Making a new sprocket.

[jl42206]

Hey guys im trying to get a big top speed out of a murray explorer. I found a big sprocket with 45 teeth on it that im going to order. My problem is the mini sprocket. I am wanting 20 teeth on it. But i can not find one that uses a #40 chain which will fit the big sprocket. So i was thinking i would make my own sprocket on a lathe. Is it possible to make a 20 tooth sprocket with a pitch for a #40 chain.

 

[Poboy kartman]

Congratulations !!!!!!!

The Poboy is speechless. ........

EDIT:...... (forgot to thank Mama).....

 

[firemanjim]

Congratulations !!!!!!!

The Poboy is speechless. ........

Hey guys im trying to get a big top speed out of a murray explorer. I found a big sprocket with 45 teeth on it that im going to order. My problem is the mini sprocket. I am wanting 20 teeth on it. But i can not find one that uses a #40 chain which will fit the big sprocket. So i was thinking i would make my own sprocket on a lathe. Is it possible to make a 20 tooth sprocket with a pitch for a #40 chain.

Yes, it can be done, but because you had to ask, I'm not sure you have the skills needed to do so. Not only that, but, you would also need some mill to complete the sprocket. Too time consuming.

You want to go faster, so your gonna take off the 72 tooth sprocket and swap with a 45?? Right now, you have a 9 tooth drive sprocket and a 72 tooth driven sprocket. Buy a 10 tooth to replace the 9 tooth. That changes you from a 8:1 to 7.2:1..... More Top speed with out killing your clutch trying to use a 2.5:1 on that big kart. I have one here in front of me and there is NO WAY in H€££ that you are gonna be able to use a 2.5:1..... Just no way.......

 

[landuse]

I totally agree

 

[n3480h]

Diameters can be turned on a lathe, but how are you planning to position the sprocket teeth at precisely 18° apart? And then precisely round every tooth with the correct radius? Do you know the correct type of steel to use? There is a reason they don't give sprockets away. They look simple at first glance, but there is a lot of geometry involved, and a lot of skill required to make one. Perhaps you are that skilled and have the proper machinery and instruments.

"Why buy a (insert part name) for $30 when I can make one for $200?"

 

[firemanjim]

EXACTLY.......

 

[OzFab]

"Why buy a (insert part name) for $30 when I can make one for $200?"

I will, & have made any & all parts that I can but, there's a line I don't cross, it comes down to price & availability vs level of difficulty...

If it will take less than an hour & I can make it from scrap I have laying around, I'll make it; if I have to research "how to" & spend stupid money just to make it, I'll go ahead & buy it...

The only reason I override the above guidlines is if the part in question is not easily available...

Having said that, I recently sourced a sprocket from England simply because I couldn't find one locally & I don't have the machinery & "know how" to make one...

 

[Orange Krate]

You can't cut the teeth on a lathe. For that you would need a mill, a form cutter and a dividing head plus knowledge.

I also recommend seeking other sourcing or other gear combinations but if you can get access to the machinery and just want to learn, go for it! it has been a very lucrative career for me
http://youtu.be/xRmQpSGUAY8

Gear making and sprocket making are very similar, just different geometries. Most industrial gears/sprockets are made with a hob...it's like a worm gear with teeth!


http://youtu.be/RG4mrzmGgcg



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[qtband]

You can get sprockets from mcmaster.com but heed the advice given above. They've been doing this a long time.