520 offset counter sprocket

hello everyone.Searching throughout an internet,I found pretty much interesting information. Especially so many guys cries over 520 counter offset sprocket. What I found is that chain with pitch of 520,525,and 530 has egzact same pitch of 5/8, same roller diameter of 0.400" but the only difference is roller width.Where 520 has 1/4", 525 has 5/16" and 530 has 3/8" width. So I was thinking if someone who already has 530 set up and have a problem with dragin a chain over a frame,Could possibly cut front offset sprocket on desire thickness of 1/4" of 520 sprocket.If it is build of good strength material. And just have to replace rear sprocket ,witch is easy to find and chain,voila. I am starting to believe it is possible.Just my two cents.

I wonder if the sprockets are surface-hardened? If so, then machining them would remove the hardened layer resulting in accelerated wear.

Fritula wrote: ... difference is roller width. Where 520 has 1/4", 525 has 5/16" and 530 has 5/8" width....

Would suspect 5/8" is likely a typo that should say 3/8".

Good Fortune!

TexasKZ wrote: I wonder if the sprockets are surface-hardened? If so, then machining them would remove the hardened layer resulting in accelerated wear.

Sprocket material is "soft" and easily cut, even with a hacksaw.

if its that easy (easy being relitive) I wonder why no one offers any?

TexasKZ wrote: I wonder if the sprockets are surface-hardened? If so, then machining them would remove the hardened layer resulting in accelerated wear.

Many sprockets are advertised as case-hardened.
Good Fortune!

done that when i needed a 520 front sprocket in a hurry before a race, used a grinding wheel and attached the sprocket to a hand drill..... fishy but worked for a whole season.

but have a look into JT or AFAM sprockets online catalogs and you'll find plenty of options to 520's having the same spline. they off the shelf, no grinding needed. some will have quite a bit of offset and you can increase it by fitting a washer behind the sprocket too, the shaft has some overhang you can take advantage off.

i use nowadays 520 afam's, the quality is great

zed1015 wrote:

TexasKZ wrote: I wonder if the sprockets are surface-hardened? If so, then machining them would remove the hardened layer resulting in accelerated wear.

Sprocket material is "soft" and easily cut, even with a hacksaw.

zed i know you know what you are talking about.

the one time i had tried to cut down a front sprocket(without first heating it cherry red and letting it cool) i used a carbide inserted tool and smoked the tip right off the tool.

what tooling do you use to cut sprockets with?

here is a sprocket in progress (5/8's offset) and one finished (3/8's offset).




and here is the 5/8's finished.





leon

I've cut sprockets for a variety of reasons ( for the steel to make spacers and brackets etc) and only ever used a HSS blade in the hacksaw with no problems ( Maybe i've been lucky ? )
Last one i cut was a JT rear a couple of weeks ago, i machined out the center (with carbide tip) to leave a ring with the teeth on which i used to repair an old worn brit drum .
The discarded JT center was cut up with ease with the hacksaw and recycled.
I will say that i haven't cut an kosman offset though and they do seem to last forever.
I've had one of those on my Z1R for the past 12 years with no sign of wear.

thanks for the reply zed.

i guess i am lazy and mosly use carbide inserts for machining :pinch: .

i have made some custom form tools out of hss but only use them in alu.

maybe i should try some hss on steel and see what results i get.

leon

TexasKZ wrote: I wonder if the sprockets are surface-hardened? If so, then machining them would remove the hardened layer resulting in accelerated wear.

Yes I would agree with you,some are just teeth hardened,some all of them. But can it be hardened again after work done.I bet it could and that is going to happens soon.

i built an offset sprocket last week.

a carbide bit would not touch them until i heated them redhot and then let them cool.
then i could cut them with a carbide insert,but the material was till very tough.
i ruined one cutting insert and one boring insert getting greedy trying to hurry :sick: .

after i have welded them all back together and they are still red hot i dunk them in used engine oil.

that is what puts the black on them.

i am sure there is better stuff out there to use to harden steel :blush: ,but used oil is free and seems to work fine.

in my experience.

here is a 5/8's oscss


here is a 3/8's oscss next to the 5/8's


here is the 1/2 oscss



leon