Summary of tests on power used on insert-point circular headsaws

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Title:
Summary of tests on power used on insert-point circular headsaws
Physical Description:
Unknown
Creator:
Telford, C. J
Forest Products Laboratory (U.S.)
Publisher:
USDA, Forest Service, Forest Products Laboratory ( Madison, Wis )
Publication Date:

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All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 29310077
oclc - 230458832
System ID:
AA00020559:00001

Full Text
7.,
FOREST PRODUCTS LABORATORY t FOREST SERVICE
S.4S213 (Power)" U. S. DEPARTMENT OF AGRICULTURE

SMALL SAWMILL IMPROVEMENT /
PRACTICAL POINTERS TO FIELD AGENCIES '


Summary of "

TESTS ON PObTER USED 01, INSERT-POINT CIRCULAR IEA7JA:T3


The users of insert-point circular headsaws are guided by saw manufacturers
plus their own experience in selecting headsaws of the diameter, gage, style,
and number of teeth, width of bits, operable speeds, and probable horsepower
requirements suited to their needs. A series of tests has been made by the
Forest Products Laboratory for the purpose of relating this guidance to defi-
nitely measurable effects. The forces used in sawing were determined by use
of recording instruments, and could readily be converted in terms of horse-
power where desired. The test results of direct interest to saw users follow:

1. Dull teeth required 8 percent more horsepower than did sharp teeth.

2. A saw having a wobble of the rim or teeth and holders out of line so as to
score the board face with definite ridge and groove pattern used 11 percent or
more horsepower than did a smooth cutting saw. These observations emphasize
the handicap in using a dull saw or one that visibly scores the cut faces.

3. The horsepower required varied directly vith the diameter, a 5-foot
S diameter saw requiring 1/5 more horsepower than a h-foot diameter saw. This
further substantiates the use of a saw no larger than required to reach
through the largest logs encountered.

4. The horsepower increased with the number of teeth (2-1/2 style) by approxi-
mately 1 percent for each additional tooth.

5. The B style tooth required 6-1/2 percent more horsepower than the No. 3
style, each saw with O40 teeth; the 2-1/2 style vrith 48 teeth required 38 per-
cent more horsepower than the No. 3 style with 40 teeth. Other styles were
not tested. It seems probable that style is less important than number of
teeth and that in increasing the number of teeth th(.'re ri r- ',ir-r', -
are increased. V, .X L, BA
HUlV11 LIBRARY
6. On an 8-rage saw having shanks of a maximum thi kness of 0.205 inch
(13/64 inch full) bits 7/32 inch in width were inad quate, 8V2 inch require d
the least horsepower, 9/32 inch used h2 percent, an( iO/32 4h l 4$725 per
cent more horsepower than did the 8/32 inch bits. his indicates the desir
ability of using the narrcv.:.it bits that permit effi lent saw operation.
i.F.A. .. L',;>,. of, F1or'da
7. An increase in horsepower developed when gullt 11: er.-o*,rJ 0.: a:l.n
sawdust. Overloading developed when the gullet area was less than 2.5 the
wood area for oak and ash, or 2.4 for Douglas-fir. Overloading was not
perceptible when these relationships were 2.3 for cherry, 2.2 for bass-,ood,
elm, and cottonwood, and 2.1 for soft maple. As mills install higher capacity

Rept. No. R899-26 -1-

t Maintained at Madison, Wisconsin in cooperation with the University of Wisconsin
*See outline in Small Sawmill Improvement Working Plan, March 1930, for explanation of indexing system proposed







power units, the capacity of the gullet to chamber sawlust properly places
a ceiling on feed rates and disqualifies saws having relatively small gullets. *

8. Excluding the horsepower used to run the machinery, the horsepower con-
sumed by cutting was proportionately less as speed increased It increased
directly with the rate of feed at rates of fewer than 16 teeth per inch and
directly with the cutting depth, and density (specific gravity) of the wood.

Tables 1, 2, and 3 give definite measurements of the effects of saw speeds,
feed rates, cutting depths, and wood densities. The average densities
(specific gravity) for species when green are given in the reference listed.
The tests upon which the tables are based were made with a saw 48 inches in
diameter having 4O B-style teeth with bits 9/32 inch in width.



Contributed by:
C. J. Telford, Small-mill Specialist
Forest Products Laboratory
Madison 5, 1isconsin

March 1949


-2-


Re~t. No. R8099-26







Table 1.--Cutting horsepocr exclusive of machine loss horspovoer-
(Speed of sar = 300 r.9.m.}

Bite per:Carriage faced: Specific : Depth of cut inches
tooth : for a 140- : Cravity-:---------
: tooth saw : : 10 : 12 : 114 : 16 : 1
-- ----- -------- ------ -------- ------ --------: --:.-----


Inch : Ft. per min.:


0.03 :
.04 :
S06
.08
.10
.12
.13

.03 :
.04 :
.06 :
.08
.10
.12
.13

.03
.h04
.06
.08 :
.10
.12
.13 :

.03
.014 :
.06 :
.08 :
.10
.12:
.13

.03 :
.014
*06
.08 :
.10
.12
.13


30
140
60
8o
100
120
130

30
40
60
80
100
120
130

30
140
60
80
100
120
130

30
o40
60
80
100
120
130

30
40
60
80
100
120
130


0.3
.3
.3

.3
* 14
* 1
.I

.14
,U



.4
.L


.4
.1


0.
.5
.5
.5

.5

.6
.0

.5
.6
.6
.6
.6
.6
.6
.6
.6

.65
.6^p

.65;

.65


1.4 : 4.1
2.0 : 4.
3.i : 6.1
4.1 : 7.3
5.1 : 8.5
6.1 : 9.7
6.6 : 10.2

3.6 : 6.7
5.1 : 8.5
8.0 : 12.0
10.5 : 15.0
13.0 : 1.0
. : 21.0
16.3 : 22.6

5.8 : 9.14
.I : 11.9
12. 17.
16. : 22.7
20. : 27.5
25.. 32.4
27.1 : 33.)

8.0 12.0
11.2 : 15.)
17.6 : 23.5
23.2 : 30.3
2E. : 37.0
34., : 13.7
37.3 : 47.2

9. 1 : 13.3
12*. : 17.8
20.0 29.3
26.), : 36.2
22 : 143.0
32.2 : k4.9
2.4 : 53.3


]^. 3.._;_.
: r. : '~ :.
6.8 : 9.5 : 12.3
7.7 10. 13.
S9.2 : 12. 15.3
10.5 : 13.6 17.0
: 11.9 : 15.3 : 1.7
S13.3 : 16. : 20.)4
S13.9 : 17.5 : 21.2

9.9 : 13.0C 16.2
12.0 : 5.* 0/.
16.1 : 20.1 : 24.2
S19.6 : 24.1 : 28.7
: 23.1 : 28.1 : 33.2
: 26.6 : 32.1 : 37.7
28.h : 34.2 : 0.0

13.0 : 16.6 : 20.2
S15.7 : 19.5 23.3
22. : 27. : 32.C
2.5 : 314.3 40.1
31.1 0: 40.7 1 47.)
: 39.9 : -7.3 54.E
: 142.8 : 5.6 5.5

16.1 : 20.1 2 2
20.6 : 25.3 : 2 .9
29.5 : 35.1 141-.4
37. 4 : 1 .. 51.5
S45.2 : 53. 6.
53.1 62.14 : 71.
57.1 : 67.0 : 7.

17.6 21. : 26.1
: 22.8 : 27. : 32.:
: 36.6 : 47. : 57.3
4i. 6r
16.0 : 5. 65.5
53.2 : 63.4 73.7
: 60.6 : 71.3 : 1.9
64.2 : 75.1 : 86.1


1]
-Add idling horsepovr =r
on the saw.


4.43 horsepower; add 2 horsepower for carria,;e pull


2
-Use specific gravities for oven-dry material based on volume at time of test
as given in U.S. Depart...ent of Agriculture Tech.-ull. iUo. 479.
Rept. Ao. R399-26





1
Table 2.-Cuttin horsepoycr exclusive of machine loss horsepo.-r-
(Speed of saw = 450O r.p.m.)

Bite per:Carriage feed: Specific : Depth of cut inches
tooth : for a 40O- : gravity:--------------------------------------------
: tooth sawr : : 10 : 12 : lh : 16 : 18
--. --.--------- ----------: ---------.- -- -----:------- ------


Inch : Ft. per min.:


0.03
.014
.06
.08
.10
.12
.13

.03
.C4
.06
.08
.10
.12
.13

.03
.014
.06
.08
.10
.12
.13

.03
.04
.06
.08
.10
.12
.13

.03
.01
.06
.08
.10
.12
. 13 :


45
60
90
120
150
1 o
12$

4$
60
90
120
150
180
1 9$

45
60
90
120
150
180
19$

4$
60
90
120
150
180
195$

4$
60
90
120
150
180
19$


0.3
.3
.3
.3
.3
S .3
.3
9
.4
.4
S .4
.4
.4
.5

.5
9$
.5
: .h :



1)
.'$
^-5

.5

.6
S .6
.6
S .6
.6
.6
( 5


.6

.65

.05

.65
.65
_____ .6$ :


Hr- Hp. 11-r

1.8 : 5.5 : 9.
2.6 : 6.5 : 10.0,
h.4 8.7 : 13.
5.8 10.3 : 14.
7.2 : 12.0 : 16.
8.6 : 13.7 : 18.
9.3 : 1~4.5 : 19.

4.6 : 8.9 : 13.
6.7 : 11.4 : 16.
11.1 : 16.7 : 22.
114.6 : 20.9 : 27.
18.1 : 2$.2 : 32.
21.6 : 29.4 : 37.
23.5 : 31.6 : 39.

7.3 : 12.1 : 17.
10.7 : 16.2 : 21.
17.8 : 34.7 : 31.
23.5 : 31.6 : 39.
29.2 : 38.14, 147.
3I4.9 2 : 45.3 : 55.
37.8 : 48.7 : $9.

10.1 : 15.5 : 20.
lh.7 : 21.0 : 27.
21.6 : 32.9 : 41.
32.5 : 42.4 : $2.
40.4 : $1.8 : 63.
48.2 : 61.2 : 74.
52.1 : 65.9 : 79.

11.5 : 17.2 : 22.
16.8 : 23.$ : 30.
2.0 : 37.0 : 46.
36.9 : 47.7 : 58.
45.8 : $8.14 : 71.
$54.7 : 69.0 : 83.
$52.2 : 74.4 : 89.


!Add idling horsepower = 6.64 horsepo er; add 3 horsepower for carria-e
lull on the saw.
2
-Use specific gravities for oven-dry material based on volume at time of test
as biven in U. 0. Department of Agriculture Tech. Bull. Lo. 479.
Rept. :',. R899-26


: HD.

13.0
S1..3
: 17.2
:19. li
21.6
: 23.9
25.0

17.5
20.9
: 27.9
33.6
S39.3
S45.0
S147.8

: 21.8
27.3
: 38.
: L7.8
$6.9
S66.1
S70.6

26.3
S33.7
: 19.$
S62.2
S74.7
S87.2
S93.5

20.6
: 37.0
$55.0
S69.3
: 3.
: 97.7
S104.9


HPo.



21.5
214.0
: 26.5
: 29.u
30.3

21.9
25.7
33.6
: hO.O
:46.h
$2.8
$ 5.9

26.7
32.9
145.6
f 5,.9
66.2
76.$
81.6

31.8
40. 1
$7.9
57 ,
72.1
: 6.2
: 100.3
: 107.4

34.3
43.6
614.0
80.1
96.1
: 112.1
: 120.2






1
Table 3.--Cutting horsepoiur exclusive of machine loss horsepower-
(Speed of saw = 600 r.p.m.)

Bite per:Carriage feed: Specific : Depth of cut -- inches
tooth : for a 40- : gravity.: -------------------------------------
Stooth saw : : 10 : 12 : 14 : 16 : 18
I.. ..------- ------- --- ----- ------- -------


Inch : Ft. per min.:


0.03
.04
.06
.08
.10
.12
.13

.03
.04
.06
.08 :
.10
.12 :
.13 :

.03
.04
.06
.08 :
.10
.12
.13 :

.03
.04
.06
.08
.10
.12
.13 :

.03 :
.04 :
.06
.08 :
.10
.12
* 13 :


60
80
120
160
200
21 0O
260

60
80
120
160
200
2o40
260

60
80
120
160
200
2)40
260

60
80
120
160
200
240
260

60
80
120
160
200
240
260


0.3
.3
.3
.3
.3
.3
.3

1
4
.4
.4
.4

.5


.5
.5
.5
.5
.5
.6
.6



.6
.,
.6


b,
.6
.6
(,





.65
.* 5


.065
.6
.6

.65


.65
.6$s
.6$
.65


1.9
3.0
5.4
7.1
8.8
10.5
11.14

4.9
: 7.7
: 13.7
18.1
22.5
26.9
229.0

S Y. S
12.3
22.0
: 29.0
:33.0
43.0
:U6.6

10.8
17.0
30.4
40. 1

59.5
6U.3

: 12.3
19.4
: 314.5
34.$
145.5
:53.5
67.5
73.1


lip..
Ii -

6.5 : 11.1
7.8 : 12.6
10.7 : 16.0
12.7 : 18.3
14.8 : 20.6
16.8 : 23.1
17.9 : 24.4

: 10.1 : 15.3
13.4 : 19.2
20.6 : 27.6
: 25.9 : 33.7
31.1 : 39.8
336.U : 45.9
39.0 : 49.0

13.5 : 19.3
18.9 : 25.6
30. : 3.2
39.0 : 19.0
: U7.U : $6.L.
:55.8 : 68.6
: 60.1 : 73.6

: 17.1 : 23.5
S2.6 : 32.2
40.7 : 51.0
52.3 : 64.5
63.9 : 78.0
75.5 : 91.6
81.3 : 98.4

: 18.9 : 25.6
: 27.5 : 35.6
45.6 : 56.7
58.8 : 72.1
72.0 : 67.5
85.2 : 102.9
91.9 : 1310.7


: T'D.

15.7
17.',
21.3
23.9
: 26.7
29.U
30.9

20.5
2U.9
314.5
141.5
U l.5
: U8.14
: 55. I
59.0

25.o
32.2
117. F
59.0
70.2
: .L
: 87..

29.'-
39.
61.3
76.7
92.1
: 107.6
: 115. Ji

: 32.2
)13.7
67.t
: 85.14
103.0
120..
129.5


1"J.

20.2
22.2
26.5
2' 2


32.7
3 35.3
37.3

25.6
S30.7
:41.5
: h9.3
57.1
(5.0
69.0

30.6
: 38.9





36.2
*L7.14
3C. 6
U^ U



106.3
10023.7
L7.4


106.3
123-7
132.5

38.9
51.7

98.7
: 11.6
: 138.4
1h48.14


-Add idling horsepower = 6.85; adcd 4 horsepower as maximum for carriage pull
on the saw.
2
-Use specific gravities for oven-dry material based on volume at time of test
as given in U. S. Department of agriculture e Tech. "ull. ho. h1479.
Rept. No. R899-26




UNIVERSITY OF FLORIOA


3 1262 089I I I543
3 1262 08926 8543


'. *. ..