Rohan said:
B.Rad said:
Yes.
Early and later AMC gears CANNOT/SHOULD NOT be mixed, they are not the same tooth form.
Gear PAIRS are OK to use togther.
Commando gears can even be used back into quite early gearboxes.
As long as that gear pairing is adhered to.
Ask the new phone support guy at AN if you want any more details,
they have all the eng drawings and blueprints.... ?
Gidday Rohan. Thanks for your prompt reply. Exactly why can they not be interchanged?.
and what do you mean by tooth form. I think you mean profile and pressure angle.. There may have been a change in pressure angle but I dont think so. I will research and find out.
Tooth form is a meaningless term when referring to interchangeability. all gears of same tooth size but different tooth numbers have a different profile. look at 17 T and a 50T profile. they will still have conjugate action but very very different looking profiles.
So to support your claim you must give the specific reasons leading to the conclusion that they are not interchangeable.
Was it a change in pressure angle. And when. I wiill check this out.
If any 2 gears have the same centre distance, DP, pressure angle, and same porportions regarding addendum, working depth and so on they will interchange. gee, they sometimes even have different addendums and still have conjugate action.
tooth shape has very little to do with interchangeability.
All AMC boxes after 1950's are 10 DP 20 degrees pressure angle. I have not comfirmed this yet.Some pairs have long addendums and these will not interchange with standard addendum's. .
Some very very early boxes may have 14 1/2 degree pressure angle. it is now almost obselete. this makes a difference. But I reckon after about 1940 or even 1950 all AMC boxes run 20 degrees pressure angle. all twins will be 20 degrees so any twin box gear will interchange.
so it depends on what u mean by early. They never did change the centre distance and that is a telling point.
if there is no change in pressure angle, the gears will interchange if proportions are the same. Again the definition of interchange becomes important.
mate you still have not rebutted my claim that the main reason not to interchange a pair is because of the consequences of wear. technically an old and new gear will mesh and run.
but for reasons previously described the mixing of old and new is all about the consequences of wear, not interchangeability. As to gear pairs are ok to use together, technically can I make at home a 12 tooth pinion of correct proportions, and run it with a new AMC 28 T gear ?. the 12T replaces a14T.
of course I can. the new 12T and standard 28T are now a pair.
Mate, gearing is an incredibly complicated subject. it is very very difficult to have a discussion about the technical aspects in one or 2 paragraphs here. Volumes have been written on gear design.
By trying to reduce discussion to a short format, it is so easy to have the subject taken out of context.
And we still have not discussed your claim about " root thickness" being the main reason for more strength. and durability is just as important as strength. It is important not to give did\sinformation to interested lay persons.
In any discussion on gearing, it is absolutly essential to use the same precise terms used in the gear engineering field. comparing apples to apples. terms like long addendum, drop tooth, pressure angles, base circle, strength and durability ,tooth profile shift are essential to any discussion about gearing.
You cannot have a simple debate about technical aspects of gearing. So much is inter related.
So the debate about interchangeability comes down to one question .
"Did AMC ever run 14 1/2 degree pressure angles". This should be very easy to establish.. Then the discussion can continue once this is established for certain.
I will start a new thread on this very subject as it is too easy to hijack this one.
I do thank you for your reply and look forward to further discussion in another thread. Best wishes Aussie bradley