25 series chain skipping

[philso]

We are using some 25 series chain to drive our shooter wheel since we could only find sprockets in this series to fit the shaft on the CIM-u-Lator. We are using a 10-tooth sprocket on theCIM-U-Lator shaft and a 22-tooth sprocket on the shooter wheel shaft. There is a total of about 12 inches of chain. Both sprockets and the chain are from AM. We tension the chain by sliding the gearbox and tightening the mounting screws. The chain will deflect about 1/8 inch when "pushed firmly" half way between the two sprockets.

We have noticed that the chain skips every once in a while causing a lot of vibration. At speed, the chain can be seen "whipping around". Turning the mechanism very slowly by hand, one can see the chain climbing up the teeth such that over a span of about 3 links, the point of the sprocket tooth it directly under the center line of one of the pins holding the chain together. Turning the mechanism further, the chain then slips back into alignment with the sprocket. It is as if the spacing of the teeth on the 22-tooth sprocket is larger than the spacing of the chain links.

We notice a similar kind of thing happening on the 10-tooth sprocket but that seems to come from the teeth on the sprocket being a bit too long and the small tooth count forcing the chain to "bend" around too sharp of an angle.

We have some larger sprockets on order (16-tooth and 32-tooth, I think). We have also considered filing down the sprocket teeth on the smaller sprocket. We have verified that the chain is not hitting any of the set screws on any of the sprockets and that the two sprockets are in the same plane. The chain does not appear to be twisting.

Can anyone suggest a solution or point out what we may be doing wrong? I have only found posts here where people have used chains very successfully though they may be using sprockets larger than what we are using. We are in the process of building a second robot for practice so we will try out the larger sprockets and any suggested solutions once enough of it gets built.

Thanks for your help.

Phil