Tom Lammonby fell five short of a century as Somerset cemented their advantage on the second day of the Rothesay County Championship match with Glamorgan at the Cooper Associates Ground, Taunton.

The home side extended their first-innings score from an overnight 92 without loss to 441 all out, Lammonby’s 95 coming off 173 balls, while Josh Thomas contributed 59, James Rew 52 and Archie Vaughan a season’s best 68. That meant a first-innings lead of 247, despite Mason Crane’s 4 for 95.

Glamorgan were left with six overs in the day to launch their second innings and closed on 30 for 1, Crane caught at silly point off the last ball of the day, bowled by Jack Leach.

For the second successive day the start was delayed, this time for 35 minutes. Unbeaten on 46 overnight, Thomas moved to an attractive 86-ball fifty with nine fours. He had helped Lammonby take the opening stand to 114 when carelessly chasing a very wide ball from Mir Hamza and edging to wicketkeeper Chris Cooke.

Lammonby, 37 not out at the start, played with restraint to reach a 99-ball half-century and shared a second-wicket stand of 30 with Lewis Goldsworthy, who had faced 45 balls for his 11 when caught at square leg off Crane. Ten more runs were added before lunch, which was taken at 164 for 2, with Lammonby unbeaten on 73.

The afternoon session saw the left-hander bat positively to move into the nineties before losing concentration. Twice he was caught behind off Dan Douthwaite no-balls before the seamer had him caught and bowled advancing down the pitch to drive.

Douthwaite and Crane bowled tightly in tandem and soon the latter had Henry Nicholls caught at slip edging an attempted sweep. At 212 for 4, Rew and Tom Abell were obliged to be cautious.

Rew brought up 250 with a boundary off Connor O’Riordan. When Abell pulled a four off O’Riordan to move to 27, it meant he has scored 25 or more in 18 consecutive Championship innings. By tea, the pair had shared a 76-run partnership, taking the score to 288 for 4, a lead of 94. The second new ball was due and Glamorgan took it immediately play resumed.

Rew responded with a boundary clipped through the leg side off Timm van der Gugten, which resulted in the ball being changed in only the fourth over with it. Rew then promptly deposited the next new one to deep square for three to bring up a 78-ball fifty.

Abell edged van der Gugten to Colin Ingram at first slip having also faced 78 deliveries and hit five fours in his 45. At 306 for 5, Somerset’s lead was 112.

With only eight runs added, Rew was caught behind down the leg side off Hamza, who then became the second Glamorgan bowler to suffer frustration as Vaughan gave a catch to mid-off before scoring only to be saved by another no-ball call.

It proved a key moment as Vaughan and Craig Overton put together a half-century stand off 47 balls. Overton is having a fine season with the bat and, having survived a loud lbw shout first ball, hit eight fours before being stumped for 41, advancing down the pitch to offspinner Ben Kellaway.

The partnership of 69 with Vaughan had put Somerset in sight of a fourth batting point at 383 for 7 in the 99th over. Skipper Lewis Gregory achieved it with a boundary off Crane before being caught at long-off to give the spinner his third wicket.

Vaughan had eyes on maximum batting points, accelerating to a 59-ball half-century and then twice depositing Kellaway over wide long-on for six. But Kellaway responded by bowling Jack Leach and when Vaughan was stumped off Crane in the 110th over, Somerset were nine runs short of their target.