Hi all,

I've searched around the net for sprockets for a project and am
suffering a case of sticker shock for what seems to me should be a
common product.

We're making a home-brew 'tower clock' with one hand on a 0.750" OD
shaft and the other hand on a 2.250 inch shaft, and planning on driving
the two shafts separately, each with its own servo/stepper motor.

I'll put a small sprocket on the servo motor and a larger one on the
'hand shaft' - and for simplicity in the servo driving software I'm
planning on both hand shafts using the same number of teeth.

What I can't find is cheap sprockets (either chain or cog belt) about 3"
in diameter that I can bore out the center to 2.250" to allow the larger
hand shaft to fit through.

As a side question, if I find steel sprockets are they hardened or
easily machinable?

Anyone got a favorite sprocket source they'd like to share?

Thanks in advance

Carla

"Dear God: please grant me a fat bank account and a slender body - I
hope you don't get it backwards like last year..."

"Carla Fong" wrote in message
...
Hi all,

I've searched around the net for sprockets for a project and am
suffering a case of sticker shock for what seems to me should be a
common product.

We're making a home-brew 'tower clock' with one hand on a 0.750" OD
shaft and the other hand on a 2.250 inch shaft, and planning on
driving the two shafts separately, each with its own servo/stepper
motor.

I'll put a small sprocket on the servo motor and a larger one on the
'hand shaft' - and for simplicity in the servo driving software I'm
planning on both hand shafts using the same number of teeth.

What I can't find is cheap sprockets (either chain or cog belt)
about 3" in diameter that I can bore out the center to 2.250" to
allow the larger hand shaft to fit through.

As a side question, if I find steel sprockets are they hardened or
easily machinable?

Anyone got a favorite sprocket source they'd like to share?

Thanks in advance

Carla

I used both bicycle and motorcycle sprockets and chain on my home-made
sawmill. Since both had to transmit substantial power I left the
sprockets hard and splined the shafts slightly oversized so the
sprockets broached a tight-fitting seat when pressed onto the softer
shaft.

I used a 52-tooth lathe change gear to index the transmission shaft to
machine it for the 13-spline motorcycle sprocket.

Annealing isn't difficult because you have the visual indication of
color change to dark blue, or the red glow, and can check for
machineability with a file.

-jsw

cheapest source I know of is weldon units at Mills Fleet Farm

"Karl Townsend" wrote in message
...
cheapest source I know of is weldon units at Mills Fleet Farm

I haven't used them because every time I weld together parts machined
to final size I have to correct for some heat distortion, for example
a built-up fork joint that closed tighter. Do they generally run true
after welding?
-jsw

On Friday, August 22, 2014 6:10:46 AM UTC, Carla Fong wrote:


Anyone got a favorite sprocket source they'd like to share?



Thanks in advance



Carla



My favorite source is the local scrap yard.
I have not picked up any sprockets, but there is always a bike or two there.
A bike shop might be worth checking.

Dan

On Thu, 21 Aug 2014 23:10:46 -0700, Carla Fong wrote:

Hi all,

I've searched around the net for sprockets for a project and am
suffering a case of sticker shock for what seems to me should be a
common product.

We're making a home-brew 'tower clock' with one hand on a 0.750" OD
shaft and the other hand on a 2.250 inch shaft, and planning on driving
the two shafts separately, each with its own servo/stepper motor.

I'll put a small sprocket on the servo motor and a larger one on the
'hand shaft' - and for simplicity in the servo driving software I'm
planning on both hand shafts using the same number of teeth.

What I can't find is cheap sprockets (either chain or cog belt) about 3"
in diameter that I can bore out the center to 2.250" to allow the larger
hand shaft to fit through.

As a side question, if I find steel sprockets are they hardened or
easily machinable?

Anyone got a favorite sprocket source they'd like to share?



This is too easy.

Old bicycle freewheels/casettes. 99% are are steel, and hard. Older ones
would be better for you as newer ones are thinner and have specialised tooth
forms that vary and are intended to make it easier for the chain to derail,
which you would not want. Look for five-speed or six-speed; they came in
common combinations of teeth, won't be too hard to get matching teeth.

They get tossed as junk when the teeth are a bit worn but you don't care, you
want registration and a few percent power-loss or remaining wear (decades,
likely) is no matter.

A 30-tooth rear has a diameter of just under 5 inches. The central bore is
usually around 1.5 inches, and frequently they have cutouts; so you can hit
them on the "spider" with a blowlamp and soften them there for
cutting/drilling.

Any good bike shop will have loads, and chain. Tell them what you're doing &
smile and they could be free.

On Thu, 21 Aug 2014 23:10:46 -0700, Carla Fong
wrote:

Hi all,

I've searched around the net for sprockets for a project and am
suffering a case of sticker shock for what seems to me should be a
common product.

We're making a home-brew 'tower clock' with one hand on a 0.750" OD
shaft and the other hand on a 2.250 inch shaft, and planning on driving
the two shafts separately, each with its own servo/stepper motor.

I'll put a small sprocket on the servo motor and a larger one on the
'hand shaft' - and for simplicity in the servo driving software I'm
planning on both hand shafts using the same number of teeth.

What I can't find is cheap sprockets (either chain or cog belt) about 3"
in diameter that I can bore out the center to 2.250" to allow the larger
hand shaft to fit through.

As a side question, if I find steel sprockets are they hardened or
easily machinable?

Hmm, good question. It probably depends on the intended use.
I don't know.


Anyone got a favorite sprocket source they'd like to share?

SPACELY, of course. Ask George Jetson. (Sorry, had to do it.)

There's a guy in Canuckistan (Canada, for those of you in Rio Linda)
who does wooden sprockets/gears, if you want a DIY project. He has
tons of vids on YouTube. Matthias Wandel is a wonder.
https://www.youtube.com/results?sear...ooden+gears+ca
I'm kinda partial to his square and oval gears, but I'm odd.

Otherwise, see these:
https://www.youtube.com/results?sear...en+gears+clock



"Dear God: please grant me a fat bank account and a slender body - I
hope you don't get it backwards like last year..."

Love it.

--
The unexamined life is not worth living.
--Socrates

On Friday, August 22, 2014 2:10:46 AM UTC-4, Carla Fong wrote:
Hi all,



I've searched around the net for sprockets for a project and am

suffering a case of sticker shock for what seems to me should be a

common product.



We're making a home-brew 'tower clock' with one hand on a 0.750" OD

shaft and the other hand on a 2.250 inch shaft, and planning on driving

the two shafts separately, each with its own servo/stepper motor.



I'll put a small sprocket on the servo motor and a larger one on the

'hand shaft' - and for simplicity in the servo driving software I'm

planning on both hand shafts using the same number of teeth.



What I can't find is cheap sprockets (either chain or cog belt) about 3"

in diameter that I can bore out the center to 2.250" to allow the larger

hand shaft to fit through.



As a side question, if I find steel sprockets are they hardened or

easily machinable?



Anyone got a favorite sprocket source they'd like to share?



Thanks in advance



Carla



"Dear God: please grant me a fat bank account and a slender body - I
hope you don't get it backwards like last year ... "

Interesting request. Go by a vitamins or health food store. And if you can find the time, gradually start taking 20 grams and then more of dietary supplements twice a day. But don't miss a day !!

On Fri, 22 Aug 2014 07:09:33 -0400, "Jim Wilkins"
wrote:

"Karl Townsend" wrote in message
.. .
cheapest source I know of is weldon units at Mills Fleet Farm

I haven't used them because every time I weld together parts machined
to final size I have to correct for some heat distortion, for example
a built-up fork joint that closed tighter. Do they generally run true
after welding?
-jsw


Only if you clamp the **** out of them first, then weld a bit on one
side, then a bit on the other. SOP for not warping when welding.

On Thu, 21 Aug 2014 23:10:46 -0700, Carla Fong
wrote:

snip
What I can't find is cheap sprockets (either chain or cog belt) about 3"
in diameter that I can bore out the center to 2.250" to allow the larger
hand shaft to fit through.

As a side question, if I find steel sprockets are they hardened or
easily machinable?

Anyone got a favorite sprocket source they'd like to share?
/snip
http://tinyurl.com/k4umphk
http://tinyurl.com/oqfvt49
http://tinyurl.com/o86d4c7

--
Unka' George

"Gold is the money of kings,
silver is the money of gentlemen,
barter is the money of peasants,
but debt is the money of slaves"

-Norm Franz, "Money and Wealth in the New Millenium"

On 8/22/2014 1:10 AM, Carla Fong wrote:
Hi all,

I've searched around the net for sprockets for a project and am
suffering a case of sticker shock for what seems to me should be a
common product.

We're making a home-brew 'tower clock' with one hand on a 0.750" OD
shaft and the other hand on a 2.250 inch shaft, and planning on driving
the two shafts separately, each with its own servo/stepper motor.

I'll put a small sprocket on the servo motor and a larger one on the
'hand shaft' - and for simplicity in the servo driving software I'm
planning on both hand shafts using the same number of teeth.

What I can't find is cheap sprockets (either chain or cog belt) about 3"
in diameter that I can bore out the center to 2.250" to allow the larger
hand shaft to fit through.

As a side question, if I find steel sprockets are they hardened or
easily machinable?

Anyone got a favorite sprocket source they'd like to share?

Thanks in advance

Carla

"Dear God: please grant me a fat bank account and a slender body - I
hope you don't get it backwards like last year..."
Golf carts and people buggies have sprockets and drive motors... They
are tough and sizable.

Martin

Carla Fong wrote:


What I can't find is cheap sprockets (either chain or cog belt) about 3"
in diameter that I can bore out the center to 2.250" to allow the larger
hand shaft to fit through.

As a side question, if I find steel sprockets are they hardened or
easily machinable?
MyMaster-Carr has sintered toothed-belt sprockets (I'm guessing that
is what you are looking for, not metal chain sprockets). They are
VERY machineable. Not REAL cheap, but a lot cheaper than Stock
Drive Products or W. M. Berg.

Jon

Hey Carla,

Buy up a couple of old bicycles at garage sales. The sprockets they
use are "good stuff".

Take care. Good luck with the project.

Brian Lawson
XXXXXXXXXXXXXXXX
On Thu, 21 Aug 2014 23:10:46 -0700, Carla Fong
wrote:

Hi all,

I've searched around the net for sprockets for a project and am
suffering a case of sticker shock for what seems to me should be a
common product.

We're making a home-brew 'tower clock' with one hand on a 0.750" OD
shaft and the other hand on a 2.250 inch shaft, and planning on driving
the two shafts separately, each with its own servo/stepper motor.

I'll put a small sprocket on the servo motor and a larger one on the
'hand shaft' - and for simplicity in the servo driving software I'm
planning on both hand shafts using the same number of teeth.

What I can't find is cheap sprockets (either chain or cog belt) about 3"
in diameter that I can bore out the center to 2.250" to allow the larger
hand shaft to fit through.

As a side question, if I find steel sprockets are they hardened or
easily machinable?

Anyone got a favorite sprocket source they'd like to share?

Thanks in advance

Carla

"Dear God: please grant me a fat bank account and a slender body - I
hope you don't get it backwards like last year..."

"Brian Lawson" wrote in message
...
Hey Carla,

Buy up a couple of old bicycles at garage sales. The sprockets they
use are "good stuff".

Take care. Good luck with the project.

Brian Lawson
XXXXXXXXXXXXXXXX

I needed two identical sprockets to drive the two lift screws at the
same rate so I went to a bicycle shop. Two new-old-stock 3-speed rear
hub sprockets plus a short chain remnant cost me $13, IIRC.

I do a lot of engineering design while poking through piles of used
stuff. The necessary preparation is knowing the minimum size that's
strong enough and the maximum that will fit, plus the limits of my
machining ability to make adapters for other than standard-sized keyed
shaft hubs.
-jsw

On Thu, 21 Aug 2014 23:10:46 -0700, Carla Fong
wrote:

Hi all,

I've searched around the net for sprockets for a project and am
suffering a case of sticker shock for what seems to me should be a
common product.

We're making a home-brew 'tower clock' with one hand on a 0.750" OD
shaft and the other hand on a 2.250 inch shaft, and planning on driving
the two shafts separately, each with its own servo/stepper motor.

I'll put a small sprocket on the servo motor and a larger one on the
'hand shaft' - and for simplicity in the servo driving software I'm
planning on both hand shafts using the same number of teeth.

What I can't find is cheap sprockets (either chain or cog belt) about 3"
in diameter that I can bore out the center to 2.250" to allow the larger
hand shaft to fit through.

As a side question, if I find steel sprockets are they hardened or
easily machinable?

Anyone got a favorite sprocket source they'd like to share?

Thanks in advance

Carla

"Dear God: please grant me a fat bank account and a slender body - I
hope you don't get it backwards like last year..."

Crap..I had 1500 POUNDS of exactly what you are looking for 4 yrs ago.

Then I scrapped em all. Brand new and still in the boxes.

Ill check out in my Stuff this weekend.

Gunner

--
"Living in the United States now is like being a Tampon.
We're in a great place, just at a bad time."

On Fri, 22 Aug 2014 05:33:58 -0500, Karl Townsend
wrote:

cheapest source I know of is weldon units at Mills Fleet Farm

Might want to check here...

http://www.surpluscenter.com/Sprocke...ore-Sprockets/

http://www.youngssurplus.com/sprockets.htm

Key search terms "surplus sprockets"


Gunner

--
"Living in the United States now is like being a Tampon.
We're in a great place, just at a bad time."

Thanks George, that was the winning solution!

From your links I got the tradename of what we needed and then found
'Weldasprockets' at my local farm / implement store for about $13 each
(40 chain, 26 teeth) and was easily able to bore out the center to my
spec... Threading the material for setscrews near the perimeter was a
bit dicey as that area seems to be hardened... but everything worked out
fine.

Thanks again!

Carla

On 8/22/2014 4:55 PM, F. George McDuffee wrote:
On Thu, 21 Aug 2014 23:10:46 -0700, Carla Fong
wrote:

snip
What I can't find is cheap sprockets (either chain or cog belt) about 3"
in diameter that I can bore out the center to 2.250" to allow the larger
hand shaft to fit through.

As a side question, if I find steel sprockets are they hardened or
easily machinable?

Anyone got a favorite sprocket source they'd like to share?
/snip
http://tinyurl.com/k4umphk
http://tinyurl.com/oqfvt49
http://tinyurl.com/o86d4c7