Magnetic head hammer

A more or less conventional claw hammer is equipped with a special magnetic insert in its head for convenience in picking up nails and tacks prior to driving with the hammer. The special magnetic insert is comprised of high carbon hardened steel which is heat treated prior to magnetizing and then press-fitted into a hard metal non-magnetic shield and the assembly is further pressed into a recess in the hammer head presenting a flush face which may then perform the combined functions of magnetic pick-up and driving over long periods of time without impairing the function of the magnet.

BACKGROUND OF THE INVENTION 
In my co-pending patent application Ser. No. 654,371 I disclose a 
combination nail starting and driving tool. This invention comprises 
essentially a two-headed tool having a driving head composed of 
conventional heat treated steel and on the opposite axial end a magnetic 
head having a magnetic insert for use in picking up nails and tacks and 
starting them in the material to be fastened prior to driving with the 
opposite end. 
This combination represented a vast improvement over old style tack hammers 
having a magnetized head. These old devices were quite useful but were 
inclined to rapidly lose their magnetism after some hammering. My earlier 
invention avoided this disadvantage by providing a combination in which 
the magnetic or pick-up end of the tool is used only for picking up the 
nail or tack and getting it started. The final hammering or nailing was 
done by swiveling the tool through 180.degree. and utilizing the driving 
end. This tool has proved particularly advantageous in light work or 
elevated work where only one hand is available for the hammering 
operation. The latter could be carried out quite effectively without 
impairing the efficiency of the magnet. Prolonged hammering on the magnet 
end with this device would still result in loss of magnetism. 
SUMMARY OF THE INVENTION 
I have now discovered that I may provide a magnetic insert or a magnetic 
head hammer in which the same hammer head may be used for pick-up and 
starting of the nails or tacks as well as hammering them home. This I 
accomplish by utilizing a hardened steel magnetic insert pressed into a 
shield of non-magnetic hard material such as austenitic stainless steel or 
other high nickel alloys known for their hardness, durability and 
non-magnetic properties. The combination of shield and magnetic insert are 
then heavily press-fitted into a recess in the head of a conventional 
hammer, the face of which is then ground off to present a smooth surface. 
The use of the magnetized hardened steel insert plus the effect of very 
tightly enclosing it in the shield and tightly pressing it into the hammer 
head produces the effect of having the magnetic insert retain its 
magnetism over a very long period of time despite the impact on the head 
of the hammer when used. 
I have discovered that for some reason very violent hammering on hard 
material over a great many repetitions for a long period of time does not 
diminish the magnetic properties of the head to any perceptible degree. I 
have discovered also that the actual force of the magnetism provided by 
such a head is actually increased many-fold by this combination and 
construction.

DESCRIPTION OF A PREFERRED EMBODIMENT 
Referring now to the figures, there is seen first the hammer handle 1 which 
may be of conventional wooden construction. The hammer head 2 is equipped 
with an also conventional claw end 3. 
In the driving end 4 I provide a cylindrical axial recess or counterbore 5. 
In a typical application I may make this counterbore one-half inch 
diameter and one-half inch deep. I then provide a shield which is 
generally of thimble-like or cup-like configuration 6, having an open end 
and a closed end as seen best on FIG. 3. In the typical application I may 
make this member with an outside diameter of one-half inch and the length 
of one-half inch allowing proper tolerance in the outside diameter to 
provide a heavy press-fit into the hammer head. The inside diameter of 
this member may be three-eighths of an inch. I next provide a 
cylindrically shaped hardened steel magnetic insert 7. This I make of high 
carbon steel which is heat treated, hardened and ground to the proper 
dimensions and then magnetized by subjecting it to the action of a 
magnetic flux to the saturation point. In the illustration given here my 
insert would be one-half inches long and three-eighths of an inch in 
outside diameter, again allowing the proper tolerance for a heavy 
press-fit into the shield. The walls of the latter would thus have a 
thickness of one-sixteenth of an inch. 
I next press insert 7 into shield 6 by means of an arbor press or similar 
machine and then press the combination into recess 5 in hammer head 4. 
After thus assembling I may grind off the face of the hammer to present a 
flush driving face which may be seen on FIG. 1 and FIG. 2. 
The material for my special magnetic shield thimble 6 must be of a hard, 
tough, and non-magnetic material. I have found that a number of the 
stainless steels of the austenitic type, having various ranges of nickel 
and chromium are satisfactory for this purpose. These may be hardened by 
cold working to obtain the desired properties for this application. 
The hammer head itself is, of course, of conventional forged steel 
construction and depending on the material used, the counterbore 5 may be 
made prior to any later heat treatment which it is desired to effect on 
the head itself. After the latter heat treatment, if any, the magnetic 
components are inserted as described above. 
The use of this combination in the manner set forth above produces the 
unusual and unexpected results on the finished product. The tight 
confinement of the previously hardened and magnetized insert 7 within the 
magnetic shield thimble 6 and the recess 5 produces two effects. The first 
of these is to tremendously increase the magnetic pull of the insert 7. 
The second is to cause the insert to retain its magnetic pull over a very 
long period of time despite heavy hammering and pounding of the head. 
In this manner I am able to realize the many advantages of my previous 
invention described above and in addition improve on them to a very great 
extent. The increased safety, ease of operation, and convenience, as well 
as a tremendous saving in labor costs and permitting one arm operation 
should now be evident to those skilled in the art. 
As with my previous tool, suitable receptacles may be employed for holding 
the nails or tacks prior to their use. These may be such that the nails or 
tacks are permitted to slide down one at a time from suitable chute where 
they are picked up by the magnetic head or they may be placed in a 
container in a vertical position with only the heads exposed so that they 
may be readily picked up and driven home. These receptacles may be placed 
on the ladder or scaffold if necessary or they may be equipped for 
fastening on the person of the worker using my tool.