Thread: Making A Fishtail Chisel from an Old Worn faithfull friend.

Originally Posted by Bushmiller

David

I think the fishtail chisels are deemed easy to make as they don't have a lot of mass. That means a fairly rudimentary heating arrangement can be used. As the size of the work increases, more and more heat is required to achieve the hardening temperature. That becomes a limiting factor for most of us. We go from a modest propane flame perhaps to a heating head and then finally to a forge. Forging itself requires a good deal of heat.

Regards
Paul

Definitely a good point. it takes confinement to heat treat larger items like knives, longer chisels or plane irons wider than about an inch. At least to do it well.

And it takes confinement and power to heat the larger things to forging temperatures at all or at least in a tolerable amount of time.

Today was a day that put the Fishtail chisel to the test.

Plus a bit of refining on the the DT jig. It s been neglected for a while. I glued the two vertical bolt heads in place to stop the bolts dropping down when I loosen them. Dropping down hampers the adjustment of the top bearer. That was an improvement. There is a Masonite shim in that picture which was there for doing through dovetails. That was removed . And I gave it a little shellac for a quick shine .

So that is a drawer front and side on top for marking out the dovetails with the marking knife.
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Then with the front taken out , cut to the marked lines put back in the jig facing out and routed using a better sized bit than my previous picture, you can see whats left to take out with the chisel in the right socket. The left has been cleaned up .
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Moving from left to right and for the first time in 44 years of cutting dovetails Ive got a two sided Fishtail chisel to help clean out the little angles up the back.
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I got three sets of fronts done today after working on other things that needed doing , Like making a batch of Saurkraut .
And marking out all fronts and backs off the cut drawer sides. So six set of sockets routed and chiseled then fitted. The cutting edge of the FT chisel couldn't be better. It's working well cutting, levering and even scraping a little end grain, and is still almost as sharp as when I started. No chipping or folded edge though. That heat treatment will be used again on the resin handled Stanley's again if needed and even tried on a Titan or two with hopefully the same results.

Having a fishtail is only slightly easier /more handy than using any of the other two chisels in the picture though, The narrow titan does a brilliant job of it . So does the other ebony handled Stanley. Narrow is a fierce cutting action because less pressure required so it cuts easier. One of the good things about the fishtail is the rounded handle for pushing with the palm of the hand. A smaller FT with a palm friendly handle will be good to try. (Thanks Derek.) The steel and brass back ferrule on those other two is not good for the hand .
I'm glad I now have the FT chisel and will be flipping between it and the standard way with straight chisels from now on trying to decide what is best. Its so close , the difference between the three of them. It has been worth the effort to find out.



The Saurkraut.
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Rob

Originally Posted by Bushmiller

That means a fairly rudimentary heating arrangement can be used. As the size of the work increases, more and more heat is required to achieve the hardening temperature. That becomes a limiting factor for most of us. We go from a modest propane flame perhaps to a heating head and then finally to a forge. Forging itself requires a good deal of heat.

I made several plane irons out of Starrett O1 bar stock, up to 2 3/8" wide. I took them to David's workshop for heat treatment and the setup was simple: metal paint can, insulating material, and plumber's blow torches. Additionally, quenching oil, a toaster oven, thongs, a pair of metal plates, over thermometer, a freezer. None of the above are hard to get, or expensive. A temperature controlled furnace may be nice to have, but it's not a necesity. The irons turned out well and I like to use them

Plane irons and bench chisels are not really a difficult thing to do in your workshop. Bar stock only needs to be cut, drilled, ground and filed to achieve the proper form.

Seeing the youtubers hammering a piece of iron to shape them into large chisels is popular. It's misleading though, it's impressive to see the sparks and the pounding, but there's no need for that if you get flat bar stock.

There is appeal to the hammering on an anvil to shape something, I know someone trying to use the rings of a steel ball bearing wheel to make a chisel. It will be a lot of work, but the steel might not produce a good edge for woodworking.

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I should probably add for anyone thinking about hardening, until I got an induction forge, I still heated most things in a paint can forge.

I have a large forge, but you can't control heat of an item well enough in it - edges and thin parts will always heat more than the rest of the tool, which is no good. The forbidden fruit among the current knife folks is heating the object and shielding the heat enough to be able to heat the object without it cooling or not getting hot enough. This is, however, the fruit needed for good results.

so if forging isn't really on the menu, it's actually better to devise something simple where you have more spot control than to assume moving onto a propane forge will be required.

The only reason I'm using the induction forge is because it's faster and in some cases, it will get me to forge welding heat without any other finagling (mostly for chisel bolsters). it's faster than the paint can forge, but it's not quite as easy to use by eye for certain things because of certain aspects of the speed.

The paint can forge idea and heating items to a color temperature is very practical, and I guess two TS4000s, a can forge and warmed vegetable (half a gallon at least, gallon is better if quenching more than one or two things) - $150? Add another $50-$60 for fast oil if wanting to reheat files and other water hardening steel.

I won't say my large propane forge was a waste but it was a waste for the most part.

I have no mill, just a drill press, files and a die grinder and sanders. A mill would allow me to make flat plane irons faster, but I don't want to get stuck in that. I think anyone who is serious with hand tooling is missing out of they don't give hardening and tempering a shot - being able to make your own tools will open a huge world of options that are not otherwise easy. Anyone tried to find a modern infill plane iron? It's a minefield. You can get an iron that by measurement will fit only to find out that your cap iron's screw isn't a good match for it and then what? What about finding things like an English bullnose plane for near free because it's missing an iron? Dandy little planes. Specialty chisels like this, moulding plane irons, marking knives and little cutting tools and gauges. much of what's on the market for those at low prices is trash for the irons.

you'll never buy a utility knife again, either -why deal with a somewhat soft utility knife blade when you can hammer the tip of a file into a wedge and heat treat it to tool hardness and sharpen it over and over? if someone came to my shop looking for a trinket, they could leave with a little fixed blade file utility knife that is hair raising.

too, if anyone is thinking about forging rolled stock (bars), if you make a chisel and you want to experiment with shaping the steel to refine the grain size, hammering the first inch and a half of a bench chisel is more than enough.

I'm the guy I guess who beats the drum on this and some "tycoons" (people who consider themselves master furniture builders without the success to actually prove it) think too much of it is a threat to the furniture making hobby. It's an aid to it.

Steve V, just as a tangent, has done some recent work talking about making oil finishes and actually making them in excellent quality so that they rival what was a favorite. For folks wanting to work by hand, i think he's going to yield more than just oil from a can, true oil or violin varnish (which I've made and works wonderfully, but having more than one option would be dandy).

Raffo can attest that if you came to my shop thinking that I was some kind of tycoon, you'd be disappointed. There's not much in it. There doesn't need to be. I've started to indulge lately in things like the hardness tester and the induction forge, but I made book matching and book beating samples without any of the stuff.

and lastly, a tip of my cap to rob for posting a thread about making the chisel and showing it in use. The forums are slowing down a lot - this is off the beaten path and I guarantee posting a thread like this is valuable.

I cheered a little when this thread showed up.

Good thread Rob, and now I think I will finally have to make myself a fishtail - been 'thinking about it' for 30 years (so not quite your 44!), but never got the 'round tuit'. As an amateur I do a significant set of half-blind dovetails maybe twice a year, and depending on the wood, quite often I just use a small straight chisel to clean the corners out. It's easy to do with woods that cut very cleanly like Qld maple, but some need a sharp point to get in & cut those corner fibres off.

Quite a long while back I bought a pair of Lee Valley skews - they are ok for large sockets, but too big (1/2") for small sockets, & I seem to do a lot more "small" stuff these days & the LV skews are way too big & clumsy. So I made a pair about 3/16" wide out of some HSS bar stock, & they see far more use than the LV pair. But skews are a pita, really. Having to use a different chisel on each corner is a major inefficiency - I waste more time looking for the opposite skew in the bench clutter than I do using them!

Learning to keep a tidy bench (I used to be a lot better than I am now, I'm getting worse with age!), would be a help but a small fishtail would be a better answer, methinks I reckon the time it will save me looking for 'the other one' will add up to a couple of extra sets of D/Ts per day....

Cheers,

These chisels are very useful - when you need them.
I have made a couple, simply by grinding to shape some older chisels that were duplicate sizes in my toolbox.
Here they are
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For reference, over the years I of making drawers with half blind dovetails, clearing the corners of sockets is best with a small fishtail chisel. That is, one with a 3/8" wide bevel. Wider than this and it becomes cumbersome. Most of the waste is removed with a paring- or bench chisel. It is only the last bit in the corner of the socket which requires a fishtail chisel.

Fishtail chisel may be replaced with two skew chisels. However ... the skew's action is different if the skew angle is acute. A slicing action is then preferred using one. Whereas a fishtail chisel is simply pushed, which is more ergonomic. Make a skew with the ratio angle of the dovetail.




Rob, the chisel is on its way to you. Let us know whether it is up to standard

Regards from Perth

Derek

Originally Posted by Scribbly Gum

These chisels are very useful - when you need them.
I have made a couple, simply by grinding to shape some older chisels that were duplicate sizes in my toolbox.
Here they are
20211014_111910.jpg

20211014_111752.jpg

20211014_100717.jpg

If you have never looked at chisels before 1800, or some current chinese chisels, you'll find there is precedent for them. The amount of tapering varies, and some have convex curved sides, but the use of tapering in the length of chisels used to be common.

Which means your idea isn't a bad one, of course, and that it's no surprise that you found them useful.

The lack of constricted sides makes a chisel like that ideal for pushing, of course, but if you have to do a considerable amount of bulk removal and the sides of the removal or mortising is going to be pared off at the end, a chisel like this will mortise faster in cavities that are some multiple of the chisel's width. You have to have your wits about you since it doesn't just create a neat visual wall, but it would've been more typical in work like that to trade the speed for paring the walls down to size.

I get fairly regular requests to make seaton chest style chisels , which are between that amount of taper and modern chisels, and made famous just because they were able to be studied. In the book for them are chisels with a similar profile to yours, albeit thinner. I think the thinness of those older chisels may have a lot to do with hardenability of the steel though, as well as the fact that beveled side profiles other than just at the tip weren't common.

Thanks for the comments above.

One thing I think is a good idea if someone was to make a FT chisel is how large you do your bevels on the side looking down on the chisel . I have about 4 to 5mm between the yellow lines in picture 3. That bears up against the surface and I found I could sweep the chisel for a slice at the base of the remaining timber. I am using White Oak though so a push straight method would be better on soft timber. I don't think large bevels on the chisel leaving a very small side wall would be good. You wouldn't have the slicing option.

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Why we don't see FT chisels in old tool boxes much?
We probably all have a narrow chisel in our sets. My narrow one on my standard set of bench chisels is 1/8.

Here though I'm using a custom re ground Titan at around 4.5 mm wide. When I press that in to take a chop at the remaining wood there is not much left to worry to much about. The red line is where I'm finishing. After scribing a line when setting out then cutting my first set I adjusted the jig to cut in from the scribed line . Scribed line has has arrows in yellow third picture,
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If I press in the chisel to the back I have that small red triangle left . Its like an end grain match stick split in half worth. But I can go through that to chop right through it and the extra marking wont be seen . If I don't go right through it, with the chisel flipped sideways the little bit left breaks off at its base and any rough wood is brushed away.
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Ive been using both FT and the 4.5mm today and they both do the same thing.

Once again its good having three differing sharp chisels to attack this six drawer job half blind dovetails.

I think the lack of fishtail chisels has something to do with the progression of cutting a half blind when there are no power tools involved. After marking:

* the side boundary is sawn
* the waste is chopped from the middle
* the remaining waste is pared or chopped into the corners until the back side of the waste triangle on the sides is leafed off until the waste is removed to a point that it's even with the boundary of the saw cut.

While the leafing is occurring, paring into the base until reaching the baseline is done at the same time. Cutting across the grain while doing the "leafing" removes any chance of overcutting the corner, and then the bottom is just pared to depth.

The leaves are not strong enough to damage a chisel, so as this is going on, they're just flipped/broken off and flung out of the joint or pushed out and all that's left is a back joint corner that can't be reached by the original chisel being used. I would call them tiny stalagmites of fibers sticking up.

a couple of prods of a very narrow chisel into those corners and the joint is done.

When the joint is routed out in the center leaving no waste to work against along the sides, this isn't as easy to do.

I'll look in the seaton chest book tonight when I get home, but I don't recall seeing anything like this in the chest. There number of chisels and carving tools is otherwise enormous.

I don't think most experienced woodworkers would've used or bought more than they needed, and mentioned to someone on another forum at one point that I didn't care for the card scraper trick pounding down the waste, because it actually takes longer than what I mentioned above. He relayed that in the headley shop, they do something similar to what I described above. The sawing leaves plenty of visual cues to pare the side material away very quickly, and it becomes a pain if that material isn't attached to the sides (it's sprung) where the saw doesn't cut. In the end, there just isn't much for a fishtail to do, though you could certainly use one to cut off the stalagmites.

Rob, the choice between using a fishtail chisel and a 1/8” bevel edged chisel into the corner of a socket has been debated on forums many times in the past. What gets missed by those making pins as wide as your example is that the pin is pretty sturdy. Compare this with a drawer front which uses slim “London” pins …

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If you use the 1/8” chisel into the corners of the sockets for the pin, it is likely that you will destroy it as it is fragile. This is where the fishtail chisel rules.



Regards from Perth

Derek

Fairly sure in the US, we never saw the point. I don't care for the aesthetics and saw an interesting alternative take that the virtue of them was to limit the step that eventually occurs on all old furniture.

That leads to a follow up question - they were widely done in practice at the same time the seaton chest was filled with tools.

I doubt they used fishtail chisels and understanding what they did is probably more valuable than guessing. Whether we do or not (understand that), I don't know, but fishtail *gouges* were common with the sides straight or convex. Not sure they were always common in something more acute than dovetails.

I'll know later tonight when I browse the Seaton book.

I've kind of gotten away from making modern guesses at things and many other people should do. That includes any older advice that doesn't match what I find with toolmaking. We are all running around at probably a tiny spec of the competence that existed at speed back then because we're not forced to learn it.

If I were making furniture, I'd have dovetails more like boston or philadelphia furniture (they look better to my eye) and spend a lot more time on curved elements. That won't happen for at least 10 years - hopefully in retirement if time and wallet allows.

I don't go back and edit posts, so I figured it would be worth clarifying - i'm not interested in devolving into what style of dovetail or furniture or whatever.

More interested in the subject of figuring out how this joint would've been done when it meant something to do it fast and clean and not waste time.