Thomas Conroy wrote:
> I don't think it would be printing blocks, at least not for use on a press.
One absolute requirement of a boxwood block for end-grain engraving, Bewick's
technique and the dominant illustration technique for most of the 19th century,
was that the block had to be absolutely even in thickness and exactly type-high,
in order to register with the type. Of course, for most ot the 19th century
every typecaster had his own type height, so the printer would have to adjust
the blocks to the type he was
> using. But the way to do this would not have been to use a small plane; it
would have been to place the block between type-high runners and use a plane
long enough to span from runner to runner, working perpendicular or perhaps at
45 degrees to the axis of the plane. I don't know that this was done for
surfacing woodblocks, but the basic process was that used in making type,
planing the bottoms of many individual types at once to bring them all to type-
height. At the end of the 19th century,
> printers' suppliers offered sets of plane and support table for doing this.
The low angle would be fine, but neither the strike block nor the block plane
seems well adapted to the planing-down of printers' blocks using fixed-height
supports.
>
> Blocks for textile printing were different. These were cut with knives,
chisels, and gouges "on the plank," not with burins on the endgrain. Then a
handle was screwed to the back, and the block was inked and inverted, printed
while held in the printer's hand, just like a [very large] rubber stamp. You
wouldn't need precise type-high blocks fo this. But you wouldn't have any
particular difficulty in planing the working surface, either, since it was just
radial or tangential surfaces.

Interesting - I shall (for exposition, and google) transcribe the second advert;

Manchester Times - Saturday 15 September 1849

Removed for Convenience of Sale - To Calico Printers, block
   makers, Cutters and others - Sale of Holly, Pear-tree, Oak
   and Sycamore Boards, Planks, Printers' Press and Blocks,
   Tools, &c. &c.
By Mr CANDELET, on Wednesday, September 19th 1849, in a
   Warehouse situate in Hodson's Square, Cannon-street Man-
   chester (where the property has been removed for convenience
   of sale):
A LARGE Qauntity of Half-inch Holly, Pear-
tree, Oak and Sycamore BOARDS, two-inch sycamore
planks, one-inch sycamore boards, printers' presses, about 200
new blocks, and a variety of other articles used by printers' block
makers. Also a 200 gallon pan, quite new.

    The sale to commence at eleven o'clock

There are two keywords in all this that confirm Mr Conroy's interpretation;
the list of timbers does not include boxwood, and the first line specifically
mentions Calico Printers.

So - further to the qualification of "block makers" to "printers' block makers"
it seems we must further qualify to "textile printers' block makers".1

(as an aside, it is not beyond possibility that the boxwood blocks
were finish-surfaced on their cut surface using a small low angle plane,
and thicknessed to type height on their rear face, using a large plane)

  BugBear