« back to Designing Woodworking Projects forum
Forum topic by bignastyweather  posted 04262014 04:25 AM  1489 views  0 times favorited  21 replies 
04262014 04:25 AM 
Topic tags/keywords: question Hello everyone, brand new to the forum here…and a novice woodworker. I have a question regarding an “X” leg table design. However I didn’t see a response (admittedly I just skimmed the posts) that answered my question. My question is this…how do I calculate the miter angle cuts necessary to make this design work, given the following measurements/data? And let me say this, I’m looking for math related answers here. I don’t have any cardboard or spare wood to draw up a template. I’d rather have a formula anyways b/c I can solve that quickly for any future projects I might do with this type of design. Does that make any sense? And sorry if I’m not using the right terminology or leaving out pertinent details here. Thanks in advance! 
21 replies so far
#1 posted 04262014 05:44 AM 
If you can’t type, “how to calculate the angles of a triangle” into Google then I hold little hope you will make heads or tails of sines and cosines. edit: less smarmy answer—Google “solve SSS triangle” or “law of cosines” 
#2 posted 04262014 11:58 AM 
Rick, To your response about the “SSS triangle”...that won’t work. I only know 1 side for sure. The others, the hypotenuse (length of 4×6 edge between miter cuts) and the base (distance between inside edge of apron on one side and inside edge of mitered 4×6 on the other) depend on the angle I cut on the 4×6 post. Got any other helpful tips? 
#3 posted 04262014 12:38 PM 
bignasty, I apologize for the way you were treated above. I can’t help you, maybe someone else can. Good luck with your project. 
#4 posted 04262014 12:51 PM 
B&N weather,the only helpful tip I could give you is to keep it simple,you could draw the the actual “X”leg on paper to the angle that you like the best , measure the angle using a protractor,transfer that measurement on a couple of scrap pieces of wood,cut,dry fit,adjust for a tight fit.it,s not complicated if you don’t over think it.  Ken from Ontario, Canada 
#5 posted 04262014 12:56 PM 
There are extra considerations in wood working. Wood dimensions, for instance. In theoretical geometry/trig, one works on lines and planes. Two dimensions. A 2×4, for instance, has 3 dimensions, and does not represent a line. You need to account for thickness. All in all, you say you have 30” in width, and 30.5 ” in height. That sounds remarkably close to being a 45 degree angle. (Assuming the legs extend to the outer dimension of the table top, and intersect at their mid point.) Are we doing a picnic table? But many a math challenged person can get this without math. No jig required. Create the rectangle you mention. (30×30.5) on a sheet of ply, or on a floor, paper or whatever. (Just draw it) place a board (the lumber you’re going to use for your legs) diagonally. I would allow the board to center on the corners, forming at right angle top and bottom of the leg, meeting at the center of the board width) then place another board on top, intersecting to the other diagonal. Use some scrap of the same thickness to support near the ends. Now scribe both sides of the edge at the intersection, and at the outer perimeter of the rectangle. If you want to know what that angle is, measure it with a speed square or protractor. Do a couple spots to verify accuracy. The top and bottom angles, should be complimentary (= 90 degrees) to the intersection angles. This method helps eliminate mistakes from overlooking various factors, and gives a visual of what you’re doing. Speaking of visuals…
 Support woodworking hand models. Buy me a sawstop. 
#6 posted 04262014 01:04 PM 
+1 Buckethead….sometimes the best math is no math at all  Measure "at least" twice and cut once 
#7 posted 04262014 01:18 PM 
Draw it in full dimension on a piece of paper. If you can’t draw it you can’t saw it. Then you can transfer the the correct angle to your sliding bevel gauge to set the table saw miter gauge.  Bondo Gaposis 
#8 posted 04262014 01:32 PM 
Yes to drawing, but remember… You need to account for the width of the board. On this X, the long point of the top, will be the short point of the bottom. Changing the width dimension of the theoretical rectangle by the rate of the cut dimension. (And subsequently changing the angle) Work from the center of the board? Same problem… Rate of the cut is unknown. (“Rate of cut” is the length of the cut edge of the board) Far easier to simply lay it out beforehand. Literally less than five minute’s work.  Support woodworking hand models. Buy me a sawstop. 
#9 posted 04262014 02:21 PM 
^+1 to BH’s method, did the same thing for my bedside table. Drew out a full size template on 1/4 ply and took all my angles from that Angled half laps BTW did not have a pic of the half lap on the drawing so I’m showing the angled tenon at the end.  "With every tool obtained, there is another that is needed" DonW ( Kevin ) 
#10 posted 04262014 02:37 PM 
yeah i cant elaborate much on what has been said already… but on a side note … ergonomically, if you are interested. the top of your table should be designed to a maximum of 30” tall. to suit most chairs and match the average human scale. one inch may not sound like much.. but it make a huge difference in comfort. just a suggestion.  " 'Truth' is like a beautiful flower, unique to each plant and to the season it blossoms ... 'Fact' is the root and leaf, allowing the plant grow and bloom again." 
#11 posted 04262014 02:39 PM 
Kevin… Your joinery is immaculate. Your scholarly approach is paying off.  Support woodworking hand models. Buy me a sawstop. 
#12 posted 04262014 06:46 PM 
Thanks for the help everyone. Turns out my mathematical approach was indeed correct. However, there were a couple of really helpful tips/visuals presented here. I’ll have to stash those away for the next project. Thanks for the feedback once again. I’m looking forward to utilizing this forum for future projects. 
#13 posted 04262014 06:49 PM 
Also…EPJartisan…thanks for pointing that out. I did make that measurement wrong; I measured to the underside of the table and, since I started with 2×8’s (planed to about 1.25”) I do probably need to shave a little off the legs to bring that back down. 
#14 posted 04262014 08:30 PM 
Glad i could help. A bad measurement at the beginning gets really frustrating later. :)  " 'Truth' is like a beautiful flower, unique to each plant and to the season it blossoms ... 'Fact' is the root and leaf, allowing the plant grow and bloom again." 
#15 posted 04272014 02:10 AM 
Got any other helpful tips? Yes, skip the math because it’s excessively complicated and doesn’t necessarily solve your problem. If you end up with a weird angle like 51.4 degrees, it can be tricky to nail that exactly with a saw. I’ve built one X leg table and never picked up a calculator, pencil, or paper. I made the X (the legs) the width I wanted, used a straightedge to mark the angles, then a bevel gauge to transfer them to my saw. No math and it doesn’t matter if it’s a weird angle. 
Have your say...
You must be signed in to reply.

Forum  Topics 

Woodworking Skill Share

11850 
Woodturning

1951 
Woodcarving

409 
Scrollsawing

324 
Joinery

1278 
Finishing

4682 
Designing Woodworking Projects

6488 
Power Tools, Hardware and Accessories

27214 
CNC Woodworking

192 
Hand Tools

5235 
Jigs & Fixtures

1369 
Wood & Lumber

6036 
Safety in the Woodworking Shop

1339 
Focus on the Workspace

2070 
Sweating for Bucks Through Woodworking

1168 
Woodworking Trade & Swap

4669 
LumberJocks.com Site Feedback

2177 
Coffee Lounge

8682 