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Filing Band Saws for Hardwoods 



There is just as much difference in filing band saws for mixed 

 hardwoods and for soft woods as there is between night and day. 

 The outputs of a day 's sawing of hardwood and of soft woods are 

 80 divergent as to quantity as to be scarcely believable to one 

 without experience in that line. AVhen a mill equipped with a band 

 and resaw has sawed for five or six years in soft wood and then 

 is run on hardwoods for three or four years, and on about a dozen 

 different kinds every day, it is possible to begin to judge the 

 difference in the outputs of the two types of wood. A band saw 

 filer will then fuUj' realize how much more difficult his work is and 

 will be confronted with the fact that the output of a day's cut is 

 anywhere from twenty-five to thirty per cent less in hardwood than 

 in soft wood. 



Comparing saw practice or fitting in soft wood with that of 

 hardwood a radical difference will be found in the fitting, the shape 

 of the teeth and the bench work, and the mill must be in perfect 

 condition to get the best results. Suppose a mill saws hemlock 

 or spruce; all the equipment is supposed to be in proper order, but 

 yet the finer points aren't as essential to get good results as when 

 sawing hardwoods. Mills that cut hemlock and spruce are sawing 

 material that is used mostly in the rough. If it is a little snaky 

 or if some pieces aren't just the standard thickness, they will 

 go on the market just the same, but in hardwood it is a different 

 proposition altogether. In that case stock is cut for furniture 

 factories and all kinds of fine woodworking establishments, and 

 in every case the demand calls for perfectly sawed lumber. A 

 furniture factory can come nearer making a No. 1 out of a No. 2 

 ■common than it can to making a crooked board straight. It isn't 

 only that that decreases the cut of a hardwood mill. It is the 

 getting the best out of logs that keeps hardwood lumbermen in 

 business and when good sawyers make good grades, logs must be 

 handled three or four times more than when sawing soft wood so 

 it can easily be seen why the cut falls off so much changing from 

 soft wood to hardwood. The question might be asked "if the cut 

 decreases so much why is the filing of the saws more difficult?" 

 That is the result of handling many different kinds of wood. Most 

 hardwood mills cut red and white oak, sugar and soft maple, chest- 

 nut, basswood, poplar, cucumber, buckeye, birch, beech, and ash 

 with a small per cent of wild cherry which makes thirteen — 

 surely enough to make a filer sometimes think it is an unlucky 

 number. The difficult thing is to so fit a saw that it will stand 

 up to the requirements of so many grains and degrees of hardness 

 and do equally good work in each. I believe that basswood should 

 be sawed by itself because it is almost impossible to saw it mixed 

 with sugar maple, ash or oak, owing to its fibrous nature which 

 requires more swage on saws. 



As I have said before in the fitting of saws for hardwood there 

 are several essentials to first class work as follows: The right 

 hook and pitch of teeth, the right throat room, the right tension, 

 the right fitting of cutting points, the absolute accuracy of the 

 back, the proper condition and speed of the mill, and more im- 

 portant, the proper swage. When a mill starts to saw hardwood it 

 should be repaired thoroughly; all gearings and bearings should 

 work snug. Especially is it necessary to have the band wheels 

 ground more frequently than in soft wood as more or less dust 

 gets on the wheels, the logs are more gritty, the wood is much 

 harder, causing more strain on the saws and naturally the edges 

 of the wheels wear much sooner. The carriage should be kept in 

 first class condition. Should it have a little play, seemingly not 

 enough to hurt in soft wood, or should the set works have a little 

 lost motion — even A of an inch — it will cause lots of trouble saw- 

 ing high-grade hardwood. The carriage track requires more atten- 

 tion, the tremendous weight of sugar maple, ash or oak falling on 

 the head blocks while handling the logs so much oftener with the 

 nigger, causes it to get out of level and out of line so much more 

 quickly. Another very noticeable defect often found is that in 

 cutting the last cut of a log the board dogs aren't in good enough 



holding and working order to prevent the two or four inch cant 

 from springing. As a result there are often dozens of thick or 

 thin boards in a day's cut. 



The speed of the mill very frequently has much to do in making 

 crooked lumber. Some millmen think if thej- speed a mill up like 

 lightning it ought to go through the cut of a log like lightning. 

 A mill with a speed of ten or eleven thousand feet per minute in 

 soft wood does the work nicely, but to try that speed in hardwood 

 without changing the spacing of the teeth in the saws means so 

 many miscuts in a day and so many saws that the mill could not 

 be run successfully. About eight or nine thousand feet is the best 

 speed. With speed conditions satisfactory and a good sawyer the 

 mill will do up-to-date work provided the saws are put up in 

 good shape. 



When fitting saws for hardwood it is very important to give 

 the teeth more attention. A little less hook should be carried. If 

 the filer is accustomed to extreme hook in soft wood it should 

 be about one-fifth less in hardwood. By pitch I mean back of 

 teeth — they should be lowered so as to have more clearance on 

 back of teeth in sawing some hardwoods. Pitch is liable to gather 

 on a high back tooth and cause it to snake. The depth of the 

 tooth should be full % of an inch in frozen timber and about -fe 

 more when the timber is not frozen. A nice round throat such 

 as common sense dictates is very essential to assist in throwing the 

 sawdust out easily. 



The bench work on the saw requires the finest kind of work in 

 hardwood or else "bull heads" and "snaky" lumber will result. 

 It is necessary to look over the saws every day. Hardwood sawing 

 requires more tension along the edges of the blade and it seems 

 impossible to level them too much. All small lumps should be 

 removed because the more level a saw is the smaller a swage can 

 be run and the less chance of the saw getting hot. The back of 

 the saw must be kept in such a condition that it fits the back 

 gauge the whole length of saw without any variations whatever. 

 Too much oscillating isn 't beneficial to saws in any kind of wood 

 as it seems to throw them out of balance, especially as they enter 

 the cut on large logs. A saw that oscillates also has a tendency to 

 cause band wheel boxes to run warm. It is a good idea to run the 

 back of the saw with a crown of about 1/64 or ^ of an inch in 

 five feet. That makes the tooth edge the tightest. When the 

 strain is on the saw in hardwood, very often the tooth edge gets 

 warm, in which case the steel expands and if the saw is run with- 

 out a crown or with a straight back it makes the tooth edge the 

 longest and therefore not tight on the cutting edge. The result is 

 the saw snakes very easily. 



The most important question is the amount of swage a filer runs 

 on his saws. If an estimate could be made of the amount of timber 

 that is cut into sawdust by excessive swaging, it would be aston- 

 ishing. However, I believe most filers are trying to do justice in 

 that respect. In some cases millmen are constantly causing trouble 

 and making bad lumber by forcing their filers to run saws with 

 not sufficient swage; but filing saws in hardwood in clean logs on 

 a seven and eight gauge swage on fourteen saws is entirelj* too 

 much. Some filers swage a saw every three or four runs. Of 

 course that saves work but not lumber. The best and most eco- 

 nomical plan is to swage light and often— to make lumber — not 

 sawdust. It requires a few more emery wheels and is a little 

 harder on filing room machinery but the cost of that is small com- 

 pared to the amount of lumber saved. In sawing gritty logs a nine 

 gauge light is plenty of swage. If the logs are clean nine gauge 

 tight is sufficient. If all these things are adhered to a sawmill is 

 sawing hardwood at its highest efficiency. H. .T. K. 



As the date of the Forest Products Exposition approaches plans 

 are becoming more fully developed. Most of the lumber associations 

 and large machinery houses are planning elaborate exhibits, while 

 the Forest Service is now assured of $10,000 for its display. 



