Entry hall table for a niece: Part 3

Re: Entry hall table for a niece: Part 3

Brian from monument colorado

Derek,

I really appreciate your pix of your work. You are indeed a skilled craftsman.

Keep up the great work. And please keep the pix of your projects coming.

Re: Entry hall table for a niece: Part 3

Clint Searl

Is there a structural or esthetic rule to dictate the number of dovetails to use for a join? It seems to me that half the number usually shown on this forum would serve the purpose. Does it count how skinny the pins are?

Re: Entry hall table for a niece: Part 3

John Jardin

Thank you, thank you, thank you!!

Re: Entry hall table for a niece: Part 3

Derek Cohen (in Perth, Australia)

Is there a structural or esthetic rule to dictate the number of dovetails to use for a join? It seems to me that half the number usually shown on this forum would serve the purpose. Does it count how skinny the pins are?

Clint, the choice of the number and shape of the dovetails for the case is essentially aesthetic, as they are for drawers. There are other factors that need to be weighed in to determine strength, such as the type of wood, its thickness, and the glue used.

In regard to strength of dovetails, I do not believe that the ratio angle makes much, if any, difference. The ratio here 1:6, chosen because it looks better to my eye. The strongest joint is a finger joint, particularly one with many fingers. This increases the glue area .. which is where the strength comes from. A dovetailed joint does not need as many “fingers” as it is also a mechanical joint, which the finger joint is not.

Regards from Perth

Derek

Thank you for the kind words, Brian.

And thank you, too, John.

Great post, Derek

Ellis Walentine

Your advice about tuning the miter was spot on. This is the last step in fitting this joint, and your choice of a file was excellent. Good rasp and file techniques are sorely lacking in the literature but they can be very precise and should be part of everyone's arsenal.

Amazing wood you're working with. Keeping the grain moving around the case is another masterful touch.

Thanks for posting.

Ellis

Rasps and files

Derek Cohen (in Perth, Australia)

Good rasp and file techniques are sorely lacking in the literature but they can be very precise and should be part of everyone's arsenal.

Thanks Ellis and agree about rasps and files. These can be a tremendous aid in fine tuning pins (when necessary, I always tune a pin and never the tail).

The provisor with these tools is that they have safe sides, otherwise you cannot use them into a corner.

Files are easy to make safe - just grind away the teeth on the edges. You cannot do this with rasps as a good rasp will be destroyed - they are typically round on one side and flat the other, meeting at a point. However, the Japanese Iwasaki rasps come with safe edges.

Regards from Perth

Derek

size shape and number of dovetails

Bill Tindall, E.Tn.

Is there a structural or esthetic rule to dictate the number of dovetails

Your question is two part, but there is a 3rd historically most important part.

Esthetics: If one studies dovetails over the ages and regions you will find everything imaginable- big blocky ones, slender ones, this angle and that. Now days where dovetails are considered a design element in much furniture anything is fair game that pleases the customer, who could also be the maker. Hence, the shape, number and size is largely determined by fashion. I can imagine a customer in a gallery buying or rejecting a piece because of their preference in dovetail design, which would not have been the case in 1780.

Structural: This consideration rarely is important. The dovetail joint is typically over engineered. You are correct that what you see is usually more than enough to hold something together.

Economic: While a dovetail is often the best way to hold a joint together it is also an expensive joint to make. Size, shape and number will affect the cost of making this joint. Maybe not relevant for the hobby woodworker or even the studio furniture maker, but the most important element for the historical cabinet maker or factory.

For example, take the slender dovetails common in 19th&20 century English furniture. According to Alan Batty who worked in an English furniture factory this style enabled him to meet his quota of 6 drawers per day. The tails could be cut in difficult to work white oak drawer sides with three saw kerfs and one paring cut with the chisel. The corresponding large sockets in the pin board where then excavated in soft easily worked mahogany. In the "colonies" easily worked poplar and pine were used for drawer sides and this version of dovetail was not an economic advantage and it was not commonly used. Dovetails size was balanced between harder to work drawer fronts and nearly as easily worked sides.

In American Period furniture dovetails were not considered a design element and one can detect many ways that the number, shape and size were optimized to achieve sufficient strength and efficiency. For example, there will be fewer and larger dovetails on the back of a drawer where structural stress is minimal.

Bottom line, if cost is not object do what pleases the customer which will be some version of current fashion. If cost is important there are many ways to optimized strength and cost by adjusting size, shape and number.

For example

Bill Tindall, E.Tn.

Shown are the dovetails on the front of a drawer on a piece of family furniture from mid 1800's. Can't argue that the drawer is under engineered. This piece has been in use for 150 years. But the joint shows every effort was made to take labor out of making it. Every saw kerf is over sawn to aid waste removal. The size of the pin is such that the makers chisel size could remove the tail waste with one cut. One can see the chisel nick where the sides were stacked for chopping out waste and the chisel broke through and nicked the board underneath.

As an American antique this piece would readily sell in a shop and nobody would even notice the dovetail. As a reproduction it would never get in a gallery shop for it would be rejected because of its "sloppy" dovetails which have become a measure of furniture quality. As a reproduction built to modern standards it would have to sell for about $4000. Made to the standards of 1850 it could sell for substantially less.

Re: Rasps and files

Buckaroo

I have a good flat noes/end scraper i ground down from/using old rasp.

Use it with flat side on TOOL REST!!!

Re: Rasps and files

William Duffield

I wasn't paying close attention when I posted the following response on the Hand Tool Forum. Derek's post over there looked just like this one, but there are probably more people watching this forum, so I'm posting it here, too. There are several interesting responses to Derek over there, and a response to me from Bill T. on unsafe files, that some of you might want to check out.

otherwise you cannot use them into a corner

But, you can use unsafe files and rasps "out of the corner." I use this method for final finessing only, because it is slow and I have to pay very close attention. I lay the file down right in the corner, stopped. Then I apply pressure to the top, and push forward and away from the corner. This removes a small amount of material from the bottom of the corner without removing any appreciable material from the side of the corner. I repeat as many times as necessary. The only reasons to do this technique instead of using a safe file or rasp, is if you don't have one that is safe and the appropriate profile, or you are trying to fit while shaping and find yourself wasting time repeatedly swapping tools (Not applicable to your dovetails with all faces flat).

Re: Rasps and files

Derek Cohen (in Perth, Australia)

Thanks William. I replied on the Hand Tool forum, and will cross post here ....

My statement: otherwise you cannot use them into a corner

William's comment: But, you can use unsafe files and rasps "out of the corner.

William, I agree with you that an unsafe file or rasp can be used in the way you describe. My warning was not to use an unsafe file into a corner. No matter how careful you are, it is likely you will do damage to the adjacent side. DAMHIK!

Regards from Perth

Derek