I have a collection of straight router bits and a few mortising router bits.
Can any one tell me how to tell the difference other than the straight bits
being typically longer? What makes the mortising bit unique?
The mortising bit moves waste chips better than a straight router bit.
The mortising bit is designed to run at a slower speed to reduce heat
buildup in deep mortises. May not be true for your bits, but that's
the take on mine.
Sorry, meant to say my straight cut bits have a carbide cutting edges with
a slight spiral twist just like the mortise bits. I have a couple of solid
carbide spiral bits that I use with my D4. These however IIRC are not
technically called Mortising bits.
mortising bits should have a blade running across at least the full
radius of the bottom of the bit... better is across the whole
The reason is that mortising bits need to plunge straight in. Carbon
spirals (from what I've seen) have an edge on the bottom as well
also, these folks have something else
Now this is the type of answer I love.
1. The posters name is "routerman"... think he knows his shit?
2. References an existing webpage he maintains that covers the
3. He also references his own lab experiements, and describes improved
bits he is manufacturing and testing.
4. Makes it clear that "who cares" what the manufacturers call their
bits, here is how they perform and what you should use.
Thanks for the info Pat.
Pat *IS* the router man. It's been his passion for many years, and he's
even written a book:
(Amazon.com product link shortened)
It's over 10 years old, but still has lots of good info.
A buddy of mine met Pat a couple of years ago. He had some questions he
thought Pat could answer, and he just happened to be visiting the
vicinity where he lives, so Pat invited him out to his shop. Heckuva a
nice guy, evidently.
See Nad. See Nad go. Go Nad!
To reply, eat the taco.
OK, I got the answer. Mortising bits produce a downward sheer and
therefore produce very clean cuts and they are better suited for entering
into the side of a piece of wood rather than plunging.
Straight cut bits are better suited for plunge routing.
Having said that I am working on a project where I have several rabbet
joints on the back panels of some towers that I am building. I used the
mortising bit in my router table to create stopped but short rabbets. After
assembly I used a free hand router to finish the rabbets. I pulled out an
old end mill bit that I used to plunge and cut slots in Ipe several years
ago for Steve Knight. I literally made a few thousand of these slots and
this bit ran circles around any of my quality carbide tipped straight bits.
The end mill was still sharp enough to cut you if you were not careful. The
4 flute end mill bit cut like butter in the oak and there was no grabbing
what so ever.
Seems strange that end mill bits are not sold over spiral carbide straight
bits as they hold up really really well and are relatively cheap!
Well there is that but I guess what I was going for was the guys that sell
end mill bits could also go after the wood worker instead of limiting
themselves to the steel business.
If you can make an end mill to out perform a carbide bit surely you could
also make other design bits also. My end mill bit is a work of art compared
to any of my carbide bits, they have the know how and resources. IIRC my
end mill had a value of around $20, 3 years ago.
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