Out of interest, does anyone know how a blind bush is reamed to size?
A blind bush is often reamed using a "machine reamer".This is a reamer with no taper lead-in on the cutting part (unlike a hand reamer)and usually (but not always) has a morse taper so that it can be inserted into the spindle of a mill or drill or lathe tailstock.
Because it is parallel for the length of its cutting blades it produces the desired result.Reamers can be purchased in any size you require but you will have to pay a lot more to have one specially made to a non-standard size.
So if you wish to ream out a blind bush in a crankcase or similar you can do it if you have a correct sized m/c reamer and a pillar or bench drill (that you know drills truly square to the work) .You may wish to revolve the drill spindle by hand for this.
Another way is to use a "D" bit which is a simple (often home-made) type of reamer usually made from silver steel or drill rod.
If i had to finish a blind bush and lacked any sort of reamer i would (and have on many occasions) scrape it to size using a 3 cornered scraper or bearing scraper and engineers blue on the shaft to be fitted.
When I was a machine toolmaker apprentice a few years ago now, the old fitters there would have a block of wood with their reamers stored standing vertical in it.But they would have 4,5 or maybe 6 reamers of each diameter . They would be arranged in order of the amount they were worn.With maybe 2-3 thou difference between the newest and oldest .
So if you required a dowel or pin to be a tight fit you would use the first reamer. if you wanted a light tap fit, you would work your way up to the middle one and if you wanted an easy fit you would use the newest and sharpest one.I was also taught how to make an undersize reamer cut a bigger hole and make an oversize reamer cut a smaller hole.
Mike