cabinet basics

Re: shell bits-hijack

Dean J in MN

>

See, I don't agree with some of Greene's (this is Greene, right?) techniques and assumptions.

We really need you to write a book Adam!

And I'm not being flip. I'd like a signed copy please.

Ubiquitous shell and spoon bits have their advantages (low angle drilling, easy to change angles, easy to sharpen) but many have found them difficult to position.

I have to defer to you on the shell/spoon bits. My augers all have lead screws. However, should I ever come across some, I will have a little more info to go on!

Shells and spoons don't typically cause break out and this is easily solved by boring into a piece of scrap. (I'm not sure if this is what was meant or if inserting the pin was the problem. But that's easy enough solved as well.)

I think he was refering to the insertion of the pin, not the boring of the hole.

So Greene may be right that drawboring wasn't done, but I reject the argument that their tools prevented this sort of workmanship (or I could be misunderstanding the whole thing).

Well, for me, drawboring is a bit slower then the method of clamp, bore, pin. By not drawboring one eliminates the need for accuracy. It isn't that the craftsmen were not able, but as I have found I'd rather avoid things which require it. Rip to width, then cross cut parts, things like that.

Dean

Re: Glued.

Dean J in MN

>

is greens theory on no drawboring univerally excepted? or am i possibly right in why he overlooked vansihed drawbores?

That is a great question. And good points. And I wish I knew, which prompted me to ask!

Thanks all!

Dean

Re: Glued.

Adam Cherubini, NJ

>All good points. I can only add one thing:

(Now I forget the guy's name) But a furniture conservator at Williamsburg mentioned at this year's conference that wood swells and shrinks each year, but he thought it would swell to the same width each year, but shrink incrementally more each year until it reached some minimum diemnsion.

With that in mind, one would wonder how or why any M&T joint that old still looks remotely tight if it weren't originally drawbored?

So again, I don't know jack about what was done. I'd think you'd have to have a lot of experience taking apart old furniture. I don't know that conservators' make a habit of disassembling sound joints, so one wonders if their notions aren't skewed a bit.

I just don't know, but I'm comfortable drawboring and I tend not to glue when I drawbore.

adam,

Re: Glued.

Dean J in MN

>Now, where did I put my plans for that time travel machine...

-Dean

Thx. for filling the rest Joel.

HC Sakman

>

This is what I do to big or......

HC Sakman

>...under stress M&T joints:

First, "the fit" is as usually described; Parts will not come apart when they are dry fitted, yet no need to force to dry fit them either. This is how I do my M&T joints. I use router, table saw, bandsaw, Japanese and Western saws, shoulder planes depending on wood, size and end purpose of the piece. (No Hollow Chisel Mortiser) Once I get them to fit as I described above, I apply poly in the mortise and PVA on the tenon. They are there for good! ;-)

Chico...

Re: Glued.

William Duffield, on the Cohansey

>the tenoned piece had the tenon shown with gaps on either end

There are some other very good reasons for this construction detail. It allows you to adjust the fit of the rails to the panel during glue-up (or when draw boring the pins, if you are using them), so you don't have to worry so much about the length of the mortise or the height of the tenon while you are constructing the mortises and the tenons. Remember that the vertical movement of the panel is negligible, so during assembly, you can tap the rails tight against the ends of the panel. If you are building a pair of doors, and have created two panels that are slightly different heights, (or the grooves in your rails aren't the same depth) you can adjust the rails so both panels appear to be the same size. After the frame and panel assembly is complete, you can fit the door to the opening in the carcase with a saw and plane. The ends of the stiles were often left proud, and the door cut to length, or to fit, after assembly.

Something similar, but a lot easier, happens with aprons and table legs. During assembly, you just tap each apron up and down until the top edge is flush with the tops of the legs. As you apply clamps during glue up, you can adjust the ends of the aprons up or down until you have removed any wind from the top surface of the frame, which has to be flat so the table top doesn't warp when you screw it down to the frame. If you can't get everything flat, it is easy to leave one end of an offending apron proud of the tops of the legs and come back later and plane it flush with the rest of the frame.

Re: shell bits-hijack

Pam Niedermayer - Austin, TX

>I just acquired a gimlet shell with lead screw. Haven't had a chance to use it yet, but they were available, at least in the UK.

Pam

Innovation Alert!!!

Don Thompson - Cutler Ridge, Florida

>Chico,

You wrote, "...I apply poly in the mortise and PVA on the tenon."

I have never heard of using two different glues in the same joint. Do I understand you correctly to mean that you use both poly (polyurethane) glue and PVA (Polyvinyl Acetate) glue in the same joint?

How/where/when did you learn to do this? What are the advantages? Inquiring minds want to know!

Re: Innovation Alert!!!

HC Sakman

>I first discovered this when I was gluing an unevenly bandsawn wide piece of wood (well, thickness tapers from 1/4" up to 7/16" or so...) It had a twist and some areas were thin so couldn't clamp it down to plane it without the risk of cracking it. So, I thought polyurethane glue needs moisture to cure and this wood needs moisture to soften up, after planing the thicker parts, I applied PVA to the wood and POLY glue to the substrate (22mm Baltic birch) and pressed it like I am pressing veneer. It got foamed up to high havens, but it cleaned up fine and it did not let go for the last 9 years! Since then, I use these two glues where it would be sensible to use them, such as M&T joints where maximum strength as well as some (unavoidable) void filling is necessary.

Chico...

Re: Innovation Alert!!!

Don Thompson - Cutler Ridge, Florida

>Cool. I have never used polyurethane glue - why do you not just use it alone when you need gap-filling properties? Is it too weak?

Re: Innovation Alert!!!

HC Sakman

>Extra water in PVA makes the poly glue foam up denser, which fills the gaps. I guess just extra water would do the same, but water+glue sounded better to me and it does work better indeed. (Did I say my middle name is "Overkill" ?) Don't know the chemistry of it, but works (denser foam) better than just water.

Chico...