# Question on using longer bits and plunge depth limitations



## BrianDe (Jul 24, 2017)

Hi all, new to the forum and routing and had a question I'm hoping you might be able to answer. I bought a 1/2 x 4 inch (cutting length 2 inch) up cut bit to use with my DW618 plunger base. I quickly found out that once I have installed the bit it extends beyond the base of the plunge router. This left me scratching my head as to how I use a plunge router to cut my 1/2 wide x 2 inch long x 1 inch deep mortises Are bits longer then the plunge depth only meant to be used in conjunction with a fixed router on a router table? I was really hoping to use the 1/2 dia bit so I wouldn't have to make multiple passes with a smaller dia/shorter bit. I hope I am missing something very basic here but found nothing about this when searching the web. Thanks in advance for any advice.


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## DesertRatTom (Jul 3, 2012)

This is more like a job for a drill press or mortising machine with chisel bits. If you're only looking for an inch depth that and good, sharp chisels will get the job done. 

Yes you can use a SHORTER router bit for this in a plunge base. Just make sure you have a well lined up straight edge for the router. Make a mark at one point on the rim of the router plate and keep that against the straight edge, or use a square router plate. Alignment is easier on a drill press with a fence

Really long bits like that are something I rarely use, only to cut a dado in many passes. You have to slow down a bit like that as well.

If you don't have a drill press now, check out the larger model WEN bench top press, which is identical to the twice as expensive JET. WEN model 4214, 12 inch bench drill press. This runs about $300, but I got mine from Home Depot, delivered to the store just a little cheaper. This has a long enough plunge to do the trick. You will want to mount a table on it and a clamp on fence (2 inch angle iron or extruded aluminum L shaped, will do, or a really square chunk of wood).

You could also get a kit that lets you drill and chisel in one operation on the drill press, although some folks aren't impressed. But it is likely the drill press is your best answer, including use of a very sharp, high quality chisel. Watch a video on the topic to see how it's done. Note that you don't use a mallet with the chisel, you slice the excess off instead using just hand pressure. Very good control that way.


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## Ray Newman (Mar 9, 2009)

Simple answers: 

-- You purchased a bit that was too long for _your_ intended purpose. 

-- Depending upon the needed work, longer bits can/might be utilized in a hand-held router, but, the longer the bit there very well could be excessive vibration from too cutting too deep and/or feeding too fast. Have seen pictures of 1/2" shanks bents/broken as a result.

Eagle-America catalogue states the diameter, shank size, overall length, and flute length for their various bits. As for Eagle-America straight bits, see:

Straight Bits - Straight Bits / Plunge Cutting Bits

Whiteside has the same information and probably other manufacturer's on-line catalogues have the same.


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## DesertRatTom (Jul 3, 2012)

One more thing, if you do a lot of mortises, you might wish to buy a mortising machine, similar in price to the drill press. It makes and cleans out the mortise in one action. Quick, clean, done. Match the tennon to the mortise, a little bit oversize, use a rabbiting plane to size it exactly. Mortise & tennon joints inevitably require hand fitting in the end.


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## Ray Newman (Mar 9, 2009)

As D-R-T mentioned a mortiser is handy if you do a number of mortises.

Or, you could shop-fabricate a mortising jig for a hand-held plunger router. See: 

How to Cut Mortises with a Plunge Router - FineWoodworking

The original article is in_ Fine Woodworking_, issue No. 172. Back issue available at:

#172?Sept/Oct 2004 - FineWoodworking


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## Cherryville Chuck (Sep 28, 2010)

I'm just finishing up a door where I needed deep mortises to withstand the racking forces. I built a jig to sit on the edges and ends of my pieces and used a spiral that was short enough to get me down about 1 1/4" and then switched to a much longer bit to deepen the existing mortises. Because the jig kept the bits in the same place on the pieces I was able to put the longer bit into the mortises and then start the router and finish to the deeper depth without issues. The jig I used was just a slot that a guide bushing rode inside of.


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## old55 (Aug 11, 2013)

Welcome to the forum Brian.


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## neville9999 (Jul 22, 2010)

BrianDe said:


> Hi all, new to the forum and routing and had a question I'm hoping you might be able to answer. I bought a 1/2 x 4 inch (cutting length 2 inch) up cut bit to use with my DW618 plunger base. I quickly found out that once I have installed the bit it extends beyond the base of the plunge router. This left me scratching my head as to how I use a plunge router to cut my 1/2 wide x 2 inch long x 1 inch deep mortises Are bits longer then the plunge depth only meant to be used in conjunction with a fixed router on a router table? I was really hoping to use the 1/2 dia bit so I wouldn't have to make multiple passes with a smaller dia/shorter bit. I hope I am missing something very basic here but found nothing about this when searching the web. Thanks in advance for any advice.


4 inches long! I have a few like that and I have added some pics on how I often use them, if they hang down from your router then there are only two comments, one its too big for that router, you can make a thick temp base plate so it would not hang down but that would only let it work for some of its length, that being what can plunge out, a plunge router cutter should not be out before the cut and you should not be starting any cut with the cutter out, I do sometimes but I have a very strong grip and experience, my advice it that if you need that depth of cut you need a different router too. N


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## DesertRatTom (Jul 3, 2012)

:grin: Lots of ways to skin a cat, aren't there?


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## Simon Ma (Jul 26, 2017)

That's amazing


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## Simon Ma (Jul 26, 2017)

That's very amazing.


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