Polygons revisited #1: !!! I am going to end up in the Polyclinic!

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Blog entry by robscastle posted 08-15-2013 03:13 AM 1389 reads 1 time favorited 2 comments Add to Favorites Watch
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OMG how hard can it be!

Four days later and still working on my 20 deg slope sided Trays.

Last night I again revisited the info available regarding making polygons looked at all the mind boggling formulas drank heaps of beer and wondered if it was all worth it.

By chance I checked out, a very interesting site I must say, always been impressed with the information Matthias presented.

As it so happened there is a very detailed video and associated information regarding making slopeing polygons.

It was most informative and there is a single sheet of precalculated angles to set for various slopes from 90 deg to zero.

  • From the chart I needed to set the miter to 8.06 deg and the tilt to 21.08.

With my new found knowledge and re motivated from the night before I returned to the garden to try yet again.

By this stage I had made a series of sacrificial polygon sides to experiment on.
I stopped working on the second tray as no matter how much I cut off it kept getting smaller!

So a reset of the saw with a angle of 22.5 and slope of 8 deg as opposed to my original setting of 10 I resawed the test pieces and set about reassembling them.

Well the gaps were certainly better but still not perfect so I rechecked the table saw again and made a slight adjustment towards 7 deg, (all by eye on the index and pointer) and sawed everything up again.

Even butting them together by eye there was not enough gap for the last piece, this meant to me that the cut angle was too much and needed reducing.

I then made up a couple of test jigs at 45 deg as regardless of the slope angles of the sides the 2 dimensional base sections will be at 45deg.

I ran a check and set the pieces in place and checked the slope angles for parallel, there was still some error!

So I checked the saw again using a tilt indicator from my table saw, I could not see much difference but again resawed everything, a small amount of material was removed so there must have been a slight change, upon reassembly everything looked OK.

A point to note here I did not change the 22.5 to 21.08, as it was almost impossible for me to estimate

So now to the tray.

As I had glued part of the second tray it up I needed to saw it apart again, I then resawed everything with the “new” setting.

The Glue up dilemma.

Now I tried almost everything! trying to develop a way to hold the sections together

A revisit to the video changed my tack to doing it in two halves.

Its a bit cluttered but I have migrated to yet another work area and set up a jig to hold the handle section, some 20 deg blocks and a bar holding the pressure on to the half frame with a Horizontal ” Good Hand” Clamp

This may provide a better view.
I cut the biscuits out in the re saw so they stayed out this time

Its all drying as I go to therapy.

In closing here is the first tray with the base insert in, the joints will remain as is and hopefully I can fill them with wood filler and finish the project, even if it only goes under the bench for carrying in and out tools for my work.

In closing my appreciation has to got to Matthias and the work he conducted in answering a school boys question, and assisting me in my mental recovery.

Now if you want to see something really funny check out his Wooden Air raid Siren !!

-- Regards Rob

2 comments so far

View waho6o9's profile


9019 posts in 3660 days

#1 posted 08-15-2013 04:27 AM

Your persistence is admirable Robert.

The more you do the better at it you’ll get.

View Doe's profile


1437 posts in 3913 days

#2 posted 08-15-2013 10:27 PM

It’s a lovely tray—but geez the math makes my brain hurt . . . a lot. I really admire your determination; I would have fired the bits out the door and gone for refreshments (mental note to self: stick to rectangles at all costs).

-- Mother Nature talks, I try to listen

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