Home Made Counterbore

[Patrice Lemée]

Following what I read in another thread about getting a flat seat for your screws in softer handle scale material I decided I needed a counterbore and after seeing what they look like I thought “why not try and make one?”

Well it turns out that it is quite easy, provided you have a lathe of course. I used some 304 stainless rod. First turn your pilot diameter (screw clearance). Then the larger one (screw head size). And finally, using a small cut-off wheel in the Foredom, cut some flutes. Doing your best at every step to keep things as crisp as possible, we are making a cutting tool after all not a rubbing one. Here what it looks like.

(Usual disclaimer: no machinist was hurt in the making this tool).



Not exactly like a factory made one but it does work and I was surprised by how well. I first thought that I would have to use a drill first and use this to clean up the bottom of the hole but it works so well that I can go it all with just the counterbore. Of course this is for wood, bone, etc. I have no illusion that this would work in steel. I am sure that if you actually know what you are doing as far as flutes geometry you can make it work even better. If you think of ways to improve this, feel free to share.

Thanks for watching.

 

[Carcara]

Why not make one out of O1 or W1 drill rod and heat treat it?

 

[FTO_dude]

Good tutorial on how to make some really fancy ones here

 

[DukeHarley]

When in need........the needy get busy! Good job!

Jay

 

[Patrice Lemée]

Why not make one out of O1 or W1 drill rod and heat treat it?

Cause I did not have any.

Thanks a lot FTO, great explanation of the geometry of it.:thumbup:

 

[butcher_block]

if you had a tool post grinder you just make them out of old drill bits

 

[Patrice Lemée]

Yes Butch, sadly that's one of the tools I still haven't got.
So many tools so little money.

 

[Don Hanson III]

Nice work Patrice!

You can also rig up a fixture to turn drill bits/reamers into counter bores on your surface grinder, but will need to use the stone wheel.

 

[Patrice Lemée]

Interesting Don. I'll have to do some research cause I dont see how you can keep things concentric.

 

[Frank Niro]

Hey, Pat, since it works well as you did it, that's a good way. Frank

 

[Patrice Lemée]

Exactly Frank. That is something I am working on, trying to do what is necessary to to the job done and not more. Not that there is anything wrong with doing a better job of it of course. But in my case it usually means researching how to do it perfectly and getting all the required materials and tooling which usually takes a very long time. Time I need to spend on actually making knives.

 

[Idlewild]

Very interesting Patrice! You have so much skill and experience making the fine knives that come off your bench, it's not surprising that you're fabricating any part that you may require for your work/Art!

 

[longun]

If it works well, what more could you ask for? Next time you build one, try putting some relief (or body clearance) behind the cutting edge of the flute. That way the body doesn't rub and it may cut cleaner.

 

[butcher_block]

a rotery table or spin indexer might be able to be use also (i know all aboubt tool want there is a lathe with all the tooling down the road i want) but i have a 9 ich SB i hardly use already. i need more tooling for my mill before i can set funds aside for new fun toys

 

[aarongough]

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.

 

[Frank Niro]

Now that's interesting too, Aaron. Frank

 

[aarongough]

Now that's interesting too, Aaron. Frank

It's worth noting I made sure to cover up the ways of the mill with toweling before I did this... I'm not so sure grinder grit is good for milling machines.

 

[Salem Straub]

Nice job Patrice, sure beats buying one for $20, doesn't it?

 

[Patrice Lemée]

Thanks for the good words Robert. I don't fabricate as much as I used to for the reason stated above but I still do from time to time. I find it very rewarding and good exercise for the mind, trying to achieve what you want in the simplest way possible.

Longun, that is a very good idea, I may even do it on this one. Thanks a bunch. :thumbup:

Interesting Aaron, thanks for sharing.

Salem, it sure does.

 

[Stacy E. Apelt - Bladesmith]

You guys with your big tools !

I just chuck a broken drill bit in a cordless screwdriver and go to the belt grinder, turning the bit the opposite direction of the belt. Once the end is somewhat reduced I chuck it in the drill press and use a diamond plate or diamond file to clean it up to the exact size pilot desired.. It doesn't have to be smooth or pretty as long as it is concentric. The bit should be only long enough to make the seat, so I use the shortest broken bits for this.