drilling a hole in plated silver

wrote: (clip) Would I need any special tools/drill bits to do that? ^^^^^^^^^^^^^^^^ No. You will want to drill from the inside of the dish toward the back, so any small burrs will be behind the clock. The edges of the hole on the "face" side will be hidden behind the nut that holds the movement in, and not seen, so the hold doesn't really have to be perfect. Strongly recommend center punching the location, so you can be SURE the drill doesn't skate across the surface and create an ugly scar that is not hidden by the hub and hands.

Hi Katie,

What kind of tools do you have at your disposal? If you have a drill press, or even a hand drill motor, you can drill the necessary hole easily, but, in order to prevent damaging the dish, it would be a good idea to drill through a couple of pieces of other material, one piece on each side, with the dish sandwiched between them. Even some small pieces of this wood (plywood, for example) would be better than nothing, but some thin (1/8") aluminum would be better. Use paper between the pieces to prevent them from marring the dish. Drilling through the added pieces will prevent the drill from leaving an irregular hole as it goes through the dish, which is most likely very thin. Thin materials don't drill well with common twist drills, which are what most folks have for drilling holes. If you are stuck with drilling the hole using a hand drill motor, use lots of care to get the drill located perpendicular to the dish, so the hole is drilled straight. That's important for the drill, which needs to stay in contact uniformly with the dish in order to cut properly. The base metal is likely brass, so it should cut fairly well. Deburr the hole using a three cornered scraper if you have one available, or you can use a larger drill (like a 1/2") turning it by hand, not power, to remove the burr that is raised in drilling.

Good luck. Ask more questions if you're lost in all this.

Harold

And he also wants to put some masking tape on the front to avoid scratches. I guess.

Nick

A step drill will make it all easy, that's what I'd use.

John

I second that. Called a uni-bit by some?

My own .02:

I'd drill from the back to avoid scratching the front if the drill gets away from you.

Centerpunch first of course. Easiest way I can think of for you to locate the center is to use a pencil compass to draw a circle on stiff paper a tiny bit smaller that the diameter of the plate and cut it out with scissors. Place it on the plate so that it's well centered by eye and then mark through the compass point hole.

Start with a small drill (say 1/8") and work your way up in size.

If you are using a hand held drill, have your faithful and trusting assistant hold the plate firmly face down onto a piece of wood small enough so that the the front surface of the plate rests on it.

Jeff

P.S. Watcha' gonna use for hour markings, if anything?

_One_ _small_ (2..3mm) pilot hole is OK. But not more (diameter and # of holes). Otherwise, the bit will be pulled through in not time, catch, rotate the dish, ruin the hole, ruin the dish, ruin the day, and and and.

Nick

That sounds right, that's a brand name isn't it? Anyway, they're the best thing for drilling thin metal that I know of.

John

I agree, but lots of folks don't have them.

Harold

Yep! Pilot drilling thin material can be a mistake. That's one of the reasons additional material is wise (front and back)---it helps control the drilling process, especially when using a twist drill. They're not very good for thin material.

Harold

I propose we suggest the OP purchase one, generally for around $12-15, and do the best job with the least effort;-D

John

You guys did read my words, "......hold the plate firmly....." didn't you?

She's only trying to get a 5/16" drill through it, not a 3/4" one fergosh sakes, and the edges of the hole (if imperfect) will be covered by a nut anyway.

While you're right in the concept, sometimes it just isn't worth overcomplicating a setup for a one off simple job. "Gilding a turd" is the term I often use to refer to doing that.

Jeff (Who's got a set of homemade "sheet metal drills" he uses for that kinda stuff anyway....)

That's not the only issue here.

But how will she flatten the possibly now distorted plate to her satisfaction? Have you ever had a drill break through on thin brass and see how it pulls the material up the flute?

By following my advice, the chance of ruining the plate is minimized. I've lived long enough, and drilled enough holes in thin items, to know the hazards. Unless the OP has more than one plate to risk, stabbing a hole blindly isn't a good idea, not if she wants something useable when she's finished her attempt at drilling the 5/16" hole. In this case, a small amount of prep work will almost guarantee a good result. Sorry, can't agree with you this time. This isn't "gilding a turd", it's taking the necessary steps to insure a good result. Sort of like opening the garage door before driving in.

Harold

Nope, because I use sheet metal drills to do stuff like that. They don't grab as they break through:

Jim

Pretty cool, Jim. I've never gone out of my way to grind any, due mostly to my limited demand. I've hand ground countless flat bottomed drills (for counterboring for socket head cap screws. They work far better than counterbores do), so one of them wouldn't be much of an issue.

When I have a project that's critical, one I don't want to screw up, and sandwiching it isn't feasible, I usually use a two flute end mill so I end up with the hole where I want it, and on size. Even that requires a careful feed, however. End mills don't make great drills, as you know. From that you can conclude that I don't use a drill press. I don't. I always use my mill for drilling holes unless it's a real rough job.

Thanks for sharing.

Harold

I do a *lot* of electronic chassis work Harold. Over 3/8 inch I use greenlee punches, but for 3/8 inch holes (for the commonly-found BNC connector) sheet metal drills like this are invaluable. They can be run in a hand-held drill motor, and will place the hole within a few thou of the small pilot hole that has to be drilled first.

They cut out a slug of material so there's very little swarf left inside the chassis, and only a tiny bit of de-burring on the inside - which is where it's always tough to get at!

Jim