Best way to deck a large piece of steel?

[Christianstark]

Hi all,

I am in process of making a belt grinder (Vendelay) and am working on the main part. Hot rolled steel 500mm x 160mm or about 20" x 6.4"

I have used carbide face mills to get it nearly to final thickness, but I want to get a more consistent surface finish. Let me to fly cutter, but nothing off the shelf is big enough to get a 160mm wide pass. Thoughts on best way to get a better surface finish? I want to cold blue the part, so trying to get it looking as good as I can.

Thanks for any suggestions. I own a 1340 lathe and an 833 mill, so I can make something if needed.

 

[woodchucker]

Fly cutter. Make your own...

It will do the job. you can make a standard big one, or just a disk with the HSS tool pointing out the bottom perpendicular. Either way.
If you had a surface grinder that would be the best way to finish it. Don't rule out taking a WW random orbital sander to it to get the finish you want, or a 1/4 sheet palm sander. I did that to my tablesaw to get the finish I wanted. At then end you probably will need to hand sand to get the scratches going in one direction, but at that point it will be a few minutes work.

 

[Winegrower]

I have a 10” steel disk about an inch thick. I’ve been thinking about making a giant fly cutter, press, weld or screw in an arbor, broach a square hole for a stick of HSS and give it a try. It seems that accuracy would not be a big issue with only one cutting edge, so most usual error sources cancel out. What stops me is that I have a 4” face mill andca very well trammed mill, so the surface finish is nice with very minor overlap discontinuities…and a little scrubbing working through the Scotch Brite colors, ending with a Blue Magic polishing…and I think why do more?

 

[Christianstark]

I have a 10” steel disk about an inch thick. I’ve been thinking about making a giant fly cutter, press, weld or screw in an arbor, broach a square hole for a stick of HSS and give it a try. It seems that accuracy would not be a big issue with only one cutting edge, so most usual error sources cancel out. What stops me is that I have a 4” face mill andca very well trammed mill, so the surface finish is nice with very minor overlap discontinuities…and a little scrubbing working through the Scotch Brite colors, ending with a Blue Magic polishing…and I think why do more?

I have a 4" face mill as well, but it is APKT so it is quite noisy, and finicky. I may give the face mill a try again, but I will take the vise off the mill, and clamp the steel down to the table. 2 passes. the vise was causing me to either move the part over, or get too much chatter once outboard of the vise. I also have a new face mill coming with SEHT inserts that cuts at 45 degrees, which should help over the APKT inserts.

 

[woodchucker]

I have a 10” steel disk about an inch thick. I’ve been thinking about making a giant fly cutter, press, weld or screw in an arbor, broach a square hole for a stick of HSS and give it a try. It seems that accuracy would not be a big issue with only one cutting edge, so most usual error sources cancel out. What stops me is that I have a 4” face mill andca very well trammed mill, so the surface finish is nice with very minor overlap discontinuities…and a little scrubbing working through the Scotch Brite colors, ending with a Blue Magic polishing…and I think why do more?

it doesn't have to be a square hole. You can use an old endmill and grind it down, or get round HSS. I have an assortment of round HSS for my old style boring bars. The smallest ones use round, and gravitate to larger and larger until they are square.

I save old end mills for the sole purpose of re-grinding them to new tools.

 

[whitmore]

I am in process of making a belt grinder (Vendelay) and am working on the main part. Hot rolled steel 500mm x 160mm or about 20" x 6.4"

I have used carbide face mills to get it nearly to final thickness, but I want to get a more consistent surface finish. ... I want to cold blue the part

If it were my project, I'd be inclined to flip it over and hand-stone the 'bad' side. You
want the face smooth, but there's no burrs on a hot-rolled surface, just soft oxide. The oxide will
rub off anyhow (and blueing will come off the rubbed surface too), but you can take it down quick with
a bit of elbow grease. It's imprecise, but the tooling is simple and easy.

 

[ErichKeane]

So to disagree with the others: I suspect a a large enough fly cutter wouldn't work in a single pass, I don't think the 833 has enough room on each side of the plate to make that work.

A 20" long surface grinder is going to be tough too... 18x6 is the common size for that, so I think you're outside of the work-envelope for a single pass.

MY Suggestion is to go with a large shaper/planer. With a nice cutter, they leave an absurdly nice/cool looking finish, with the striations already in the 'belt' direction. Not sure if you have access to a friend with a large enough one, but I DO know that Kieth Rucker has a quite-large planer, but is a decent ride from you (~3 hrs it seems, he's out in Tifton I think near the Georgia Museum of Ag).

EDIT: I say the part about 'doing it in a single task' on the 833, because even my 10x54" mill could only do it with a bit to spare (looks like a 9x49 Grizzly can do it, at 28" of travel). A 20" long cut, with a 6.5" face mill/fly cutter, means you need to travel almost 27" and it looks like your mill is <22" travel.

 

[mikey]

I have used carbide face mills to get it nearly to final thickness, but I wanta to get a more consistent surface finish. Let me to fly cutter, but nothing off the shelf is big enough to get a 160mm wide pass.

A Suburban Tools flycutter will easily cut 160mm in a single pass.

You don't need a flycutter to do it all in one go. You can use a smaller fly cutter and make several side-by-side passes. As long as it is flat then you should be okay. If the finish is not ideal for you then sand it on some plate glass afterwards.

 

[woodchucker]

So to disagree with the others: I suspect a a large enough fly cutter wouldn't work in a single pass, I don't think the 833 has enough room on each side of the plate to make that work.

A 20" long surface grinder is going to be tough too... 18x6 is the common size for that, so I think you're outside of the work-envelope for a single pass.

MY Suggestion is to go with a large shaper/planer. With a nice cutter, they leave an absurdly nice/cool looking finish, with the striations already in the 'belt' direction. Not sure if you have access to a friend with a large enough one, but I DO know that Kieth Rucker has a quite-large planer, but is a decent ride from you (~3 hrs it seems, he's out in Tifton I think near the Georgia Museum of Ag).

EDIT: I say the part about 'doing it in a single task' on the 833, because even my 10x54" mill could only do it with a bit to spare (looks like a 9x49 Grizzly can do it, at 28" of travel). A 20" long cut, with a 6.5" face mill/fly cutter, means you need to travel almost 27" and it looks like your mill is <22" travel.

I'm going to disagree. I had to face, mill, and surface grind a piece of 304 SS for my bathroom. It was bigger than all the machines could handle. It came out fine, and is in my shower and looks good. You will work hard to get it done if it can't be done in one pass, but you will have something without finding someone to PLANE it. Know anyone with a planner? I don't. I could tell you many different ways of doing what you are doing, including how to mount it on your table. None of them will be perfect, and all would have to be adjusted to your situation. All of us give ideas here, when we can. Telling you to go find a planer when planers are so RARE just baffles me how that's advice.

One question, do you have a belt sander for wood working? If you do, I would get a fine belt (Freud DIABLO) and put the finish you want on it. It will look ground.

 

[ErichKeane]

I'm going to disagree. I had to face, mill, and surface grind a piece of 304 SS for my bathroom. It was bigger than all the machines could handle. It came out fine, and is in my shower and looks good. You will work hard to get it done if it can't be done in one pass, but you will have something without finding someone to PLANE it. Know anyone with a planner? I don't. I could tell you many different ways of doing what you are doing, including how to mount it on your table. None of them will be perfect, and all would have to be adjusted to your situation. All of us give ideas here, when we can. Telling you to go find a planer when planers are so RARE just baffles me how that's advice.

One question, do you have a belt sander for wood working? If you do, I would get a fine belt (Freud DIABLO) and put the finish you want on it. It will look ground.

You'll note that I actually suggested a large shaper OR a planer. It seemed the requirement was to do it in 1 pass/setup, which there are very few machines that could do that. You'd be surprised at how many shapers and planers are around.