The saga of making replacement parts for my "no longer supported" pruner
continues...

The bolt that the shear and hook rotates on looks like a hardened and ground
0.375" roll pin for 1/2 inch, then 3/8 NF threads. The head on the standard
part is very unusual, but I can remanufacture a different part so I can use
a standard 9/16 or 5/8 bolt head.

Anybody seen a bolt like this? Where?

Karl

On Mar 10, 4:26*pm, "Karl Townsend"
wrote:
...looks like a hardened and ground
0.375" roll pin

Karl

Got pix?

Shoulder screws look like socket-head ground dowel pins, with threads
a size smaller than the shank.

Grade 8 bolts can be machined to a very smooth finish with HSS.

"Karl Townsend" wrote:

The saga of making replacement parts for my "no longer supported" pruner
continues...

The bolt that the shear and hook rotates on looks like a hardened and ground
0.375" roll pin for 1/2 inch, then 3/8 NF threads. The head on the standard
part is very unusual, but I can remanufacture a different part so I can use
a standard 9/16 or 5/8 bolt head.

Anybody seen a bolt like this? Where?

Karl


http://www.mcmaster.com/param/images...ter_130x70.gif

Is that what it looks like? If so, McMaster-Carr search shoulder bolt.

Wes

On Tue, 10 Mar 2009 15:26:42 -0500, "Karl Townsend"
wrote:

The saga of making replacement parts for my "no longer supported" pruner
continues...

The bolt that the shear and hook rotates on looks like a hardened and ground
0.375" roll pin for 1/2 inch, then 3/8 NF threads. The head on the standard
part is very unusual, but I can remanufacture a different part so I can use
a standard 9/16 or 5/8 bolt head.

Anybody seen a bolt like this? Where?


Shoulder screw, as Wes and Jim mentioned, if you can get away with
coarse threads. Keep in mind that shoulder screws are not awfully hard
(Rc40) and the tolerances on the shoulder dia are relatively loose.

How about a 3/8 x 1/2 drill bushing with a 3/8 cap screw thru it?

--
Ned Simmons

On Tue, 10 Mar 2009 15:26:42 -0500, "Karl Townsend"
wrote:

The saga of making replacement parts for my "no longer supported" pruner
continues...

The bolt that the shear and hook rotates on looks like a hardened and ground
0.375" roll pin for 1/2 inch, then 3/8 NF threads. The head on the standard
part is very unusual, but I can remanufacture a different part so I can use
a standard 9/16 or 5/8 bolt head.

Anybody seen a bolt like this? Where?

Karl

"shoulder bolt"

Google is your friend


"Human nature is bad. Good is a human product*
A warped piece of wood must be steamed and forced
before it is made straight; a metal blade must be put to the whetstone
before it becomes sharp. Since the nature of people is bad, to become corrected
they must be taught by teachers and to be orderly they must acquire ritual
and moral principles."
—Sun Tzu
*

Shoulder screw, as Wes and Jim mentioned, if you can get away with
coarse threads. Keep in mind that shoulder screws are not awfully hard
(Rc40) and the tolerances on the shoulder dia are relatively loose.

How about a 3/8 x 1/2 drill bushing with a 3/8 cap screw thru it?

No, neither of these will work. The tightening of the bolt is what holds the
hook and shear together. There is "A LOT" of force here, over 1000 lbs. on
the pushrod to the shear plate. Its got to be one piece. The fine thread
adjustment is finicky enough, coarse threads would be terrible.

I know McMasterCarr don't have it. The Fastenall store near me is run by
idiots. I'll go to Fastenal when I get to the cities sometime.

Karl

"Karl Townsend" wrote:

No, neither of these will work. The tightening of the bolt is what holds the
hook and shear together. There is "A LOT" of force here, over 1000 lbs. on
the pushrod to the shear plate. Its got to be one piece. The fine thread
adjustment is finicky enough, coarse threads would be terrible.

Maybe the question would be what tool steel and heat treat schedule would work in this
application. I've never seen fine thread shoulder bolts, not that me not seeing any means
much.

Re-reading things, you need the bearing diameter and major diameter of thread to be the
same. I should have paid a bit more attention.

I think we are talking DIY.

Wes

Re-reading things, you need the bearing diameter and major diameter of
thread to be the
same. I should have paid a bit more attention.

I think we are talking DIY.

I'm afraid so too, but I want to double check. If I fire up the CHNC for
this job, I'll make a hundred or so. So, what material are roll pins made
of? And, what's the heat treat parameters?

Karl

"Karl Townsend" wrote in message
anews.com...
Re-reading things, you need the bearing diameter and major diameter of
thread to be the
same. I should have paid a bit more attention.

I think we are talking DIY.

I'm afraid so too, but I want to double check. If I fire up the CHNC for
this job, I'll make a hundred or so. So, what material are roll pins made
of? And, what's the heat treat parameters?

Karl

\


Get a shoulder or die bolt a litttle longer and turn and cut a new fine
thread on turned down end.


John

On 2009-03-10, Gunner Asch wrote:
On Tue, 10 Mar 2009 15:26:42 -0500, "Karl Townsend"
wrote:

The saga of making replacement parts for my "no longer supported" pruner
continues...

The bolt that the shear and hook rotates on looks like a hardened and ground
0.375" roll pin for 1/2 inch, then 3/8 NF threads. The head on the standard
part is very unusual, but I can remanufacture a different part so I can use
a standard 9/16 or 5/8 bolt head.

Anybody seen a bolt like this? Where?

Karl

"shoulder bolt"

Also called a "stripper bolt".

Go to MSC's site http://www.mscdirect.com and look up their
part number "67656827" for one sort of close. Here's the description:


================================================== ====================
Socket Head Stripper Bolts - Alloy Steel Convenience Packs Type:
Stripper Bolts/Shoulder Screws Shoulder Diameter: 1/2 Shoulder Length:
1-1/2 Thread Size: 3/8-16 Material: Alloy Steel - Grade 8
================================================== ====================

I suspect that the shoulder length is too long for you, but this was the
first which I stumbled across with 1/2" shoulder diameter and 3/8"
threaded section (3/8-16).

Enter "stripper bolt" in the search tool for a more complete
list, and have fun wading through those to find what is closest.

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"Karl Townsend" wrote in message
anews.com...


Shoulder screw, as Wes and Jim mentioned, if you can get away with
coarse threads. Keep in mind that shoulder screws are not awfully hard
(Rc40) and the tolerances on the shoulder dia are relatively loose.

How about a 3/8 x 1/2 drill bushing with a 3/8 cap screw thru it?

No, neither of these will work. The tightening of the bolt is what holds
the hook and shear together. There is "A LOT" of force here, over 1000
lbs. on the pushrod to the shear plate. Its got to be one piece. The fine
thread adjustment is finicky enough, coarse threads would be terrible.

I know McMasterCarr don't have it. The Fastenall store near me is run by
idiots. I'll go to Fastenal when I get to the cities sometime.

Karl




Use a lock nut and a spring washer to keep tension on the 2 pieces. with a
drill bushing and thru bolt. Then the adjustment is not as critical.

On 11 Mar 2009 03:46:14 GMT, "DoN. Nichols"
wrote:

On 2009-03-10, Gunner Asch wrote:
On Tue, 10 Mar 2009 15:26:42 -0500, "Karl Townsend"
wrote:

The saga of making replacement parts for my "no longer supported" pruner
continues...

The bolt that the shear and hook rotates on looks like a hardened and ground
0.375" roll pin for 1/2 inch, then 3/8 NF threads. The head on the standard
part is very unusual, but I can remanufacture a different part so I can use
a standard 9/16 or 5/8 bolt head.

Anybody seen a bolt like this? Where?

Karl

"shoulder bolt"

Also called a "stripper bolt".

snip

Not a shoulder or stripper bolt, per Karl's original. Threaded
portion and ground portion are same diameter. I looked for a while,
couldn't find one like that. They probably exist, but who knows
where. Were it me, I'd hit my favorite fastener vendor and see what
they could come up with.

Otherwise, it looks like he'll have to make one. It might save a lot
of work if he could figure out how to make and fasten the head onto
O-1 or A-2 ground stock. Just thread as needed before heat treat.

Shoulder bolts are intended to provide a fixed length "axle" for a
rotating tooling component. I gather that Karl's application requires
tension adjustment for the pruner jaws, hence the same diameter fine
pitch threads.

Pete Keillor



Pete Keillor