Home Made Counterbore

Stacy, a good thing that my wife doesn't read the forums or that would not be very helpful in helping me convince her that I NEED those big machines. ;)
 
aarongough said:
Looks nice Patrice!

I have made counterbores in the past from drill bits by using my milling machine in an unusual way. Basically I put the drill bit that I want to turn into a counterbore in a drill chuck on the mill as if I was going to drill something.

I then fit a small vise to the milling table, and secure a dremel with a grinding stone in the vise. I then turn on both the spindle of the mill and the dremel, then use the controls for the mill table to move the dremel into the drill bit. I basically move the dremel sideways until it's just touching the drill then use the quill feed to grind up/down the length of the drill.

The nice thing about a counterbore made this way is that it can actually drill both the primary hole and the counterbore in one go if you're careful! It's probably best to use stub-length drills if you can as they'll be easier to grind because they're stiffer, but I've done it with jobber length drills just fine.
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A GREAT IDEA
I tried it on my little mill and it only took a few minutes but I used my right angle high speed grinder clamped in the vice.
Thank you for the idea.

Richard



 
Those dumb pictures do it to me every time !They make it look so simple to do. Now I'm going to have to try to make one. Frank
 
Tinbasher said:
A GREAT IDEA
I tried it on my little mill and it only took a few minutes but I used my right angle high speed grinder clamped in the vice.
Thank you for the idea.

Richard



Click to expand...

That looks amazing! Right angle grinder looks like the perfect tool for the job! I'll have to get one of those!
 
I haven't read this thread carefully, so perhaps I've missed this, but you guys realize you need to grind some clearance behind the cutting edge, right? You're basically making a 180 degree drill point, so there is a little more to it than just the pilot. The relief doesn't have to come all the way to the cutting edge, a small flat there is not the end of the world, but the end shouldn't just be flat or it's going to rub and chew rather than cut.
 
Nathan the Machinist said:
I haven't read this thread carefully, so perhaps I've missed this, but you guys realize you need to grind some clearance behind the cutting edge, right? You're basically making a 180 degree drill point, so there is a little more to it than just the pilot. The relief doesn't have to come all the way to the cutting edge, a small flat there is not the end of the world, but the end shouldn't just be flat or it's going to rub and chew rather than cut.
Click to expand...

Yes you're correct, ideally there would be some relief there. However the counter-bore that I made in this manner seems to work great in soft materials (like G10) even without the relief. Not sure it would do so well on steel or other metals...
 
I heard of people cutting gears on just a lathe. The spindle gets locked down and the apron advances to just gouge the metal like in a power scrapper operation, but moving the apron manually.

Maybe that would be more controlled than a grinder. I've not tried it yet, but I bet it would work well with annealed steel.
 
Nathan the Machinist said:
I haven't read this thread carefully, so perhaps I've missed this, but you guys realize you need to grind some clearance behind the cutting edge, right? You're basically making a 180 degree drill point, so there is a little more to it than just the pilot. The relief doesn't have to come all the way to the cutting edge, a small flat there is not the end of the world, but the end shouldn't just be flat or it's going to rub and chew rather than cut.
Click to expand...

Used a diamond file to relieve this one just forgot to mention it .

Richard
 
Nice work! One of my favorite things to see, is people making their own tools. That's what got me into blacksmithing. Ironically I haven't fired up the forge in 8 months.
 
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