4835 HYDROGRAPHIC MANUAL PaGE 432 



After use the pen and its reservoir should be thoroughly cleaned so that ink will 

 not harden in the fine orifice. Cleaning fluids are manufactured for both types of pens. 

 Alcohol may be used to advantage before the ink has begun to harden but it is not 

 effective in dissolving hardened ink. 



Lettering sets are furnished to survey parties with templates and pens suitable for 

 use on hydrographic sheets (see 7231). The Leroy set has the advantage of permitting 

 the draftsman to see the letters better while they are being drawn. Also, a graduated 

 scale on the lower edge of this set facilitates the centering of titles. Faster progress, 

 however, is possible with the Wrico set after the draftsman has developed facility in 

 its use. 



4835. Paperweights 



Iron paperweights covered with thin leather are obtainable in 1- and 2-pound sizes by 

 requisition on Form 11a. After considerable use the leather becomes worn, exposing 

 the metal which will leave marks on the paper on which it is placed. Weights in this 

 condition must not be used on smooth sheets until they have been re-covered. Light 

 weight canvas is a convenient material for this purpose. 



An excellent weight may be made by nearly filling a pliable leather or heavy chamois 

 bag with lead shot. The bag should contain about 3 pounds of shot and be securely 

 sewed on all sides. A weight of this type stays in place better than an iron weight and 

 is especially serviceable when the survey vessel is rolling. 



484. Pens 



Pen points used in drafting and lettering and drawing inks are discussed briefly in 

 725 and 726. 



4841. Drop Bow Pen 



The drop bow pen is the most convenient instrument for drawing small circles in 

 ink. It consists of a ruling pen which pivots around a pointed center rod. It may be 

 adjusted by thumbscrew for circles of various diameters. The width of the ink line 

 may also be varied. 



On suTvey sheets, station symbols and all other circles of small diameter are inked 

 with this pen. 



4842. Ruling Pens 



Ruling pens are used for inking straight lines of even thickness. Those furnished 

 to hydrographic parties are of good quality carbon or stainless steel, usually 6 inches in 

 length with solid blades, one of which springs away from the other when not held 

 closed by a thumbscrew. Pens with such blades have been found to hold their setting 

 better than those with one blade hinged. Adjustment for any desired thickness 

 of line is made by the thumbscrew. It is important that ruling pens be thoroughly 

 cleaned after use. 



4843. To Sharpen a Ruling Pen 



A ruling pen that has become dull may be sharpened on a fine oilstone if extreme 

 care is used. To restore the nibs to their original parabolic shape, the blades should 

 be brought into light contact, the pen held in a vertical plane and whetted with a back- 

 and-forth motion through an angle of about 120°. To sharpen the pen, the outside 

 surface of each nib is held nearly flat on the surface of the oilstone and whetted with a 

 rotary motion to conform to the shape of the nib, care being taken not to alter the para- 

 bolic shape of the ends. The edges should not be too sharp or they will cut the paper. 



