View Full Version : Drilling out bronze screw heads
I have a few unsightly bronze screws that were not countersunk enough to bung. So I'm wondering if, since bronze is soft, can I drill them down a bit, say a quarter inch or so, and epoxy bungs in? Its an epoxy plywood boat, this will have no structural effect what so ever. Purely aesthetic. I know the bungs will look better than the screw heads showing. I mostly want to know what drill bit I might buy and if it will stay sharp enough.
05-08-2005, 01:56 PM
Those 'bullet point' types made by Black and Decker and sold in the big box places might do it.
05-08-2005, 02:04 PM
Just about any jobber bit from CanTire will drill bronze. Your biggest problem will be staying on centre after you've drilled the head of the screw off, since that bronze pin is going to be harder than the surrounding wood. Have you tried heating the screw head with a soldering bolt and then just backing it out? [Heat to break epoxy bond, and a good fitting driver with lots of torque] Seems about the worst thing that'll happen is you'll have a screw with no head, and you can see where this is going....
I'd be tempted to run a really skinny pilot down the centre of the screw pin [after taking the head off with a drill], then wasting a cheap brad point. A little grinding work might give you a bit without spurs which would stay centred on the rounded Brad point following the pilot hole.
Just my 2c. Let's see what real boat builders suggest smile.gif
Edited to add : There you go, one of the real boatbuilders can type faster than me, too smile.gif
[ 05-08-2005, 02:06 PM: Message edited by: DerekW ]
05-08-2005, 07:31 PM
I've used a product tool called "Unscrewums" with great success for pulling buggered bronze screws, broken bronze screws and tired bronze screws. Basicly it is a set of roll pins with saw teeth cut on one end in reverse.
The pin can be centered with a jig plate. Run drill motor backwards. The tool cuts through the head like cheese, grabs the shank and voila, out comes the screw.
05-08-2005, 08:26 PM
Like Derek, I am wondering why, if the screws do not matter, you are not simply removing them completely? Why go to the trouble of drilling down the heads when you can just unscrew them and plug the holes?
Another reason to remove the screws is because, as Derek hinted, the bung hole will be best drilled with a dedicated wood drill such as a Forstner bit or a brad point, and hitting bronze with that will likely muck up the drill bit.
If you do still want to drill down the heads then regular high speed steel drill bits should do the job just fine. You only need a bit as big as the shank of the screw because once you drill down a quarter inch the head will of course come of and be left as a ring around the drill bit (assuming you keep the drill bit centered).
Like Derek, I am wondering why, if the screws do not matter, you are not simply removing them completely? Cuz I stripped the @#*& heads :mad: :D (but I'll try removal first)
[ 05-08-2005, 08:57 PM: Message edited by: JimD ]
05-08-2005, 09:05 PM
Ah yes, been there, done that!
In that case drilling down the screws may well be the fastest solution. However, if you feel like it you can try the various tools designed for removing buggered up screws (somewhere I heard the principle that if there are multiple tools designed to do the same job then chances are none of them do the job really well?!?!).
To drill down further than the head to really get rid of a lot of the screws to make space for drilling for the bung what you may want to do is use a drill bit that is a bit smaller than the shank so that you have some chance of keeping it within the shank. Use a punch to make a divit to start the drill bit in at the center of the head and then go slowly. The reason to go slowly is because if the drill bit slips out of the bronze and into the wood and if you are pushing hard on the drill, it will start drilling really fast in the wood and you could find yourself with a hole that goes all the way through to the other side! That said, this technique has worked for me when I need to get rid of a screw. You are left with bits of bronze in the hole but with a little care these can be cleaned out. You just need to get rid of enough bronze so that you have space to spare to drill the bung hole.
05-08-2005, 10:20 PM
If what you are trying to do is remove the screw, try using a left hand drill bit. If your lucky the drill will go in a short way then grab and the screw will come out all in one try. I would sugest screwmachine length drills because they are aprox half the length of a jobbers drill and substantially stronger.
05-09-2005, 12:36 AM
I've been there. I finally decided the only right thing to do was to use a screw extractor - the kind where you drill a hole into the screw (empirical evidence shows that using light oil really speeds this up :D ), then used the left handed extractor with vise grips to get the screw out. There were a few times I thought I would snap that extractor.
It might have been easier to go the route you are proposing, but I realized that I would know I had done a sloppy job and one of the reasons I was doing this was to put my best effort into it.
Can't say it looks anything other than an amateur's dinking around, though.... ;)
[ 05-09-2005, 12:37 AM: Message edited by: Dave Gray ]
Can't say it looks anything other than an amateur's dinking around, though.... What a coincidence! That sounds like my boats. :D
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