Description, Parallel & Diagonal Lengths Information

FIGURE 2:

DESCRIPTION

The trammel gauge consists of the following components (Fig. 2):

A - Main tube E - Short angled pointer

B - Adjustable spirit level F - Long angled pointer

C - Sliding rule G - Vernier scale

D - Straight pointer

NOTE: The vernier scale (G) on the main tube has 5 graduations spaced 1 mm apart.

The trammel gauge is used for:

^ Checking by comparing parallel lengths

^ Checking by comparing diagonal lengths

^ Checking by comparing heights

FIGURE 3:

CHECKING BY COMPARING PARALLEL AND DIAGONAL LENGTHS

This is a comparative check between body/frame sections that are parallel or diagonal. The diagonals must be checked and compared as well as the parallels to ensure alignment accuracy.


^ Checking parallel lengths

^ Check AC in relation to BD

FIGURE 4:

^ Checking diagonal Lengths

^ Check AD in relation to BC

FIGURE 5:

FIGURE 6:

A diagonal check on a vehicle with front end damage may be correct but the lengths may differ as shown (Figs. 5 and 6).

FIGURE 7:

FIGURE 8:

A check of length on the same vehicle having front end damage may prove correct but the diagonals may be unequal as shown (Figs. 7 and 8).