Carpentry

by Ira Samuel Griffith

APPENDIX III

USEFUL TABLES

FRACTIONAL EQUIVALENTS FOR DECIMAL VALUES

.0156	1/64	.2656	17/64	.5156	33/64	.7656	49/64
.0312	1/32	.5312	9/32	.2812	17/32	.7812	25/32
.0468	3/64	.2968	19/64	.5468	35/64	.7968	51/64
.0625	1/64	.3125	5/16	.5625	9/16	.8125	13/16
.0781	5/64	.3281	21/64	.5781	37/64	.8281	53/64
.0937	3/32	.3437	11/32	.5937	19/32	.8437	27/32
.1093	7/64	.3593	23/64	.6093	39/64	.8593	55/64
.125	1/8	.375	3/8	.625	5/8	.875	7/8
.1406	9/64	.3906	25/64	.6406	41/64	.8906	57/64
.1562	5/32	.4062	13/32	.6562	21/32	.9062	29/32
.1718	11/64	.4218	27/64	.6718	43/64	.9218	59/64
.1875	3/16	.4375	7/16	.6875	11/16	.9375	15/16
.2031	13/64	.4531	29/64	.7031	45/64	.9531	61/64
.2187	7/32	.4687	15/32	.7187	23/32	.9687	31/32
.2343	15/64	.4843	31/64	.7343	47/64	.9843	63/64
250	1/4	.500	1/2	.750	3/4	1.000	1

Where rafter lengths are determined by multiplying unit lengths by the run, the answer will almost invariably result in a decimal. Such decimal values may be readily translated into fractional forms by means of the accompanying table.

Example: A roof of ⅓ pitch has a common rafter run of 14'; find the length of common rafter. Answer: 14 × 14.42" = 201.88" or 16.82'. By the table, .82 = 53/64. A carpenter, however, would not care for such accuracy; the nearest 1/16" or even ⅛" would be sufficient.

WOOD AND MACHINE SCREW SIZES

The difference between consecutive sizes is .01316".

No. of Screw Gage	Size of Number in Decimals	No. of Screw Gage	Size of Number in Decimals	No. of Screw Gage	Size of Number in Decimals
000	.03152	16	.26840	34	.50528
00	.04486	17	.28156	35	.51844
0	.05784	18	.29472	36	.53160
1	.07100	19	.30788	37	.54476
2	.08416	20	.32104	38	.55792
3	.09732	21	.33420	39	.57108
4	.11048	22	.34736	40	.58424
5	.12364	23	.36052	41	.59740
6	.13680	24	.37368	42	.61056
7	.14996	25	.38864	43	.62372
8	.16312	26	.40000	44	.63688
9	.17628	27	.41316	45	.65004
10	.18944	28	.42632	46	.66320
11	.20260	29	.43948	47	.67636
12	.21576	30	.45264	48	.68952
13	.22892	31	.46580	49	.70268
14	.24208	32	.47896	50	.71584
15	.25524	33	.49212

Frequently the carpenter wishes to know the diameter of hole necessary to receive the shank of a screw of a certain gage. Should a screw gage be accessible, he may readily determine this. Should no gage be at hand, he may determine the size of hole by consulting the accompanying table of Wood and Machine Screw Sizes.

Example: What size bit must be selected to bore a hole for a No. 10 screw. By the table, a No. 10 screw is .18944" in diameter. By the table of Fractional Equivalents for Decimal Values it will be seen that a 3/16" bit must be used. The test for gage of screw is always made over the shank just below the head.

LENGTH AND NUMBER OF WIRE NAILS TO THE POUND

Size	LENGTH INS.	COMMON	CASING	FINISH	CLINCH	FENCE	FINE	GAL. SHINGLE
¾	¾
⅞	⅞
2d	1	900					1440
3d	1¼	615					810	568
4d	1½	322	473	584				250
5d	1¾	254
6d	2	200	180	300	157	114
7d	2¼	154
8d	2½	106	112	190	99	74
9d	2¾	85
10d	3	74	90	134	69	42
12d	3¼	57
16d	3½	46
20d	4	29
30d	4½	23
40d	5	17
50d	5½	14
60d	6	11

Nails are sold in quantity by the keg, 100 lbs. of nails, exclusive of the keg. Twenty, 30, 40, 50 and 60d are "base." Other sizes have certain fixed additions per keg to this base price. For example, the price list adopted by manufacturers in 1896 allows an addition per keg of $.70 for 2d common, $.45 for 3d common, etc.

Wire nails are also bought and sold by weight, the size of wire according to the standard wire gage and the length in inches being taken into consideration in specifying the size and in fixing the price per pound.

Common wire nails are thick and have large flat heads. They are used in rough work where strength is desired. Finishing nails are used for fine work such as inside woodwork and cabinet work. Casing nails are somewhat thicker and stronger than finishing nails; they have smaller heads.

WIRE BRADS

Size, inches	½	½	⅝	¾	¾	¾	⅞	⅞	1
Wire Gage, nos	20	18	19	19	18	16	18	17	18
Approx no brads to lb.	7500	7200	4267	3556	2758	2600	2364	1781	2069
Size, inches	1	1	1¼	1¼	1½	1½	1½	1¾	1¾
Wire Gage, nos	17	16	17	16	16	15	14	15	14
Approx no brads to lb.	1558	1143	1246	913	761	584	500	500	406
Size, inches	2	2	2½	2½	3	3	3
Wire Gage, nos	14	13	13	12	14	12	11
Approx no brads to lb.	350	268	214	164	150	137	105

BOARD MEASURE TABLE

Size in INCHES	Length, in Feet, of Joist, Scantling and Timber
	12	14	16	18	20	22	24	26	28	30	32	34	36	38	40
2 × 4	8	9	11	12	13	15	16	17	19	20	21	23	24	25	27
2 × 6	12	14	16	18	20	22	24	26	28	30	32	34	36	38	40
2 × 8	16	19	21	24	27	29	32	35	37	40	43	45	48	51	53
2 × 10	20	23	27	30	33	37	40	43	47	50	53	57	60	63	67
2 × 12	24	28	32	36	40	44	48	52	56	60	64	68	72	76	80
2 × 14	28	33	37	42	47	51	56	61	65	70	75	79	84	89	93
3 × 6	18	21	24	27	30	33	36	39	42	45	48	51	54	57	60
3 × 8	24	28	32	36	40	44	48	52	56	60	64	68	72	76	80
3 × 10	30	35	40	45	50	55	60	65	70	75	80	85	90	95	100
3 × 12	36	42	48	54	60	66	72	78	84	90	96	102	108	114	120
3 × 14	42	49	56	63	70	77	84	91	98	105	112	119	126	133	140
4 × 4	16	19	21	24	27	29	32	35	37	40	43	45	48	51	53
4 × 6	24	28	32	36	40	44	48	52	56	60	64	68	72	76	80
6 × 6	36	42	48	54	60	66	72	78	84	90	96	102	108	114	120
6 × 8	48	56	64	72	80	88	96	104	112	120	128	136	144	152	160
8 × 8	64	75	85	96	107	117	128	139	149	160	171	181	192	203	213
8 × 10	80	93	107	120	133	147	160	173	187	200	213	227	240	253	267
10 × 10	100	117	133	150	167	183	200	217	233	250	267	283	300	317	333
10 × 12	120	140	160	180	200	220	240	260	280	300	320	340	360	380	400
12 × 12	144	168	192	216	240	264	288	312	336	360	384	408	432	456	480
12 × 14	163	196	224	252	280	308	336	364	392	420	448	476	504	532	560
14 × 14	196	229	261	294	327	359	392	425	457	490	523	555	588	621	653

STRENGTH OF MATERIALS

YELLOW PINE POSTS

Load in Tons

Length in ft.	Size in inches
	4 × 4	5 × 5	6 × 6	7 × 7	8 × 8	9 × 9
8	4	5	6	7	8	9
10	3	4	5	6	7	8
12	2	3	4	5	6	7
14	1	2	3	4	5	6
16		1	2	3	4	5
18			1	2	3	4

HARD PINE BEAMS AND GIRDERS

Load in Tons

Length in ft.	Size in inches
	2 × 6	3 × 6	4 × 6	6 × 6	8 × 8
6	1	1½	2	3	5½
8	¾	1	1½	2½	5
10		¾	1¼	2	4½
12		½	1	1½	3
14			½	1	2½
16				½	2
18					1

STEEL I BEAMS

Load in Tons

Length in ft.	Size in inches
	6	8	12
10	7	14	18
12	6	12	16
14	5	10	14
16	4	8	12
18	2	6	10
20		4	8
22		2	6
24			4

BRICK PIERS

Load in Tons

Heigth in ft.	Size in inches
	6 × 6	6 × 8	8 × 8	8 × 12	12 × 12	12 × 16	16 × 16
6	2	3	4	5	6	7	9
8	1½	2½	3½	4¾	5½	6	8
10	1	2	3	5	5½	6	7

STRESSES FOR STRUCTURAL TIMBERS

WORKING UNIT STRESSES USED IN DRY LOCATIONS

	Bending		Compression
Species of Timber	Stress in extreme fibre Lbs. sq.in.	Horizontal shear stress Lbs. sq.in.	Parallel to grain "Short Columns" Lbs. sq.in.	Perpen- dicular to grain Lbs. sq.in.
*Fir, Douglas
Dense grade	1,600	100	1,200	350
Sound grade	1,300	85	900	300
Hemlock, eastern	1,000	70	700	300
Hemlock, western	1,300	75	900	300
Oak	1,400	125	900	400
Pine, eastern white	900	80	700	250
Pine, Norway	1,100	85	800	300
*Pine, southern yellow
Dense grade	1,600	125	1,209	350
Sound grade	1,300	85	900	300
Spruce	900	70	600	200
Tamarack	1,200	95	900	350

* NOTE: The safe working stresses given in this table are for timbers with defects limited according to the sections on defects in the rules of the Southern Pine Association for Select Structural Material. "Dense" southern yellow pine and "dense" Douglas fir should also conform to the other requirements of this rule. "Sound" southern yellow pine and "sound" Douglas fir require no additional qualifications, whereas the other species should, in addition to being graded for defects, have all pieces of exceptionally low density for the species excluded.

This table gives working unit stresses for structural timbers used in dry locations, and is compiled in the main from material furnished by the Forest Products Laboratory, Madison, Wis.

TABLE OF BRICK WALL CONTENTS IN NUMBER OF BRICKS

Seven Bricks to Each Sq. Ft. of Wall Surface

No. of sq ft. of wall	Thickness
	4"	8"	12"	16"	20"	24"
1	7	15	23	30	38	45
2	15	30	45	60	75	90
3	23	45	68	90	113	135
4	30	60	90	120	150	180
5	38	75	113	150	188	225
6	45	90	135	180	225	270
7	53	105	158	210	263	315
8	60	120	180	240	300	360
9	68	135	203	270	338	405
10	75	150	225	300	375	450
20	150	300	450	600	750	900
30	225	450	675	900	1,125	1,350
40	300	600	900	1,200	1,500	1,800
50	375	750	1,125	1,500	1,875	2,250
60	450	900	1,350	1,800	2,250	2,700
70	525	1,050	1,575	2,100	2,625	3,150
80	600	1,200	1,800	2,400	3,000	3,600
90	675	1,350	2,025	2,700	3,375	4,050
100	750	1,500	2,250	3,000	3,750	4,500

Example—Determine the number of bricks in a wall 12" × 18' × 60'.
Solution—The wall contains a surface area of 1,080 sq. ft. By
the table 100 sq. ft. contains 2,250 bricks, then 1,000 sq. ft. will
contain 22,500 bricks. 80 sq. ft. will contain, by the table, 1,800
bricks, making a total of 24,300 bricks.