Heartwood Pine table - trestle base design and fabrication

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Henry W

Henry
Corporate Member
In starting this project I had posed a few questions, both here and on WoodCentral.

One question I asked was what type of wood I should use
http://www.ncwoodworker.net/forums/showthread.php?t=35638

Another was the base design – specifically how the top of the trestle posts should be attached to the underside of the table.
http://www.ncwoodworker.net/forums/showthread.php?t=35969

The ideas that came from there – particularly from Matt from Morehead City and from Bill Clemmons - were incorporated. They suggested a saddle joint to join the battens into/onto the top of the posts. Matt also suggested creating a smaller tenon on the bottom of the posts where joining the posts to the mortises in the base beam. I used both suggestions.

The picture that was suggested to me as something that was liked was this one at Restoration Hardware:
http://www.restorationhardware.com/...p?productId=prod1593082&categoryId=cat1537023
Much of the trestle design of this table comes from that picture – a large beam at the base of each trestle, a curved cut to taper the end of each beam, and a large flat stretcher beam between the two trestles. I just looked to be certain that I was using the term correctly – and Wikipedia starts the definition with “A trestle is a rigid frame used as a support…”, so each end of this table base will be called one trestle.

The change from the Restoration Hardware table is the double post design. I found Osborne Wood products was likely the vendor of the posts used in the kitchen island. I was able to order these exact posts in knotty pine, and we decided on two posts per trestle.
http://www.osbornewood.com/product/1494.cfm

The turned portion of these posts is just over 22” high, but the overall post with the square unturned portion on each end is 34 ½ “. Clearly that length was not going to work as supplied, because the table height was targeted at 30”. Additionally that 30” needed to allow for the 2” thick top and the 4” thick beam at the bottom of each trestle. That left only 24” for the height for the posts; thankfully this design left large square unturned portions at the top and bottom of the post. The turned portion in this design is listed as 22 3/8” – just enough to work. Seeing the number makes me think that I have an error somewhere in there because I had more than 1.5 inches left to split between the two ends. Nevertheless you get the point, the turned portion fit the design and the square ends would be used for joinery (mortise and tenon at the bottom and a saddle joint at the top).

Dimensionally the beam at the base of each trestle was 4” thick, 8” wide and 36” long (for a 40” wide table). I had a choice of 5” or 6” wide posts from Osborne and decided on the 6” version. With a 8” wide beam, I would have an inch of base beam exposed around the posts.

Cross cuts - tenon and length

So I needed to cross cut the posts to length, allowing for the tenon length on the bottom, and then cut the shoulders on the tenon. Normally I make all these cuts using my table saw using a cross cut sled. However I have not had to cross cut a 6" thick leg before. My cross cut sled allows for maybe 2.5" thickness (I have a blade guard piece of plexiglass over the blade), so that would not work. These were too long and heavy for a cut using just the miter gauge, even with a long extension. I ended up clamping these to the leading edge of of my crosscut sled to make these cuts.
Here's the tenon shoulder cut:
DPP_0014.JPG

and another view:
DPP_0015.JPG

And here is the stack of posts cut to length and with the tenon shoulder cuts completed:
DPP_0016.JPG

Then I moved over to the band saw to cut the cheeks on the tenon:
DPP_0017.JPG

And here is the completed tenon cut on the bottom of one post
DPP_0018.JPG

These were to be individually fit using a shoulder plane. The power tool cuts were made to keep a slightly oversize tenon.


Mortises in beam of trestle

Then on to the mortises. My strategy was to use a pattern bit in a router to excavate the mortise. I hate dealing with the offsets of a template guide, although I will if I have to.

In this case I cut a piece of scrap MDF identical in size to the desired tenon - blue square in the picture. I cut slots into the middle of each size so that I could locate the piece on my center marks for the mortise location.

DPP_0020.JPG

Then I cut two other MDF pieces that would form the square template for the mortise. Here are the three piece in place for a test cut.

DPP_0019.JPG

I would remove the blue piece, and then route the mortise suing the L pieces as a template. Here is a pic with that first level of routing completed.

DPP_0021.JPG

I don't always do a test run in cases like this, but here I was glad I did. I found out what happens when template routing and the template moves!

DPP_0022.JPG

I was glad that was not the real thing in my first run. You can be sure that I did a better job of clamping the templates in place when I routed the real pieces.
DPP_0023.JPG

Quite honestly I can recall the exact sequence of cuts here. I believe I made the first routing cuts using a 1/2" bit and a template guide in a plunge base. This created a offset at the edges, but once I was deep enough to use my 3/4" pattern bit (bearing at the top of bit - the router end) I used that. That moved the cut all the way to flush with the template (no offset).


With the template in place I chiseled the corners square - using the template to act as a guide and keep the chisel perpendicular
DPP_0024.JPG

Using that same 3/4" pattern bit I routed to the desired mortise depth - the nice part of using a pattern bit for deep holes is the you don't need to worry about the template depth. The template and the cut are flush cut so if cutting deep in a series of routing cuts, the bearing just rides on the edge of the hole. I believe I went 1 1/4" deep and cut the tenon just over an inch long.



Here's the base with the first post joinery completed.

DPP_0025.JPG

Side note - I have never used my rubber mallet as much as I did here - getting large piece together required some persuasion. Here's one base with both posts set in place (not glued).
DPP_0026.JPG

Just repetition to join the second set of posts for the second trestle.


The same process was used for the mortises needed for the floor stretcher beam joinery with the beams at the base of the trestle. In this case I cut the template from one piece of MDF and used a multi-tool to plunge cut and define the mortise size (Dremel version - $50 reconditioned and I have loved it).
DPP_0029.JPG

Then route the mortises.


Floor stretcher beam - flattening and mill the tenons

I needed to select a floor stretcher beam and picked this one. I had cross cut to length - allowing for tenon length. However setting it on the bench I noticed it rocked - it had a twist - and one corner always sat about 1/8" high. Hmmmm - no jointer 'in the house'. I could lean on my NCWW friends - but that always takes time and I was already behind schedule! I have a planer with a 6" depth and had seen several planar sleds (not in person - but the internet is a wonderful thing!). Fine Wood Working had one video series that I recall watching.
All I'd need is a flat base to work from that would not twist under the feed rollers and knives of the planar. I decided on 2x4's on edge and found two reasonably straight ones keft over from basement renovation; I screwed them together with spacer blocks in between to get to a sled with about 6"width. I ran this sled through the planar by itself to ensure flatness.


Here is a picture of the sled with the board on it - you can see the near corner of the board above the 2x4

DPP_0027.JPG

The next picture shows the board on edge and the series of drywall screws that I set in the surface at about 6" spacing to support the board going through the planer (so rollers would not press the twist out of the board). Sorry the focus is not great on the screws, but they are the blacks dot syou see on the near edge of this sled. This pic also shows the two little brackets I screwed onto the ends to keep the board in place and not slip of the end
DPP_0028.JPG

I lost 1/8 to 3/16 of thickness here, but it was straight and flat finally. Besides there was no rule that said I need a 2" thick beam there.


I then rough cut the tenons on the ends of this beam on the BS
DPP_0031.JPG

and with this beam so much longer than my BS table (everything on this project was outsizing the tables on my power tools) I needed a platform on my TS extension to keep the beam level while cutting.

DPP_0032.JPG

These too were cut large and fit with a shoulder plane (Lee Valley medium - for this project I should have had a large one, but I managed). These tenons were fit to their mortises and the pieces came together.
DPP_0033.JPG

Here's one of the two base beams and the floor stretcher beams all fit together and standing on end
DPP_0034.JPG



The last bit deals with shaping the curved ends of the beams, and the saddle joints on top of the posts - but I will leave that to another post.


Henry
 

Bas

Recovering tool addict
Bas
Corporate Member
Absolutely fantastic writeups so far, both on the top and the base. I'm getting inspired!
 

Henry W

Henry
Corporate Member
Thanks Bas.

My only regret on this project so far is that I chose not to borrow the long clamps from you - and get to oooowww and aaahhh about your shop in person, and drool on your tools. I'll have to rectify that someday.

I did get to ooohh and aaawww at Chris' shop though (I was truly jealous of his space, especially the high ceilings, and grand plans for fitting up the space). The day I visited there it was cold enough that the drool froze before it hit his tools.

Henry
 

Bas

Recovering tool addict
Bas
Corporate Member
Thanks Bas.

My only regret on this project so far is that I chose not to borrow the long clamps from you - and get to oooowww and aaahhh about your shop in person, and drool on your tools. I'll have to rectify that someday.

I did get to ooohh and aaawww at Chris' shop though (I was truly jealous of his space, especially the high ceilings, and grand plans for fitting up the space). The day I visited there it was cold enough that the drool froze before it hit his tools.

Henry
You know, if that's your main regret, I think your project came out really really well :gar-La;
My shop is covered in a thick layer of drywall dust right now, so it'll be a while before visits, but the offer still stands...
 

Glennbear

Moderator
Glenn
Thank you Henry for a VERY thoroughly documented explanation of your building process. :wsmile:
 

Jeff

New User
Jeff
Henry,

I'm fascinated by your write-ups so far; very compelling reading with clear explanations. :icon_cheers

You've also provided several innovative solutions to "how to execute this task?".
 

Henry W

Henry
Corporate Member
Thanks Jeff and others

There is no rocket science here - but I hoped to provide some benefit (as I have benefited sooooo much from others advice and ideas in their postings here and elsewhere).
One more thread to go - then I am done for awhile.

Henry W
 
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