Important Warning: This is a historical archive text, not a current machine specification, capacity calculation, risk assessment or operating manual. Tightening methods, models, dimensions, speeds, formulas, testers and procedures must be checked according to applicable regulations, manufacturer’s documentation and safe work rules.

This text is not an offer of machines, testers or service documentation of Savo Kusić. The current offer is focused on windows, doors and related solutions.

Tensioning the saw in the frame

With gutters, the saws must be well secured and tensioned in the frame. When working with weakly tensioned saws, a shard in the form of a wavy cut, etc. is obtained. The most common way of tightening the saw is by means of a wedge, eccentric, screw (picture 1), as well as the way of tightening using hydraulic devices. Tightening the saw with wedges is worse than other methods. A large number of industries produce a large number of types of powerful, fast-moving, highly productive saws. These highly productive sawmills work in large wood processing plants in the construction industry. The technical characteristics of these gaiters are given in table 1.

Historical display of saw tension in the gater frame, archive tag 20190926 162509 1

Image 1:  Tensioning the saw in the gater frame

The main types of high productivity garters

Table 1: Technical characteristics of the main types of high productivity gaters
Technical indicators Unit of measure Types of Gaters
With one crankshaft With two workers
RD
75-2		 RD
60-2		 RD
50-2		 RD
40-2		 RLB
75		 RD
110		 R-65 R-65-2 Moving RP–65 RK-65
Opening width mm 750 600 500 400 750 1100 650 650 650 650
Walk height mm 600 600 600 600 500 600 360 410 410 360
Number of turnovers rpm 300 315 315 350 290 225 250 250 240 250
Maximum displacement at 1 turn of gater shaft mm 45 45 60 60 22 20 20 20 20 20
Moving system Continuously Intermittent
Allowed number of testers in frame com 12 10 8 8 12 20 10 10 10 10
Tier tilt mode Combining constant pitch of the gater with variable pitch of the saw Slope of the saw in clamps
Number of rollers to start com 4 4 4 4 4 4 4 4 4 8
Weight t 12 12 12 12 9 13 3,25 3,8 5 4,44

Light saws of low productivity are used for cutting logs in the conditions of rural construction and in smaller enterprises for the production of building elements from wood. The characteristics of these child gaiters are in the table 2. 

Light gaiters

Table 2: Technical characteristics of light gaiters Pointers Unit of measure Types of Gaters RS – 50 RS – 52 GGS -2 RP Types – One-story with transmission from below One-story with transmission from below One-story with transmission from below Movable single storey Opening width
Frame stroke mm
mm 500
300 520
400 534
300 550
400 Number of revolutions
Type of displacement rpm 200
One-stop during the working stroke 250
One-stop during the working stroke 200
One-stop during the working stroke 250
Bi-interrupted Maximum Displacement
Weight mm
kg 7,2
2000 10
3000 8
2500 15
6000

The productivity of the gater is calculated according to the formula: P = K -  Δtnq/1000L m3. Where K is the gater utilization coefficient. For mechanized lathes K = 0.93, and for semi-mechanized ones K = 0.90;  Δ - displacement for one turn of the gater shaft; n - number of revolutions of the gater shaft per minute; t - gater working time in minutes; q - log volume, m3; L - length of logs, m.

Historical calculation of productivity

When determining the average annual productivity of the gatekeeper for one shift, stoppages that occur due to various causes (repairs, lack of raw materials, etc.) must be taken into account. These losses are determined by the experimental coefficient Kgod = 0.9 - 0.92.

Therefore, the average annual productivity of a gater for one shift is determined by the formula P = Kgod x K x Δntq/1000L m3 for one shift.

Technical characteristics of gater testers are given in table 3.

Dimensions and profiles of gutter saws

Table 3: Technical characteristics of gater saws Length Width Thickness The pitch of the teeth (the distance between the adjacent tips of the saw teeth) 1100 150 and 180 1,2; 1,4; 1,6; 1,8; 2,0 15; 19 1250 1,6; 1,8; 2,0; 2,2; 2,4 18; 22 1400 1,8; 2,0; 2,2; 2,4 18; 20; 22 1500 2,0; 2,2; 2,4 22; 26 1650 2,2; 2,4 22; 26 1830 2,2; 2,4 22;26

Saws are made in two tooth profiles: with a broken back edge and with a straight back edge (fig. 2). When choosing the desired dimensions of the saw, you should be guided by the length of the frame of the gater, the size of its stroke and the diameter of the logs to be cut. The required length of the saw can be determined by the formula L = Dmax + H + (300 to 350) mm, where L is the length of the saw, mm; Dmax - maximum diameter of logs to be cut; 300 - 350 - supplement due to installation of inserts for boards and slats; H - stroke height, mm.

Historical view of the profile of the teeth of gutter saws, archive mark 20190926 162330

Picture 2: Profile of the teeth of the miter saws

The thickness of the saw and the pitch of the teeth should correspond to the height of the cut and the type of cut. This mutual relationship is given in table 4. 

Table 4: Interrelationship of saw thickness, tooth pitch of cutting height Slicing type Diameter at the thin end of the log or beam thickness, cm Tooth pitch, mm Saw thickness, mm Cutting Logs
Ditto
“
“ Up to 20
21 – 26
27 – 34
35 and above 15 and 18
18
22
26 1,6 – 1,8 – 2,0
1,8 – 2,0
2,2 – 2,4
2,2 – 2,4 Cutting logs into beams
Ditto
“
“ Up to 22
23 – 24
35 – 44
45 and above 15 and 18
18
22
26 1,8 – 2,0
1,8 – 2,0
2,2 – 2,4
2,2 – 2,4 Beam cutting
Ditto Up to 20
21 and above 15
18 1,6 – 1,8
1,8 – 2,0

The saws are installed together with stirrups that attach to the lower end of the saw and with a set of two stirrups and seven bolts for the upper end. The stirrups are attached to the saw at right angles to its back edge. The beveled edges of the stirrup must be facing each other. Before riveting the stirrup, the edges of the saw should be checked to see if they are straight and parallel, and if they are not, they should be trimmed on a saw sharpening machine.