How would you do this? (pic)

[Bill Grumbine]

Greetings all

I am working on a piece of furniture, a table to be specific, and I had to cut four very deep mortises, two each on two posts.

<img src="http://www.enter.net/~ultradad/deepmortise.jpg">

The wood is curly maple, solid (i.e. not laminated) turned to a finished diameter of 3 3/4". The ends will be sawn off where the cut at the end of the mortise is, making it sort of a bridle joint. The mortises are 5" long on one end and 3" on the other end, 1" wide, and all the way through. I did this on my Legacy milling machine equipped with a 3 1/2 HP Porter Cable router. Many electrons died. There is some hand tool work to clean them up and fit the feet and tabletop supports, but I got to wondering. If I did not have the Legacy, I would have had to do this all by hand. I would be interested to hear how some of you dedicated Neanders would do this, especially if you have had previous experience in doing so. I am not interested in just the cutting part, but also the layout, etc.

Thanks.

Bill

[Roger Myers]

Bill,

I'm much better at flat work than round work.... my approach would be to layout and chop the mortises on the square stock before taking it to the lathe. Not sure how much of a problem I'd have with holding the sharp edges during turning... Do the legs cover the mortise edge at all..like on many tripod tables?

If I weren't trying to do it all by hand, and didn't have a legacy mill...I'd use the same approach as for a shaker tripod table dovetail in the column. Turn the column first, then...Box on the lathe to hold the router, and indexing the part around for location. I'd probably only plunge about 1/2" deep (this would give the crisp edges, and provide a cut line)...then after doing all 4 on both ends, cut the excess end off..take a handsaw and from each end cut the sides of the bridle joint using the plunge cut edges to guide..and then chop out the waste...

perfectly clear???


Roger

[Bill Grumbine]

Hi Roger

I thought about doing the mortises before turning it, but there are a couple of considerations. First, I need them to be very accurate, and the rough stock was very rough, and slightly warped. It was also not square, but more rectangular, and even close to a parallelogram through its cross section. Planing it down to a uniform size would have potentially lost me diameter. Additionally, if a mortise like this is cut into a turning, and the hole is not filled back in for the turning, there can be a lot of chip out on the trailing edge. The feet do cover some of the mortise, but not a lot, and if the chip is bigger than the relief, I am done. There aren't many ways to hide mistakes on a piece like this, and the wood is $$$$! :eek:

This design is based on a table built around 1830. I found it in a book titled Making Authentic Shaker Furniture by John G. Shea. It includes photos and measured drawings. This particular table is found on pages 148 and 149 of the book, and he shows mortises made in this fashion. While I suspect that he did not disassemble the table to verify this, there are ways to determine the type of construction used. One of them is the use of pegs through the center of the turning to hold the foot and the top cleat (what I have been calling the tabletop support). All I know is what I am seeing in the book. I have no way of verifying its accuracy, but at this point I have no reason to doubt this is the way the table was made.

I have made tables in the past by joining the foot with a dovtail to the pedestal, but I would be leery of doing it on this piece because of the stresses involved.

Bill

[Roger Myers]

.....made tables in the past by joining the foot with a dovtail to the pedestal, but I would be leery of doing it on this piece because of the stresses involved.

Bill

Right..the chipout would worry me...
I wasn't suggesting a dovetail on the column, just using that approach to cut shallow mortises...and then after trimming the excess length off, using a hand saw to cut the full bridle joint...the edges of the shallow mortise being the guide marks.

To layout the mortises and chop in the square stock..you are correct that the stock would have to be perfectly squared up, and the centers located right when you do turn.

I like the approach you took :D They look terrific...and yes, very nice wood!!

It would be fascinating to know how the original was done....

Roger

[Jim Becker]

Bill, start with actually square stock, cut the mortises and put a scrap plug in them with a little hot-melt glue that you can knock out after turning them. That way, you have the ease of flat work for the mortising and retain both the balance and chip-free nature of solid stock when turning them afterward.

Roger's suggestion in post #4 is interesting, too...

[Bill Grumbine]

Hi Jim

I thought about chopping the mortises before turning it, but I was concerned about the lack of accuracy because of the roughness of the blank. The blank was very rough, with a rectangluar parallelogram cross section, nonsquare ends, and a little bit of warp. Planing it to square would have lost too much material, while sticking it right on the lathe allowed me to get it round and keep the diameters I wanted. Even so it was a squeaker.

I am familiar with waste blocks to prevent chip out, and that was part of the consideration when I was still hoping to square it before turning, but that point turned out (ha ha) to be moot.

Bill

[Christopher Pine]

Looks like your process did a wonderful job. The only way I could see to do it by hand is perhaps obvious and I wouldn use the backsaw..and chisels. With it being round of course is where the real challenge is. perhaps the use of a sled and clamp on the drill press ( I know not hand tool) :) with a forestner bit to drillout the bottom side of the bridle. Then use backsaw ( a sharp one!) to cut out the remainder.. touch it up with chisels...
Time intensive method but with lots of patience I think you could do a nice job this way.

Chris

[tod evans]

bill, i have cut bridle joints in turned stuff by simply screwing the workpiece to a square of 1/4" plywood and passing it over the tablesaw. the same approach could be taken using a handsaw (back or jap) and chisel the end square.....02 tod

[Bill Grumbine]

Hi guys

Thanks Chris, I thought it went well too - even better than I had hoped actually. There is some cleanup to do, but that is very minimal. I am not a dedicated neander either, but I got to wondering how this was built originally 175 years ago.

Tod, I have used that method as well, but not for something 5" deep!

Bill

[David Fried]

Looks like it came out great! I hope you're not working on your IT contest entry!! I've never attempted anything like that but think I would lean toward Jim's method. If you have any questions watch the Grumbine video, I hear it's really good!

Dave Fried

[Bill Grumbine]

If you have any questions watch the Grumbine video, I hear it's really good!Dave Fried

Hi David

You're joking, right? :cool:

Bill

[Jim Dunn]

Hmmmmmmmmmmmmm a neander turning project. Hope your using a treadle lathe:) Good looking joint no matter how it was done. I really like the wood too.

[Jesse Sylvester]

you could build a square jig to hold it. it would have to be like a box that one face comes off then you could clamp your piece and cut your mortises

[Andy Hoyt]

No electrons, hmmmm.

Take the parallelogramish stock to the treadle lathe and bodger it right up to finished dimensions.

Saw off excess at the parting cut as shown in photo.

Locate center of spindle and make all 3" and 5" layout lines on the endgrain using center as datum point. Square down along round face to locate 1" layout lines.

Construct a cradle that holds it parallel to the work surface the cradle will rest on. Cradle also provides a mechanism whereby you can accurately rotate leg 90° (assuming the aprons are at 90° to one another) and re-secure it.

Clamp cradle mounted leg securely in your bench's end vise in an upright configuration.

Grab a bow saw and engage sawing muscle along the 3" and 5" layout lines.

Secure cradle mounted leg to work bench between dog and vise.

Grab chisel and mallet and engage mortising muscle along the 1" layout line to remove waste.

Grab rasp and engage squinted-eye-for-detailed-work-and-cleanup muscle.

Do not post results on woodworking forum as that would require use of electrons.

I'm no neander. Does this work?

[Bill Grumbine]

Hi Andy

Sorry for the delay in getting back to answer you on this. I think you have the right of it, at least how it would have had to been done with this particular piece of wood. A very good answer. Thanks!

Bill

[Dennis McDonaugh]

Bill, since you didn't want to true the stock before turning, you're left with trying to index the mortises after turning. I'd screw a couple of square pieces of wood, one on each end, slightly larger diameter than the turning so it would sit like it was square. Then I'd find the center of the mortise, mark the outline, auger out most of the waste, and finish with a chisel.

[Alan Turner]

Bill,
Not without electrons, but I think I would jig it square after turning, and use a reasaw bandsaw to cut the cheeks, and then remove the waste with a DP and chisels.

[Dennis McDonaugh]

I have to call it on you Alan. Tweeeet, foul unless you have one of those hand cranked drill presses like Roy.