How to mill a flat surface

Flycutter

Ignoramus9931 fired this volley in news:6-WdnREl96QoB6PVnZ2dnUVZ snipped-for-privacy@giganews.com:

Iggy, you need to square up the bit to the work. Your vertical axis is off-kilter. The ridges are an artifact of each cut being a slightly radiused groove, rather than a "true" face-milling.

Usually, it just involves squaring up the head in its rotation. Rarely, but on old, worn machines, the table might not be square vertically along the y axis. That one's harder to fix, and often not worth it.

LLoyd

A flycutter is an excellent suggestion. That is what I used when doing the exact same job. Be sure that the mill head is trammed. No flycutter? Use a boring head and a single point tool set to the diameter needed to cover the area in one pass.

A surface grinder works too.

Bob

Wrap a piece of coarse-grit wet-dry sandpaper around a flat piece of metal, and wet sand the surface flat by hand. Change sandpaper often. If the mill has done its work well, it will not take very long before all miil marks are gone. If desired, use finer grades of sandpaper to eliminate the frosted surface. This can be carried to any extreme, including mirror surfaces, which seems extreme for an anvil surface. Unless you are a jeweler.

Joe Gwinn

Joe, I agree, I think that 5-10 minutes with sandpaper will get me covered.

It's hard to tell from a photo, but it looks to me as though your endmill is not sharp.

I was waiting to see if someone came up with this. Or as I thought first off was "draw filing" . ...lew...

I don't know about that - my friend the armorer (plate, various sorts, Italian 15th century being his favorite, as I recall) always kept the anvil faces and hammer faces polished to a mirror shine. Not overly difficult to maintain when in regular use. Takes a good deal of work to get an abused rusty farm anvil up to that standard in the first place, however.

Mine look like crap, comparatively, but that's mostly because they are sitting around in one of the interminable phases of not getting much work done while trying to get the shop ready to use. The older one did get a full workover when I got it, and I oil them to slow the surface rust while they wait for me to get things set up.

What the others said about tramming, flycutter instead of end mill, hand sanding the finish, etc. Also you should have this:

Ignoramus9931 wrote:

I kind of like this sander a lot because it is so small. I have a hand held electric sander also. All good ideas.

In a few days I will be similarly refurbishing a 4" vise (this one was a 5").

It doesn't appear that you're looking for a mechanically flat surface here, only one that *looks* flat, right? Because getting a truly flat surface with hand sanding or files is a specialty that requires some understanding. And getting a truly flat surface with a belt sander is nearly impossible. Look at the sole of a new Stanley plane, and take a good straightedge with you to check it, and you'll see that they're a swaybacked mess. They're "abrasive-belt machined." Right.

But filing or hand-sanding can do a credible job if you use your head. For the initial flattening on my chunk of railroad track, which I try to keep flat for whacking on odds and ends with a hammer, I used an angle-head grinder and a straight edge. Then I draw-filed it. Then I struck it (filed straight along the length.) Then I cross-filed it, then struck it diagonally. All of this filing took less than five minutes. It's pretty darned flat.

This is the same method I have used in the past for flattening cylinder heads on lawnmowers, BTW. And don't tell anyone, but I also used it to flatten the manifold faces on the aluminum heads of a Mitsubishi V6 motor. I took them to a machine shop and they said it was better than anything they could do with machine tools.

Once you get it flat, you can use abrasive sanding to make it smooth. But that's smooth, not flat.

You probably know all this but just in case...

-- Ed Huntress

...

I didn't reply here earlier cause I knew iggy wanted smooth not flat.

I'm curious. When I need both, I've used your procedure, only with stones and kerosene. It does take a lot of time. Good idea or am I wasting time?

Karl

On Thu, 29 May 2008 06:59:49 -0500, with neither quill nor qualm, Ignoramus9931 quickly quoth:

-- I wish the Department of Homeland Security knew what ol' Unca Doug did, instinctively, so many years ago:

There is no security on this earth, there is only opportunity. -- General Douglas MacArthur

To me it looks like the vise might have been slightly unstable on the swivel base when you milled it. I have cleaned up import milling vises, my anvil, and a PYH end mill sharpener like this:

If the top surface wasn't milled, level it with wedges and take a light pass to remove high spots and see how it cuts. Shiny spots are harder and may be high afterwards. Flip it over and block it up on the just-milled surface. Cut enough off the base to see fresh metal all around. Turn it back upright, locate clamps over the cuts on the bottom so the casting doesn't warp, fly-cut the top. I take no more than 0.005" per pass and often 0.001" for the last one, after stoning the bit.

I tried this on an RF-30 mill-drill once without success, the vertical feed was too sloppy. I had to take the vise home to mill it.

Since I have a surface grinder I next grind the bottom side until the wheel cuts at least most of the area, turn it upright and grind the top to taste.

Previously I filed most of the tool marks off and then finished with SiC paper wrapped around a file or a piece of scrap tooling plate. You can file in the middle of a surface without rounding the edges with a file that curved during hardening, which is common for the cheap ones.

I would clean up the swivel base of your beautiful red vise separately on a faceplate in a lathe.

Jim Wilkins

No, I removed the vise from the swivel base and bolted it directly to the milling table ways.

Don't have one... And most sadly, do not have space for one...

I removed exactly 1mm from the anvil surface, and that was too much, should have removed 0.5mm.

I guess it will work, but if the material can be filed, it's a whole lot quicker. If the material can't be filed, and if the part is small enough, I've sometimes "lapped" it on an old marble table top with a piece of emery cloth taped or glued (with rubber cement) to the marble. This is a method sometimes recommended for fixing Stanley planes that are new and which therefore suck.

I have a good collection of files and I save my best ones for jobs like this. If the part is work-hardened steel or c.i. and kind of hard, striking with a file can be iffy. If the file skates you'll wreck it. The file has to bite. But my piece of RR track was no problem, despite lots of work-hardening from years of use.

-- Ed Huntress

As a cheat you can 'wet sand' with normal sandpaper and some type of light oil- WD40 works well for this.

Dave