A quick question on skew chisels

[carlb40]

.....
Jacob says the correct angle is 90 degrees. ;-)

BugBear

No I didn't say that. You are getting in to troll mode again BB - have you stopped taking the pills?

I could simply do without your repeitive negativity:

.. I will keep banging on in the same vein, 'til the cows come home!

BugBear

We all could do without that.

However i started this thread for a specific reason, and that has been answered / explained.

I did not start this thread for whether such chisels are needed or can be done with normal chisels. If you both wish to continue, please take it to another thread.

If you both continue in here i shall request the thread be deleted.

 

[David C]

Acute corners may be cleared with an 1/8" chisel. The amount of undercutting is negligible.

David Charlesworth

 

[Corneel]

However i started this thread for a specific reason, and that has been answered / explained.

If your question heas been answered allready, why do you bother if the thread takes another turn? Thread drift is normal in forums. And the OP doesn't really OWN the thread.

 

[Jacob]

Acute corners may be cleared with an 1/8" chisel. The amount of undercutting is negligible.

David Charlesworth

Yes. Or wider in fact. Not necessarily text book perfect but they hardly ever are - if you have the chance to look at a drawer DT socket on a typically trad (even high quality) piece they are often fairly untidy, with chisel marks and a lot of undercutting. It's a compromise between finished appearance and speed of production and the bits nobody is supposed to see don't matter at all.
So an answer to the OPs question - any angle might do the job one way or another but, if you want a skew, approximately 30º is a good for a lot of things.

PS IMO the reason why these threads get conflicted is that the answer to many woodwork questions is not always specific; it's not like engineering where a mechanic's socket set has to be spot on with the right sizes all arrayed in tidy rows.

 

[Paul Chapman]

If you have a grinder, there is no need to buy anything special. Just modify regular chisels, (with care regarding overheating).

I did exactly that. Bought two very inexpensive sets from Lidl and ground them quickly on my Tormek. They are not something that I'd use a lot, so didn't think it was worth buying expensive ones.



Cheers :wink:

Paul

 

[Carl P]

I'm really sorry about this, but I'm going to have to ask thatquestion - polite and sensible replies please, but what are the favoured methods of sharpening, I only ask because Paul's look so beautifully done,

Cheerio,

Carl

 

[Jacob]

I'm really sorry about this, but I'm going to have to ask thatquestion - polite and sensible replies please, but what are the favoured methods of sharpening, I only ask because Paul's look so beautifully done,

Cheerio,

Carl

No different from any other chisel (why would it be?) so mine would be freehand on an oil stone - not so beautifully done, but quickest and easiest.

 

[Trafalgar]

Yes, or manage without them altogether, they are by no means essential.

Would you kindly describe your process of cleaning waste from the corners of lap dovetails?
On the face of it, there does seem to be an obvious difficulty, which is nicely addressed by some of the chisels described in this thread.

BugBear

An eighth inch chisel. Doesn't even need to be a bevel-edged chisel. The last tenacious little bits clinging in the corners can even be picked out with an awl. Most of the time a quarter inch chisel works just fine. Tail sockets are big allowing a lot of scope for changing the angle of attack to get the last little bits. Nothing hard at all.

In stringy woods tap a thick scraper or old bandsaw blade in the saw cuts to finish the cut into the corner of the half laps. See Tage Frid. Saves much time in wood that doesn't chisel cleanly. Done correctly, the corners will almost be dead clean. Some will be, others will have only a small amount hanging that's been severed from the tail wall. A straight cut in releases this bit and is easily done with a quarter inch chisel or even larger chisel.

 

[Derek Cohen (Perth Oz)]

For cleaning out the corners of half blind dovetails, I prefer a fishtail chisel over a skew. The skew cuts on the slice and the fishtail cuts on the push, which is much easier ..

While one could possible use any small chisel (1/8" is better) to clear these corners by undercutting, you cannot undercut when there is little separating the pins, such as in very fine dovetails ...

Clearing the corner is so much easier if there is a release cut. Tage Frid used to hammer a bandsaw blade into the corner. Some use a scraper blade to do so. I built a dedicated "kerf chisel" ...

Link to build one: http://www.inthewoodshop.com/ShopMadeTo ... hisel.html

Regards from Perth

Derek

 

[Peter Sefton]

I agree that using a Fishtail is much better for Lapped Dovetails. Ashley Iles are making this Square End Fishtail chisel for the tool shop. I would rather use a single Fishtail than use a left and right handed skew for such work much more productive IMO.
Peter

 

[bobbybirds]

These days I always reach for my fishtail for half blinds as well, but 1/8th inch bevel edge works just fine as well...

 

[David C]

Peter,

I wonder what the angles are on that fishtail chisel?

From the photo they don't look as if they would get into the corner of a 1:6 socket.

Derek, I don't like to undercut the base of the pins, no matter how fat, but I do undercut the base of the lap. Seems safer!

The nice thing about a regular skew chisel is that it slides along the side of a pin without damage, if one is careful with cutting direction.

best wishes,
David Charlesworth

 

[Peter Sefton]

Well spotted David they would be a little tight to fit 1:6 Dovetails, they will do 1:7 or 1:8.
IMO Dovetails in hardwood should be fine and slender 1:7 to 1:9 to look right 1:8 as a standard, I feel 1:6 and 1:5 are for softwoods and I see no merit in cutting one of our most expensive joints in the cheapest timbers. We do also stock left and right skew chisels and sets of Dovetails chisels if people desire them. I always try to advice my students to spend their money wisely every tool they buy should pay it's way. As said before a 3mm chisel will cope well in the corners with only minor under cutting but it does leave the sockets a little untidy.
Cheers Peter

 

[Jacob]

.....
IMO Dovetails in hardwood should be fine and slender 1:7 to 1:9 to look right 1:8 as a standard, I feel 1:6 and 1:5 are for softwoods and I see no merit in cutting one of our most expensive joints in the cheapest timbers. .....

Historically they weren't "our most expensive joints" but were merely the normal way to join drawer fronts to sides, or box corners, etc. in cheap or expensive timbers. There weren't many alternatives.
All the waffling about angles is just a modern affectation - you will find many variations in old furniture - especially the hand made "production line" stuff where the makers were under pressure to be cost effective.
You can find out a lot about how to do things by looking at stuff - IMO people don't look at stuff enough, and it really shows - the difference between 1:6 and 1:5 is so little as to be meaningless. If you take the trouble to actually look you will find DTs varying from 1:2 through the whole range to to straight "box" joints.
Give yourself a break - start looking at stuff! You have nothing to lose!
Also try thinking about it - logically hardwoods being generally stronger could take a steeper DT angle than weaker softwoods. The popular view is quite opposite, and basically nonsense.
Suggestion for new years resolution - in 2014 make more effort to look at things and think about them!

 

[bugbear]

Angle of Dovetails - there is a tendancy amongst the inexperienced to make
the angles of the sides too acute. Such dovetails, though appearing strong,
are really weaker than if cut more nearly parallel.

Ellis describes a DT marker with an 80 degree angle, which is around good old 1:6

Mind you, Jacob said this concern with angles was a modern thing, and Ellis' book
is indeed called "Modern Practical Joinery"

Ian Kirby (who is modern) points out that in many scenarios
a DT joint is so very much stronger than what is actually required
that a very great deal of design flexibility is allowed, which he suggests
can be exploited for aesthetics.

BugBear

 

[Jacob]

But what you find if you look at stuff is that the majority of makers obviously didn't obey these little rules. I find it endlessly fascinating how the text book or armchair theory of how things "should" be done is at variance with how things actually were done. Nothing wrong with text books and rules of thumb of course - everybody has to start somewhere.

 

[MMUK]

Having looked at the differing options and opinions here, I think I would tend towards dovetail chisels purely to save myself time in putting down a LH skew to pick up a RH one. Having said that, I'd still equip myself with a set of LH and RH skews as I like to have every eventuality covered. I may have to take a trip to Lidl :lol:

 

[David C]

Peter,

Thank you.

Joyce suggests 1:6 for carcase work where the joints may be hidden, also secret miter and double lap.

I would agree that exposed pins, such as drawer fronts, look better with less slope. However with thin stuff, say 5/16" or 8 mm, the through dovetails at drawer backs benefit from 1 : 6 as 1: 8 looks barely sloped at all.

These are just my personal choices.

David

 

[MMUK]

Personally I don't look into specific gradients for dovetails, I generally sketch them out to a rough scale and decide what looks best if they are going to be seen or what's best structurally if not.

 

[Derek Cohen (Perth Oz)]

Hi Jacob

Personally, I see no issue with the way anyone wants to cut dovetails. I agree with you and I agree with BB - see, I am flexible! :lol:

If one wants to replicate the dovetails that were used by those in past centuries, then do so. I suspect that you will find that they varied, however. I'm not a historian, so am open to correction (hey, I'm always being corrected!).

I do view the "modern dovetail" to be just that, but it has become one feature by which standards are judged - just as much as you consider that they are not where standards should be judged. It's just the present day focus. By present day I do not mean the last 10 - 20 years. I think you will find examples of finely cut dovetails going back at least 100 years, so the "modern" emphasis is not that recent. Perhaps the focus on them is more modern - Alan Peters was shaping his dovetails with care in the 60s, and he apprenticed to Edward Barnsley.

The slim "London" style dovetails (where on Earth did that name come from - is there a more appropriate name?) that were a feature of Alan Peter's drawers are just one example of the focus placed on dovetails as a design element. Another is the influence of Jim Krenov. He combined the structural (placement and spacing) with the aesthetic (make it interesting).

My theory is that one draws attention to workmanship either through attention to details such as mouldings and other intricate carvings such as ball-and-claw feet, which were more prominent 100 years ago, or we find some other focus. The current zeitgeist appears to have been influenced by the Shakers, Danish and other contemporary stylings which seem to be dominated by their silhouette instead.

Regards from Perth

Derek