# Cutting mortises with a plunge router?



## Beginningwoodworker (May 5, 2008)

I am looking getting a Milwaukee 5615-24 for cutting mortises. You guys know I told you I wonted to try my hand at some morris chairs for my mom, I am thinking I can use the plunge base to cut the mortises but I am a tough time find a 3/4'' sprial upcut router bit, I may be better off buying a benchtop mortiser. I am wondering do you guys know where I can find a 3/4'' sprial upcut router bit.


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## b2rtch (Jan 20, 2010)

Why do you want a 3/4 bit?
You would be better of to cut the mortise in two or more times.


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## Wood_Chuck (Feb 19, 2009)

Hi Charles,

Woodcraft… has Onsrud HSS Spiral Upcut Router Bit, 3/8" D, 1-1/4" CL, 3-3/4" OL, 1/2" SH, Onsrud# 40-135 for a little over $20.00. I did the same thing at first then I ended up getting the Jet Mortisie Machine, the chisel bits works excellent.

Mike


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## Beginningwoodworker (May 5, 2008)

The plan calls for 3/4'' mortises.


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## Eric_S (Aug 26, 2009)

Bosch has one, Bosch 85967M but its very expensive, http://www.nextag.com/Bosch-85967M-NA-SC-506781663/prices-html. You can get away with using a straight bit also, or use a smaller bit and make a template and just use a guide bushing.


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## Rick Dennington (Aug 27, 2009)

Charles : You might try Rockler, MLCS, Woodpeckers, Amazon.com, and others. I've never seen a 3/4" spiral router bit…..the biggest I have is a a 1/2", but they make make them…don't know, but somebody on here will. Good luck finding one….... later.


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## patron (Apr 2, 2009)

like eric said ,
use a smaller bit , and a slightly bigger template and guide bushing .
try it out on scrap first , the big bit will want to jump and tear maybe ,
the smaller one will be much calmer and just do more passes .


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## mattg (May 6, 2008)

I would get the mortiser, but remember, the largest chisel they give you with it is a 1/2" You could always lay them out, then drill out the majority of the mortise with your drill press, then chisel them square.


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## Beginningwoodworker (May 5, 2008)

I think you can get a 3/4'' mortise chisel.


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## teenagewoodworker (Jan 31, 2008)

Eric_S thats quite a bit… but it's a 3/4" diameter shank. and its 4" in length!!!! that's giant!!!


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## patron (Apr 2, 2009)

charles ,
http://grizzly.com/products/mortising-machine/g9976

they have a 3/4 bit there too .


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## Beginningwoodworker (May 5, 2008)

Thanks guys, I am going to get the Delta 14-651 benchtop mortiser. I think Home Depot has it for $249 free shipping.


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## jack1 (May 17, 2007)

I have that mortiser. It's a good one for the price and you can get a 3/4" chisel for it. Good luck and practice on a bunch of scrap! ;0)


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## Wood_Chuck (Feb 19, 2009)

You might have to buy the rest of the chisel set, not famaliar with the Home Depot in your area. The chisel are very sharp and do a remarkable job.


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## jcsterling (Aug 1, 2008)

Your asking a lot from the machine to chop a 3/4 mortise. You have to have some serious power and leverage . If I want a mortise that big I cut it in 2 passes using a 3/8 bit , I am using a general int 75-075 with a 1 hp motor.


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## b2rtch (Jan 20, 2010)

I read good stuff about the HF mortiser and it is just above $120.00 on sale.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=35570


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## EEngineer (Jul 4, 2008)

I would second getting a smaller bit (say 1/2" or 3/8") and making multiple passes. I have yet to find that any 3/4" stock exactly matches any 3/4" bit. With a smaller bit, you can sneak up on the exact size you need and guarantee a snug fit.


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## Beginningwoodworker (May 5, 2008)

I already have a router!


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## Beginningwoodworker (May 5, 2008)

Its a fixed base router.


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## Ger21 (Oct 29, 2009)

Most solid carbide bits have shanks equal to the cutting diameter, so most 3/4" bits will have 3/4" shanks. I've used a lot of them in a big CNC router. They cost $200-$300 each. If you want, I'm sure you can get the shank ground down to 1/2". 
http://www.vortextool.com/index.cfm?fuseaction=category.display&category_id=13


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## stefang (Apr 9, 2009)

You could just mount your router in a simple router table and use that to cut your mortises. A horizontal router table works really well for mortises and tenons, and a whole lot more too. Here some pictures of my shop-made one. The plans for it came out of Bill Hylton and Fred Matlacks book Woodworking with the Router. It was very inexpensive even if you have to buy the book to get the plans.

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## Wood_Chuck (Feb 19, 2009)

Charles,

Do you have a router table? Saw this on a closeout from Rockler. Just another option for you.
It is STS Slot Mortiser Kit, thought that was pretty neat.

Heh Mike like your Router Table.

http://www.rockler.com/product.cfm?page=18053&filter=tablel%20tops

Mike


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## Beginningwoodworker (May 5, 2008)

I built me a router table, Mike!.


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## Gofor (Jan 12, 2008)

Don't discount HSS metal mill cutters. If you get a 1/2" upcut milling bit, it will work fine in your router (providing you have a 1/2" collet; 1/4" if you only have 1/4"collet). Might find one at MCS or Graingers. I have some left over from my machinist days that I use frequently. They will also work in a drill press, (you move the wood, not the bit) but you have to allow for any side play in the quill (it will pull the quill into the wood). Best to take cuts at less than 1/4" at a time.

Go


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## a1Jim (Aug 9, 2008)

There are a number of ways to do this ,You can build a very simple version of Mikes type router table pretty easily. There are a number of jigs that with mortising they can help if you search mortise jig on LJs.


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## stefang (Apr 9, 2009)

I guess we got way off track with this Charles, but you don't need a 3/4" bit. Like the others said you can use a 1/2" regular bit and just move the fence back on your router table to widen the cut to 3/4".

A way to do this accurately is to make your first series of 1/8" cuts down to the bottom of the mortise and then mark the first fence position with a piece of tape or a pencil mark and then move your fence back to widen the cut. When you get the new fence position set, just clamp a board behind it so you can find that position again after the next first cut series.

Remember that on the 2nd series of cuts you should be cutting the inside edge of the mortise on the left side and pushing the work through as you normally do from right to left. This should give you nice clean and accurate mortises.

I realize this might be unwanted advice and that you might already know this or have a different way to do it, but if not, then I hope you find it helpful. Don't be afraid to ask if there are details that seem unclear. Good luck with your project.


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## miles125 (Jun 8, 2007)

I just hate the wear and tear on a router from the shearing forces in such an application. I'd get the mortiser which is specifically made for this application and be kinder to your router and your ears too.


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## richgreer (Dec 25, 2009)

I've made mortises with both a router and my mortising machine (benchtop Jet). I find that I can cut a mortise very quickly and quite accurately on my mortising machine. However, it just doesn't look as nice as a clean mortise cut with a router. Fortunately, most mortises are never seen after the furniture is assembled. My rule - if the mortise is going to be visible, use a router - if not, use a mortising machine.


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## Beginningwoodworker (May 5, 2008)

Thanks guys I am going to get the Delta benchtop mortiser, I think its the best tool for the job.


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## patron (Apr 2, 2009)

thats a good choice , charles .

get the tools that you feel comfortable with ,
you will do a better job .

sooner or later you will have them all anyway !


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## EEngineer (Jul 4, 2008)

I don't get "wear and tear on the router". Aside from the initial plunge in a stopped mortise, the stresses should be the same as any "normal" routing. Aside from edging, mortises are what I use my router and table for most (I'm including regular through mortises; i.e. just routing a channel down the center of stock).


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## Beginningwoodworker (May 5, 2008)

I was taught at school to use a mortiser to cut mortises.


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