dollythelw Posted August 17, 2007 Share Posted August 17, 2007 so I'll put you down as an "undecided" then? Quote Link to comment Share on other sites More sharing options...
Daan Posted August 17, 2007 Share Posted August 17, 2007 Daans winch has a nice big chunky dog on it - Its a dibnah dog. Quote Link to comment Share on other sites More sharing options...
dollythelw Posted August 17, 2007 Share Posted August 17, 2007 if he built it - you just know its never gonna break all hail hallowed name of Fred Quote Link to comment Share on other sites More sharing options...
lard Posted August 17, 2007 Share Posted August 17, 2007 Speak to Dan - he knows the most about 8074's (his ego will love that statement )The 80 has wider gears, and roller bearings on all of the shafts - it could be improved by having a wider narrower dia drum running on roller bearings rather tha bushes. so could any body hazzard a guess to how much more power you would get from roller bearings on the drum instead of plastic bushes ????? Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted August 21, 2007 Share Posted August 21, 2007 so could any body hazzard a guess to how much more power you would get from roller bearings on the drum instead of plastic bushes ????? I think you'd probably see an increase in line speed rather than a noticable increase in pulling power. It'd be easier to engineer a way to keep the oil in the gearbox wilst a bearing conversion was in progress. Quote Link to comment Share on other sites More sharing options...
Tonk Posted August 21, 2007 Share Posted August 21, 2007 so could any body hazzard a guess to how much more power you would get from roller bearings on the drum instead of plastic bushes ????? i've fitted bearings to the drum on the opposite end of the gearbox and the winch runs alot smoother and quicker unloaded, haven't tested it under load yet. Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted August 22, 2007 Share Posted August 22, 2007 Why do you consider metric being a poor thread form when compared to unified? The only poor choice is the pitch in this instance.They are both 60° with very similar depths and pitches, the choice should be M8 fine which is 1mm pitch against the standard metric M8 pitch of 1.25mm. In fact, IIRC they are the only thread whose true form should have flat crests, creating even more similarity, which is never done in mass production, including taps! Metric Coarse to Metric Fine is what Unified Coarse is to Unified Fine! Usually cheaper and easier to get hold of metric fine tools and bolts. Most about all the unf bolts i've come across have much better root radius control to that of conventional metric bolts. Think about it when you over tighten bolts, metric normally snap at the root of the tread whereas unf thend to rip the thread out of the nut. I've found just as you have metric fine can bring it's own problems with tooling, whereas soursing unf tooling is almost always straight forward. Horses for courses really, but given the task in hand i'd rather have a unf in tension that a metric one. Quote Link to comment Share on other sites More sharing options...
istruggle2gate11 Posted August 23, 2007 Share Posted August 23, 2007 This might help.... ^^All credit to Bolt Sciences.com, a very easy read, with lots of good data. Most about all the unf bolts i've come across have much better root radius control to that of conventional metric bolts.Think about it when you over tighten bolts, metric normally snap at the root of the tread whereas unf thend to rip the thread out of the nut. You said, relaively poor thread form - they are almost exactly the same. Thats down to the quality of manufacture from tools to finished goods, not the fault of the thread form. Poor root radius is usually the result of a "one tip does many pitches" cutting carbide, which is "cheating", to get a true form, you roll or full form the thread. The problems you seem to be recalling here are quality related, not design. The point Im getting to is that that the thread forms are so similar, it would take serious measurement and testing (Lab Standard) to determine the better one. It is a mistake to consider the forms of UNF being better than metric form or vice versa. I've found just as you have metric fine can bring it's own problems with tooling, whereas soursing unf tooling is almost always straight forward. ? I worked in engineering for a very long time as a machine operator, programmer, machine shop manager and draftsman and tooling purchaser using every thread you can think of, from metric course to 6 start trapezoidal. Although I cant quantify it at the moment, I am 99% sure I could get quality metric fine taps a lot quicker, easier and cheaper than unf. I know for sure it is a lot harder to get imperial taps with different tolerances on limits and fits, most imperial seem to be 6H/6g (which is medium fit) like it or pay through the nose, where I know I could go and buy a metric fine 5H/4h (close fit) today. Its also a lot easier to buy full form cutting carbides in metric, roll taps etc. Quote Link to comment Share on other sites More sharing options...
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