Even with that material in hand, you may not enjoy success unless you work with each individual piece, and if it's centerless ground (most likely is) it may not be straight, round, or uniform in diameter from piece to piece. Don't assume any of those features. Check the material. It should meet those specs, but it's all too easy not to, especially if the material starts life less than straight (most likely) and is not ground by one with experience (a centerless can very easily generate three sided material that measures round, but isn't---if not operated by one skilled in centerless operation).Brakeman7.5 wrote: ↑Mon Sep 18, 2023 7:42 pm McMasters sells rotary shafts thatIt's 3/4" shaft has a (Tolerance: -0.003" to 0")are turned, precision ground, and polished to meet tight diameter and straightness tolerances.
Excluding the need to mill a keyway, is it possible to anticipate a slip fit, press fit or you really don't know till you get them both together?
Note that when one machines a keyway, the material is subject to movement, yielding a less than straight shaft. A short keyway isn't much of a problem, but a long one will definitely bow the material. That's due to uneven relief of internal stresses, created when the shaft is rolled.
It is commonly accepted that a half thou spells the difference between a press and slip fit.
The very best scenario is for you to obtain shafting that is functional, then machine the mating piece(s) to fit according to your needs. Commercial shafting is made to fit commercial fittings---and may or may not be a size that lends itself to your particular project. There is generally considerable clearance to assure that the pieces will assemble. Hoping for a proper press fit would be unreasonable (especially with .003" tolerance).Also, McMasters sells keyway stock that is either "oversized" or "undersized". Since it's only around $1.25 for 12" of each do you just buy both kinds and see what works best?
Bottom line here is it all depends on how much you're capable of doing on your own. If you have no machines, you may be forced to buy what is available and hope you can make it work.
These are my thoughts. Others may or may not agree.