What is a Tile Boss

[Robby]

I’m about to fit a Parker Hale 5A Aperture Sight to a No1 Mk3* SMLE. The fitting instructions mention that the sight may not stand vertical and/or square and that some packing may be required. No problem so far.
The instructions then go on to say ‘Alternatively tile boss on the bed of the sight can be adjusted to suit the action body by filing’ Can anyone enlighten me as to what a tile boss is. Thanks

[glevum]

Do you have a set of original instructions, or are they from the rifleman.org website?

If it is the latter I suspect that 'tile' may be a typo for 'the'

[Robby]

It was Rifleman and when you pointed it out, looks like an obvious typo. Thanks for thereply