# Mortising Router Bit?



## Cheeks (Nov 3, 2012)

I have a Bosch 1617EVSPK and am in need of a router bit for making mortises. If my calculations are correct I'm looking at 38 mortises so I don't want to be stingy. I already have an old Vermont American HSS set(my dad's) with 9, 1/4 shank bits. Am I looking in the right direction or will one of my straight bits work? First time using the router, so want to do it right to avoid burning the wood.

My wood is 1x2 S4S Maple from HD. Nothing fancy. 

Amazon.com: Freud 16-110 1/2-Inch by 1/2-Inch Mortising Router Bit with 1/2-Inch Shank - $14.03

Amazon.com: RU4700 SOLID CARBIDE 2 FLUTE UP-CUT STANDARD SPIRAL ROUTER BIT 1/4 DIA X 1" CL X 1/2" SHANK - $24.62

Can't make a mortise without a tenon, so any recommendation for a bit for that job, that is if the bits I have are unusable.


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## Phil P (Jul 25, 2010)

Hi Michael

To see if your bits are suitable all you need to do is see if they are plunge-type bits. TCT plunge bits generally have a small carbide insert brazed across the bottom to allow them to "bore" into the timber. The only other thing I'd say about mortising with a router is that when you get to 1/2in diameter _or above_ cutters you're better going to 1/2in shank bits - they are stronger and far less likely to break than 1/4in shank ones. On the cutter front almost everyone here will advise going for a spiral - personally I just find them to be overpriced for a lot of what I do so I tend to stick to brazed tip straights or staggered tip straights

Regards

Phil


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## mgmine (Jan 16, 2012)

The spiral is what you want. Here is s site that offers free shiopping
MLCS solid carbide router bits. The tenon is made after the mortise and I would use a table saw or band saw if you have one. You are working with pretty small pieces of wood so unless your router is mounted in a table the tenons will be hard to make freehand. You can build or buy a jig to make what you need and with having to make 38 of them that would be the way to go.


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## Cheeks (Nov 3, 2012)

What should my bit diameter be? What should the dimensions of my mortise be?


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## richjh (Jan 14, 2013)

Spiral bits are designed to pull the shavings out of a mortise. I found a free article in PDF format on the woodsmithshop.com website for making mortise and tenon joints. I think it was from season one.


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## Mike (Nov 22, 2004)

Michael, a good general rule to follow for tenons is half the thickness of the material; in your situation a 1/2" solid carbide spiral up cut bit is a good choice. If you plan to continue routing it is a good idea to buy up cut spiral bits in 1/4", 3/8" and 1/2" sizes. MLCS sells these as a set with a slightly discounted price. These bits should last you a fair amount of time. When they wear out I would suggest going to a higher quality bit like Whiteside. They cost more but last longer.

Tenons are cut so there is a shoulder on all four sides unless it is a through tenon which would have the shoulder on 3 sides. This allows the piece with the tenon to overlap the mortise and hide it.

Since your dad's bits are HSS odds are you will be replacing them. Carbide tipped bits stay sharp many times longer than HSS bits and having a sharp bit is key to making clean cuts. Woodcraft sells a 10 piece bit set with the most commonly used bits for a very reasonable price. MLCS has a good 15 piece set for a few dollars more. I think one of these should be the next item on your wish list.


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