The lining to indicate the thickness of the standard, and to show the place and width of the slot is now completed ; and if the article is cast without any slot it next requires circles to be scribed along the intended slot to prepare it for drilling; but if the slot is already cast it is ready for planing.

If a standard is thus lined on its broad sides and narrow sides previous to any planing of it being executed, it is necessary that those surfaces which are put into contact with the parallel blocks should be uniform and parallel with the remainder of the broad sides, so that such surfaces may constitute tangible and definitely formed planes that are capable of being easily referred to; if not the lines scribed on the broad sides cannot with certainty be made right-angular to the lines on the narrow sides. It ia therefore advisable that all roughly cast guides be first put upon a planing-machine instead of upon a lining-table, that some portion of the planing may be done before lining, and that the uniform surfaces referred to may be produced. By this mode, either the foot or the broad sides may be planed previous to lining for the slot; and the entire lining of the standard is executed while it is on the planing-table. In accordance with this method the centre of the narrow side must be determined and a periphery scribed around in about the same manner as if the object were on a lining-table; it is also requisite to mark a line above and below the centre one to show the thickness, to which lines the metal is to be planed off. Without these the standard cannot be properly adjusted parallel with the table, nor the quantity of superfluous metal indicated. The adjustment for commencing the planing therefore consists in packing up the standard with wedges and blocks beneath the broad sides until the scribed lines on the narrow sides are placed parallel with the table as required. During this planing the length of the slotportion should be situated right-angular to the length of the table; and the holdfast plates should at first be situated across the extremity of the guide-portion adjoining the slot, and also across the foot, thus exposing the entire slot-part free to be planed. This mid portion being planed, the plates are removed from the foot, and are fastened across the planed slot-portion without shifting the standard on its packing-blocks. After being fastened the second time the foot is planed, and will be parallel with the planed slot-portion. It is, however, proper to so place the plates that both the foot and the slot-part can be planed at one fastening, if the shape of the casting permits, because shifting and again fastening the plates is liable to prevent the surfaces being planed parallel with each other.

After the standard has had one broad side planed it can be put upside-down and the opposite side planed; and if it were properly lined wedges are now dispensed with, and only parallel blocks are put between the table and the object, the blocks being now put into contact with the planed surfaces. Previous to fixing fortius second planing, the centre length of the slot should be determined ; and the condition of the foot or base ascertained. If it is found that the extremities of the foot are tolerably square to the intended centre length of the slot, the article can be adjusted for this planing either with regard to the foot or to the slot-part, the particular portion selected for adjusting being in any case that which possesses the least quantity of metal to be cut off, according to the elements of planing and lining in page 220. If the standard is properly made, it has a comparative great thickness of metal to be removed from the foot because this is usually a much shorter portion than the guide-portion containing the slot. The centre length of the slot is therefore considered to coincide with the centre length of the entire guide-part, and after this length is shown by placing a straight-edge and marking with a scriber, the line is used as a gauge-line for adjustment; whether or not it is right-angular to the extremity of the foot. To effect this adjustment the line is placed exactly across the table or right-angular to the direction of the table's motion. For this purpose a scriber-block having a straight bottom-edge is put to both ends of one of the short gauge-lines on the table, and the scriber-point is put to both ends of the line on the guide, that the relative positions of the two lines may be observed and the guide shifted accordingly.

It may now be perceived that the length of the slot-portion or guide-portion should be across the table during the planing of the broad sides, as directed, because at the two fixings of the standard, the two sides of the foot, and also its outer extremity, can be accurately planed, in addition to planing the broad sides parallel with each other and to the specified thickness. The extremity of the foot is also planed right-angular to the length of the slot as required, because this part is planed with the vertical traverse of the rest while the standard remains adjusted with regard to the slot's centre line. With proper care at each fixing, and at the cutting off of the metal to the gauge-lines on the narrow sides, the standard is finished, except the slot-surfaces, and these can be completed with only one more fixing; therefore three fixings suffice to execute the entire planing.

At the third planing of the standard its length is right-angular to its position during the two previous planings, in order to now plane the slot. To shape this part, the centre line of the slot is put exactly parallel with one of the long gauge-lines on the table, and therefore parallel with the table's motion. A scriber-block may be used for this adjustment, as for previous ones, with the difference of placing the block upon a long line instead of a short one. This centre line is the same which was used at the previous planing, the guide not having been put upside-down, but merely shifted to alter its position on the table. If the guide is adjusted by means of this line for planing the slot, the correct position will be obtained if the same line were exactly right-angular to the table's motion while the foot was being planed; but because it may not have been in this condition through some fault in the fixing, it is preferable to adjust the object by means of an el-chuck. For this purpose the chuck is fixed with its length across the table, the bottom edge of the chuck's face being exactly adjusted to one of the short gauge-lines. To the face of the chuck the foot or bottom of the standard is bolted in close contact, which must necessarily so place the slot-portion that the slot shall be planed exactly right-angular to the foot, whether or not the foot were right-angular to the centre line while being planed. The parallelism of the length of the slot with a long line on the table is, therefore, not considered when an el-chuck is used, the right-angular position being obtained by merely bolting the planed extremity of the foot to the chuck's face. At this fixing the standard must rest on parallel blocks, as at the previous fixing, the blocks being in contact with portions of the planed broad sides, and situated in proper places to avoid contact with the cutting tools extending through the slot while planing.