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    Default What Stone Do I Need?

    I've just bought a second hand pillar drill, a traditional manufacturer in the UK called Meddings. It's in pretty good shape but has a few battle scars on the drill table. Nothing too serious but big enough to catch the odd small bit of swarf and consequently upset an accurate set up.

    Having searched posts on this subject my plan is simply to clean and fill the holes with epoxy metal (JB Weld or similar) and then make flat.

    So here's my question - what stone do I need to use? I'm planning to leave the epoxy metal just proud of the existing surface and then grind/polish flat, but I have no experience of stones or how best to use them. What is the best size, shape, grit and type to use and how best to use it?

    As you may have guessed I'm a noob in this area so any/all advice would be gratefully received.

    Thank you.

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    Work it down selectively with a bastard or mill cut file at first because a stone will clog up quickly. Use a stone after it's flattened with the file. You can avoid scratching the table surface by taping paper to the table or just be mindful of how much pressure you put on the file when it contacts the table. Use a carborundum or india stone. There's plenty of stones that are double sided with coarse/medium sides for applications like this, a good thing to have around anyway. Use some sort of liquid like kerosene, mineral spirits, WD-40, or light oil to keep the pores of the stone from clogging up. Apply the liquid with a small paint brush to the stone. Use a wire brush or plastic scrub brush on the stone when you notice it's getting clogged with material, about every 6 stokes or so and replenish the stone with more liquid. If you're stoning the entire table use figure 8 motions to more evenly remove material. If you pay attention to how the stone feels on the table you'll notice/feel a bump when material is proud, smoother when it's flush with the surface being worked. To be quite honest it's not that important to fill small dents, most machine tables have them too. Just stoning the table will be sufficient for an accurate set-up unless the battle scars are quite large/deep or you just want to fill them anyway. A good habit to be in is to lightly stone the surface before every set-up and you should be clamping the vise/work to the table anyway to prevent accidents (several types here) so getting chips in the battle scars shouldn't affect anything. Battle scars stoned flat/flush shouldn't be a problem, most machines have them.

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    Quote Originally Posted by GabrielB View Post
    I've just bought a second hand pillar drill, a traditional manufacturer in the UK called Meddings. It's in pretty good shape but has a few battle scars on the drill table. Nothing too serious but big enough to catch the odd small bit of swarf and consequently upset an accurate set up.

    Having searched posts on this subject my plan is simply to clean and fill the holes with epoxy metal (JB Weld or similar) and then make flat.

    So here's my question - what stone do I need to use? I'm planning to leave the epoxy metal just proud of the existing surface and then grind/polish flat, but I have no experience of stones or how best to use them. What is the best size, shape, grit and type to use and how best to use it?

    As you may have guessed I'm a noob in this area so any/all advice would be gratefully received.

    Thank you.
    .
    use a precision ground block of metal like a 1,2,3 block and stikit sandpaper.
    when its clogged or worn take off in a second and replace. the adhesive usually doesnt get on block but if it did a citrus based cleaner usually cleans sticky glue in seconds
    .
    stikit sandpaper comes in rolls like tape. been using a few decades and its usually much faster than stones. a little 2" or 3" right angle air grinder with sanding pads use for the bigger stuff first
    .
    3m stikit - Google Search

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    I was stoning my mill table recently. It seemed to work fine but afterwards there were tiny metal chips imbedded in the stone surface. Did I do something wrong?

    metalmagpie

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    Quote Originally Posted by metalmagpie View Post
    I was stoning my mill table recently. It seemed to work fine but afterwards there were tiny metal chips imbedded in the stone surface. Did I do something wrong?

    metalmagpie
    Nah, that happens if there are chips present while you're stoning. As soon as they embed (you can usually feel this immediately, as the stone will "skate" instead of having its normal drag) stop stoning and pick the chips out. I use the pointy jobby from my file card for that. If you don't get them out they tend to scratch the surface you're stoning.

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    Whatever rock comes on the Clarke $9.99 angle grinder......

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    I think a good quality flat file should do the table fine enough.then do your filling if thinking it needs more than just flat. Most often holes/dents in a drill table don't bother the use.

    Spinning work is dangerous. A spinning vise just as bad, good to have a stop on the table like a C clamp or a bolted on block. .Work following the feed back up is another big hazard.
    Drill and tap drill chart and chuck key should be hung near the machine.

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    Quote Originally Posted by metalmagpie View Post
    I was stoning my mill table recently. It seemed to work fine but afterwards there were tiny metal chips imbedded in the stone surface. Did I do something wrong?

    metalmagpie
    It is perfectly normal. You need a second stone to rub it against. The chips will imbed out of harms way.

    You should be using precision ground stones to assure you are only taking high spots off of your table or tool.

    You can make your own by running them through your surface grinder. If no surface grinder, the poor man's method is to flatten the stone on a diamond sharpening stone that is a bit larger than your aluminum oxide stone.

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    Northern Lights ?

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    Can you stone jb weld? I've never tried...

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    Since it is a second hand tool, the first thing I would, before any epoxy is added, would be to go over the table surface to get rid of any burrs that are there now. The file idea is OK, but be aware that files are NOT completely flat. Every two sided file that I have is slightly bent: concave on one side and convex on the other. You want to use the convex side on the table and light to medium strokes. Of course, the file should have the handle removed.

    After that has been done, I would explore the table with a good straight edge and a flashlight to see if it reasonably flat. I don't mean one of those scraped true, straight edges that are used for scraping work, just a good quality rule's edge. This will tell you just how good the present surface is. You may be chasing your tail if it has hills and valleys of several thousandths to begin with. You should know this before starting.

    Unless the dings are super big and the table is super flat, I see no reason for having them completely level with the surface of the table. But If that is what you want, then go for it.

    Yes, I would use the file first on the epoxy, but remember you will be using the convex side so, if the dings are large, it can sink them below the surrounding table level.

    As for stones, common stones are NOT flat. They can be even worse than the files: I have observed stones that are as much as 0.015" off; they are made for sharpening knives, not making surfaces flat. This does not easily produce a flat surface as you will probably be working with only two points or, at best, a line across the stone's surface in contact with the table. This is why they sell stones that have been ground flat, which are well within 0.001" flat and are sold in pairs. If you do not have such ground flat stones, then I would not recommend using a stone at all.

    A decently flat sanding pad will probably work much better. Or you could just wrap a sheet of fine sandpaper around a flat block of aluminum or even a good quality plywood. This should be more than flat enough for your used drill press table. You could start with a 100 grit and then follow it with a 220 grit. You will be working more with the law of averages here than with any precision flat. Go easy at the edges so you do not round them. If you do not get overly aggressive with the sanding, you should wind up with a surface that is as good as the basic one you started with, just minus the dings.

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    Quote Originally Posted by Rickyb View Post
    It is perfectly normal. You need a second stone to rub it against. The chips will imbed out of harms way.

    You should be using precision ground stones to assure you are only taking high spots off of your table or tool.

    You can make your own by running them through your surface grinder. If no surface grinder, the poor man's method is to flatten the stone on a diamond sharpening stone that is a bit larger than your aluminum oxide stone.
    Mine were precision ground stones. Thanks for your input.

    metalmagpie

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    This sounds like Home Shop Harry paradise. Precision ground stones? Oh please. And this is not a Moore jig grinder he's playing with here. Get a grip!!!!

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    Quote Originally Posted by tdmidget View Post
    This sounds like Home Shop Harry paradise. Precision ground stones? Oh please. And this is not a Moore jig grinder he's playing with here. Get a grip!!!!
    Hence my post ...."Clarke" = "Harbor Freight"
    Clarke: No1 for Tools & Equipment

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    I like a precision honing stone for surface grinder use, one only for the chuck and another for only parts. The Norton 6x2x1 (or 8x) is a go/OK choice being low price and the older ones were square to the sides so made a decent rough part square check device. stones are best usd with oil because they cut and wear flat that way.
    I would rarely use a good stone on a drill press table.
    *A decent name brand (or checked for flat) file should kept handy for a drill press table. File vary so much in quality one/they should be checked for flatness at purchase.

    These may be OK but I haven't bought one lately. so even they need be checked for(near dead) flat.
    https://www.mscdirect.com/product/details/80755317

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    Unless I'm doing fussy work on the grinder, I just rub a relatively flat stone against a diamond lap. Plenty good enough for almost all the work I do.

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    normally you use mineral spirits where stoning to keep the stone clean of getting metal stuck to stone.
    .
    a lapping block using a precision ground block of metal and stikit sandpaper works better in that when sandpaper or lapping film is worn you replace it is a few seconds.
    .
    if you magic marker the surface you can better tell where you are sanding/lapping. usually if using 180 grit and you remove marker mark you have removed .00005" to .0001", obviously it would take a long time to remove a lot of metal. I have removed by sanding/lapping .0001" many times over the decades
    .
    polishing stones .12x.5 to .25x.25" are smaller stones (pencil eraser size) for polishing molds. the square inch size is never that big cause it requires a certain psi pressure and a bigger stone would require too much pressure for a person to apply for fast stoning (fast being removing more than .0002" at a time).

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    Quote Originally Posted by DMF_TomB View Post
    normally you use mineral spirits where stoning to keep the stone clean of getting metal stuck to stone.
    .
    a lapping block using a precision ground block of metal and stikit sandpaper works better in that when sandpaper or lapping film is worn you replace it is a few seconds.
    .
    if you magic marker the surface you can better tell where you are sanding/lapping. usually if using 180 grit and you remove marker mark you have removed .00005" to .0001", obviously it would take a long time to remove a lot of metal. I have removed by sanding/lapping .0001" many times over the decades
    .
    polishing stones .12x.5 to .25x.25" are smaller stones (pencil eraser size) for polishing molds. the square inch size is never that big cause it requires a certain psi pressure and a bigger stone would require too much pressure for a person to apply for fast stoning (fast being removing more than .0002" at a time).
    The OP is leveling off "JB Weld" applied on a Drill press table......

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    Quote Originally Posted by digger doug View Post
    The OP is leveling off "JB Weld" applied on a Drill press table......
    and a sanding/lapping block and magic marker mark (or bluing) on metal would indicate when the epoxy filler is sanded near level with table top. can also use indicator and surface height gage to measure
    .
    industrially many times a printing press roller scratch is filled with gold plating. the gold color and being softer, makes it easier to sand/lap it flush with surrounding metal. sometimes copper is used for larger areas as obviously gold is more expensive. I used to do selective brush plating gold repairs.
    .
    usually did tape test. apply masking tape and remove so adhesive is pulling straight up on filler material. if tape adhesive can remove the filler material it was not that strong and needs to be redone. polishing repair area was done so printing ink did not fill uneven area and print on to film.
    .
    polishing stones and small lapping blocks were always needed usually used micron or ultra fine grit lapping paper. it looks like regular paper but its actually a type of sandpaper or lapping film. double sided tape was used before i found you could buy rolls of stikit sandpaper with adhesive already on, like a roll of tape. lapping film is actually a roll of plastic with a abrasive coating. its more water proof when using water when lapping

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    Personally for big dings I have a small sharp piece of file that I used with a wrap of masking tape at either end. The piece is from a 1" file and cut about 6" long. The wrap of tape keeps the teeth suspended above the flat table surface but lets them cut anything that juts above that plane. Once that didn't cut anymore I'd use a flat file to knock it down even closer, then a stone. For table stoning I'd use a 400ish grit silicon carbide puck about 4" in diameter that has been flattened on a diamond plate.

    Most of the time dings were so small they'd only require a couple dusts with the stone. I had to get the files out about once a year when some knuckledragger was running the machine before me.


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