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I am restoring a razor for which I want to widen the pivot hole to 1/8"
Is this possible, and, what type of drill bit would I need? I have a set of those cobalt coated drills for stainless and machine steel, but I don't know if it can handle the razor.
I also don't know if the razor can handle this.
You have a couple options. If you wanted to leave the tang and the area around the pivot hole at their current level of hardness, then the cobalt drill bit could do the job. A slight test cut to see if the cobalt bit will turn a shaving would be in order. All you do is chamfer the edge of the hole a little. IF that cuts, it may mean the tang is soft enough. Or, a simple file test shows the area around the hole to be "relatively" soft compared to the harder edge the cobalt bits may be sufficient.
Otherwise, some sort of heat fence to protect the parts that need to stay hard, and a little propane and heat the tang until the steel around the hole loses all the pretty colors and goes to a gray past purple and you should be able to drill it with ordinary bits.
Next choice is a carbide drill bit. I like the single flute bits because they leave a round hole that doesn't require a reamer to make round again. They are rated to cut harder materials.
The problem with moving from high speed steel in ordinary bits to cobalt to carbide is the expense. Eventually you will probably find it worth the money to get the job done the way you wanted the first time. I can't count how many times I approached a job from the cheap end and when done, wished I hadn't.
I UES A DREMEL WITH A CARBIDE BIT THAT HAS A POINT AND IS ROUGH ON THE SIDES IT WILL DO THE JOB WITH OUT HARMING THE TANG
Thanks guys.
I know the cobalt coated bits are very expensive. But they were a present so that's ok :)
I also have to go to the hardware store today, and I'll have a look at the dremel bits to see if they have the baride tipped thingies. Might always come in handy.
I figured I'd just go ahead and try it on a restoration blade that I had lying around.
If had some other issues as well, so no loss if it got damaged.
As it turns out, the cobalt coated tip went through is like a hot knife through butter.
I forgot a 'before' pic of the pivot hole, so you'll just have to take my word for it.
You can see the setup I used: be sure to clamp the blade securely. I clamped it between 2 blocks of wood to prevent the drill from ripping loose and throwing it through my body.
The second pic is the result: a beautiful round 4mm hole that should be ideal for a 1/8 folder pivot pin.
Now, I also tried drilling a new hole through the tang of a bust gollow ground solingen razor. That didn't work. The drill refused to bite. I suspect this is because that has been hardened all the way. For that you probably need carbide, if anything.
If a hole in a very hard razor is to be enlarged, try these bits with a drop of diamond paste for "lubrication". The hole will be very slightly larger due to the paste, but it can be drilled fairly easily. The Black&Decker Masonry (carbide) Bit is from Wal-Mart(approx.$3) the Desco Bit is about $8. Use caution with blade. Wear safety glasses. I taped the edge and drilled from the side that produced torque allowing spine- leading if the bit snagged even if clamped. Go slow and with minimum down pressure. I am making a junk shorty shaver out of this blade. More about it later. Robert
safety tip clamp what ever you are drilling down before making the hole
if need be i ll get pictures of knife makers that have not and paid the doc bills to prove it
when i need to inlarge a hole i get a soild carbide ball end mill and clamp the work in my mini mill (its my drill press) carbid does not flex so any wobble can amke the bit snap into shards
did i say have googles on
I just took the scales off an old w&b and the hole is somewhat square on one side, definitely not a nice perfect round, I'll have to drill it but maybe larger than 1/8". I guess I coudl bush it after that if it is soft enough to tap. hmmm...
Red