# ¼” Shank versus ½”



## JohnnyB60 (Jun 15, 2009)

I thought someone posted a question about this already but I can’t find it or maybe I’m not using the correct terms in my search. 

Anyway, I have ¾” straight flute w/½” shank and I don’t remember at the moment exactly how long it is, but I was thinking that I only use the 1st ½” and it seems like a waste to wear out only the top 3rd of the cutter.

I found a ¾” x ½” Mortising Bit with ¼” Shank that is a reasonable price and better fitted for what I need. I’ve only been buying ½” shank stuff since I got my ½” router, but I have not had an incident where the ¼” became a problem. 

I have not priced a Mortising Bit with ½” Shank and so far I’ve paid higher prices for the ½” shanks.

I was just wondering if anybody actually had a problem with the ¼” versus ½”


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## Gene Howe (Jul 10, 2007)

With smaller cutting surfaces and light cuts, you won't have a problem. I bent a 1/4 shaft once by trying to cut too deep. That's an experience I never want to repeat! 
Sometimes the 1/4" adapters won't clamp tight enough and the shank will creep out. (up, in a router table) That's another experience not worth repeating. Changing the collet to 1/4 is a much better option.


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## jlord (Nov 16, 2009)

Taking a 1/2" deep pass using a bit with a 1/4" shank will probably stress the shank & it will break after awhile. You have to remember you are also spinning a large cutter on the end of the shank. 

I did this recently cutting a 74" circle with a 5/8" bit with a 1/4" shank in 3/4" mdf. The shank broke while in the middle of the first cut. I would either make more passes or stick with the 1/2" shanks for these type of cuts.


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## JohnnyB60 (Jun 15, 2009)

Hi Guys,

OMG, well that’s good enough for me, I’m going to stick with the ½” shank. I just never heard an actual mishap and thought it was all just in theory. :fie:

I just had an incident were my router mounting screws came loose on my router table over the weekend and it sounds as if I were to have used the ¼” shank, I would have hurt myself if the shank would have bent.


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## Phil P (Jul 25, 2010)

JohnnyB60 said:


> I just never heard an actual mishap and thought it was all just in theory. :fie:


I've bent and even snapped a few over the years - normally cheape Chinese 1/4in cutters. Only 1/2in shank cutters I've ever broken were 1/4in diameter straights and dovetail bits - both relatively weak designs. BTW in all instances the bit end just dropped to the floor or jammed in the cut.

Regards

Phil


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## jschaben (Jun 21, 2009)

Hi Johnny - I've broken a few, from 1/8" up to 1/2"(that was with a CNC). Invariably, they just sorta stay where they broke. 
It's not a good thing though, expensive to begin with and usually messes up the workpiece. My rule of thumb is anything less than 3/8" is 1/4" shank, anything larger than 3/4" is 1/2" shank. I have both for most common sizes between the two. Yeah, there are some duplicates but I like my trim routers for a lot of jobs and I don't like 1/4" bits in the table as I will tend to push them a bit more than I probably should.


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## bobj3 (Jan 17, 2006)

Hi 
I will 2nd John's post but add a note ,I don't abuse my tools,small bits take a light touch the King Kong way will break most cutting tools and I use Chinese bits all the time..i.e. drill bits..

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jschaben said:


> Hi Johnny - I've broken a few, from 1/8" up to 1/2"(that was with a CNC). Invariably, they just sorta stay where they broke.
> It's not a good thing though, expensive to begin with and usually messes up the workpiece. My rule of thumb is anything less than 3/8" is 1/4" shank, anything larger than 3/4" is 1/2" shank. I have both for most common sizes between the two. Yeah, there are some duplicates but I like my trim routers for a lot of jobs and I don't like 1/4" bits in the table as I will tend to push them a bit more than I probably should.


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## JohnnyB60 (Jun 15, 2009)

Oh wow, more broken bits. This is really an eye opener. :wacko:

I searched for a short ¾” by ½” long bit, but couldn’t find one in ½” shank, so I guess I’ll just have to continue using the 1” long bit. :sad:


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## bobj3 (Jan 17, 2006)

Dado Clean Out Router Bits

#7684 3/4" 1/2" $19.95 

MLCS Dado Clean Out Router Bits

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JohnnyB60 said:


> Oh wow, more broken bits. This is really an eye opener. :wacko:
> 
> I searched for a short ¾” by ½” long bit, but couldn’t find one in ½” shank, so I guess I’ll just have to continue using the 1” long bit. :sad:


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## jschaben (Jun 21, 2009)

Hi Johnny - If your looking for shorter cutting lengths, try searching on "hinge mortise bits" or "dado cleanout bits". Both are straight bits with shorter cutting lengths. They may come with or without shank mounted bearings. 

Here's a 3/4 CD by 3/8" CL
Woodworker.com: Freud174 Mortising Router Bits, 12ct Mortising Bit
item 1239-128 

or

a 3/4" CD by 3/4" CL
Whiteside Router Bits from Woodworkersworld.net--Straight router bit
item 1033

Sorry, didn't find a 1/2" CL right off the bat but I'm sure somebody makes one


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## JohnnyB60 (Jun 15, 2009)

Thanks Bob and John! 

I’ve been thinking about the top-bearing bit. I could have used that a number of times and I think I’m going to buy one of those.

Also after looking at the list from woodworkersworld.net, I just now finally figured out what the “plywood” bit was. I can’t remember who it was now, but someone mentioned the plywood bits before and I thought it had something to do how it cut. Now that I know that it is the size of the cutter for undersize plywood, I may just buy a set of those to. :yes2:


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## jbrukardt (May 1, 2012)

Gene Howe said:


> With smaller cutting surfaces and light cuts, you won't have a problem. I bent a 1/4 shaft once by trying to cut too deep. That's an experience I never want to repeat!
> Sometimes the 1/4" adapters won't clamp tight enough and the shank will creep out. (up, in a router table) That's another experience not worth repeating. Changing the collet to 1/4 is a much better option.


eek.... i dont even want to know what happens when a 22k rpm bit goes off center and wobbles itself to death.


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