the saw blade shown in the fig1 , and 3 has an indentation of indent 11 which serves to fix the blade to the saw and to drive it by a motor . the saw blade has along its edge a row of teeth 12 . the blade has a closed aperture 13 ; this means the aperture 13 is all around surrounded by the blade body . on each side of the blade face there is a shallow section , which extends from the border line 14 to the border line 15 at the teeth 12 , which is located over a part of height 16 ( fig3 ) of the teeth 12 . the points 17 of the teeth 12 are therefore thicker than is the thickness of the teeth 12 in between the line 15 and the base of the teeth . they are aso thicher than is the thickness of the saw blade between the teeth 12 , respectively , the border line 15 , and the border line 14 . thus it can be seen that the provision of an aperture 13 appreciably reeuces the surface of the blade which comes into contact with the material to be cut , as compared with a full blade or blade body . if , after the sawing process , the row of teeth 12 and its strip - like element 18 have passed through the cut , a friction can take place only at two arms 19 . therefrom there result the above - mentioned advantages of a cool cut and an improved surgical working condition . under normal conditions it is of advantage if , as shown in fig3 the height 16 of the teeth 12 is approximately equal to the width of the element 18 . in view of the specific construction of the teeth , they do not have to be set . they are arranged parallel to the center plane , which is parallel to the side faces of the blade . therefrom there results that the blade , in comparison to regular blades with a setting , has practically no vibration during operation . this again means that this sort of saw blade is particularly well suited to be provided with an aperture . the embodiment shown in fig4 and 5 has again an indent 11 for the fixation and the drive of the saw blade . the latter is again provided with a row of teeth 12 along its outer edge . as shown in the foregoing example , an aperture 13 is provided . between the border lines 14 and 15 and on both side faces of the saw blades there is a shallow section which extends at the location of the teeth 12 outwardly over a part of their height . a strip - like element 21 carries a row of teeth 12 and indentations 22 , each of which is in registry with a tooth . it is seen that in this way the surface contacting during cutting will be even smaller and the weight of the blade will be even lighter than it is in the embodiment shown in fig1 , and 3 . according to the embodiment of fig4 and 5 , the edge of the aperture 13 is bevelled , which means the edge has a broken rim 23 as can be seen in fig5 . this bevelled rim can extend over the entire perimeter of the aperture 13 or only over a part of it . this bevelling causes the edge to be more resistant and stronger . the formation of hair cracks in the blade material is thereby reduced . the formation of hair cracks in the blade material can also be reduced if the indentations 22 are rounded , in particular at their deepest location . the same is true for the base of the teeth 12 . the widening of the indentations 22 in the direction away from their deepest location and toward the aperture 13 causes the saw chips to be moved in the direction toward the aperture 13 . they will , therefore , move only slightly into the area between the element 21 and the teeth 12 and the cutting faces of the object to be sawn . the aperture 13 shown in fig4 has a form tapered in the direction away from the element 21 , which is shaped similar to an isosceles triangle , of which the base line extends along the row of teeth 12 . the structure shown in fig4 represents a stable saw blade , which is free from vibrations and has comparatively small sidefaces . according to the circumstances and particularly for deep cuts , in lieu of the blade shape of fig4 an aperture 13 of a form may be chosen in which the entire length of the arms is substantially equal to the width , which the arms of fig4 have in the neighborhood of element 21 , i . e . the arms over their entire length are of constant width . another embodiment is shown in fig5 in the form of a circular saw blade which is provided with teeth 25 over its entire perimeter . additionally there is provided a plurality of apertures 27 . also , this blade has on its upper and lower side face a shallow section . the shallow section shown in fig6 extends from the borderline 28 toward the outside in such a way that it will include the part of the height of the teeth up to the border line 29 . while it is known that with a circular saw a great deal of the saw chips is moved away sideways , the apertures 27 still add to the fact that a smaller amount of saw dust will get between the sides of the blade and the sides of the cut . particularly , in a mutual contact of the side faces and the cut , for instance due to an inaccurate guiding of the saw , less heat is produced , because with a circular saw blade , relatively little surface is present which will cause friction . the circular saw serves in particular for industrial use . the saw blade according to fig7 which is still a further embodiment , is for a hack saw . the blade is tightened with the holes 31 to a bow ( not shown ). along a longitudinal edge of the saw blade there is provided a row of teeth 12 . a bridge 34 is provided between two apertures 33 . on each side face of the saw blade there is a shallow section . these shallow sections extend from the border lines 36 over the entire width of the blade , i . e . to the longitudinal side of the blade opposite to the teeth 12 . this kind of blade also is intended mostly for industrial use . still another embodiment is shown in fig8 and 9 and relates again to an oscillating saw . it has again an indent 11 . three apertures 43 extend in the direction away from the eeth 42 . the apertures are limited on the sides by arms 44 , which are to improve the stability , in particular to reduce vibrations , and to keep the row of teeth 42 in a straight line . as can be seen in fig9 this blade has no shallow sections , but its teeth 42 are set . also with a saw blade with set teeth , the provision of an aperture has the advantage of reduced obstructions by the saw chips , of less friction and therewith a cool cutting . the cold welding of chips is practically avoided . the present invention is also applicable to saw blades with a wavy setting . in using a saw blade of hardened steel , it is very important that in the manufacture of the blade the hardening process is made first and the aperture in the blade is made afterward . a warping of the blade is thereby avoided . the waste pieces resulting from the production of the apertures can be used as valuable basic material for other kinds of tools . also , in the use of a blade according to the invention there result the advantages that the waste chips stick less onto the blade so that the detrimental heating up of the blade , the jamming and the decrease of the quality of the cut are prevented or greatly reduced . in particular , in bone surgery the resulting cool sawing process is of high value . additionally , the tissue coming into contact with the saw blade is less subject to bleeding . applicant is the owner of application for u . s . letters patent ser . no . 394 , 187 filed july 1 , 1982 , entitled &# 34 ; saw blade with shallow section ,&# 34 ; the disclosure of which is made a part of this application by way of reference . although the invention is described in detail for the purpose of illustration , it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims .