219 Chain Dimension

JOHN PARSON · Posted: Wed Jul 08, 2009 9:58 pm Post subject: 219 Chain Dimension

I'm doing some CAD drawings and don't have a piece of 219 chain handy. Could someone give me an accurate measurement of the OD of the rollers? I've found online the chain pitch is .306" (center to center of pins). I'm trying to draw an accurate sprocket.
Thanks

Pete Muller · Posted: Wed Jul 08, 2009 10:05 pm Post subject:

According to Azusa, the pitch is .306", and the roller diameter is .200".

Info here: http://azusaeng.com/Sprockets/AzSDno219.pdf and here: http://www.azusaeng.com/chain/krtchn.html#Anchor - 219 (you may need to scroll down the page on that second link, I don't think the anchor works correctly).

JOHN PARSON · Posted: Wed Jul 08, 2009 10:08 pm Post subject:

Thanks Pete. Good source.
John

Kyle Vallarino · Joined: 23 Nov 2008 Posts: 72

hey john, when your drawing a sprocket how do you figure out the diameter of the sprocket?
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JOHN PARSON · Posted: Tue Jul 14, 2009 9:49 pm Post subject:

Kyle,
You can start with the nice table from Azusa Engineering or use a CAD program that allows you to specify the number of teeth and then lay in the proper chain pitch (if you know the roller diameter). From there it's similar to drawing gears.
John

Pete Muller · Posted: Tue Jul 14, 2009 11:49 pm Post subject:

Just don't forget that a chain actually doesn't lay along an arc, per say.

There is a straight line that connects each roller to the next, so technically it's a bit different to draw than a gear. More like a polygon.

On sprockets with large numbers of teeth, the difference is minute -- on the order of only about .002" in diameter on a 90T 219 sprocket. On a 10T 219 sprocket though, the difference becomes just over .016"... very significant!

Kyle Vallarino · Joined: 23 Nov 2008 Posts: 72

i was taught on mastercam. i have actually only done it once, for a #35 chain, and i was taught to draw half the recess then half the tooth and just mirror it over at 360 divided by # of teeth. just trying to remember how to calculate the diameter at the center of the roller. want to try to make 219 stuff.
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Pete Muller · Posted: Sat Jul 18, 2009 11:03 pm Post subject:

You can get close by just using (pitch x N) / pi

However that's not quite correct as mentioned in my previous message. On a big sprocket, the difference is almost nothing, but on a small (drive) sprocket it's significant.

You can do one iteration from the initial diameter you get using the formula above -- and then you'll have it nailed.

PM

Dan Haynes · Posted: Mon Nov 26, 2012 8:29 pm Post subject:

Sorry for resurrecting an old post but found it in a search. I bought a small CNC machine a few months ago and am learning Mastercam. Thought I would try making a rear gear. I have gear software called Sprocketeer. It will create the DXF that I will import into Mastercam to finish up.

How did your gear work for you?
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