Dual Disc Clutch Intermediate Ring Stud

Romano,



You won't find a comparison with metric fasteners (TPI = Threads Per Inch) because metric threads are configured in the lead of the thread. Crest and crest (lead) is measured in metric (.5, 1. ,1.5 etc.) English threads are specified threads per inch. example: 8 TPI=.125" lead. The distance of the root or crest to each other is the lead. That is how metric threads are specified. I hope you understand what I'm trying to explain. British threads also have a 55 degree thread form instead of 60 degree. You can't believe how many American machinists get this confused.



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thank you for explaining david

this I have know also. only the english words root, crest and lead have been unknown to me. can not find in any translatror

but this special thread here has an angle from 47.5°

 

Romano,
I can not to begin your struggle with English. I would be lost with German.
(Root) would be the valley or bottom of thread. The (crest) would be the peak or top of the thread. The (lead) would be the distance between the peaks of the threads. The lead would be the 1.25 of the 10mm- 1.25 of a metric thread spec. The 47.5 degree is very unusual.

 

Nice information on the threads..I must admit I was stumped and ended up drilling out the broken pins and making new pins and taping the holes.

I previously posted this information below when I took my clutch apart and it looked like I still had plenty of clutch surface but it was still slipping. It took a while to figure it out but here you go:

If your flywheel and centerplate have been resurfaced and/or you need to resurface, take note of the taper pins that have a shoulder on them, I have seen several clutches with a lot of wear left that the pressure plate is stopping on the shoulder pins (note there are 6 pins total and only three have the shoulder) before the clutch is worn out. This is because at the factory, the assembly was designed and matched to prevent the metal plates from grinding metal on metal (I assume). The issue is that you need to make new pins with a lower shoulder or turn down the shoulder. The old pins are hard to find anyway but if you do find them, simply find someone with a lathe and turn them down to correct size. Calculation is in the shop manual but nothing about the pins so you need to check the travel and determine if the shoulders will hinder travel (the holes where the pins go through on pressure plate catch the shoulder and you can see witness of that). The other issue is that the pins most often need to be drilled (pressed in pins) and the three that screw in tend to break off (they have a hex on them). So I end up machining new pins.

 

I wish I had read this before, dang! Had the broken piece removed and it didn’t go very well.