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Mortise Quality Survey

Mortise Quality Survey (post #167896)

steve25 on Wed, 06/29/2011 - 19:53

Joinery

My just out of the box Delta 14-650 mortiser with the cheap, but new, delta chisels produces mortises with slight auger gouges down the sides of the mortise. This occurrs on the 1/4" and 1/2" chisels, the only ones I have tried. I have sharpened and squared the the chisels and have tried different end of chisel bit exposures. Nothing helps. Delta tech support believes the sides of the mortise should be smooth. I searched the web and found pictures of mortises made by two different woodworkers. While both of these mortises had the same auger marks as mine, the woodworkers seemed satisfied with the mortises and mentioned nothing about the auger marks. I am trying to determine what others expect as far as auger tracks in the mortise. Should the mortise sides be smooth or do most bench top mortisers leave auger tracks.

Get out the mics (post #167896, reply #1 of 10)

by trialnut in reply to steve25 [original] on Thu, 06/30/2011 - 06:31

I would drill a hole with just the auger, no chisle, and then measure the hole to see if it is exactly the same diameter as the auger. If it is larger then the auger is not sharpened equally on each side and will drill oversize, thus leaving the marks.

The Professional Termite

Hone Them Down (post #167896, reply #2 of 10)

by gpssam in reply to steve25 [original] on Thu, 06/30/2011 - 10:22

Mine did that also. I just put the chisel and bit in the machine started it up and held the edge of an old sharpening stone against the side of the chisel. Any part of the rotating bit that was proud of the side of the chisel was quickly removed. I actually pressed hard enough to deflect the chisel a little bit just to make sure that that auger was smaller than the chisel.

Awesome sugggestion, solved my problem (post #167896, reply #10 of 10)

by skeezaroonie in reply to gpssam [original] on Tue, 09/13/2011 - 12:47

Thanks gpssam. I found myself needing to chop some 5/8" square holes, not oblong mortises, in some pecan and mesquite. These will not be covered with a shoulder or escutcheon. I found and ordered the 5/8" chisel & bit and I was most discouraged on trying it by the scallop left by the auger bit. Thanks to your suggestion and my internet ferret (aka significant other, who can find what year the first refrigerator was sold to Eskimos, not to mention brand) I gave my bit your sharpening stone treatment. Figured what the hey, it's worthless to me anyway unless I can drill truly square holes and voila!, now I can. Made my day but, hey, I'm pretty easy. Thanks again.

chuck check? (post #167896, reply #3 of 10)

by RalphBarker in reply to steve25 [original] on Thu, 06/30/2011 - 15:56

Before doing any grinding, you might also want to check your chuck. If the auger isn't centering properly, you might be getting some run-out/wobble that would explain the auger grooves. Check the chisel alignment, as well.

thanks for bringing this up (post #167896, reply #4 of 10)

by stantheman in reply to steve25 [original] on Wed, 07/13/2011 - 17:54

Steve25

Thanks for bringing this up. I thought it was just my problem.

Not something you asked for, (post #167896, reply #5 of 10)

by routerman in reply to steve25 [original] on Sun, 07/17/2011 - 20:09

Not something you asked for, just a picture.
Have not seen a perfect mortice hand or machine-chisel cut mortice, tho Ian Kirby is damn good. Have had success routing. Sample is typical. http://patwarner.com/images/508_a.jpg

Very nice cut. Would you (post #167896, reply #6 of 10)

by Willie in reply to routerman [original] on Sun, 07/24/2011 - 16:07

Very nice cut.

Would you mind posting up how you do that, home made jig, how you hold the stock?

Rough description (post #167896, reply #8 of 10)

by routerman in reply to Willie [original] on Mon, 07/25/2011 - 20:02

Rough description here:

http://patwarner.com/router_morticing.html

Very nice cut. Would you (post #167896, reply #7 of 10)

by Willie in reply to routerman [original] on Sun, 07/24/2011 - 16:10

Very nice cut.

Would you mind explaining how you do that with your router, what kind of jig, how you clamp the stock?

Hollow chisel mortises are (post #167896, reply #9 of 10)

by Willie in reply to steve25 [original] on Sun, 07/31/2011 - 05:11

Hollow chisel mortises are never smooth as with routered mortises. The problem with smoothing using a chisel afterwards is you loose the time you are supposed to save, as hand finishing the mortice would mean also tuning each tenon to fit.