John Murray
Been Around the Block
Do you have a picture?
Will post some tonight, I have to go to work now.
Do you have a picture?
Will post some tonight, I have to go to work now.
Will post some tonight, I have to go to work now.
That AJR set looks very good..
Yes, like that.
Here are some pics. First is some worn factory plates:
View attachment 226910
Next is from L to R, cork Japanese plate, cellulose Japanese, Barnett
View attachment 226911
Finally laser cut steel inner (slotted), l/cut steel inner (unslotted, used), l/cut steel outer
View attachment 226912
Notice how the original factory plates have a big, wide contact surface; this was pretty standard practice up to the late 60s to early 70s. Now of course all the manufacturers use a narrow contact band right out at the edge and these work much better.
I am curious. What made you decide to go back to steel plates?
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..As you said before then the outer contact patch has greater grip than the inner. I wonder how the measured that?
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I didn't - I'm using thin laser-cut steels with Japanese style outers. But if future power increases (nitro?) require it I can go to a full set of thin steels. The full steel set had enormous holding power, so much that I had to delete a couple of plates before I could make it slip and then adjust the readings accordingly. I was very surprised by this - the friction coefficient seems to be more related to how well the surfaces can maintain a thin, uniform oil film than anything else and the dry material COF has little or no relevance.
A friend of mine said he had the same result with steel plates and that they were damaging his clutch basket so he went back to turning Japanese.
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Torque is simply force x distance, so increasing the distance from the contact patch to the shaft centre increases the torque capacity for a given value for friction. In practice, the greater pressure (from the smaller area) gives a thinner oil film and more friction per cm2, so this along with the increased radius gives a stronger clutch.
I use an early style clutch basket, all steel and made in one piece with the sprocket. Very tough and doesn't get beaten up an aluminum basket.
Mine is steel and that is one reason why I wanted to get it to work instead of going directly to AJR. Teazer says it is all about optimization.
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I agree. I think the Barnetts could be made to work. As Teazer said machine off the inner half of the facing and see how they go. If need be you can always use thinner steels and an additional plate later. BTW, how old are your Barnetts? All the ones I've seen have Kevlar facing, the one in your photo looks like cork or something similar.
That is a good question. This is the first set we fried on the dyno and they only way 1.3 lbs. for the set.
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