SKIP TOOTH COG VS. SKILSAW

[Charles]

Will be building a few skip tooth cycles this fall.
Wanted to see first hand whether or not grinding the teeth off modern cogs would work so I did one.
I don't have a metal shop with a cool bunch of tools but I do have a skilsaw with a cutting wheel on it.
First I marked the teeth to be removed on this Bendix 20

Next I set up my skilsaw on the tongue of my motorcycle trailer.....

....and got to grinding.
WARNING! I do not advise the use, nor would RRB for that matter, advise the use of any tool in an unsafe manner.
ALWAYS: wear Eye & Ear protection. USE: gloves for your Hands. KEEP: power cutoff within reach at all times.
With that in mind I found this homemade table grinder effective and felt comfortable behind it at all times.

Here is the finished Skippy 10 cog.

I'll let you all know how this cog works out for me in a week or two.

Ride on!
Charles

 

[Charles]

Here is how Skippy 10 looks next to an original J.C.Higgins skip tooth cog...

 

[Jpromo]

Looks awesome; I like the look of the little rounds that remain.

You could also etch a slash through the 20 and write in a 10 if it's going on something ratty :wink:

 

[scrumblero]

WARNING! I do not advise the use, nor would RRB for that matter, advise the use of any tool in an unsafe manner.
ALWAYS: wear Eye & Ear protection. USE: gloves for your Hands. KEEP: power cutoff within reach at all times.

not sure thats a strong enough disclaimer for that setup... :lol:

 

[NewOrleansFlyer]

Never thought of that.....but now, I don't have to buy an expensive skip cog for the rear, I can do some "surgery" on something I have...or something I don't have, but can buy.....cheap! Thanks

 

[bicycleguy]

A little sketchy but awesome! I'd call it ghetto-tech (use what you have on hand to make amazing things).

 

[Charles]

"GHETTO TECH" Ha! I love it! :lol: :lol: :lol: That's my "trailer grinder".... gettin' prop's!
Deburred Skippy for lunch today w/ a small hand file. IT"S DONE!

 

[StreetCrwlr]

Yikes! I personally would have clamped down the piece itself and used a grinder but that's just me... The end result is really sweet!

 

[B607]

Cool ghetto tech! The only thing I would have done differently is wear long pants. Gary

 

[fatkid]

Those abrasive wheels can get nasty if they shatter. I wouldn't recommend this type of set up to anyone, but if you must, do not flex the blade by pressing too hard against it while grinding. Also, no sharp, "stabbing" movements into the blade. I had a friend/customer at the autobody supply I worked at who had scars (big nasty, got mauled by a bear scars, not the ones that chicks dig) that he received when an abrasive wheel shattered on him. These babies produce nasty shrapnel. You can be inventive, just be safe. Oh, and wear eye protection --> 8)

 

[Charles]

viewtopic.php?f=16&t=37491

 

[ozzmonaut]

I've done a couple of these. I just cut mine with a handheld grinder (cog in one hand, grinder in the other)[insert generic disclaimer here], then you can shape the areas in between the teeth at the same time. I leave those rounds as well. It is closer to the look of the originals, and without them the chain won't ride as well. The indentions in the chain links ride on these, and I feel that some homemade skip cogs wear a chain out prematurely partially for this reason if those are left out. I know that the cog not being as thick can cause some slop, but I think those humps between the teeth relieve some of the stress on the links that would be damaging if the link was trying to pull itself deeper into the cog instead of having that support. However, I'm no physics major, I just ride a lot of skiptooth bikes.

 

[Charles]

Well put oz... the crowns do something to enhance smooth skip tooth chain operation. My homemade works really good w/crowns.

 

[Chris Crew]

I admire the hillbilly engineering---how many fingers do you have?
I used a dremel tool with a cutoff wheel to mod a rear sprocket and it worked fine--had to finish up with a round file since the cutoff left a square end.

CC