Advice for attempt to machine flat a sheet of 1/4 steel plate

Does anyone here know whats required to machine steel. I just beed to remove a light layer of the top and bottom to try and get it as flat as possible on both sides. I bought it shear cut 2x2.5feet and we beat it flat with a sledge hammer.

Its currently mabey bowed about 1-2 mms mabey 3-4 in the worst spot. But i figured its close enough. Mabey i could just graze off the top layer till its flat. Then flip it and repeat.

It just needs to be smooth enough to not throw off my cuts.

Some people here will recognize this project. Its part of my magnetic waste board system. And im far enough to see why it’s uncommon. But it worked really well. And ive already invested in it.

Any help is appreciated

I recommend a vertical milling center. (Like a Tormach)

If you want it truly flat, it should be mounted to a suitable surface and then scraped — this can be done by hand, see the book Foundations of Mechanical Accuracy:

Can anyone elaborate. Ive never worked with metal before.

I primary work g10 and wood.

But my dad is a metal worker. The sledge hammer was his best idea

Bolt it to the machine.

Ensure that the machine structure is absolutely rigid, and that there is no flex in the steel, or the structure which it is fastened to.

Take light skim passes w/ a suitable endmill — repeat until the surface is flat enough.

So pretty much what i expected. Any recommendations on feeds and speeds. Im fairly certain carbide endmills are the only way to go with steel.

1/4 inch 2 fluter should do right.

Slowest speed on the router, skim cuts, maybe coat the surface with some light cutting oil. Don’t try to get it flat in 1 pass.

Going to a machine shop won’t make sense ’cause it’ll cost too much, and will be very difficult to do w/ the balance of the structure I place, and it won’t be guaranteed to be planar w/ the machine.

The other option would be to use a tool which supports leveling such as bCNC and a conductive probe.

I thought about this. But its strength properties arnt my need. Its magnetic properties are. It just lays on the bed of the xcarve and gets clameped through along with the plywood wasteboard and g10 sheet that i wish to cut. And the 3-4mm error area is very small. The rest is less than 1-2mm. Not to mention 4 may be a slight exaggeration now that I think about it, i was eyeballing it with a level. Its not that bad

Then the 1inch cube magnets take over the clamping needs for thin flexible material that vibrates when crazy large portions are removed. And i can move them during the cut. And they are very strong and clamp very tightly.
And i over cut rather deap to make my bits last longer as g10 chews up the fishtails of my cutters and wears them out fast. Mutch faster than the burs on the bit. Which are still normally in great shape.

So overcut like that is bad for a vacuum table.

As someone who trained as a machinist, my advice would be to buy a piece of plate that is the required size that is already flat.

The cost in tool bit’s would vastly outweigh the cost of the material if you try and do this yourself. And doing it yourself would result in a piece of plate that will neither be smooth or flat.

Something only a couple of feet square would be considered an off cut in many places.

Ring around. Cutting what you want from a full sheet will be ‘relatively’ expensive. Cutting what you want from some left overs, will cost you a couple of beers or a few bucks in cash.

Get on the phone and ring some metal suppliers. Also ring any local metal fabricators. Off cuts that size are often sold for theirs scrap value, offering them $20 would be vastly more appealing to them.

X Carve is great for many things. This ain’t one of them.


Yeh. But of course with all the steel mills in the area. Machined flat is not much of an option. Its all shear cut.

And my cutting bit is slated for death any ways.

So. I considered a grinder try tip and im thinking about it.

Dad also said if we owed one of the massive handgrinders. We could just lay it down flat and slide it around till it was close enough. Like he did when he worked for dogan steel.

I don’t think the Xcarve is going to work, if you try a very light cut the tool will most likely push off and start to rub, at the lowest rpm setting you can go, the tool will last about 3 seconds. You would be better off lapping the bar on something that is relatively flat. (I’m assuming you don’t have access to a surface plate that is large enough) A thick sheet of glass covered with a sheet of sandpaper makes for an ok lapping plate.

So i haven’t started yet. Specifically because i was waiting for a response like that.

Because deep down inside i felt like that was what might happen and this lapping you speak of sounds easier, and more promising. Now i would just need a big enough setup for a 2x2.5foot sheet. I have the flat surface. I just need the sandpaper that big.

This is not something I would put to my X-Carve and expect good results. At lease not without a bunch of mods.

Depends on how much you’re willing to spend. For a plate of that size, I would take it to someone who had a double disc grinder or blanchard grinder. It might cost you $250, but it will be flat within 0.005" and probably parallel within 0.010".

For my machining business I use Simcox Grinding in Brimfield, OH.