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First time dealing with 135 degree joints, need help

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Forum topic by FishyRichy posted 12-09-2015 02:44 AM 1158 views 0 times favorited 10 replies Add to Favorites Watch
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FishyRichy

8 posts in 714 days


12-09-2015 02:44 AM

Hi Guys, I am new to the forum, and I am in the process of setting up a little shop at my house. I am currently working on a custom island for our kitchen that is a pentagon that has 3 90 degree angles and 2 135’s. I have never joined 135 angles, and was wondering what my best bet is. I am using 3/4” primed plywood where these joints will be. I was thinking pocket screws may be the best way to get a solid joint, but I haven’t used pocket screws on plywood before. Any suggestions would be much appreciated.

Thanks,

Richard


10 replies so far

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jerryminer

782 posts in 1255 days


#1 posted 12-09-2015 04:42 AM

Pocket screws work OK in plywood. I’ve used them many times. But you might find a full-length spline will help keep things lined up better (and provide additional glue surface).

Be sure to test your set-up on scrap.

-- Jerry, making sawdust professionally since 1976

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Kelly

1809 posts in 2758 days


#2 posted 12-09-2015 05:51 AM

This should get exciting, the most I know how to do is something 360 degrees, when I count each combo miter. In fact, thinking about building a 540 degree cabinet will probably excite even mathematicians.

On the 135’s, are you by chance talking about, hmm. Some elaboration would help, since a pentagon is just five angles [or ten miters] and can be figured by dividing a circle by the number of sides.

When I was trying to cut 120 angles for a triangle on my saw, it took a moment to figure I just needed stand the boards up and cut them at 30 degree angles….........

Now, all that said, I just used splines, which inspired me to buy a biscuit machine. Never tried my Kreg pocket hole beast, but the suggestion has potential.


Hi Guys, I am new to the forum, and I am in the process of setting up a little shop at my house. I am currently working on a custom island for our kitchen that is a pentagon that has 3 90 degree angles and 2 135 s. I have never joined 135 angles, and was wondering what my best bet is. I am using 3/4” primed plywood where these joints will be. I was thinking pocket screws may be the best way to get a solid joint, but I haven t used pocket screws on plywood before. Any suggestions would be much appreciated.

Thanks,

Richard

- FishyRichy


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jerryminer

782 posts in 1255 days


#3 posted 12-09-2015 06:45 AM

Kelly—

I believe the OP is building a pentagonal cabinet similar in layout to this drawing (not a regular pentagon, with equal sides and angles, but one with 3- 90’s and 2- 135’s):

-- Jerry, making sawdust professionally since 1976

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jerryminer

782 posts in 1255 days


#4 posted 12-09-2015 07:02 AM

In fact, thinking about building a 540 degree cabinet will probably excite even mathematicians.

- Kelly

Even in a regular pentagon the included angles add up to 540 degrees (108×5 = 540). I doubt this would excite many mathematicians, as they probably learned this in high school geometry.

-- Jerry, making sawdust professionally since 1976

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FishyRichy

8 posts in 714 days


#5 posted 12-09-2015 05:35 PM


Pocket screws work OK in plywood. I ve used them many times. But you might find a full-length spline will help keep things lined up better (and provide additional glue surface).

Be sure to test your set-up on scrap.

- jerryminer

Hi Jerry, Thanks for the reply. I had considered this, but I am not sure how I would clamp the piece for the glue to set. The 135’s will be at the top with a 50” panel in the middle and 21” panels on either side. I don’t have the rendering on my work computer, but this is pretty close to what the overhead will look like.

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jerryminer

782 posts in 1255 days


#6 posted 12-09-2015 09:39 PM

Some custom clamping blocks would help:

-- Jerry, making sawdust professionally since 1976

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FishyRichy

8 posts in 714 days


#7 posted 12-09-2015 09:52 PM

I do believe thats the ticket sir! Thanks again…btw what design software are you using?

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jerryminer

782 posts in 1255 days


#8 posted 12-10-2015 07:35 AM

I use SketchUp. It is a free, download-able program, originated by Google, but now owned by Trimble. Great program!

-- Jerry, making sawdust professionally since 1976

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716

502 posts in 731 days


#9 posted 12-10-2015 08:51 PM

-- It's nice!

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jbay

1798 posts in 713 days


#10 posted 12-10-2015 09:16 PM

I know I would butt the points of two edges together and put two or three rows of tape down each joint, then glue and fold and let the tape be the clamp. Tape method will make the seams very tight and even. Might have to do it in sections so that you could handle the sizes.

-- If anyone would like to see my Portfolio, PM me and I would be glad to send you the link.

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