If you stick with one-syllable words (which HAVE to have the stress!) there are many examples – batter, hitter, chopper, mugger (Cf. adjectives – redder, bigger). The rule, as you can observe, is that the final consonant is DOUBLED before adding the -er.

For longer words, it is much less common for the stress to be on the final syllable of the root. But the RULE is the same –when the stress is on the final syllable the consonant is to be doubled before adding endings like -er, -ed, -ing.

Examples: forbidder, admitter, propeller

Now in AMERICAN English this rule generally does NOT apply for words with this pattern (final vC + er..) when the final root syllable is NOT accented. Thus, standard American English would be “worshiper”. British English, however, tends to still double in this case (thus “worshipper”).

RE:
To add the er suffix to words ending in a stressed syllable with one vowel and one consonant? an example?
i need the answer, and quick. it must be right. first person gets best answer!