Lotus Elan and Lotus Elan Plus 2 Forums

Hello everyone!

I'm working on converting a 5 speed transmission to work in my Elan. I'm in the process of making a bellhousing adapter plate and I'll be replacing the transmission front bearing carrier. When doing that I'll be pressing in a hardened sleeve the throw out bearing slides on. It will be pressed into an Aluminum bearing carrier. Does anyone know or know how to calculate what the interference fit should be? In other words, should the hole the sleeve is pressed into be .001, .002, .003 of an inch larger than the sleeve or ???

Thank you all,
Frank

Google BS4500a limits and fits.

Why is it that I should remember that after more than 30 years yet cannot remember where I put something 5 minutes ago

You are looking for a light interference fit bordering on a transition fit.

TBH these days for things like that I ignore the tolerances and machine to a sliding fit and then secure with Loctite.

Chancer,

Thank you for the excellent reference on how to calculate these things. I glanced at it and will read in detail over the holidays, ......especially when the in-laws are over.!!! Ha! And when I discuss these things with the shop that has the CNC machine, ....................well, as the say, "A little bit of knowledge is a dangerouse thing" !

Thank you,
Frank

I used to work using those charts those day in day out, memory is a bit hazy but they are really destined for production work where as long as all your shafts and holes (male and female parts) fall within the precribed limits then they will always assemble with the required clearance, transition or interference fit.

You will simply be measuring exactly the existing part and machining your other bit to fall within the required tolerances for the correct fit.

Seem to remember that there were 2 charts, hole basis and shaft basis, if you were working with standard shafts, bolts, dowels whatever then you would bore the hole to within the limits using the shaft basis table and ditto for say machining a pin to go into a reamed hole you would use the hole basis table.

Or of course that might be backwards!

Why do I remember this stuff, I will never use it again, i use a pair of calipers, my eyes and loctite now!!!

Anyone else need to know any useless info on geometric tolerancing perhaps?

I'd love to read one or two pages on geometric tolerancing, but more than that could be too much.
regards
Richard

Sooo....apparently you did get the machining program for the Isuzu trans from NZ, Frank. Gonna share???

Kurt
26/3754

An Essay on Criticism is one of the first major poems written by the English writer Alexander Pope

Correct quote is: -

?A little learning is a dangerous thing.
Drink deep, or taste not the Pierian Spring;
There shallow draughts intoxicate the brain,
and drinking largely sobers us again.?

This is in reference to the spring in the Pierian Mountains in Macedonia, sacred to the Muses. The first line of this couplet is often misquoted as "a little knowledge is a dangerous thing".

The Essay also gives this famous line: -

To err is human, to forgive divine.
The line "Fools Rush In Where Angels Fear to Tread" from Part III has become part of the popular lexicon, and has been used for and in various works.

Jon the Chief