THE MILL AND MILLING. If the operator is already provided with a mill, the size of his operations will depend on the power and capacity of that mill. If he plans to purchase a new mill, he 'should figure on one with the power, capacity, and equipment necessary to meet the requirements of his capital, his market, and his logging equipment. Lack of sufficient power, even for driving the saw, is a common handicap for small mills. An effective 25-horsepower engine will, if properly handled, keep a circular saw working to capacity and at the same time will run a small planer and edger. The type of mill in most general use in Forest Service District 4 is one cutting from 2,000 to 20,000 feet per day. The following discussion, therefore, will be confined to two classes of this type, one cutting from 2,000 to 10,000 feet per day and a heavier one cutting from 10,000 to 20,000 feet per day. The smaller mill will be called Class A, and the larger, Class B. Sawmills are generally classified as right and left hand mills, according to whether the log passes to the right or to the left of the saw, viewed from the front. In ordering equipment for an old mill it is always necessary to specify whether the equipment is needed for a right or left hand mill. Portable mills are usually equipped with rack and pinion or cable drive, and friction or belt feed or a combined belt and friction feed. Shotgun feed is not used in small mills. The variable friction feed is so called because the sawyer can vary the feed to correspond with the power or the size and species of timber to be cut, easing down on knots and frozen timber and increasing the feed at will. With the same power a variable friction-feed mill is said to cut from 25 to 40 per cent more than a belt-feed mill.. There are no belts or springs to break or give trouble. The belt feed is a combination of belt and flat face frictions so arranged that the feed and gig back frictions are continuously driven in opposite direction by an endless belt direct from the mandrel. A single lever operates the feed and gig back by shifting the bull wheel from one friction to the other. The shaft of the bull wheel has a pinion on the opposite end which operates the wire cable drum, doing away with all intermediate gears and securing a strong direct drive for the carriage. The friction shafts have babbitted boxes with screw adjustment to take up the wear in the frictions, and a substantial idler is provided to keep the endless feed belt always tight. Wire cable or rack and pinion drum can be used on both belt-feed and friction-feed mills. "Never buy anything because it is cheap" is a form of advice that applies very particularly to a sawmill. Going a little further, it might be laid down as an excellent business maxim: Never buy an old second-hand mill, no matter how cheap it can be purchased. Re gardless of type or make, however, a mill will turn out to be a liability rather than an asset unless it is set up properly and kept in good running order, and the work conducted on a business basis. The word "portable" as defined in the dictionary means "capable of being borne or carried, easily transported, conveyed without difficulty." The average portable mill owner, however, seems to take this definition too literally, for when he purchases a new mill, or moves to a new site, he pays as little attention to setting it up or lining the machinery properly as he would in the case of a thrashing engine or a steam plow. The usual procedure is to clear off a level space of ground, set down the engine and boiler and block them up a little, adjust the belting, get up steam, and start the saw. The moving and setting up is not taken seriously. Regardless of the length of time a portable mill is to remain on the same site, the engine bed should be solid, the belting properly adjusted, the engine, sawmill, and carriage properly lined up and housed and all working parts oiled and the shafting in line and all parts in good working order. Otherwise it is impossible to manufacture good lumber. In general, the life of a portable mill may be placed at from 12 to 15 years. One hundred and fifty days is the maximum time it is in active operation each year, so that, if not properly cared for, a portable mill may be said to "rust out" faster than it wears out. REGULAR EQUIPMENT. CLASS A. Following are the various parts and equipment of a class A mill complete and their cost in 1916. Since the entrance of the United States into the war, prices have fluctuated to such an extent as to make it impractical to give those likely to be in effect when this bulletin is issued. It has been thought best, therefore, to give 1916 prices throughout as a basis for estimates. The equipment of the sawmill usually consists of Husk frame, 7 by 3 feet, built of 3 by 7 inch timbers. Variable-friction feed. Steel mandrel, 2 inches by 4 feet 4 inches. Board roll and spreader wheel and saw guide. Carriage 16 feet long and 26 inches wide, of 3 by 5 inch timber. Four trucks with 6-inch wheels and 13-inch steel axles. 40 feet of V and flat rolled steel track. Two head blocks, opening 34 inches, with duplex dogs. 14-inch polished-steel set shaft. There is also furnished a mandrel pulley up to 24 inches diameter, belt tightener, foundation bolts, cant hook, oil can, and wrenches for rack and pinion-carriage drive. Also trackway timbers bolted together with steel track attached. The price of a sawmill 'so equipped, as shown in the preceding cost statement, is $254 f. o. b. Chicago. The manufacturers allow 15 per cent discount on time, and 20 per cent for cash. The total shipping weight is 2,550 pounds. Way timbers are 450 pounds extra. Extra equipment: A top-saw attachment is too heavy for this type of mill. All mandrels are made for saws with 2-inch center hole and two ğ-inch pinholes on 3-inch circle, and are adapted to any power from 6 to 15 horsepower. This outfit can cut 2,000 feet per day with a 6-horsepower engine, or from 7,000 to 8,000 feet per day with a 15-horsepower engine. It will carry a saw up to 52 inches and logs up to 36 inches diameter. CLASS B. The class B mill is heavier and of larger capacity than the class A mill, and has an independent rack beam near the center of the carriage. It is adapted to engines of from 15 to 40 horsepower, and will cut from 10,000 to 20,000 feet per day. Saws up to 60 inches may be used. The headblocks will open to receive a log as large as 54 inches in diameter. The parts and equipment are— The equipment of the sawmill consists of Husk frame 8 feet 6 inches by 4 feet built of 4 by 11 inch timbers. Steel mandrel 21 inches by 5 feet 6 inches long. Mandrel pulley 24 by 12 inches. Board roll, spreader wheel, and saw guide. Carriage 24 feet long, 40 inches wide, timbers 5 by 5 inches. Feed rack 32 feet long. Six trucks with 10-inch wheels and 18-inch steel axles. Fifty-six feet of V and flat rolled steel track. Two head blocks opening 48 inches with Grant duplex dogs. Twenty feet polished-steel set shaft. Trackway timbers framed and bolted together in sections with steel track attached, belt tightener, foundation bolts, cant hook, oil can, and wrenches. Rack-and-pinion carriage drive. Saw not included. Weight 5,250 pounds. Sawdust conveyor fixtures (weight, 142 pounds). Top mandrel is 11 inches diameter and made for standard saws with 2-inch hole and ğ-inch pin holes on 3-inch circle. Weight, 1,075 pounds. The average cost of setting up the mill is Mill (with machinery on the ground). Housing Boarding and sleeping camps. Total__ $300 250 200 750 AUXILIARY EQUIPMENT. EDGERS. A 33-inch pony gang edger with a capacity of from 5,000 to 11,000 feet per day has two saws with single-pressure roll, and cost in 1916 With solid-tooth saws_. With inserted-tooth saws_. $145 175 A discount of 40 per cent is allowed from these prices. Specifications for edgers of this size are— Floor space, 18 feet 6 inches by 48 inches. Width inside, 33 inches. Guide adjustment, 4 inches. Mandrel pulley, diameter, 11 inches. Mandrel pulley, dimensions, 8 by 8 inches. Saws, diameter, 14 inches.. Speed, revolutions per minute, up to 2,000. Feed belt, 8 feet long, 4 inches wide. Maximum opening between saws: Two-saw edger, 24 inches; three-saw edger, 20 inches. Weight: Single roll, 1,300 pounds; double roll, 1,400 pounds. PLANER. Planers are built in two sizes, to surface up to 16 inches and 20 inches wide and from inch to 6 inches thick, with or without countershaft, as ordered. No belting is furnished. Feed belts require 13 feet of 11-inch belting. One pair planer knives, weight 745 pounds: 16-inch machine with countershaft__ 20-inch machine with countershaft_ Pony planer, weight 1,700 pounds: 20-inch__ 24-inch. Planer and matcher__. Prices are subject to discount of 20 per cent, Chicago. SAWDUST CONVEYORS. $152 169 275 325 360 Sawdust conveyors are labor-saving devices that constitute a good investment. The standard 25-foot conveyors consist of the necessary sprocket wheels, bevel gears, sprocket and gear shafts, boxes, collars, 50 feet of carrier chain with conveyor attachments, and 10 feet of drive chain. |