[modeleng] Re: Chain Sprockets

It may also depend on the source of the sprockets. I was machining a number
of sprockets on the weekend. The no-name Chinese ones were very soft. The
ones by Tsubaki (Japanese) cut nicely with carbide tooling but seemed to be
of much tougher steel than the Chinese ones. Tsubaki claims that their
sprockets are "minimum 35 Rockwell hardness" and I haven't seen a mention of
the desirability of hardening them.

You might find the following from Tsubaki's website of interest:

Does a chain really "stretch"?
The term "stretch" is misleading. A chain will elongate when the pins and
bushings wear down. This is due to poor lubrication, under sizing and
overloading of the chain. As the components thin, the space between the pins
and bushings increase, thus making the chain longer than originally.

> -----Original Message-----
> From: modeleng-bounce@xxxxxxxxxxxxx [mailto:modeleng-bounce@xxxxxxxxxxxxx]
> On Behalf Of Peter Beevers
> Sent: Wednesday, January 28, 2009 12:47 PM
> To: modeleng@xxxxxxxxxxxxx
> Subject: [modeleng] Re: Chain Sprockets
> 
> Clif,
> 
> Don't harden either - that's the way they are meant to be, so leave them
> like that. Yes, they will wear, and you will have to replace them,
> eventually. But if you harden the sprockets (because they are difficult to
> change later) then they will rip the chain apart, so it will not last
> long.
> 
> At our railway (Swanley New Barn Railway) our 10 HP 7.25" gauge diesels
> use
> 1/2" duplex chain and we replace the chain much more often than the
> sprockets because it stretches. And some of our engines do in excess of
> 1,000 miles per year. . . .
> 
> If you're still worried, then go to 3/8" pitch chain and sprockets, i.e.
> over engineer.
> 
> Peter
> ----- Original Message -----
> From: "Clif Walker" <clif.gwr@xxxxxxxxxxxx>
> To: <modeleng@xxxxxxxxxxxxx>
> Sent: 28 January 2009 17:35
> Subject: [modeleng] Chain Sprockets
> 
> 
> Hi All,
> I am modifying one of my electric powered 5" gauge models from toothed
> belt
> drive to chain drive and have a puzzle which I thought that I would throw
> out for discussion.
> The Chain Sprockets which are bought in items and seem to be made from
> very
> nice free cutting mild steel.
> 
> Should they be Case Hardened or left in their soft state?.
> 
> My thoughts go along the lines that if I case harden them will it wear the
> chain? and if I leave them soft will the chain wear the sprockets?
> Bearing in mind that the chain can easily be changed, whilst the sprockets
> require major work to replace,it would seem the be best to harden the
> sprockets.
> 
> Also could a compromise be the thing, with only the small sprockets being
> hardened as the large sprockets have the load spead out more evenly.
> 
> The chain is 1/4" pitch, the small sprockets have 8 teeth and the large
> sprockets have 30 teeth.
> 
> I await with  Blowlamp and Kasenite poised.
> 
> Regards
> 
> Clif
> MODEL ENGINEERING DISCUSSION LIST.
> 
> To UNSUBSCRIBE from this list, send a blank email to,
> modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject
> line.
> 
> 
> 
> --
> No virus found in this incoming message.
> Checked by AVG.
> Version: 7.5.552 / Virus Database: 270.10.14/1917 - Release Date:
> 26/01/2009
> 18:37
> 
> MODEL ENGINEERING DISCUSSION LIST.
> 
> To UNSUBSCRIBE from this list, send a blank email to,
> modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject
> line.

MODEL ENGINEERING DISCUSSION LIST.

To UNSUBSCRIBE from this list, send a blank email to, 
modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.

Other related posts: