Round X Base Pedestal Dining Table

Submitted by bRick on Thu, 12/18/2014 - 18:05

We wanted a round table that would seat a full Monopoly game. To do this we needed about a 5' diameter tabletop.  The base was made consistent with the plans.  

A few tips on the base:

  1. Get your angles as close to 45° as you can.  Otherwise, there will be much sanding and puttying in your future.  
  2. If you want to hide your lag screw like I did, I used a spade bit to recess an area for the screw head.  Then I glued in a plug made from dowel and sanded flush.  

If you want to make a round tabletop, here is what I did (there may be better methods).  Keep in mind this was for a ~60" diameter table, I was assuming that the perimeter arc pieces would be about 4.5" wide and that I would cut the inner circle at a 50" diameter.

  1. Picture 1 - I built two 5' slabs of (7) 2x4s pocket-holed together.  
  2. Picture 2 - Then I cut two pieces from each slab that would later make up the 90° "pie slice" pieces.  Make sure to remove the screws that will be in the way your saw blade. Also, you just have to concern yourself with the angle since the radius will be dealt with later.  There is a lot of wood waste with this method, but I think it avoided headaches. 
  3. Picture 3 - I assembled (screwed and glued) the "pie pieces"to the cross pieces. The length of the cross pieces don't matter much since they will also be to cut to a specified radius.  Since I would be cutting a 50" diameter circle, the large cross piece had to be at least 50" and the two small pieces had to be at least 22.25" (subtracting the 2x6 width).  
    1. Picture 3 - I mounted my router to a piece of MDF and drilled a hole at the necessary distance to cut a 50" diameter circle. This distance is 25" + half of the bit diameter.  Since I used a 1/2" straight bit, my point was 25.25" from the center of the router bit.  I screwed this jig to the center of the tabletop assembly so the router could pivot and cut a circle.  As for logistics, I rested this assembly on some scrap wood and kneeled on the tabletop as I was cutting it.  It took a large number of passes with the router since I was cutting through 1.5" of material. 
  4. Picture 4 - The perimeter pieces required some time and geometry. I found that I would need (8) 23" 2x8 pieces (the 23" is approximate because I was a little off for some reason, though I can't recall why).  From those pieces, I used the same router jig to cut the perimeter arc pieces. You will need to make two new radius holes in teh jig to accomplish what you need.  To cut the inner arc you need a hole set at 25" - half of the bit diameter (24.75" for me).  To cut the outer arc, I used a hole that was 29 5/8" from the center of the router bit.  You may need to do some fine tuning to these pieces to get them to fit correctly, but for me it pretty minor.  I trimmed a couple pieces with a miter saw but that was it. 
  5. The rest is screws and glue. 
Estimated Time Investment
Week Long Project (20 Hours or More)
Type of Wood
pine?, and cedar (4x4s)
Finish Used
Sanded using 60, then 120 grit. The stain was Rust-Oleum's Ultimate Wood Stain in Dark Walnut. The top coat was General Finishes water-based polyurethane in flat. One coat of stain, six coats of poly, while sanding with grade #0000 steel wool after every other coat.
Required Skill Level
Intermediate

Comments

ILoveDIYing

Sun, 03/08/2015 - 10:23

Hi, your table is beautiful! I was wondering if you had to increase the size of your base since your table top is 60". I'm going to be building a round one the same size and wanted to make sure it would be stable at the current size.

bRick

Fri, 03/13/2015 - 20:36

The only modification I made to the base was the to the lengths of the 2x4 pieces that make up the "X" that sits between the base and the tabletop. In the plans, this "X" is made of (1) 32" piece and (2) 14.5" pieces. I believe I increased these to 36" and 16.5", respectively. Truthfully, I don't think this modification added much value.

I did some calculations and at a 60" diameter, it would've taken over 100 lbs placed at the edge of the table. This was also a function of the weight of the table. The heavier the table, the more stable it will be.

Momma Gladden

Sun, 04/05/2015 - 19:21

I want to put a concrete top on this base and increase the diameter to 72". Would I need to increase the size of the base to accommodate the larger and heavier top? Thank you

bRick

Tue, 04/14/2015 - 20:20

It all depends on how much your tabletop weighs. I'm going to take a wild guess that your tabletop will weigh around 500 lbs (~28 sq. ft. at ~18 lbs/sq. ft.). For reference, I think my wood top weighed about 80 lbs. I will also assume the wood base weighs 50 lbs. Using these assumptions, the result is a worst-case scenario (weight placed at edge of table, tipping between two table legs) of tipping at 300 lbs. The lighter the tabletop, the less stable it will be. Since your concrete table is likely to weigh a lot more than my wood top, it will be a lot more stable.

That addresses the design and assumes none of the wood or connections (screws) fail under the increased load (weight of concrete). I can't speak very confident to this aspect. Though I can venture a guess. I will guess that it will be stable under no load, but there will increased loads when under uneven stress (i.e. somebody leaning on one side of the table). Honestly, I don't know how valuable any further speculation would be.

X3cougsp

Tue, 09/06/2016 - 08:14

Can the pedestal hold a 66"- 72" top?  I've been searching for a table that seats 6 comfortably with an occasional squeeze for 8.  I think a 60" would work but my husband thinks 72".  We are struggling to find exactly what we want and are now investigating DIYs .  This is a beautiful table!!  

In reply to by X3cougsp

bRick

Wed, 10/05/2016 - 17:16

This is a conversation that we had in our house as well. My personal opinion is that 60" is big enough for 6 people and good enough for 8 people. What we did to "dry run" it was I cut a board to 72" and set it up at table height and we sat at oppposite ends of the board. I asked my wife if it was too big and we both agreed that not only would really shrink the room, but it also was too big for regular use. We currently have 6 chairs around this on a regular basis. As for the stability of the table itself, you may want to increase the width of the base. I say this because 74 lbs at the edge of the table (in between legs) will cause the table to tip, which is probably a force that will be exceeded by someone leaning on it. 

bRick

Thu, 12/22/2016 - 20:58

I used the jig that I made the large circle but made a couple new radii. The inner edge was the round piece radius minus half of the bit diameter. The other radius is as wide as you want to make it. 

 

I fixed this jig to my work bench and set it up so that I would be cutting each piece identically. I have a picture that I'll add that shows it better than I can explain it. 

In reply to by Omally83

bRick

Sat, 01/21/2017 - 07:46

I believe my approach was that I cut the 2x8s to the length that would produce the arc length I was looking for. So basically the outer edge was going to (if my jig did its job) be exactly as long as I needed it to be. With that in mind, I used a piece of yarn tied to the pivot point on the jig that I was using and used that to tell me where I needed to make the cut. 

Otherwise, I could've used trig to figure it out but I was all angled out by that point. With 8 border pieces they should each cover 45 degrees (360/8) and the other two angles should be equal ((180 - 45))/2=67.5) resulting in a 67.5 degree angle. The trouble in using that method is it doesn't account for all the little screw-ups that may have thrown off certain measurements. Plus, the yarn-thing was pretty easy.