Dove tail chisel

[george wilson]

Bruce: a propane torch is plenty enough heat to make a small chisel. Take a few bricks and lay them in an "L" shape to make a corner to lay your chisel in. It is really surprising how much more heat you can bring to an object if it's laid in a corner,so the heat isn't so easily lost.

About 01: W1 will take a keener edge than 01,and is a lot cheaper since it isn't precision ground. 01 will get plenty sharp,and will stay sharp a bit longer-your choice. Precision ground is also "sharp" enough on the corners of the bar that you'll want to blunt the corners a little with a file. Cold drawn is fine,and will not irritate your hand like a precision ground corner will. You can use either steel. If you use 01,keep a gallon can,or even a quart can of vegetable oil,automatic transmission fluid or CLEAN fairly light motor oil to quench your chisel in.

The general rule is that the quench should be large enough to not get significant temper increase when you quench your tool in it.

Here are some simple chisels and small gouges I made back when I had no real anvil,only a propane torch,and just used a few bricks as a "hearth". No bolsters: these are "push" chisels. I still use them. The fishtail at 5:00 is a flat dovetail chisel.

Since the OP's post was about "making" a dovetail chisel,and this and my other post are also about making a dovetail chisel,I don't think it is out of place. Besides,it is a better approach than mutilating an old chisel,and will make an attractive tool. You'll sometimes see identical tools made long ago by some craftsman for his own use. I think the W1 steel for these was about $2.00 for a 3' piece. Not quite that cheap now,but still plenty cheap,and MUCH cheaper than buying the tools. I think I carved the lute rose with these. " Quick and dirty" walnut handles,but,actually,fairly 18th. C. style. At the time,I was re handling 75 carving tools I had bought,and used as easy a design as possible!

[Robert Engel]

I think Rob Cosman makes and sells a similar type chisel. I prefer a single bevel fishtail (that's probably what you're referring to as the LN DT chisel?).

Personally, I've tried skew chisels and for me they are of limited value because the angles are too steep, plus you have to use two chisels.

BTW, the key to a good DT chisel is a low side bevel height (thickness from the back to the start of the bevel). A high side bevel tends to bruise the corners of the tails when chopping out. Some chisels have very low SBH's (most notably LN and Ashley Iles) some are quite thick (Stanley 750 and Irwin Marples). The Narex premiums are kind of in the middle. Fine Ww'ing has an excellent chisel review with comparisons of SBH.

I have decided to start acquiring LN chisels when I have some extra cash laying around in a couple years I should have a full set.

[Pat Barry]

Bruce: a propane torch is plenty enough heat to make a small chisel. Take a few bricks and lay them in an "L" shape to make a corner to lay your chisel in. It is really surprising how much more heat you can bring to an object if it's laid in a corner,so the heat isn't so easily lost.

About 01: W1 will take a keener edge than 01,and is a lot cheaper since it isn't precision ground. 01 will get plenty sharp,and will stay sharp a bit longer-your choice. Precision ground is also "sharp" enough on the corners of the bar that you'll want to blunt the corners a little with a file. Cold drawn is fine,and will not irritate your hand like a precision ground corner will. You can use either steel. If you use 01,keep a gallon can,or even a quart can of vegetable oil,automatic transmission fluid or CLEAN fairly light motor oil to quench your chisel in.

The general rule is that the quench should be large enough to not get significant temper increase when you quench your tool in it.

Here are some simple chisels and small gouges I made back when I had no real anvil,only a propane torch,and just used a few bricks as a "hearth". No bolsters: these are "push" chisels. I still use them. The fishtail at 5:00 is a flat dovetail chisel.

Since the OP's post was about "making" a dovetail chisel,and this and my other post are also about making a dovetail chisel,I don't think it is out of place. Besides,it is a better approach than mutilating an old chisel,and will make an attractive tool. You'll sometimes see identical tools made long ago by some craftsman for his own use. I think the W1 steel for these was about $2.00 for a 3' piece. Not quite that cheap now,but still plenty cheap,and MUCH cheaper than buying the tools. I think I carved the lute rose with these. " Quick and dirty" walnut handles,but,actually,fairly 18th. C. style. At the time,I was re handling 75 carving tools I had bought,and used as easy a design as possible!

So George, you've mentioned this type of thing before but I don't recall. How do you determine if you have the material hot enough to pound it into the desired shape. Then, when it cools off too much to work, do you just reheat it and continue on? As a last step to do you heat and then quench without working it?

[Tom Bussey]

This is the first fishtail chisel I made about 15 years ago (influenced by Rob Colman). The steel came from a derelict Witherby. The bevel is 20 degrees for pushing into corners of sockets. The chisel is just for cleaning up waste in corners.

Thanks for sharing the information. I know the chisel is just for cleaning up waste in corners, but others may not, nicely stated. And down the road maybe I too will buy the Lie-Nielsen fish tail.

Influenced by Rob Colman also stands out. I hope I also influenced someone with this post.

[Pat Barry]

This is the first fishtail chisel I made about 15 years ago (influenced by Rob Colman). The steel came from a derelict Witherby. The bevel is 20 degrees for pushing into corners of sockets. The chisel is just for cleaning up waste in corners.



Inspite if of the unusual handle, it was very comfortable to push.

The chisel was eventually retired after I acquired fishtails from Blue Spruce.

Regards from Perth

Derek

Sorry Derek - do you mean Rob Cosman?

[Derek Cohen]

Yes Pat. Sometimes I get weird automatic spelling corrections on the iPad.

Regards from Perth

Kered

[Mike Henderson]

This is a bit off topic so please forgive me. I have both skew chisels in different sizes and a couple of fishtails - but I rarely use them. Traditionally, they're used to clean the corners of half-blind dovetail sockets but I find that I can clean them well enough with a narrow regular square across chisel. To do do, I'm cutting into the bottom of the socket with one side of the chisel but that doesn't matter because it doesn't show. I do it that way because it's faster - I don't have to change chisels.

Of course, if you're going for a very narrow lip on the bottom of the half-blind socket you can't do that, but I rarely go that thin. I'm mostly doing "practical" half-blinds and not "show" half blinds.

So my questions to those of you who have skews and/or fishtails is, "What do you use them for? And how often do you use them?" "Do you use them for things other than half-blind dovetails?"

Mike

[Jim Koepke]

[edited]

So my questions to those of you who have skews and/or fishtails is, "What do you use them for? And how often do you use them?" "Do you use them for things other than half-blind dovetails?"

Mike

The skewed blade presents a lower cutting angle going across grain when cleaning the bottom of a dovetail. Mostly for me it is only if the wood is causing some problem. Otherwise a sharp straight edge chisel does the job.

jtk

[Brian Holcombe]

This is a bit off topic so please forgive me. I have both skew chisels in different sizes and a couple of fishtails - but I rarely use them. Traditionally, they're used to clean the corners of half-blind dovetail sockets but I find that I can clean them well enough with a narrow regular square across chisel. To do do, I'm cutting into the bottom of the socket with one side of the chisel but that doesn't matter because it doesn't show. I do it that way because it's faster - I don't have to change chisels.

Of course, if you're going for a very narrow lip on the bottom of the half-blind socket you can't do that, but I rarely go that thin. I'm mostly doing "practical" half-blinds and not "show" half blinds.

So my questions to those of you who have skews and/or fishtails is, "What do you use them for? And how often do you use them?" "Do you use them for things other than half-blind dovetails?"

Mike

I have fishtail chisels setup to be chopped with, and just cutout the half blind with that. I make my dovetails with a 14 degree layout, so those corners are much tighter for me than for others.

[Mike Henderson]

I have fishtail chisels setup to be chopped with, and just cutout the half blind with that. I make my dovetails with a 14 degree layout, so those corners are much tighter for me than for others.

Why do you go that steep on your dovetails? Is it for looks, or...?

14 degrees is about 1 to 4. Most of the recommendations for dovetails are closer to 1:6 to 1:9

The problem I've always had with steep dovetails is that the corners can break off.

Mike

[Bruce Haugen]

So my questions to those of you who have skews and/or fishtails is, "What do you use them for? And how often do you use them?" "Do you use them for things other than half-blind dovetails?"

Mike

I use them (both skew and fishtail) only for cleaning out corners in half blind dovetails.

[Brian Holcombe]

Why do you go that steep on your dovetails? Is it for looks, or...?

14 degrees is about 1 to 4. Most of the recommendations for dovetails are closer to 1:6 to 1:9

The problem I've always had with steep dovetails is that the corners can break off.

Mike

I like how they look better, especially in small parts like 5/16", but I use it on case goods unto 3/4". Over that and I back it down to 1/6.

They aren't fragile in my experience and I've cut about 300-400 dovetails this past year.

Look at Nakashima furniture, they use something steeper still.

[george wilson]

Pat,it is necessary to reheat the steel when pounding it into the fishtail)or any other shape) if it gets cooled below red hot Otherwise it will crack if you keep beating on it.

The final heat for hardening is the one that sets the hardness of the steel. It will also affect how well it responds to the tempering heat.

As for decarbing,simple steels like W1 and 01 of course DO get a very thin layer of decarb on them.But,by the time you've polished the surface bright again,the decarb is gone.

If you want to be extra careful about decarbing,as I also do when making riffler files,you can get PBC No Scale from Brownell's Gunsmith Supply. Heat up your steel to a light brown and dip it into the no Scale. When you heat the tool and quench it in water,the No Scale just flies off,leaving a nice,clean,unblemished surface. If quenched in oil,a bit of scrubbing with soapy water will get it off. Or,you could immerse small tools in boiling water to get rid of the No Scale.

I have used an 18th. C. formula to make my own no scale,and it also worked,though not leaving quite as blemish free a surface as the PBC. Take a half cup of flour. Add a 1/4 teaspoon of yeast and a pinch of salt. Add water and stir until you get a batter thicker than pancake batter. Too thin,and the batter will not stick on the tool thick enough to sufficiently protect it. After the tool is good and coated,heat it to hardening temp and quench. The trouble with the old formula is it smells like burnt bread. And,it will rot even if left in the fridge for a few days. Stubbs,the famous English tool co.,used "beer leavings" to coat their files. Those old timers found uses for everything,it seems!

Air hardening steels like A2 will decarb badly if not protected from the air. I mean,sometimes nearly 1/32" deep. Depends upon the alloy and how hot it got,and for how long. Air hardening steels need to be hardened while wrapped in HIGH TEMPERATURE stainless steel foil. There are 2 grades of this foil. The more expensive of the 2 is the one that stands temperatures high enough to heat treat air hardening alloys. You will have to grind away decarbing if you must forge such alloys in the open air.

But,these more exotic alloys need not be of concern here. W1 and 01 will do whatever you need them to,especially in a limited use tool such as a fishtail chisel that you use for a short time ti clean out dovetails. That and a lot more.

Those miserable Mexican Nicholson triangular files I got were badly decarbed to well below the depth of their teeth. Soft as normal mild steel. They seem to have solved their production problems by now. I'd still be careful to save your receipt in case you buy an older Mexican file and find it as soft as butter. You will want to return those.

[Derek Cohen]

About the design - and choosing - of fishtail chisels for cleaning sockets ...

I have a few different types, including ones I have made. Below is a Blue Spruce along with the first Koyamaichi fishtail made ...



The first point is that the sides of the blade benefit from having a flat rather than ending in sharp lands. This is to prevent the blade digging into the sidewall of the socket.

The second point is similar - Choose an angle for the fishtail as close to the angle of the socket. If the chisel presents too sharp an angle, it will dig in. One does not need lots of angles. One close to what you most often use is best.

I hear of some using a 1/8" chisel and arguing that it does not matter if there are gouges in the corner. Well, probably not, but I will also conclude that the sockets are widely spaced. One has to be careful in this area with narrow pins since any slip will destroy it.

The area of difficulty with narrow pins is when paring away waste. A well designed and well fitting fishtail chisel helps enormously.

Regards from Perth

Derek

[Jerry Olexa]

Much good info here...Good thread