Drilng and Tapping a VERY small hole advice.....

[alex e]

Drilling and Tapping a VERY small hole advice.....

I came up with an idea for a watch modification and it involves drilling two 2.6mm holes in the lugs of my watch and tapping two 1.7mm holes opposite them, where now there is a spring loaded pin holding the watch strap on each side. Normally you depress the pin to remove it and the straps. A similar style watch made by Panerai uses these little threaded pins to hold their straps on very securely. They also are cut at the fatter end to accept a small slotted screwdriver.

Here's the watch. A monster at 47mm across!

Who could give me some guidance on tapping the smaller holes? I have a drill press and vises which will hold the watch securely but taps this small........I dunno.

 

[CruisinGA]

I've done stuff this small a couple times in a machine shop at school (Ga Tech).

I would always put the tap in a mill, put the mill in neutral and the workpiece in a vise. Usually I was using a CAM program to position the drill. Then lower the drill chuck and keep light pressure on it with the z-axis lever while turning the chuck by hand.

You ought to be able to do the same thing with your drillpress. Might have to take a belt off since most drillpresses don't have neutral.

I don't know what material the watch is made off. Hopefully something soft, if it is hard you can forget it. After the initial 2.6 drill, you might want to take a much larger drill and bevel the hole opening before tapping. This can make it easier to start the tap.

Use a little high quality tapping fluid and give it a go. Buy more than one tap.

 

[alex e]

I don't have itty frigging bitty metric taps but I am glad it seems possible to pull this off. The metal of the watchcase is not that hard so no worries there. So you spin the chuck manually? We have a milling machine that is HUGE at our shop on the farm, and maybe that would work as well? My other thought is let a jeweler do it. I am brainstorming here.

 

[LukeZero]

Those aren't that small- you can do it by hand. Or take it to the jeweler, if you're worried.

 

[alex e]

Looking for the taps right now......wonder who sells them? Maybe Wiha makes these? They have awesome quality micro screwdrivers and such. Maybe a small drillpress such as a hobby unit? Or, since there's basically a pilot hole already drilled do it by hand as Luke mentioned as long as it's clamped in a vise.

http://www.hobbytool.com/index.asp?PageAction=VIEWPROD&ProdID=668

 

[LukeZero]

The really hot ticket for this would be a tiny lathe. chuck up the pin and put the pilot drill in the tail stock and rotate the chuck by hand, then repeat with the tap.

 

[alex e]

Say what?

What about gunsmithing tools for tapping tiny screws and holes?

 

[roundrocktom]

ww.brownells.com

For a tiny screw you need a "pin vise" type holder. Just a cylinder that you can roll between your thumb and fingers. Too much weight, and you snap the taps. I've made some up right ones with a 1/4" hole down the center. With a 1/4" rod chucked in the lathe, or drill press, just acts like a guide to keep the tap orientation.

Ideal is to machine up a small holder. "U" shaped that the watch drops down into. On the upright portion of the "U" is a pilot hole a little larger than the tap needed. Acts like a guide.

Seems odd the watch case isn't hardened.

 

[Tofudebeest]

Seems odd the watch case isn't hardened.

Wanna bet that it is and that he finds out the hard way?
Is that an expensive watch?

 

[photogod]

I'd like to offer some help but I can't see the watch. Could you bring it a bit closer so I can see it? Crypes...

 

[Waorani]

Like for just about anything else - McMaster-Carr! Search for taps then go to metric - you might want to try 1.6mm.

 

[alex e]

I will probably let the watchmaker do this so I don't F it up.

 

[stayalert]

That is f-ing BIG TIME

don't go swimming with that watch....its prolly water resistant but that sucker will drag you to davey jones! eith that or you have wispy little arm/wrist

 

[alex e]

I do have wispy wrists and ankles, unfortunately.....but that 47mm watch is frigging HUGE. Luckily the rest of me ain't wispy. I don't know how to lift weights to make your wrists and ankles bigger.

 

[stayalert]

I do have wispy wrists and ankles, unfortunately.....but that 47mm watch is frigging HUGE. Luckily the rest of me ain't wispy. I don't know how to lift weights to make your wrists and ankles bigger.

Wispy hands = perfect for wrenching.

 

[Doug_S]

You can use your drill press for help here. Get what's called a "tap-guide" which is nothing more than a spring loaded tool that has either 3/8" or 1/2" shank and a spring loaded plunger that has a pointed end. With this tool you'll chuck up the 3/8" or 1/2" shank leaving the plunger pointed down toward the drill press table. Position the piece to be tapped below and on-center with the tap-guide. Your tap wrench should have a countersunk type of a hole on it's top. This is the part that goes against the plunger. With the tap touching the top of the hole to be tapped, position the drill chuck over the hole (on center) and then pull back the spring-loaded plunger. Stuff the tap handle under the plunger so that it puts tension between the tape and the hole to be tapped. Start taping SLOWLY by turning the tap handle in 1/8th turns around and around. After each 1/8th turn, back the tap out slowely so as not to either break the tap or screw up the threads. The key here is the more lube the better. I use a product called "tap-ease" but, if it's aluminum, you can use kereosine (sp) (works good on aluminum). Happy tapping!

 

[alex e]

Problem solved.