chamfering the mortise

jbacon · Post by **jbacon** » Fri Jan 13, 2006 10:46 pm

have a question on chamfering the mortise, wondering what size countersinks everyone is using. having a problem getting the stem and shank to fit smooth and have been told i need to chamfer the mortise more, i am using a 3/4 60 deg countersink any input would be great. the tenon is short enough, but still getting daylight and i have chamfered the mortise more so thinking it may be the countersink

jim

bscofield · Post by **bscofield** » Sat Jan 14, 2006 12:44 am

The problem area on a tenon that causes the need for a chamfer is usualy only about 1/64" wide by just as much high. Causing the needed chamfer to be miniscule. If you are still having problems it's probably because your tenon cutter (a PIMO or JH Lowe?) is not cutting perfectly square. To solve this I would take some sort of reliable factory straight edge'd THING and wrap a piece of sand paper over it (around 400 grit). Then use this VERY gently to sand down the "high spot" (the places that DO touch) at the shank/stem face joint. As for an idea as to what sort of factory edge'd thing to use, random (who posted this tip on here originaly) uses a piece of photocopier glass. Something with a very reliable smooth edge.

Post by **KurtHuhn** » Sat Jan 14, 2006 12:57 pm

You can also use a drill size guide, or a dowel sizing jig - one of those metal things with a bunch of holes in it. Use it as a guide to punch a hole in some sandpaper with the tenon, then take that piece of sandpaper and place it on the tenon with the rough side facing the stem face, assemble the pipe and line everything up perfectly, then rotate the *sandpaper*, NOT THE STEM OR STUMMEL. That can help you flatten out the high spots and make your stem fit flush. 320 or 400 grit is best for this procedure, as you dont want it to cut to quickly or leave too many marks.

NvilleDave · Post by **NvilleDave** » Sat Jan 14, 2006 2:58 pm

Guess I'm doing things different. I always make sure I have a radius in the corner between the tenon and the stem shoulder. A radius gives the tenon strength and will resist breaking better than one without it.

I use a 1/2" ball nosed rotary file to countersink my mortises.

Dave

JSPipes · Post by **JSPipes** » Sat Jan 14, 2006 6:43 pm

Kurt, that's a great tip! Thanks.

Progcat · Post by **Progcat** » Mon Jan 16, 2006 12:21 pm

I have used the PIMO countersinking tool with good results. It does a nice job of chamfering the mortise and I have had virtually no light gaps since. I also agress with the rest of the comments about squaring off the end of both the end of the mortise and stem. If you don't have ametal lathe this is a little harder but the sandpaper technique described has also been helpful to me.

Tim

rathpipe · Post by **rathpipe** » Tue Jan 17, 2006 2:43 am

I use the Pimo tenon cutter in my lathe, sizing it just a bit larger than I want the final cut to be and then use my cutter on the lathe to take it down to the right fit. This saves me a lot of time in turning the tenon all the way to size with my cutter on the lathe. I tend to take my time with the lathe so I find this to be quite a time saver, and I have a drawer full of bits that are too small from trying to cut them with the Pimo tool in one cut. . Someday, I'll drill a smaller mortise and use them up.

Larry

LexKY_Pipe · Post by **LexKY_Pipe** » Wed Jan 18, 2006 4:31 pm

Some great tips here fellas. Thanks.

hlp808 · Post by **hlp808** » Sat Feb 04, 2006 12:13 am

sandpaper and place it on the tenon with the rough side facing the stem face, assemble the pipe and line everything up perfectly, then rotate the *sandpaper*,

Kurt, thanks for the tip, it helped a lot.

Jaden

Post by **KurtHuhn** » Sat Feb 11, 2006 12:06 am

My pleasure.