on the ace of the form

[ИМЕ]

 Just to avoid that the dilatation of the rammed lining could deform the inside form it is necessary to prop it with two wooden listels of the suitable measure crossed on the ace of the form.

Спасибо

[Abracadabra]

face of the form?

[ИМЕ]

нет, именно ace, хотя, может бы, Вы и правы, - там просто опечатка

[D-50]

should be Face, really ;-)