Preferred bevel for paring end grain

[Ron Kellison]

I usually cut dovetails using a Leigh D1600 jig but I also keep experimenting with cutting them by hand. My primary problem area is in paring the end grain of the sockets. I get chatter and generally manage to do a rough job. I have quite a range of chisels to pick from and they are all sharp. Most are beveled at 25 or 30 degrees with a micro-bevel. I'm thinking of regrinding a couple down to 20 degrees but I suspect this will probably lead to chipped edges, particularly if I use the same chisel for both chopping and paring.

This is an interesting area of experimentation for me. I thought I would throw the discussion open to the Brain Trust to get your ideas. What is your preferred bevel angle for chopping/fitting dovetails in both hard and soft woods?

Regards,

Ron

[David Weaver]

What kind of wood and what kind of chisel?

20 degrees is iffy for all-around use, but you might be able experiment and get down close to that. You'll get more edge damage and have to sharpen more often, but that's a tradeoff you can tolerate when the chisel works the way you want it to.

[Chen-Tin Tsai]

Not that I'm any kind of expert (with only having around 12 or so sets of dovetails under my belt), but I've found that a fret saw or a coping saw to remove the bulk of the waste, and then only using the chisel to clean up works well. Even in pine, my chisels are sharpened to 30 degrees and trim the end grain pretty neatly. I don't really pare, per se, but after cutting out the bulk of the waste, I make a couple of trim "cuts" with a chisel and mallet, and then for the final cuts, I just set the chisel in the scribe line and tap out the last sliver.

[john brenton]

If you know your chisels are razor sharp, then disregard my comment...but I've known really good woodworkers, especially guys that primarily use electric tools, that don't really know what sharp feels like.

[Terry Beadle]

For cutting the end grain of dove tail sockets, a good quality chisel set to 30 degrees primary should give you good performance. It must be sharp. I highly recommend watching David Charlesworth's Using Chisels for Precision Jointery. He uses very lite taps with a barreled japanese hammer. The lite taps is a real help to keep the socket end grain from launching out in chunks. I will say Southern Yellow Pine is unpredictable for half blind dove tail socket chiseling no matter how good the chisel set up. Extremely lite taps with a 4 oz hammer can help, but the SYP just does it's own thing most of the time. If you are doing cherry, red oak, maple, or even poplar, you should get good results with proper technique.

Did I say it must be sharp ! A little honing on green rouge spread thin on a hard maple stick will keep the edge through the work.

[John Coloccia]

If you know your chisels are razor sharp, then disregard my comment...but I've known really good woodworkers, especially guys that primarily use electric tools, that don't really know what sharp feels like.



Did I say it must be sharp ! A little honing on green rouge spread thin on a hard maple stick will keep the edge through the work.

+1 When my chisels dull to "hair shaving sharp" is when I consider them ready for more stropping :) If you can take a piece of paper and push the chisel straight through the edge and get a clean cut (not slicing at an angle....dead straight , perpendicular to the edge) you're probably about where you need to be. That's more important than the angle, but a little lower angle helps. It's certainly more controllable for pairing, in my opinion, and doesn't tend to want to dig in as much, but maybe that's just my perception.

[Tri Hoang]

There isn't any set number of bevel angles. It really depends on the steel and the type of wood you want to cut. I generally start out as low as possible...say 17*. If the edge folds after a few test cuts, I gradually increase the angle up 18*, 19*... Even within a same set of chisels, the optimal angle is probably different for each. The larger sizes can generally take lower angles while the smaller ones need higher angles.

[Sean Hughto]

20 degrees should not be necessary. I've cut hundreds of dovetails, and I don't think I've ever once actually measured a bevel angle on any chisel I've used to do it. Your poor results are most likely due to not having a sharp chisel or not using a proper technique to pare. The answer to a sharpness problem is to get better at sharpening, and that's a whole topic in and of itself. But assuming that your chisels really are sharp, a few tips on paring:

- take small bites - trying to hog off too much at once will lead to tear out and having to exert too much force
- think about trying to make a slicing action rather than just pushing the chisel forward on a straight line (you may need to use a chisel that it smaller than the opening to give you room to do this)

[Jim Koepke]

For working in pine, my preference is for a low angle. I think one or two of my chisels is actually at 15°. These chisels rarely get hit with a mallet and then, a small mallet and light taps.

If a chisel needs to be whacked with extreme force, it can mean a few things; you are cutting mortices, you are working in very hard wood or your chisel is dull.

Everyone has to find their own best method. Having multiple chisels to sharpen at different angles works for me. My chopping is done away from the base line with a chisel beveled at about 30°. Then a chisel with a shallow angle is used for paring to the line.

Paring can be done with a steeper angle. However in pine the bevel tends to influence the path of the cut downward. The lower angle helps to lessen any occurrence of downward movement.

I also rarely use micro bevels. There is nothing wrong with micro bevels. Just like there is nothing wrong with not having micro bevels. YMMV

My dovetails are usually sized to my most prolific chisels. For 1X pine, that means 1/2". The narrowest part to pare in the pins or tails is just a couple saw kerfs wider than 1/2". I can think of more than a half dozen 1/2" chisels in my shop. Some for whacking, some for striking and a few for paring.

For hardwoods it is likely I would use a steeper angle.

For your purpose, it may actually be beneficial to get hold of a cheap chisel to experiment with to find your own sweet spot.

jtk

[Ron Kellison]

Thanks for all the replies!

First, let me say that I can do "sharp"! I do the primary bevel using a low-speed horizontal grinder, then hone the edge with 4000 and 8000 grit waterstones, finishing with a few strokes over .5 micron green paper mounted on a dead flat granite lapping plate. The paper test is a routine thing before I put the chisel or plane blade to use. Also, all blades are lapped to a mirror finish for at least an inch behind the edge.

My dovetail technique is a mixture of the various steps I've read about over the years. I mark the shoulder lines with a sharp knife, lay out the tails, cut down to the shoulder lines, make small incising cuts along the shoulder lines just 1 or 2 mm deep, then pare out the waste in small increments working from both sides. Sometimes I backcut at the shoulder, sometimes I don't. The problem area is when I try to pare the bottom of the joint. I have trouble getting it smooth and, even though it doesn't show in the assembled joint and it doesn't affect the strength, it bugs me that it's so difficult to get a perfectly smooth surface.

I now have a decent fretsaw from Lee Valley which I will experiment with to remove most of the waste faster than my current method but it doesn't address the issue of cleaning up the bottom of the joint. I suspect, like many other things I've learned over the years, that the answer will slowly emerge as I get more practice.

Thanks again for the replies!

Regards,

Ron

[Sean Hughto]

The problem area is when I try to pare the bottom of the joint. I have trouble getting it smooth and, even though it doesn't show in the assembled joint and it doesn't affect the strength, it bugs me that it's so difficult to get a perfectly smooth surface.


Each to their own, Ron, but I don't understand why any part of the base end grain matters as far as appearance except for the outer edges. If you have chopped out the waste, in most woods, you will have broken some of the fibers in such a way that perfection is not going to be possible. If you've sawn the waste, it may be possible, but is unnecessary.

[Rick Erickson]

Ron, a smaller bevel angle can greatly benefit you in softer woods. I keep two chisels (1/4 and 1/2) at 17-degrees for softer woods (pine, poplar). If it's a good chisel and you are careful it will hold the edge fine. You can't go at it gorilla style though. I learned this taking a dovetailing class from Cosman. It has paid off. My sockets are much cleaner.