paul womack wrote:
> Back in the days of braces, catalogues listed
> 3 types of reamer;
>
> The square-solid type, the hollow "half round" type,
> and and solid semi-cylindrical type.
>
> (The different types are for differing materials, but I don't recall
> which is which).
>
> But, apart from when enlarging holes in sheet materials,
> these all make holes with substantial taper.
>
> So - what were they used for? They're common,
> both in catalogues, and "the wild" so people clearly
> found uses for them.
>
> Who needed strongly tapering holes of varying sizes?

The suggestions so far appear to reflect current
usage of reamers;

Modern engineers use near-parallel reamers to make
very accurately sized holes - AFAIK they are only slightly tapered
at the "nose", and thus need to come in a very wide range of sizes.

Example:

http://www.asenggent.com/uploads/6/3/3/3/6333350/2157778.jpg

The very strongly tapered reamer for deburring cut pipe
are like this:

http://www.joesusedtools.com/images/Brace-Reamer-A_LRG.jpg

For cutting holes of varying size in sheet good, the modern engineer
has "cone cutters" AKA "cone bits"

http://ecx.images-amazon.com/images/I/31SRp%2BUyyTL._SL500_AA300_.jpg

I mention all these explicitly, since none of them are anything
like the "old" reamers.

http://galootcentral.com/components/cpgalbums/userpics/10152/rimer.jpg

These two pages are from 1845 (lower) and 1928 (upper).

There appears to be a distinction in use between the "tapered bit"
for wood, which comes in multiple sizes, and the "square" and "half round"
rimers for metal, which only come in one size.

The taper of these old tools is much greater than a modern
"sizing" reamer, but much less than a modern "multisize" reamer
(deburring or cone cuttter).

The only comparable modern tool I can find is a "taper reamer"

http://www.dansdata.com/images/tools/reamer500.jpg

which seems to be a "get you by" kind of tool.

So - the presence of the old shapes seems to me to imply
an old technique, now forgotten.

    BugBear

(I will point out, to save others the trouble, that there are other
VERY specific tapered reamers, including chair legs,  ladder rungs,
cask bung holes and violin pegs holes, but all of these are listed explictly, an
d are
(thus)not mysterious)
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