# Cleaning Out End Of Mortise With Chisel



## Gaia (Feb 20, 2010)

Hi,
I'm about to start practising making mortises in scrap softwood using my drill press and chisel. I have a new 12mm brad point bit and am intending to use a 12mm chisel I've had for a while, which is in unused condition to square out the ends of the mortise. Will a 12mm chisel be OK or will the chisel be too tight a fit in the mortise slot, should I use a 14mm drill bit instead?
Cheers.


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## Cherryville Chuck (Sep 28, 2010)

I'm not sure Peter. If you plan on practising, you'll find out soon enough. Just a couple of suggestions (options). You could always use the chisel to round the corners off your tenons instead of squaring the holes. Faster and easier that way. You could also buy a mortising attachment for your drill press that will make square holes without the chiseling.


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## Gaia (Feb 20, 2010)

Cherryville Chuck said:


> I'm not sure Peter. If you plan on practising, you'll find out soon enough. Just a couple of suggestions (options). You could always use the chisel to round the corners off your tenons instead of squaring the holes. Faster and easier that way. You could also buy a mortising attachment for your drill press that will make square holes without the chiseling.


Hi,
I read up on mortising attachments for the drill press, they didn't have a very good..... press, excuse the pun  I would have thought they were even less able going into hardwoods. 

" You could always use the chisel to round the corners off your tenons instead of squaring the holes "

I assume one has to do this well otherwise might effect the snugness of the fit and glue bond? Someone else before, suggested using a rasp file to round them. Will try all methods and see how I get on and which I prefer to use.
Thanks.


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## LexB (Apr 12, 2010)

Gaia said:


> Hi,
> 
> I assume one has to do this well otherwise might effect the snugness of the fit and glue bond? Someone else before, suggested using a rasp file to round them. Will try all methods and see how I get on and which I prefer to use.
> Thanks.


The snugness at the ends of the tenon isn't critical, in my opinion. The strength comes from the area of the glue bond, and that's the cheeks of the tenon. Get a good fit between the cheeks and the sides of the mortise--not too tight or the joint will be glue-starved. It should be snug enough that it won't fall apart on its own when you invert the joint, but not so tight that you have to beat the snot out of it with a mallet to make it go together.


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## JOAT (Apr 9, 2010)

Gaia said:


> Will try all methods and see how I get on and which I prefer to use.


That's exactly my advice. You should have started asking yourself first. :laugh:


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## Gaia (Feb 20, 2010)

LexB said:


> The snugness at the ends of the tenon isn't critical, in my opinion. The strength comes from the area of the glue bond, and that's the cheeks of the tenon. Get a good fit between the cheeks and the sides of the mortise--not too tight or the joint will be glue-starved. It should be snug enough that it won't fall apart on its own when you invert the joint, but not so tight that you have to beat the snot out of it with a mallet to make it go together.


OK cheers.


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## Gaia (Feb 20, 2010)

joat said:


> that's exactly my advice. You should have started asking yourself first. :laugh:


ok.


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## Cherryville Chuck (Sep 28, 2010)

Peter, I've owned a mortising attachment for maybe 15 years and used it quite a bit, including on hardwoods, and it works just fine. The chisels need to be sharp, of course. I bought a pair of sharpening cones from Lee Valley and they will sharpen the edges to razor sharpness.


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## Gaia (Feb 20, 2010)

Cherryville Chuck said:


> Peter, I've owned a mortising attachment for maybe 15 years and used it quite a bit, including on hardwoods, and it works just fine. The chisels need to be sharp, of course. I bought a pair of sharpening cones from Lee Valley and they will sharpen the edges to razor sharpness.


Umm, the power of the drill press might be involved in the proformance of the mortising attachment. Mine is 3/4 hp how about yours, how deep have you gone into hardwoods and how often and the size of the mortise? Will post on the forum for views of other members who use a mortising attachment. Can you post a link to these cones you mentioned?
Thanks.


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## Cherryville Chuck (Sep 28, 2010)

I think mine is about the same. It's a Delta 16 1/2". I've gone about 2 " into some 15 year old white birch I had a neighbor saw up for me. It approximates white oak or some species of maple I would say. I know BJ has one too, as he recently posted about it. He didn't say what kind of DP he had it on. I don't think that it really matters that much. It is like a router. If you have less power, you just have to go slower. If you want to go really deep you would probably have to clear the shavings out of the chisel a few times, much like most drill bits require. I highly recommend them and Bob did too.


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