Hi
I was wondering if anyone could help with a problem I have to do with the width of a shelf I’m constructing.
You can see the design on the first pic, the part I’m dealing with is the shelf underneath.
I’ve gone and set out and cut the angles so the shelf sits nicely on top of the brickwork but now when I come to adding the upright parts at the back that sit on top of the shelf all the angles are out.
I would like the joins in the upright sections to follow the joins in the shelf but I can’t.
As I was looking at this I called the wife out to look at what is an optical illusion, as all the boards A, B and C are all 7inches wide.
Any suggestions on the best way to clean this up without losing shelf space (I need as much as possible).
Cheers
Glynn
Most used woodworking terminology: Ooops.
Most useful tool: Wood burning stove.
Replies
You are correct about the optical illusion, Glynn. What you need to do is bisect the angles. This may mean you need new lumber since the boards will have to be re-cut. With the boards on the floor, draw a line front and back. Extend the lines so they continue and intersect each other on the back. Then draw a line from that intersection on the back to the point on the front. It looks as though you may have eyeballed an angle to fit the brick work which did not result in a bisection of the joint, just a random angle. Therefore, the front and back points won't meet.
Beat it to fit / Paint it to match
Hi Hammer 1
Thanks for the reply.So are you saying I need to exactly halve the total angle on each piece to get the front and back to meet up(it's a long time since I left school)?GlynnMost used woodworking terminology: Ooops.
Most useful tool: Wood burning stove.
Edited 9/12/2009 9:17 am ET by Guy Forks
Yep. Just lay the pieces down, mark the front and back until the lines intersect and connect the points. You can lay one board over the other for the same effect. I'll tell you a story about a similar situation, years ago. I was working with an older carpenter, we were trimming out garage doors, he took the left, I took the right. These had those 45 chamfered corners you often see. I just happened to have a Starrett protractor head square that I found at a barn sale. I carefully set the angle to 22.5, thinking how smart I am and that I was going to dust him, marked and cut my pieces, put them up and they were off a mile.He didn't have a protractor head and probably didn't even think, or know, about what the angle should technically be. He just put the trim up, marked front and rear, then connected the two points. His cuts fit like bark on a tree. I didn't think past my accurate new tool, not realizing that the side jambs were just a touch out of plumb and maybe the angles were just a bit off 45. If everything was perfect, my 22.5 would have worked. My mathematical calculations work perfectly in a perfect world but that's seldom the case. His method automatically accounted for minor discrepancies. By the way, I have a degree, he didn't finish grade school, LOL!Beat it to fit / Paint it to match
Cheers Hammer1
It’s simple when you know how (see pic 1).
If want to use a protractor then I’m going to need to go back to school.
I did put a protractor on the angle and it come in at 28 degs but the angles I cut (adjusting 3 times) come in at 15.75 degs.
That’s me lost!Thanks again
GlynnMost used woodworking terminology: Ooops.
Most useful tool: Wood burning stove.
Edited 9/12/2009 11:38 am ET by Guy Forks
Each board making up a joint must have the same angle on the end of it or the lengths of the two cuts will be different. You can make a 45 with a 20 and an 25 if you want to, you'll have a 45 degree angle, but the joint won't 'line up' the way you want it to on both sides.
Brian
FWIW, it is an easy thing to work out the angles from the SketchUp model if you have the model drawn. Use Follow Me to draw the assembly. Follow Me will automatically bisect the angles. The miters can then be drawn in with the Line tool if desired. The angles can then be measured with the Yellow Protractor tool.
View Image
Still, nothing beats laying it out full size to be accurate.
Of course the ideal angle only works if everything is made to be perfect during construction. I have an island in my kitchen that is supposed to be kind of an L shape with the corner of the L cut off at a 45 deg chamfer if you will so you get three sections meeting at 22.5 degree corners for a total of 90 degrees. But by the time the floor was put in, the plumbing was put in, the floating soffit over the island was put in (the same shape as the island) and the the island was built to match all of these they no longer where and exact 45 degrees anymore. The totaled 90 still, but each was a little bit off. So building the wood bar that sits up on posts above the counter was a pain in the butt. I ended up gluing up a templet out of some thin boards to get the exact size and shape needed, then I made my counter from that. All the angles where a bit off and I ended up having to cut them to strange angles to make the front and back work out. Looks fine when you see it done. And the only way you can tell you are off is to take a measureing devise and look at it that way (and if you tried that I would kick you in the butt).
That is the down side of building things like cabinets and such, they do not alwas work out just perfect.
I have a set of book cases that the carcuse was made in a "pro shop" with high end tools and such, I have it becasue the client changed thier mind and eliminated one set of them from thier store so the company I worked for (architectural design house) ended up with 12 feet of these, so I took them home and made shelves to match. I just last week added another shelf to each and had to adjust the shelfs to match the new layout and somehow one set of pins does not match the other perfectly so that one shelf is about 1/8 of an inch off (space from one shelf to the next is off from one side to the other so the shelf is not level and the space is not the same) and that was done with one of those multi hole drilling machines that drill a ton of holes at the same time. So counting on getting a perfect angle or anything else based on what it should be is not easy. That is why in tricks like bisecting the angle are so important. We seam to be into measuering everything now of days and I think that this may result in more issues then they solve. The point is to make the angle fit. Do we really care of the angle is 22 or 22.5 as long as the item fits in the space and looks good?
Doug M
There's an easy way to do this, used by trim carpenters all the time, that requires neither a protractoror any math, let alone higer, math. Simply lay one board over the other at the desired angle. Mark the points on each where the edges of the top board cross the edges of the bottom board. Connect the dots on each board and cut on the lines. Done.
Mike Hennessy
Pittsburgh, PA
Everything fits, until you put glue on it.
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