lo Feb., 191^-] Farm BlacksniiiJiDi^. 123 



FARM BLACKSMITHING. 



{Continued from page 5./.) 



George Baxter, Instructor in Blacksmitking, Working Men's College, 



.1/ el bourne. 



v.— WELDING (continued). 



Lengthening Bolts. 



In the article in the January i.ssue mention was made of lengthening 

 or shortening a bolt by welding. The success of doing this is dependent 

 to a great extent upon the manner in which the scarf is formed. Whilst 

 a bolt is taken here as an illustration, the form of procedure would be 

 similar if pieces of square, flat, or, in fact, almost any shaped bars re- 

 quired to be joined together. This form of scarf is known by the name 

 of the lapped scarf. 



So that the finished bolt may be of the required length, allowance must 

 be made for the waste of material which, as previously mentioned, occurs 

 during welding. In nearly all cases this can be taken as the thickness 

 of the bar. Certainly there are exceptions to the rule, but as some of 

 the more intricate are not likely to occur in the simpler and comparatively 

 rough work of a farm, no mention need be made of them. To do so, 

 might have a tendency to bewilder the amateur smith, and consequently 

 the information would be more harmful than beneficial. 



Still using the bolt as an illu.stration, let it be suppo.sed that one 2 ft. 

 in length is required and that another 8 in. long is at hand. It would 

 then be far easier to lengthen it than to make a new one outright. A start 

 would be made by cutting the existing bolt in two at the middle section. 

 Then obtain a piece of iron of the same diameter as the bolt. It need 

 not be of any particular length, excepting that it should be longer than 

 is required to make up the deficiency. 



Take hold of the bolt head in a pair of tongs and the plain bar by 

 the hand, or, if too short for that, in another pair of tongs. Then place 

 both in the fire in such a position that the length of the heated part wil! 

 be about 2 in. When a white heat has been reached take either to the 

 anvil for the purpose of scarfing ; but, previous to shaping the scarf, 

 upsetting or " jumping up " is necessary. This means thickening the 

 part at and adjacent to the weld. This is necessary to ensure having 

 the welded part equally as strong as the remaining portion of the bolt. 



In the several cases of welding already dealt with, it would he ob- 

 served that a reduction of sectional area had taken place, particularly at 

 the part where the point of the scarf joins the other bar. Therefore, it 

 is Aveaker there than anywhere else. In the case of a bolt where there is 

 great longitudinal strain placed upon it by tightening up the nut, it be- 

 comes necessary to have the weld securelv made without any reduction 

 in size. 



If the head be the first piece taken from the fire, the upsetting is best 

 accomplished by standing the heid on the anvil in an upright position 

 and striking the heated end with the hammer until it becomes increased 

 to about one and a quarter times its original diameter: e.g.. if the bolt 



