OPERATION
PROPER FEEDING
The rightfeed is neither too fast nortoo slow. It isthe rate at
whichthe bit is being advanced firmly and surely to produce
a continuous spiral of uniformchips -- without hogging into
thewood to make large individualchips or,on the otherhand,
to create only sawdust. If you are making a small diameter,
shallow groove in soft, dry wood, the proper feed may be
about as fast as you can travel your router along your guide
line. On theother hand, if thebit isa large one, thecut isdeep
orthe wood ishard tocut, theproperfeed may be avery slow
one. Then, again, across-grain cut may require a slower
pace than an identical withgrain cut in thesame workpiece.
There is no fixed rule. You will learn by experience from
practice and use. The best rate of feed is determined by
listening to the sound of the router motorand by feeling the
progress of each cut. If at all possible, always test a cut on
ascrap piece of the workpiece wood, beforehand.
SPEED SELECTION
In general, if the material being cutis hard, the cutter size is
large, orthe depth of cutis deep (maximum 1/8"), then your
routershouldbe runat slowerspeeds. When these si!uations
exist,turnthe variable speed controlselector untilthe desired
speed is reached. NOTE: Carbide cutters cut at higher
speeds than steel cutters and should be used when cutting
very hard materials.
FORCE FEEDING
Clean, smooth routing and edge shaping can be done only
when the bit is revolving at a relatively high speed and is
takingvery small bites toproduce tiny,cleanly severed chips.
If your router is forced to move forward too fast, the RPM of
the bit becomes slower than normalin relation to its forward
movement. As a result, the bit must take bigger bites as it
revolves. "Bigger bites"mean bigger chips, and a rougher
finish. Bigger chips also require more power, which could
result in the router motor becoming overloaded.
Under extreme force-feeding conditionsthe relative RPM of
the bitcan become soslow -- and the bites it has to take so
large -- that chips will be partially knocked off (rather than
fully cut off), with resulting splinteringand gouging of the
workpiece. See Figure 15.
Your Craftsman router isanextremely high-speed tool(25,000
RPM no-load speed), and will make clean, smooth cuts if
allowed torun freely withoutthe overloadof aforced (toofast)
feed. Three things that cause "force feeding" are bit size,
depth-of-cut, and workpiece characteristics. The larger the
bitorthe deeper the cut, themore slowlythe routershouldbe
moved forward. If the wood isvery hard, knotty, gummy or
damp, the operation must be slowed stillmore,
You can always detect "force feeding" by the sound of the
motor. Its high-pitched whine will sound lower and stronger
as it loses speed. Also, the strain of holding the tool will be
noticeably increased.
TOO FAST
TOO SLOW Fig. 15
TOO SLOW FEEDING
It is alsopossible to spoila cut bymoving therouter forward
too slowly. When it is advanced intothe work tooslowly, a
revolvingbit doesnot diginto new wood fast enough to take
abite; instead, it simplyscrapes away sawdust-like particles.
Scraping produces heat, whichcan glaze, bum, or mar the
cut -- in extreme cases, can even overheat the bit so as to
destroy itshardness,
In addition, it is more difficultto control a router when the bit
isscraping insteadof cutting. With practicallyno loadon the
motorthe bit will be revolving at close to top RPM, and will
have a much greater than normaltendency to bounceoff the
sides of the cut (especially, if the wood has a pronounced
grain with hard and soft areas), As a result, thecutproduced
may have rippled, instead of straight sides. See Figure 15.
"Too-slow feeding" can also cause your router to take off ina
wrongdirectionfrom the intended lineof cut. Always grasp
and hold your router firmly with both hands when rout-
Ing.
You can detect "too-slow feeding" by therunaway too-highly
pitchedsoundof the motor;orbyfeeling the"wiggle" of the bit
in the cut.
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