I’m impressed that you got that kind of accuracy!

What are you using for a tip? Fine cut or a regular tip?

@Eric , These cuts are made with standard consumables. 3/16 stainless steel is just a little to thick to process with fine cut consumables. In this case, … standard conumables, the THC was set at 131V, Standard air pressure in (~120psi-air which the plasma cutter regulates down internally), 45-A with a travel speed of 63-ipm. All settings straight from the recommended settings in the Hypertherm cut charts for 3/16in stainless steel.

Over time a few people comment that they are amazed at the achieved edge quality. I’m not sure what that is all about? Is this not normal? Where plasma cutting is concerned, I’ve got the machine set up the way I bought it from AVIDcnc / CNCRouterParts and to my knowledge, I’m not doing anything different to others running plasma.

The pair of parts in the photo below are cut from 1/4in plate and was taken immediatly after cutting this past weekend. Cut them, dried them off with a rag and snapped the photo. If one zooms in on that photo it is evident that I haven’t done any clean up yet. No belt grinder, no chipping, etc. There is a small amount of bottom side slag on these parts that doesn’t show in the photos, but that chips off super easily.

I’m just getting into plasma myself and I’ve gotten good edge quality using stock settings too. Most of the stuff that I’ve done is “fun” (signs and that sort of thing) where I’m not too concerned about high accuracy.

It’s neat that you can do things like wrenches. I’m definitely going to give it a try.

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