Why is 1/4” pin stock always bigger than the 1/4” drill hole

[David Mary]

Why!??

 

[weo]

Because a 1/4" drill hole is not a perfect 1/4" circle
(or to be more exact, no drill bit will drill a perfect circle in the size indicated).

 

[Seedy Lot]

6.4 mm drill bit for the win

 

[Taz]

Or a F letter bit...

 

[David Mary]

6.4 mm drill bit for the win

I think I just might

 

[Lorien]

it's a conspiracy!

 

[David Mary]

Finally someone with the truth

 

[Lorien]

I'll expose Big Drill Bit if it's the last thing I do

 

[David Mary]

Drilluminati goin' down

 

[Way-Barney]

because the collet chucks they have in the drill shop are1/4" and the 1/4" bar stock does not fit,
so they order the steel a few thou smaller

 

[12345678910]

.250" pin is a press fit into a .250 hole.

F = .257
or you can get oversize reamers in increments of 0.000 1"
.252 is nice.

 

[Crag the Brewer]

Drilling plastics a hole tends to be less in size.

Drilling steel, holes tend to be a bit larger. And they bellmouth. Bigger at the surface, smaller diameter the deeper you go.

Like mentioned above drills are Not accurate. Not meant to be. They are for getting a Lot of material out fast, in a "hole shape".

If you want accuracy, you first properly centerdrill. Then depending on the desired diameter drill a pilot hole, then a hole undersize of what you want. Then ream out the hole with a reamer. *Edit (Don't do this, See Below)

And this is funny....... Size on size doesn't fit.
A 1/4" dowel will not fit (slipfit) into a 1/4" hole.

If you can put a .250" pin into a hole, then it's Not . 250" . It's bigger.



Something else, we need room for epoxy.
Drill the holes larger.
On a recent, different thread.....someone was splitting wood scales trying to pound loveless bolts into the bores. Ouch. He was making everything too tight.

Just drill everything big.
We aren't making watches......


Then we Should go down the tapered hole question....?
And doing it
But That's whole nother can of worms.

 

[Nate Webb]

I had this exact conversation as an internal monologue on Monday. Trying to get six steak knives ready for glue-up, and the 1/8" drill was "significantly" smaller than the 1/8" pin stock. It was maddening. I'm going to start taking Crag's advice and just get a slightly oversized drill bit.

 

[Taz]

#30 for a 1/8" pin, F for 1/4" pin, #11 or #12 for a 3/16" pin and Letter P for 5/16" pins/lanyard tubing.

 

[Way-Barney]

for 1/4" rivets I always used to drill 17/64" that was solid riveting not knife handles so don't know if that's too big

 

[ferider]

So you can lap it and use it as a pivot

 

[Horsewright]

Yep an F for the 1/4" and a #30 for the 1/8". Years ago I simplified life and made these two the only two I use on knife work. So the only two I buy.

 

[Alpha Knife Supply]

Use a micrometer to measure pin stock. Use pin gages to measure your holes. Doing this ensures there are no surprises.

Chuck

 

[Scaniaman]

For 1/4" pins I drill the tang with a 6.6 mm bit and the handle material with 6.5 mm. Perfect.

 

[EngrSorenson]

This is a problem that's haunted me in various ways.
in wood working, dowels are usually not concentric compared to drilled holes.
it metal work, pin stock is almost always concentric and a thou or two slightly oversize, and the holes I drill aren't concentric.

It's upsetting enough to understand why Opinel under sizes their pins by so much compared to the hole in the blade tang.