Step drills or counterbores for screw holes/pivot holes in folders?

jonnymac44

jonnymac44

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Sep 27, 2007
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Hey all, bits aren't cheap if you buy quality stuff so I don't want to buy anything that I don't need in the shop. Let's hear your preferences for drilling holes for folders, especially pivot holes. I think I could accomplish the task with either step drills or counterbores, but is one better than the other. Counterbores seem like they would give a flatter cut for the screw heads to sit on. What do you think?
 
A good Counter Bore should last a long time. My thoughts are the correct tool for the job is the cheapest in the long run. Unless you are jumping into making many different size folders, you should only need one or two C'bores.
 
For pivot holes, you need to drill, ream, and counterbore.

So you need the proper size of each.

You can generally get away with just a drill and counterbore for any handle screws.

Buy Screw length, Cobalt drills, and Carbide counterbores if you can.
 
Only problem is you will find that the screws you buy most often have different sized heads one supplier to another. You either have to use a driill or turn down the screw heads. It seems 2 X 56 screws are notorius for this. Frank
 
Buy several years worth when you find some you like.

I found some nice, fat headed 2-56 button heads on eBay a while back, and bought 10k for around $100
 
Fellhoelter said:
Buy several years worth when you find some you like.

I found some nice, fat headed 2-56 button heads on eBay a while back, and bought 10k for around $100
Click to expand...

Thanks, guys

Brian, I wasn't so worried about the little 2-56 screws, I was more concerned with my pivots. After reading some of your posts with Pohan Leu over on the other forum, I decided that drilling and reaming for the 3/16" pivot body then doing the counterbore hole with an endmill was the way to go especially since most counterbores I've found don't have the right size pilot for what I'm doing. They are usually too big and would make too sloppy a hole for a pivot. Anyway, I've found the right size endmill, but I still wasn't too sure about how to line up the hole perfectly for counterboring with the endmill after drilling the pivot hole. You explained it to Po, but it was still a bit foggy for me. I've got machinery experience, but I'm no machinist:o

Thanks!
 
I've got a couple drill presses in the shop but now mill yet.
I figured I could always clamp down my handle slab really tight, drill and ream the 3/16 pivot hole, then change to the endmill and counterbore for the screw head without ever releasing the clamp pressure, but that would prevent me from setting a depth stop so the depth of the counterbore would have to be eyeballed.

If there is another easy way to do it I'm all ears.

Thanks Brian!
 
Ok then, do the same thing, but with a sacrificial piece of material.
Now you can stick a pin in the hole that comes up just enough to stay below your counterbore depth, put your already reamed pivot hole on that pin, and counterbore as many pieces as you want.

You can re-use that piece next time by chucking up a pin and bringing it down into the hole in your plate.
Then clamp the plate down, and you are centered.

If there is slop in your spindle, plunge cutting with an end mill might be sketchy.
 
Johnny: Fellhoelter's idea is a good one, but, if you don't have a mill I would use drills instead. Having a flat bottom in the hole is not nearly as important as having the hole and the C'bore be as concentric as possible. Using a drill bit as a C'bore will help you attain this.
 
RJ Martin said:
Johnny: Fellhoelter's idea is a good one, but, if you don't have a mill I would use drills instead. Having a flat bottom in the hole is not nearly as important as having the hole and the C'bore be as concentric as possible. Using a drill bit as a C'bore will help you attain this.
Click to expand...

LOL, now ya tell me!!:D:D Thanks RJ! I've already got the two end mills on the way as of last night from MSC. I'll pick up some step drills as well and try both methods I think. Eventually I will be adding a mill to the shop, so the tooling won't go to waste.

Thanks for all the input everybody!
 
I'd try the endmills first anyhow Jonny.

Centering is easy, it's just a matter of if they wobble or not...

You can do a combination of the two as well, start with a drill, getting some full diameter action going on, then cleaning up with an endmill.

Also, endmills want to "screw" their way through the material a lot less.
 
Fellhoelter said:
I'd try the endmills first anyhow Jonny.

Centering is easy, it's just a matter of if they wobble or not...

You can do a combination of the two as well, start with a drill, getting some full diameter action going on, then cleaning up with an endmill.
Click to expand...

Thanks Brian,
I'll definitely be giving the end mills first crack, but I like the idea of getting a bit of full diameter with a drill then cleaning out the bottom with the end mill. Both of my presses run pretty true so I should be good to go there. My fifty year old Atlas has a tiny bit, but my new Delta has pretty much zero.

Also, endmills want to "screw" their way through the material a lot less.
 
what size is your pivot head? .290? :) = 19/64" counterbore with 3/16" pilot. about $25.00 from Enco or more at MSC lol ...found this post because of my name mentioned
 
I do a search on myself when I havent' been on here in awhile...seems like I find my name floating around here and there

unlinke a counterbore though, you can't leave the piece unclamped with an end mill or it will be fuct! (ask me how i know lol)
 
Thrree things to consider-First, a piloted counterbore spins a non-cutting plug of material in an already finished hole. It can't be helping the size and accuracy of that hole. I'd avoid it at all costs, especially on the pivot hole. For screw holes in the frames, it's fine. But piloted c'bores are a lot more expensive than drills.
Second, there is no functional difference between the way a screw head sits in a flat bottomed piloted hole versus a drilled hole with a tapered bottom, except that the flat bottomed hole requires chamfering the edge of the hole for the radius where the screw's shaft meets the head. The only time a flat bottomed hole is better is when the liners/frames are not thick enough to get the needed c'bore depth for your screw head.
Third, every drill press has runout.
 
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