On Mon, 7 Nov 2005 22:31:07 +0100, (Nick Müller)
wrote:

John Martin wrote:

You're right, Nick - it's a key slot and has nothing to do with
expansion or contraction.

It's not that I want to be right, I want to understand why it is the way
it is. For that application, the key slot is quite odd, so I think the
usage is something different.

Same here. I could almost swear there was a set screw affair like
that on an old Singer tredle machine I tore apart once. Seemed that
th' keyed portion of th' shaft it fit over was about 2" long. Don't
recall what it's location on that shaft actually did tho.

Snarl

In article ,
says...
John Martin wrote:

You're right, Nick - it's a key slot and has nothing to do with
expansion or contraction.

It's not that I want to be right, I want to understand why it is the way
it is. For that application, the key slot is quite odd, so I think the
usage is something different.

As John says, it's not a keyway, but just makes it easier
to clamp the collar on the shaft. The pictured 1/4" collar
is at the small end of the available range of sizes, so the
slot is wide relative to the clamping diameter which makes
the slot look wide enough to be a keyway, but I assure you
it's not.

I have 4 collars (3/16, 3/8, 1/2 and 1-1/2) in front of me
and the slot in all is approx .060 inch wide. The slot does
not extend to the far side of the ID on the 1-1/2" collar,
presumably because the larger diameter collar is flexible
enough without it.

It's worth getting familiar with these collars as they're
handy for all sorts of things. They're also available with
a threaded ID, in two pieces, hinged, threaded to match
bearing locknut threads, etc. Ruland and Stafford are two
mfrs.

http://www.ruland.com/collars.html
http://www.staffordmfg.com/

Here's some photos I posted a couple weeks ago of one way I
use them. They're also useful as hubs for attaching
components to a shaft that need adjustable timing - cams,
for example.

http://tinyurl.com/eymgc
http://tinyurl.com/dz8su
http://tinyurl.com/c7gzc

Ned Simmons

John Martin wrote:
You're right, Nick - it's a key slot and has nothing to do with
expansion or contraction.


It's not that I want to be right, I want to understand why it is the way
it is. For that application, the key slot is quite odd, so I think the
usage is something different.

I'm not an engineer, nor do I play one on the internet, but my guess is
that the shallow slit has something to do with compressional force
distribution. Since we cannot make the hole smaller, the 'grip' of the
collar comes from deforming the shape of the hole around the shaft.

Without a slit on the far side, all the compressional force from
tightening the screw is concentrated at the screw end. The round hole
basically deforms most on that side, and the very least on the far
side, making a teardrop shape.

But with the narrow slit, the 'teardrop shaped' deformation takes place
at the base of the slit, in the center of the collar: not enough to
close the slit down, but enough to distribute the deformation along the
sides of the hole and effectively squeeze the collar evenly on both
sides. Instead of a teardrop shape, it closes down like a clamshell
with semicircular halves.

--humunculus

Ned Simmons wrote:

The pictured 1/4" collar
is at the small end of the available range of sizes, so the
slot is wide relative to the clamping diameter which makes
the slot look wide enough to be a keyway, but I assure you
it's not.

Yes, you are right. I looked back at the puzzle photo.
I remembered the slot to be wider than it actually is.

Thanks,
Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
DIY-DRO - YADRO - Eigenbau-Digitalanzeige

On Mon, 7 Nov 2005 22:31:07 +0100, (Nick
Müller) wrote:

John Martin wrote:

You're right, Nick - it's a key slot and has nothing to do with
expansion or contraction.

It's not that I want to be right, I want to understand why it is the way
it is. For that application, the key slot is quite odd, so I think the
usage is something different.


I tried to fool you, but couldn't.

Or maybe I'm still fooling you? :-)))


You're probably also right about broaching the slot. If I had to make
them, though, I think I'd just run the slitting cutter a little deeper
to cut the through slot and the shallow slot on the far side in one
pass.

ACK, that's what I meant.


But there is undoubtedly a good reason for a separate broaching
operation.

That's what I would like to know.


Maybe they slit it before they bore it and cut to length.

Slitting before boring would not be very clever.


Enjoy,

Hi Nick,

I think the slot is just to facilitate clamping around the
flutes on a drill bit. They stick out a bit more on their
leading edge. Most common drill bits are of a two flute
design. The slots would create a better clamping surface to
the bit when used over the flutes. I suspect that it would
thread on to the bit when it is almost tight.

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

R.H. wrote:
A new set has just been posted:

http://puzzlephotos.blogspot.com/


Rob


503, temp/emergency linemans screw in folding pole climbing / standing
foot pegs.